UNDER CONTRUCTION

Due for Release on Monday, Oct 3, 2016

tesseract.js

Tesseract.js is a pure javascript version of the Tesseract OCR Engine that can recognize English, Chinese, Russian, and 60 other languages.

Tesseract.js lets your code get the words out of scanned documents and other images.

Installation

Tesseract.js works with a <script> tag via local copy or cdn, or with npm (if you're using webpack / browserify).

Script Tag

CDN

<script src='https://cdn.rawgit.com/naptha/tesseract.js/a01d2a2/dist/tesseract.js'></script>

<script>
Tesseract.recognize('#my-image')
    .progress(function (p) { console.log('progress', p) })
    .then(function (result) { console.log('result', result) })
</script>

Local

First grab copies of tesseract.js and tesseract.worker.js from the dist folder. Then include tesseract.js on your page, and set Tesseract.workerUrl like this:

<script src='/path/to/tesseract.js'></script>

<script>
Tesseract.workerUrl = 'http://www.absolute-path-to/tesseract.worker.js'

Tesseract.recognize('#my-image')
    .progress(function (p) { console.log('progress', p) })
    .then(function (result) { console.log('result', result) })
</script>

npm

TODO

Docs

ImageLike

The main Tesseract.js functions take an image parameter, which should be something that is 'image-like'. That means image should be

• an img element or querySelector that matches an img element
• a video element or querySelector that matches a video element
• a canvas element or querySelector that matches a canvas element
• a CanvasRenderingContext2D (returned by canvas.getContext('2d'))
• the absolute url of an image from the same website that is running your script. Browser security policies don't allow access to the content of images from other websites :(

Tesseract.recognize(image: ImageLike[, options]) -> TesseractJob

Figures out what words are in image, where the words are in image, etc.

• image is any ImageLike object.
• options is an optional parameter that overrides some subset of the following parameters:

  Paramereter	Default Value	Description
  ambigs_debug_level	0	Debug level for unichar ambiguities
  applybox_debug	1	Debug level
  applybox_exposure_pattern	.exp	Exposure value follows this pattern in the image filename. The name of the image files are expected to be in the form [lang].[fontname].exp[num].tif
  applybox_learn_chars_and_char_frags_mode	0	Learn both character fragments (as is done in the special low exposure mode) as well as unfragmented characters.
  applybox_learn_ngrams_mode	0	Each bounding box is assumed to contain ngrams. Only learn the ngrams whose outlines overlap horizontally.
  applybox_page	0	Page number to apply boxes from
  assume_fixed_pitch_char_segment	0	include fixed-pitch heuristics in char segmentation
  bestrate_pruning_factor	2	Multiplying factor of current best rate to prune other hypotheses
  bidi_debug	0	Debug level for BiDi
  bland_unrej	0	unrej potential with no chekcs
  certainty_scale	20	Certainty scaling factor
  certainty_scale	20	Certainty scaling factor
  chop_center_knob	0.15	Split center adjustment
  chop_centered_maxwidth	90	Width of (smaller) chopped blobs above which we don't care that a chop is not near the center.
  chop_debug	0	Chop debug
  chop_enable	1	Chop enable
  chop_good_split	50	Good split limit
  chop_inside_angle	-50	Min Inside Angle Bend
  chop_min_outline_area	2000	Min Outline Area
  chop_min_outline_points	6	Min Number of Points on Outline
  chop_new_seam_pile	1	Use new seam_pile
  chop_ok_split	100	OK split limit
  chop_overlap_knob	0.9	Split overlap adjustment
  chop_same_distance	2	Same distance
  chop_seam_pile_size	150	Max number of seams in seam_pile
  chop_sharpness_knob	0.06	Split sharpness adjustment
  chop_split_dist_knob	0.5	Split length adjustment
  chop_split_length	10000	Split Length
  chop_vertical_creep	0	Vertical creep
  chop_width_change_knob	5	Width change adjustment
  chop_x_y_weight	3	X / Y length weight
  chs_leading_punct	('`"	Leading punctuation
  chs_trailing_punct1	).,;:?!	1st Trailing punctuation
  chs_trailing_punct2	)'`"	2nd Trailing punctuation
  classify_adapt_feature_threshold	230	Threshold for good features during adaptive 0-255
  classify_adapt_proto_threshold	230	Threshold for good protos during adaptive 0-255
  classify_adapted_pruning_factor	2.5	Prune poor adapted results this much worse than best result
  classify_adapted_pruning_threshold	-1	Threshold at which classify_adapted_pruning_factor starts
  classify_bln_numeric_mode	0	Assume the input is numbers [0-9].
  classify_char_norm_range	0.2	Character Normalization Range ...
  classify_character_fragments_garbage_certainty_threshold	-3	Exclude fragments that do not look like whole characters from training and adaption
  classify_class_pruner_multiplier	15	Class Pruner Multiplier 0-255:
  classify_class_pruner_threshold	229	Class Pruner Threshold 0-255
  classify_cp_angle_pad_loose	45	Class Pruner Angle Pad Loose
  classify_cp_angle_pad_medium	20	Class Pruner Angle Pad Medium
  classify_cp_angle_pad_tight	10	CLass Pruner Angle Pad Tight
  classify_cp_cutoff_strength	7	Class Pruner CutoffStrength:
  classify_cp_end_pad_loose	0.5	Class Pruner End Pad Loose
  classify_cp_end_pad_medium	0.5	Class Pruner End Pad Medium
  classify_cp_end_pad_tight	0.5	Class Pruner End Pad Tight
  classify_cp_side_pad_loose	2.5	Class Pruner Side Pad Loose
  classify_cp_side_pad_medium	1.2	Class Pruner Side Pad Medium
  classify_cp_side_pad_tight	0.6	Class Pruner Side Pad Tight
  classify_debug_character_fragments	0	Bring up graphical debugging windows for fragments training
  classify_debug_level	0	Classify debug level
  classify_enable_adaptive_debugger	0	Enable match debugger
  classify_enable_adaptive_matcher	1	Enable adaptive classifier
  classify_enable_learning	1	Enable adaptive classifier
  classify_font_name	UnknownFont	Default font name to be used in training
  classify_integer_matcher_multiplier	10	Integer Matcher Multiplier 0-255:
  classify_learn_debug_str		Class str to debug learning
  classify_learning_debug_level	0	Learning Debug Level:
  classify_max_certainty_margin	5.5	Veto difference between classifier certainties
  classify_max_norm_scale_x	0.325	Max char x-norm scale ...
  classify_max_norm_scale_y	0.325	Max char y-norm scale ...
  classify_max_rating_ratio	1.5	Veto ratio between classifier ratings
  classify_max_slope	2.41421	Slope above which lines are called vertical
  classify_min_norm_scale_x	0	Min char x-norm scale ...
  classify_min_norm_scale_y	0	Min char y-norm scale ...
  classify_min_slope	0.414214	Slope below which lines are called horizontal
  classify_misfit_junk_penalty	0	Penalty to apply when a non-alnum is vertically out of its expected textline position
  classify_nonlinear_norm	0	Non-linear stroke-density normalization
  classify_norm_adj_curl	2	Norm adjust curl ...
  classify_norm_adj_midpoint	32	Norm adjust midpoint ...
  classify_norm_method	1	Normalization Method ...
  classify_num_cp_levels	3	Number of Class Pruner Levels
  classify_pico_feature_length	0.05	Pico Feature Length
  classify_pp_angle_pad	45	Proto Pruner Angle Pad
  classify_pp_end_pad	0.5	Proto Prune End Pad
  classify_pp_side_pad	2.5	Proto Pruner Side Pad
  classify_save_adapted_templates	0	Save adapted templates to a file
  classify_training_file	MicroFeatures	Training file
  classify_use_pre_adapted_templates	0	Use pre-adapted classifier templates
  conflict_set_I_l_1	Il1[]	Il1 conflict set
  crunch_accept_ok	1	Use acceptability in okstring
  crunch_debug	0	As it says
  crunch_del_cert	-10	POTENTIAL crunch cert lt this
  crunch_del_high_word	1.5	Del if word gt xht x this above bl
  crunch_del_low_word	0.5	Del if word gt xht x this below bl
  crunch_del_max_ht	3	Del if word ht gt xht x this
  crunch_del_min_ht	0.7	Del if word ht lt xht x this
  crunch_del_min_width	3	Del if word width lt xht x this
  crunch_del_rating	60	POTENTIAL crunch rating lt this
  crunch_early_convert_bad_unlv_chs	0	Take out ~^ early?
  crunch_early_merge_tess_fails	1	Before word crunch?
  crunch_include_numerals	0	Fiddle alpha figures
  crunch_leave_accept_strings	0	Dont pot crunch sensible strings
  crunch_leave_lc_strings	4	Dont crunch words with long lower case strings
  crunch_leave_ok_strings	1	Dont touch sensible strings
  crunch_leave_uc_strings	4	Dont crunch words with long lower case strings
  crunch_long_repetitions	3	Crunch words with long repetitions
  crunch_poor_garbage_cert	-9	crunch garbage cert lt this
  crunch_poor_garbage_rate	60	crunch garbage rating lt this
  crunch_pot_garbage	1	POTENTIAL crunch garbage
  crunch_pot_indicators	1	How many potential indicators needed
  crunch_pot_poor_cert	-8	POTENTIAL crunch cert lt this
  crunch_pot_poor_rate	40	POTENTIAL crunch rating lt this
  crunch_rating_max	10	For adj length in rating per ch
  crunch_small_outlines_size	0.6	Small if lt xht x this
  crunch_terrible_garbage	1	As it says
  crunch_terrible_rating	80	crunch rating lt this
  cube_debug_level	0	Print cube debug info.
  dawg_debug_level	0	Set to 1 for general debug info, to 2 for more details, to 3 to see all the debug messages
  debug_acceptable_wds	0	Dump word pass/fail chk
  debug_file		File to send tprintf output to
  debug_fix_space_level	0	Contextual fixspace debug
  debug_noise_removal	0	Debug reassignment of small outlines
  debug_x_ht_level	0	Reestimate debug
  devanagari_split_debugimage	0	Whether to create a debug image for split shiro-rekha process.
  devanagari_split_debuglevel	0	Debug level for split shiro-rekha process.
  disable_character_fragments	1	Do not include character fragments in the results of the classifier
  doc_dict_certainty_threshold	-2.25	Worst certainty for words that can be inserted into thedocument dictionary
  doc_dict_pending_threshold	0	Worst certainty for using pending dictionary
  docqual_excuse_outline_errs	0	Allow outline errs in unrejection?
  edges_boxarea	0.875	Min area fraction of grandchild for box
  edges_childarea	0.5	Min area fraction of child outline
  edges_children_count_limit	45	Max holes allowed in blob
  edges_children_fix	0	Remove boxy parents of char-like children
  edges_children_per_grandchild	10	Importance ratio for chucking outlines
  edges_debug	0	turn on debugging for this module
  edges_max_children_layers	5	Max layers of nested children inside a character outline
  edges_max_children_per_outline	10	Max number of children inside a character outline
  edges_min_nonhole	12	Min pixels for potential char in box
  edges_patharea_ratio	40	Max lensq/area for acceptable child outline
  edges_use_new_outline_complexity	0	Use the new outline complexity module
  editor_dbwin_height	24	Editor debug window height
  editor_dbwin_name	EditorDBWin	Editor debug window name
  editor_dbwin_width	80	Editor debug window width
  editor_dbwin_xpos	50	Editor debug window X Pos
  editor_dbwin_ypos	500	Editor debug window Y Pos
  editor_debug_config_file		Config file to apply to single words
  editor_image_blob_bb_color	4	Blob bounding box colour
  editor_image_menuheight	50	Add to image height for menu bar
  editor_image_text_color	2	Correct text colour
  editor_image_win_name	EditorImage	Editor image window name
  editor_image_word_bb_color	7	Word bounding box colour
  editor_image_xpos	590	Editor image X Pos
  editor_image_ypos	10	Editor image Y Pos
  editor_word_height	240	Word window height
  editor_word_name	BlnWords	BL normalized word window
  editor_word_width	655	Word window width
  editor_word_xpos	60	Word window X Pos
  editor_word_ypos	510	Word window Y Pos
  enable_new_segsearch	0	Enable new segmentation search path.
  enable_noise_removal	1	Remove and conditionally reassign small outlines when they confuse layout analysis, determining diacritics vs noise
  equationdetect_save_bi_image	0	Save input bi image
  equationdetect_save_merged_image	0	Save the merged image
  equationdetect_save_seed_image	0	Save the seed image
  equationdetect_save_spt_image	0	Save special character image
  file_type	.tif	Filename extension
  fixsp_done_mode	1	What constitues done for spacing
  fixsp_non_noise_limit	1	How many non-noise blbs either side?
  fixsp_small_outlines_size	0.28	Small if lt xht x this
  force_word_assoc	0	force associator to run regardless of what enable_assoc is.This is used for CJK where component grouping is necessary.
  fragments_debug	0	Debug character fragments
  fragments_guide_chopper	0	Use information from fragments to guide chopping process
  fx_debugfile	FXDebug	Name of debugfile
  gapmap_big_gaps	1.75	xht multiplier
  gapmap_debug	0	Say which blocks have tables
  gapmap_no_isolated_quanta	0	Ensure gaps not less than 2quanta wide
  gapmap_use_ends	0	Use large space at start and end of rows
  heuristic_max_char_wh_ratio	2	max char width-to-height ratio allowed in segmentation
  heuristic_segcost_rating_base	1.25	base factor for adding segmentation cost into word rating.It's a multiplying factor, the larger the value above 1, the bigger the effect of segmentation cost.
  heuristic_weight_rating	1	weight associated with char rating in combined cost ofstate
  heuristic_weight_seamcut	0	weight associated with seam cut in combined cost of state
  heuristic_weight_width	1000	weight associated with width evidence in combined cost of state
  hocr_font_info	0	Add font info to hocr output
  hyphen_debug_level	0	Debug level for hyphenated words.
  il1_adaption_test	0	Dont adapt to i/I at beginning of word
  include_page_breaks	0	Include page separator string in output text after each image/page.
  interactive_display_mode	0	Run interactively?
  language_model_debug_level	0	Language model debug level
  language_model_fixed_length_choices_depth	3	Depth of blob choice lists to explore when fixed length dawgs are on
  language_model_min_compound_length	3	Minimum length of compound words
  language_model_ngram_nonmatch_score	-40	Average classifier score of a non-matching unichar.
  language_model_ngram_on	0	Turn on/off the use of character ngram model
  language_model_ngram_order	8	Maximum order of the character ngram model
  language_model_ngram_rating_factor	16	Factor to bring log-probs into the same range as ratings when multiplied by outline length
  language_model_ngram_scale_factor	0.03	Strength of the character ngram model relative to the character classifier
  language_model_ngram_small_prob	1e-06	To avoid overly small denominators use this as the floor of the probability returned by the ngram model.
  language_model_ngram_space_delimited_language	1	Words are delimited by space
  language_model_ngram_use_only_first_uft8_step	0	Use only the first UTF8 step of the given string when computing log probabilities.
  language_model_penalty_case	0.1	Penalty for inconsistent case
  language_model_penalty_chartype	0.3	Penalty for inconsistent character type
  language_model_penalty_font	0	Penalty for inconsistent font
  language_model_penalty_increment	0.01	Penalty increment
  language_model_penalty_non_dict_word	0.15	Penalty for non-dictionary words
  language_model_penalty_non_freq_dict_word	0.1	Penalty for words not in the frequent word dictionary
  language_model_penalty_punc	0.2	Penalty for inconsistent punctuation
  language_model_penalty_script	0.5	Penalty for inconsistent script
  language_model_penalty_spacing	0.05	Penalty for inconsistent spacing
  language_model_use_sigmoidal_certainty	0	Use sigmoidal score for certainty
  language_model_viterbi_list_max_num_prunable	10	Maximum number of prunable (those for which PrunablePath() is true) entries in each viterbi list recorded in BLOB_CHOICEs
  language_model_viterbi_list_max_size	500	Maximum size of viterbi lists recorded in BLOB_CHOICEs
  load_bigram_dawg	1	Load dawg with special word bigrams.
  load_fixed_length_dawgs	1	Load fixed length dawgs (e.g. for non-space delimited languages)
  load_freq_dawg	1	Load frequent word dawg.
  load_number_dawg	1	Load dawg with number patterns.
  load_punc_dawg	1	Load dawg with punctuation patterns.
  load_system_dawg	1	Load system word dawg.
  load_unambig_dawg	1	Load unambiguous word dawg.
  m_data_sub_dir	tessdata/	Directory for data files
  matcher_avg_noise_size	12	Avg. noise blob length
  matcher_bad_match_pad	0.15	Bad Match Pad (0-1)
  matcher_clustering_max_angle_delta	0.015	Maximum angle delta for prototype clustering
  matcher_debug_flags	0	Matcher Debug Flags
  matcher_debug_level	0	Matcher Debug Level
  matcher_debug_separate_windows	0	Use two different windows for debugging the matching: One for the protos and one for the features.
  matcher_good_threshold	0.125	Good Match (0-1)
  matcher_great_threshold	0	Great Match (0-1)
  matcher_min_examples_for_prototyping	3	Reliable Config Threshold
  matcher_perfect_threshold	0.02	Perfect Match (0-1)
  matcher_permanent_classes_min	1	Min # of permanent classes
  matcher_rating_margin	0.1	New template margin (0-1)
  matcher_sufficient_examples_for_prototyping	5	Enable adaption even if the ambiguities have not been seen
  max_permuter_attempts	10000	Maximum number of different character choices to consider during permutation. This limit is especially useful when user patterns are specified, since overly generic patterns can result in dawg search exploring an overly large number of options.
  max_viterbi_list_size	10	Maximum size of viterbi list.
  merge_fragments_in_matrix	1	Merge the fragments in the ratings matrix and delete them after merging
  min_orientation_margin	7	Min acceptable orientation margin
  min_sane_x_ht_pixels	8	Reject any x-ht lt or eq than this
  ngram_permuter_activated	0	Activate character-level n-gram-based permuter
  noise_cert_basechar	-8	Hingepoint for base char certainty
  noise_cert_disjoint	-1	Hingepoint for disjoint certainty
  noise_cert_factor	0.375	Scaling on certainty diff from Hingepoint
  noise_cert_punc	-3	Threshold for new punc char certainty
  noise_maxperblob	8	Max diacritics to apply to a blob
  noise_maxperword	16	Max diacritics to apply to a word
  numeric_punctuation	.,	Punct. chs expected WITHIN numbers
  ocr_devanagari_split_strategy	0	Whether to use the top-line splitting process for Devanagari documents while performing ocr.
  ok_repeated_ch_non_alphanum_wds	-?*=	Allow NN to unrej
  oldbl_corrfix	1	Improve correlation of heights
  oldbl_dot_error_size	1.26	Max aspect ratio of a dot
  oldbl_holed_losscount	10	Max lost before fallback line used
  oldbl_xhfix	0	Fix bug in modes threshold for xheights
  oldbl_xhfract	0.4	Fraction of est allowed in calc
  outlines_2	ij!?%":;	Non standard number of outlines
  outlines_odd	%
  output_ambig_words_file		Output file for ambiguities found in the dictionary
  page_separator
  pageseg_devanagari_split_strategy	0	Whether to use the top-line splitting process for Devanagari documents while performing page-segmentation.
  paragraph_debug_level	0	Print paragraph debug info.
  paragraph_text_based	1	Run paragraph detection on the post-text-recognition (more accurate)
  permute_chartype_word	0	Turn on character type (property) consistency permuter
  permute_debug	0	Debug char permutation process
  permute_fixed_length_dawg	0	Turn on fixed-length phrasebook search permuter
  permute_only_top	0	Run only the top choice permuter
  permute_script_word	0	Turn on word script consistency permuter
  pitsync_fake_depth	1	Max advance fake generation
  pitsync_joined_edge	0.75	Dist inside big blob for chopping
  pitsync_linear_version	6	Use new fast algorithm
  pitsync_offset_freecut_fraction	0.25	Fraction of cut for free cuts
  poly_allow_detailed_fx	0	Allow feature extractors to see the original outline
  poly_debug	0	Debug old poly
  poly_wide_objects_better	1	More accurate approx on wide things
  preserve_interword_spaces	0	Preserve multiple interword spaces
  prioritize_division	0	Prioritize blob division over chopping
  quality_blob_pc	0	good_quality_doc gte good blobs limit
  quality_char_pc	0.95	good_quality_doc gte good char limit
  quality_min_initial_alphas_reqd	2	alphas in a good word
  quality_outline_pc	1	good_quality_doc lte outline error limit
  quality_rej_pc	0.08	good_quality_doc lte rejection limit
  quality_rowrej_pc	1.1	good_quality_doc gte good char limit
  rating_scale	1.5	Rating scaling factor
  rej_1Il_trust_permuter_type	1	Dont double check
  rej_1Il_use_dict_word	0	Use dictword test
  rej_alphas_in_number_perm	0	Extend permuter check
  rej_trust_doc_dawg	0	Use DOC dawg in 11l conf. detector
  rej_use_good_perm	1	Individual rejection control
  rej_use_sensible_wd	0	Extend permuter check
  rej_use_tess_accepted	1	Individual rejection control
  rej_use_tess_blanks	1	Individual rejection control
  rej_whole_of_mostly_reject_word_fract	0.85	if >this fract
  repair_unchopped_blobs	1	Fix blobs that aren't chopped
  save_alt_choices	1	Save alternative paths found during chopping and segmentation search
  save_doc_words	0	Save Document Words
  save_raw_choices	1	Deprecated- backward compatablity only
  segment_adjust_debug	0	Segmentation adjustment debug
  segment_debug	0	Debug the whole segmentation process
  segment_nonalphabetic_script	0	Don't use any alphabetic-specific tricks.Set to true in the traineddata config file for scripts that are cursive or inherently fixed-pitch
  segment_penalty_dict_case_bad	1.3125	Default score multiplier for word matches, which may have case issues (lower is better).
  segment_penalty_dict_case_ok	1.1	Score multiplier for word matches that have good case (lower is better).
  segment_penalty_dict_frequent_word	1	Score multiplier for word matches which have good case andare frequent in the given language (lower is better).
  segment_penalty_dict_nonword	1.25	Score multiplier for glyph fragment segmentations which do not match a dictionary word (lower is better).
  segment_penalty_garbage	1.5	Score multiplier for poorly cased strings that are not in the dictionary and generally look like garbage (lower is better).
  segment_penalty_ngram_best_choice	1.24	Multipler to for the best choice from the ngram model.
  segment_reward_chartype	0.97	Score multipler for char type consistency within a word.
  segment_reward_ngram_best_choice	0.99	Score multipler for ngram permuter's best choice (only used in the Han script path).
  segment_reward_script	0.95	Score multipler for script consistency within a word. Being a 'reward' factor, it should be <= 1. Smaller value implies bigger reward.
  segment_segcost_rating	0	incorporate segmentation cost in word rating?
  segsearch_debug_level	0	SegSearch debug level
  segsearch_max_char_wh_ratio	2	Maximum character width-to-height ratio
  segsearch_max_fixed_pitch_char_wh_ratio	2	Maximum character width-to-height ratio for fixed-pitch fonts
  segsearch_max_futile_classifications	20	Maximum number of pain point classifications per chunk thatdid not result in finding a better word choice.
  segsearch_max_pain_points	2000	Maximum number of pain points stored in the queue
  speckle_large_max_size	0.3	Max large speckle size
  speckle_rating_penalty	10	Penalty to add to worst rating for noise
  stopper_allowable_character_badness	3	Max certaintly variation allowed in a word (in sigma)
  stopper_certainty_per_char	-0.5	Certainty to add for each dict char above small word size.
  stopper_debug_level	0	Stopper debug level
  stopper_no_acceptable_choices	0	Make AcceptableChoice() always return false. Useful when there is a need to explore all segmentations
  stopper_nondict_certainty_base	-2.5	Certainty threshold for non-dict words
  stopper_phase2_certainty_rejection_offset	1	Reject certainty offset
  stopper_smallword_size	2	Size of dict word to be treated as non-dict word
  stream_filelist	0	Stream a filelist from stdin
  subscript_max_y_top	0.5	Maximum top of a character measured as a multiple of x-height above the baseline for us to reconsider whether it's a subscript.
  superscript_bettered_certainty	0.97	What reduction in badness do we think sufficient to choose a superscript over what we'd thought. For example, a value of 0.6 means we want to reduce badness of certainty by at least 40%
  superscript_debug	0	Debug level for sub & superscript fixer
  superscript_min_y_bottom	0.3	Minimum bottom of a character measured as a multiple of x-height above the baseline for us to reconsider whether it's a superscript.
  superscript_scaledown_ratio	0.4	A superscript scaled down more than this is unbelievably small. For example, 0.3 means we expect the font size to be no smaller than 30% of the text line font size.
  superscript_worse_certainty	2	How many times worse certainty does a superscript position glyph need to be for us to try classifying it as a char with a different baseline?
  suspect_accept_rating	-999.9	Accept good rating limit
  suspect_constrain_1Il	0	UNLV keep 1Il chars rejected
  suspect_level	99	Suspect marker level
  suspect_rating_per_ch	999.9	Dont touch bad rating limit
  suspect_short_words	2	Dont Suspect dict wds longer than this
  suspect_space_level	100	Min suspect level for rejecting spaces
  tess_bn_matching	0	Baseline Normalized Matching
  tess_cn_matching	0	Character Normalized Matching
  tessdata_manager_debug_level	0	Debug level for TessdataManager functions.
  tessedit_adaption_debug	0	Generate and print debug information for adaption
  tessedit_ambigs_training	0	Perform training for ambiguities
  tessedit_bigram_debug	0	Amount of debug output for bigram correction.
  tessedit_certainty_threshold	-2.25	Good blob limit
  tessedit_char_blacklist		Blacklist of chars not to recognize
  tessedit_char_unblacklist		List of chars to override tessedit_char_blacklist
  tessedit_char_whitelist		Whitelist of chars to recognize
  tessedit_class_miss_scale	0.00390625	Scale factor for features not used
  tessedit_consistent_reps	1	Force all rep chars the same
  tessedit_create_boxfile	0	Output text with boxes
  tessedit_create_hocr	0	Write .html hOCR output file
  tessedit_create_pdf	0	Write .pdf output file
  tessedit_create_txt	1	Write .txt output file
  tessedit_debug_block_rejection	0	Block and Row stats
  tessedit_debug_doc_rejection	0	Page stats
  tessedit_debug_fonts	0	Output font info per char
  tessedit_debug_quality_metrics	0	Output data to debug file
  tessedit_display_outwords	0	Draw output words
  tessedit_dont_blkrej_good_wds	0	Use word segmentation quality metric
  tessedit_dont_rowrej_good_wds	0	Use word segmentation quality metric
  tessedit_dump_choices	0	Dump char choices
  tessedit_dump_pageseg_images	0	Dump intermediate images made during page segmentation
  tessedit_enable_bigram_correction	1	Enable correction based on the word bigram dictionary.
  tessedit_enable_dict_correction	0	Enable single word correction based on the dictionary.
  tessedit_enable_doc_dict	1	Add words to the document dictionary
  tessedit_fix_fuzzy_spaces	1	Try to improve fuzzy spaces
  tessedit_fix_hyphens	1	Crunch double hyphens?
  tessedit_flip_0O	1	Contextual 0O O0 flips
  tessedit_good_doc_still_rowrej_wd	1.1	rej good doc wd if more than this fraction rejected
  tessedit_good_quality_unrej	1	Reduce rejection on good docs
  tessedit_image_border	2	Rej blbs near image edge limit
  tessedit_init_config_only	0	Only initialize with the config file. Useful if the instance is not going to be used for OCR but say only for layout analysis.
  tessedit_load_sublangs		List of languages to load with this one
  tessedit_lower_flip_hyphen	1.5	Aspect ratio dot/hyphen test
  tessedit_make_boxes_from_boxes	0	Generate more boxes from boxed chars
  tessedit_matcher_log	0	Log matcher activity
  tessedit_minimal_rej_pass1	0	Do minimal rejection on pass 1 output
  tessedit_minimal_rejection	0	Only reject tess failures
  tessedit_ocr_engine_mode	0	Which OCR engine(s) to run (Tesseract, Cube, both). Defaults to loading and running only Tesseract (no Cube,no combiner). Values from OcrEngineMode enum in tesseractclass.h)
  tessedit_ok_mode	5	Acceptance decision algorithm
  tessedit_override_permuter	1	According to dict_word
  tessedit_page_number	-1	-1 -> All pages , else specifc page to process
  tessedit_pageseg_mode	6	Page seg mode: 0=osd only, 1=auto+osd, 2=auto, 3=col, 4=block, 5=line, 6=word, 7=char (Values from PageSegMode enum in publictypes.h)
  tessedit_parallelize	0	Run in parallel where possible
  tessedit_prefer_joined_punct	0	Reward punctation joins
  tessedit_preserve_blk_rej_perfect_wds	1	Only rej partially rejected words in block rejection
  tessedit_preserve_min_wd_len	2	Only preserve wds longer than this
  tessedit_preserve_row_rej_perfect_wds	1	Only rej partially rejected words in row rejection
  tessedit_redo_xheight	1	Check/Correct x-height
  tessedit_reject_bad_qual_wds	1	Reject all bad quality wds
  tessedit_reject_block_percent	45	%rej allowed before rej whole block
  tessedit_reject_doc_percent	65	%rej allowed before rej whole doc
  tessedit_reject_mode	0	Rejection algorithm
  tessedit_reject_row_percent	40	%rej allowed before rej whole row
  tessedit_rejection_debug	0	Adaption debug
  tessedit_resegment_from_boxes	0	Take segmentation and labeling from box file
  tessedit_resegment_from_line_boxes	0	Conversion of word/line box file to char box file
  tessedit_row_rej_good_docs	1	Apply row rejection to good docs
  tessedit_single_match	0	Top choice only from CP
  tessedit_tess_adaption_mode	39	Adaptation decision algorithm for tess
  tessedit_test_adaption	0	Test adaption criteria
  tessedit_test_adaption_mode	3	Adaptation decision algorithm for tess
  tessedit_timing_debug	0	Print timing stats
  tessedit_train_from_boxes	0	Generate training data from boxed chars
  tessedit_truncate_wordchoice_log	10	Max words to keep in list
  tessedit_unrej_any_wd	0	Dont bother with word plausibility
  tessedit_upper_flip_hyphen	1.8	Aspect ratio dot/hyphen test
  tessedit_use_primary_params_model	0	In multilingual mode use params model of the primary language
  tessedit_use_reject_spaces	1	Reject spaces?
  tessedit_whole_wd_rej_row_percent	70	Number of row rejects in whole word rejectswhich prevents whole row rejection
  tessedit_word_for_word	0	Make output have exactly one word per WERD
  tessedit_write_block_separators	0	Write block separators in output
  tessedit_write_images	0	Capture the image from the IPE
  tessedit_write_params_to_file		Write all parameters to the given file.
  tessedit_write_rep_codes	0	Write repetition char code
  tessedit_write_unlv	0	Write .unlv output file
  tessedit_zero_kelvin_rejection	0	Dont reject ANYTHING AT ALL
  tessedit_zero_rejection	0	Dont reject ANYTHING
  test_pt	0	Test for point
  test_pt_x	100000	xcoord
  test_pt_y	100000	ycoord
  textord_all_prop	0	All doc is proportial text
  textord_ascheight_mode_fraction	0.08	Min pile height to make ascheight
  textord_ascx_ratio_max	1.8	Max cap/xheight
  textord_ascx_ratio_min	1.25	Min cap/xheight
  textord_balance_factor	1	Ding rate for unbalanced char cells
  textord_baseline_debug	0	Baseline debug level
  textord_biased_skewcalc	1	Bias skew estimates with line length
  textord_blob_size_bigile	95	Percentile for large blobs
  textord_blob_size_smallile	20	Percentile for small blobs
  textord_blockndoc_fixed	0	Attempt whole doc/block fixed pitch
  textord_blocksall_fixed	0	Moan about prop blocks
  textord_blocksall_prop	0	Moan about fixed pitch blocks
  textord_blocksall_testing	0	Dump stats when moaning
  textord_blshift_maxshift	0	Max baseline shift
  textord_blshift_xfraction	9.99	Min size of baseline shift
  textord_chop_width	1.5	Max width before chopping
  textord_chopper_test	0	Chopper is being tested.
  textord_debug_baselines	0	Debug baseline generation
  textord_debug_blob	0	Print test blob information
  textord_debug_block	0	Block to do debug on
  textord_debug_bugs	0	Turn on output related to bugs in tab finding
  textord_debug_images	0	Use greyed image background for debug
  textord_debug_pitch_metric	0	Write full metric stuff
  textord_debug_pitch_test	0	Debug on fixed pitch test
  textord_debug_printable	0	Make debug windows printable
  textord_debug_tabfind	0	Debug tab finding
  textord_debug_xheights	0	Test xheight algorithms
  textord_descheight_mode_fraction	0.08	Min pile height to make descheight
  textord_descx_ratio_max	0.6	Max desc/xheight
  textord_descx_ratio_min	0.25	Min desc/xheight
  textord_disable_pitch_test	0	Turn off dp fixed pitch algorithm
  textord_dotmatrix_gap	3	Max pixel gap for broken pixed pitch
  textord_dump_table_images	0	Paint table detection output
  textord_equation_detect	0	Turn on equation detector
  textord_excess_blobsize	1.3	New row made if blob makes row this big
  textord_expansion_factor	1	Factor to expand rows by in expand_rows
  textord_fast_pitch_test	0	Do even faster pitch algorithm
  textord_fix_makerow_bug	1	Prevent multiple baselines
  textord_fix_xheight_bug	1	Use spline baseline
  textord_force_make_prop_words	0	Force proportional word segmentation on all rows
  textord_fp_chop_error	2	Max allowed bending of chop cells
  textord_fp_chop_snap	0.5	Max distance of chop pt from vertex
  textord_fp_chopping	1	Do fixed pitch chopping
  textord_fp_min_width	0.5	Min width of decent blobs
  textord_fpiqr_ratio	1.5	Pitch IQR/Gap IQR threshold
  textord_heavy_nr	0	Vigorously remove noise
  textord_initialasc_ile	0.9	Ile of sizes for xheight guess
  textord_initialx_ile	0.75	Ile of sizes for xheight guess
  textord_interpolating_skew	1	Interpolate across gaps
  textord_linespace_iqrlimit	0.2	Max iqr/median for linespace
  textord_lms_line_trials	12	Number of linew fits to do
  textord_max_blob_overlaps	4	Max number of blobs a big blob can overlap
  textord_max_noise_size	7	Pixel size of noise
  textord_max_pitch_iqr	0.2	Xh fraction noise in pitch
  textord_min_blob_height_fraction	0.75	Min blob height/top to include blob top into xheight stats
  textord_min_blobs_in_row	4	Min blobs before gradient counted
  textord_min_linesize	1.25	* blob height for initial linesize
  textord_min_xheight	10	Min credible pixel xheight
  textord_minxh	0.25	fraction of linesize for min xheight
  textord_new_initial_xheight	1	Use test xheight mechanism
  textord_no_rejects	0	Don't remove noise blobs
  textord_noise_area_ratio	0.7	Fraction of bounding box for noise
  textord_noise_debug	0	Debug row garbage detector
  textord_noise_hfract	0.015625	Height fraction to discard outlines as speckle noise
  textord_noise_normratio	2	Dot to norm ratio for deletion
  textord_noise_rejrows	1	Reject noise-like rows
  textord_noise_rejwords	1	Reject noise-like words
  textord_noise_rowratio	6	Dot to norm ratio for deletion
  textord_noise_sizefraction	10	Fraction of size for maxima
  textord_noise_sizelimit	0.5	Fraction of x for big t count
  textord_noise_sncount	1	super norm blobs to save row
  textord_noise_sxfract	0.4	xh fract width error for norm blobs
  textord_noise_syfract	0.2	xh fract height error for norm blobs
  textord_noise_translimit	16	Transitions for normal blob
  textord_occupancy_threshold	0.4	Fraction of neighbourhood
  textord_ocropus_mode	0	Make baselines for ocropus
  textord_old_baselines	1	Use old baseline algorithm
  textord_old_xheight	0	Use old xheight algorithm
  textord_oldbl_debug	0	Debug old baseline generation
  textord_oldbl_jumplimit	0.15	X fraction for new partition
  textord_oldbl_merge_parts	1	Merge suspect partitions
  textord_oldbl_paradef	1	Use para default mechanism
  textord_oldbl_split_splines	1	Split stepped splines
  textord_overlap_x	0.375	Fraction of linespace for good overlap
  textord_parallel_baselines	1	Force parallel baselines
  textord_pitch_cheat	0	Use correct answer for fixed/prop
  textord_pitch_range	2	Max range test on pitch
  textord_pitch_rowsimilarity	0.08	Fraction of xheight for sameness
  textord_pitch_scalebigwords	0	Scale scores on big words
  textord_projection_scale	0.2	Ding rate for mid-cuts
  textord_really_old_xheight	0	Use original wiseowl xheight
  textord_restore_underlines	1	Chop underlines & put back
  textord_show_blobs	0	Display unsorted blobs
  textord_show_boxes	0	Display unsorted blobs
  textord_show_expanded_rows	0	Display rows after expanding
  textord_show_final_blobs	0	Display blob bounds after pre-ass
  textord_show_final_rows	0	Display rows after final fitting
  textord_show_fixed_cuts	0	Draw fixed pitch cell boundaries
  textord_show_fixed_words	0	Display forced fixed pitch words
  textord_show_initial_rows	0	Display row accumulation
  textord_show_initial_words	0	Display separate words
  textord_show_new_words	0	Display separate words
  textord_show_page_cuts	0	Draw page-level cuts
  textord_show_parallel_rows	0	Display page correlated rows
  textord_show_row_cuts	0	Draw row-level cuts
  textord_show_tables	0	Show table regions
  textord_single_height_mode	0	Script has no xheight, so use a single mode
  textord_skew_ile	0.5	Ile of gradients for page skew
  textord_skew_lag	0.02	Lag for skew on row accumulation
  textord_skewsmooth_offset	4	For smooth factor
  textord_skewsmooth_offset2	1	For smooth factor
  textord_space_size_is_variable	0	If true, word delimiter spaces are assumed to have variable width, even though characters have fixed pitch.
  textord_spacesize_ratiofp	2.8	Min ratio space/nonspace
  textord_spacesize_ratioprop	2	Min ratio space/nonspace
  textord_spline_medianwin	6	Size of window for spline segmentation
  textord_spline_minblobs	8	Min blobs in each spline segment
  textord_spline_outlier_fraction	0.1	Fraction of line spacing for outlier
  textord_spline_shift_fraction	0.02	Fraction of line spacing for quad
  textord_straight_baselines	0	Force straight baselines
  textord_tabfind_aligned_gap_fraction	0.75	Fraction of height used as a minimum gap for aligned blobs.
  textord_tabfind_find_tables	1	run table detection
  textord_tabfind_force_vertical_text	0	Force using vertical text page mode
  textord_tabfind_only_strokewidths	0	Only run stroke widths
  textord_tabfind_show_blocks	0	Show final block bounds
  textord_tabfind_show_color_fit	0	Show stroke widths
  textord_tabfind_show_columns	0	Show column bounds
  textord_tabfind_show_finaltabs	0	Show tab vectors
  textord_tabfind_show_images	0	Show image blobs
  textord_tabfind_show_initial_partitions	0	Show partition bounds
  textord_tabfind_show_initialtabs	0	Show tab candidates
  textord_tabfind_show_partitions	0	Show partition bounds, waiting if >1
  textord_tabfind_show_reject_blobs	0	Show blobs rejected as noise
  textord_tabfind_show_strokewidths	0	Show stroke widths
  textord_tabfind_show_vlines	0	Debug line finding
  textord_tabfind_vertical_horizontal_mix	1	find horizontal lines such as headers in vertical page mode
  textord_tabfind_vertical_text	1	Enable vertical detection
  textord_tabfind_vertical_text_ratio	0.5	Fraction of textlines deemed vertical to use vertical page mode
  textord_tablefind_recognize_tables	0	Enables the table recognizer for table layout and filtering.
  textord_tablefind_show_mark	0	Debug table marking steps in detail
  textord_tablefind_show_stats	0	Show page stats used in table finding
  textord_tabvector_vertical_box_ratio	0.5	Fraction of box matches required to declare a line vertical
  textord_tabvector_vertical_gap_fraction	0.5	max fraction of mean blob width allowed for vertical gaps in vertical text
  textord_test_landscape	0	Tests refer to land/port
  textord_test_mode	0	Do current test
  textord_test_x	-2147483647	coord of test pt
  textord_test_y	-2147483647	coord of test pt
  textord_testregion_bottom	2147483647	Bottom edge of debug rectangle
  textord_testregion_left	-1	Left edge of debug reporting rectangle
  textord_testregion_right	2147483647	Right edge of debug rectangle
  textord_testregion_top	-1	Top edge of debug reporting rectangle
  textord_underline_offset	0.1	Fraction of x to ignore
  textord_underline_threshold	0.5	Fraction of width occupied
  textord_underline_width	2	Multiple of line_size for underline
  textord_use_cjk_fp_model	0	Use CJK fixed pitch model
  textord_width_limit	8	Max width of blobs to make rows
  textord_width_smooth_factor	0.1	Smoothing width stats
  textord_words_def_fixed	0.016	Threshold for definite fixed
  textord_words_def_prop	0.09	Threshold for definite prop
  textord_words_default_maxspace	3.5	Max believable third space
  textord_words_default_minspace	0.6	Fraction of xheight
  textord_words_default_nonspace	0.2	Fraction of xheight
  textord_words_definite_spread	0.3	Non-fuzzy spacing region
  textord_words_initial_lower	0.25	Max inital cluster size
  textord_words_initial_upper	0.15	Min initial cluster spacing
  textord_words_maxspace	4	Multiple of xheight
  textord_words_min_minspace	0.3	Fraction of xheight
  textord_words_minlarge	0.75	Fraction of valid gaps needed
  textord_words_pitchsd_threshold	0.04	Pitch sync threshold
  textord_words_veto_power	5	Rows required to outvote a veto
  textord_words_width_ile	0.4	Ile of blob widths for space est
  textord_wordstats_smooth_factor	0.05	Smoothing gap stats
  textord_xheight_error_margin	0.1	Accepted variation
  textord_xheight_mode_fraction	0.4	Min pile height to make xheight
  tosp_all_flips_fuzzy	0	Pass ANY flip to context?
  tosp_block_use_cert_spaces	1	Only stat OBVIOUS spaces
  tosp_debug_level	0	Debug data
  tosp_dont_fool_with_small_kerns	-1	Limit use of xht gap with odd small kns
  tosp_enough_small_gaps	0.65	Fract of kerns reqd for isolated row stats
  tosp_enough_space_samples_for_median	3	or should we use mean
  tosp_few_samples	40	No.gaps reqd with 1 large gap to treat as a table
  tosp_flip_caution	0	Dont autoflip kn to sp when large separation
  tosp_flip_fuzz_kn_to_sp	1	Default flip
  tosp_flip_fuzz_sp_to_kn	1	Default flip
  tosp_force_wordbreak_on_punct	0	Force word breaks on punct to break long lines in non-space delimited langs
  tosp_fuzzy_kn_fraction	0.5	New fuzzy kn alg
  tosp_fuzzy_limit_all	1	Dont restrict kn->sp fuzzy limit to tables
  tosp_fuzzy_sp_fraction	0.5	New fuzzy sp alg
  tosp_fuzzy_space_factor	0.6	Fract of xheight for fuzz sp
  tosp_fuzzy_space_factor1	0.5	Fract of xheight for fuzz sp
  tosp_fuzzy_space_factor2	0.72	Fract of xheight for fuzz sp
  tosp_gap_factor	0.83	gap ratio to flip sp->kern
  tosp_ignore_big_gaps	-1	xht multiplier
  tosp_ignore_very_big_gaps	3.5	xht multiplier
  tosp_improve_thresh	0	Enable improvement heuristic
  tosp_init_guess_kn_mult	2.2	Thresh guess - mult kn by this
  tosp_init_guess_xht_mult	0.28	Thresh guess - mult xht by this
  tosp_kern_gap_factor1	2	gap ratio to flip kern->sp
  tosp_kern_gap_factor2	1.3	gap ratio to flip kern->sp
  tosp_kern_gap_factor3	2.5	gap ratio to flip kern->sp
  tosp_large_kerning	0.19	Limit use of xht gap with large kns
  tosp_max_sane_kn_thresh	5	Multiplier on kn to limit thresh
  tosp_min_sane_kn_sp	1.5	Dont trust spaces less than this time kn
  tosp_narrow_aspect_ratio	0.48	narrow if w/h less than this
  tosp_narrow_blobs_not_cert	1	Only stat OBVIOUS spaces
  tosp_narrow_fraction	0.3	Fract of xheight for narrow
  tosp_near_lh_edge	0	Dont reduce box if the top left is non blank
  tosp_old_sp_kn_th_factor	2	Factor for defining space threshold in terms of space and kern sizes
  tosp_old_to_bug_fix	0	Fix suspected bug in old code
  tosp_old_to_constrain_sp_kn	0	Constrain relative values of inter and intra-word gaps for old_to_method.
  tosp_old_to_method	0	Space stats use prechopping?
  tosp_only_small_gaps_for_kern	0	Better guess
  tosp_only_use_prop_rows	1	Block stats to use fixed pitch rows?
  tosp_only_use_xht_gaps	0	Only use within xht gap for wd breaks
  tosp_pass_wide_fuzz_sp_to_context	0.75	How wide fuzzies need context
  tosp_recovery_isolated_row_stats	1	Use row alone when inadequate cert spaces
  tosp_redo_kern_limit	10	No.samples reqd to reestimate for row
  tosp_rep_space	1.6	rep gap multiplier for space
  tosp_row_use_cert_spaces	1	Only stat OBVIOUS spaces
  tosp_row_use_cert_spaces1	1	Only stat OBVIOUS spaces
  tosp_rule_9_test_punct	0	Dont chng kn to space next to punct
  tosp_sanity_method	1	How to avoid being silly
  tosp_short_row	20	No.gaps reqd with few cert spaces to use certs
  tosp_silly_kn_sp_gap	0.2	Dont let sp minus kn get too small
  tosp_stats_use_xht_gaps	1	Use within xht gap for wd breaks
  tosp_table_fuzzy_kn_sp_ratio	3	Fuzzy if less than this
  tosp_table_kn_sp_ratio	2.25	Min difference of kn & sp in table
  tosp_table_xht_sp_ratio	0.33	Expect spaces bigger than this
  tosp_threshold_bias1	0	how far between kern and space?
  tosp_threshold_bias2	0	how far between kern and space?
  tosp_use_pre_chopping	0	Space stats use prechopping?
  tosp_use_xht_gaps	1	Use within xht gap for wd breaks
  tosp_wide_aspect_ratio	0	wide if w/h less than this
  tosp_wide_fraction	0.52	Fract of xheight for wide
  unlv_tilde_crunching	1	Mark v.bad words for tilde crunch
  unrecognised_char
  use_ambigs_for_adaption	0	Use ambigs for deciding whether to adapt to a character
  use_definite_ambigs_for_classifier	0	Use definite ambiguities when running character classifier
  use_new_state_cost	0	use new state cost heuristics for segmentation state evaluation
  use_only_first_uft8_step	0	Use only the first UTF8 step of the given string when computing log probabilities.
  user_patterns_file		A filename of user-provided patterns.
  user_patterns_suffix		A suffix of user-provided patterns located in tessdata.
  user_words_file		A filename of user-provided words.
  user_words_suffix		A suffix of user-provided words located in tessdata.
  word_to_debug		Word for which stopper debug information should be printed to stdout
  word_to_debug_lengths		Lengths of unichars in word_to_debug
  wordrec_blob_pause	0	Blob pause
  wordrec_debug_blamer	0	Print blamer debug messages
  wordrec_debug_level	0	Debug level for wordrec
  wordrec_display_all_blobs	0	Display Blobs
  wordrec_display_all_words	0	Display Words
  wordrec_display_segmentations	0	Display Segmentations
  wordrec_display_splits	0	Display splits
  wordrec_enable_assoc	1	Associator Enable
  wordrec_max_join_chunks	4	Max number of broken pieces to associate
  wordrec_no_block	0	Don't output block information
  wordrec_run_blamer	0	Try to set the blame for errors
  wordrec_skip_no_truth_words	0	Only run OCR for words that had truth recorded in BlamerBundle
  wordrec_worst_state	1	Worst segmentation state
  words_default_fixed_limit	0.6	Allowed size variance
  words_default_fixed_space	0.75	Fraction of xheight
  words_default_prop_nonspace	0.25	Fraction of xheight
  words_initial_lower	0.5	Max inital cluster size
  words_initial_upper	0.15	Min initial cluster spacing
  x_ht_acceptance_tolerance	8	Max allowed deviation of blob top outside of font data
  x_ht_min_change	8	Min change in xht before actually trying it
  xheight_penalty_inconsistent	0.25	Score penalty (0.1 = 10%) added if an xheight is inconsistent.
  xheight_penalty_subscripts	0.125	Score penalty (0.1 = 10%) added if there are subscripts or superscripts in a word, but it is otherwise OK.

Returns a TesseractJob whose then, progress, and error methods can be used to act on the result.

Example:

Tesseract.recognize('#my-image')
.then(function(result){
    console.log(result)
})

Tesseract.detect(image: ImageLike) -> TesseractJob

Figures out what script (e.g. 'Latin', 'Chinese') the words in image are written in.

• image is any ImageLike object.

Returns a TesseractJob whose then, progress, and error methods can be used to act on the result of the script.

Tesseract.detect('#my-image')
.then(function(result){
    console.log(result)
})

TesseractJob

A TesseractJob is an an object returned by a call to recognize or detect. All methods of a TesseractJob return itself to enable chaining.

Typical use is:

var job1 = Tesseract.recognize('#my-image')

job1.progress(function(message){console.log(message)})
    .error(function(err){console.error(err)})
    .then(function(result){console.log(result)})

or more concisely:

Tesseract.recognize('#my-image')
    .progress(function(message){console.log(message)})
    .error(function(err){console.error(err)})
    .then(function(result){console.log(result)})

TesseractJob.progress(callback: function) -> TesseractJob

Sets callback as the function that will be called every time the job progresses.

callback is a function with the signature callback(progress) where progress is json object.

For example:

Tesseract.recognize('#my-image')
    .progress(function(message){console.log('progress is: 'message)})

The console will show something like:

progress is: {loaded_lang_model: "eng", from_cache: true}
progress is: {initialized_with_lang: "eng"}
progress is: {set_variable: Object}
progress is: {set_variable: Object}
progress is: {recognized: 0}
progress is: {recognized: 0.3}
progress is: {recognized: 0.6}
progress is: {recognized: 0.9}
progress is: {recognized: 1}

TesseractJob.then(callback: function) -> TesseractJob

Sets callback as the function that will be called if and when the job successfully completes.

For example:

Tesseract.recognize('#my-image')
    .then(function(result){console.log('result is: 'result)})

The console will show something like:

progress is: {
    blocks: Array[1]
    confidence: 87
    html: "<div class='ocr_page' id='page_1' ..."
    lines: Array[3]
    oem: "DEFAULT"
    paragraphs: Array[1]
    psm: "SINGLE_BLOCK"
    symbols: Array[33]
    text: "Hello World↵from beyond↵the Cosmic Void↵↵"
    version: "3.04.00"
    words: Array[7]
}

TesseractJob.error(callback: function) -> TesseractJob

Sets callback as the function that will be called if and when the job successfully completes.

Contributing

Development

To run a development copy of tesseract.js, first clone this repo.

> git clone https://github.com/naptha/tesseract.js.git

Then, cd in to the folder, npm install, and npm start

> cd tesseract.js
> npm install && npm start

  ... a bunch of npm stuff ... 

  tesseract.js@1.0.0 start /Users/guillermo/Desktop/code_static/tesseract.js
  node devServer.js

Listening at http://localhost:7355

Then open http://localhost:7355 in your favorite browser. The devServer automatically rebuilds tesseract.js and tesseract.worker.js when you change files in the src folder.

Building Static Files

After you've cloned the repo and run npm install as described in the Development Section, you can build static library files in the dist folder with

> npm run build

Send us a Pull Request!