public class

OCROptions

extends OptionsBase
java.lang.Object
   ↳ com.pdftron.pdf.OptionsBase
     ↳ com.pdftron.pdf.OCROptions

Summary

Public Constructors
OCROptions()
Constructor.
OCROptions(String json_string)
Constructor.
Public Methods
OCROptions addDPI(int dpi)
Sets the value for DPI in the options object.
OCROptions addIgnoreZonesForPage(RectCollection regions, int page_num)
Adds a zones to the IgnoreZones array.
OCROptions addLang(String lang)
Adds a language to the Langs array.
OCROptions addTextZonesForPage(RectCollection regions, int page_num)
Adds a zones to the TextZones array.
boolean getAutoRotate()
Gets the value AutoRotate from the options object.
int getDPI()
Gets the value DPI from the options object.
boolean getIgnoreExistingText()
Gets the value IgnoreExistingText from the options object.
String getOCREngine()
Gets the value OCREngine from the options object.
boolean getUsePDFPageCoords()
Gets the value UsePDFPageCoords from the options object.
OCROptions setAutoRotate(boolean value)
Sets the value for AutoRotate in the options object.
OCROptions setIgnoreExistingText(boolean value)
Sets the value for IgnoreExistingText in the options object.
OCROptions setOCREngine(String value)
Sets the value for OCREngine in the options object.
OCROptions setUsePDFPageCoords(boolean value)
Sets the value for UsePDFPageCoords in the options object.
[Expand]
Inherited Methods
From class java.lang.Object

Public Constructors

public OCROptions ()

Constructor.

public OCROptions (String json_string)

Constructor.

Public Methods

public OCROptions addDPI (int dpi)

Sets the value for DPI in the options object.

Knowing proper image resolution is important, as it enables the OCR engine to translate pixel heights of characters to their respective font sizes.

We do our best to retrieve resolution information from the input's metadata, however it occasionally can be corrupt or missing. Hence we allow manual override of source's resolution, which supersedes any metadata found (both explicit as in image metadata and implicit as in PDF).

If input is a PDF file, the SDK will render PDF page for OCR as a raster image with 300 DPI resolution. Otherwise, if input is an image, SDK will pass to OCR raster image in original resolution. Exceptionally, if the user, by using this method, suggests the resolution (say 300 DPI), the SDK will try do as suggested.

Here, some restrictions apply:

  • New image size in pixels (Width X Height) cannot exceed 75 MP (Mega Pixels)
  • Each image side (Width or Height), in pixels, cannot exceed 16 bits (65,535)

To achieve that, SDK will iteratively scale down the DPI till both conditions are met.

Parameters
dpi The new value for DPI.
Returns
  • This object, for call chaining.

public OCROptions addIgnoreZonesForPage (RectCollection regions, int page_num)

Adds a zones to the IgnoreZones array.

It is an optional list of areas that will be excluded from analysis.

The meaning and handling of the passed region coordinates will vary depending on:

  • Whether input is PDF (rather than an image), and
  • Whether setUsePDFPageCoords() is called with value true.

If either of above is true, then the region coordinates have to be given in PDF Points and coodinate space origin at bottom-left.

Otherwise:

  • The input is a raster image,
  • The coordinates has to be given in pixel units and with coordinate space origin at top-left

See also: processPDF() imageToPDF() setUsePDFPageCoords() addTextZonesForPage().

Parameters
regions The new zones to add to IgnoreZonesForPage.
page_num The page number the added regions belong to.
Returns
  • This object, for call chaining.

public OCROptions addLang (String lang)

Adds a language to the Langs array.

OCR engine is prepared for recognition of a predefined set of language scripts. Various scripts have differences in glyphs and it is recommended that OCR engine is instructed to use a correct glyph set to match the appropriate Unicode. At this moment, there are two avaliable engines for use. Let we refer them by their executable names: OCRModule and OCRModuleIRIS.

Here is a list of supported languages by their codes that may be passed as a parameter. One language per call to addLang(). Use multiple calls to addLang() to add additional languages.

Warning: Be aware that adding too many language codes at once may lead to wrong altertnatives regarding Latin characters with accents.

Language CodeLanguage Code
English eng Chinese Simpl.chi_sim
French fra Chinese Trad. chi_tra
German deu Japanese jpn
Italian ita Korean kor
Russian rus
Spanish spa

Here are the languages supported out of the box per engine:

Executable NameSupported Codes
OCRModule eng fra deu ita spa rus
OCRModuleIRIS eng fra deu ita spa rus chi_sim chi_tra jpn kor

Note: OCRModuleIRIS allows mix of a single Asian language and just English.

Parameters
lang The new language to add to Langs.
Returns
  • This object, for call chaining.

public OCROptions addTextZonesForPage (RectCollection regions, int page_num)

Adds a zones to the TextZones array.

It is as an optional list of known text zones that will be used to improve OCR quality.

See also: AddIgnoreZonesForPage().

Parameters
regions The new zones to add to TextZonesForPage.
page_num The page number the added regions belong to.
Returns
  • This object, for call chaining.

public boolean getAutoRotate ()

Gets the value AutoRotate from the options object.

Default value is false. Setting to true will deskew the image before conducting OCR.

Note: This function doesn't apply to IRIS OCR module.

Returns
  • The current value for AutoRotate.

public int getDPI ()

Gets the value DPI from the options object.

Knowing proper image resolution is important, as it enables the OCR engine to translate pixel heights of characters to their respective font sizes.

We do our best to retrieve resolution information from the input's metadata, however it occasionally can be corrupt or missing. Hence we allow manual override of source's resolution, which supersedes any metadata found (both explicit as in image metadata and implicit as in PDF).

If input is a PDF file, the SDK will render PDF page for OCR as a raster image with 300 DPI resolution. Otherwise, if input is an image, SDK will pass to OCR raster image in original resolution. Exceptionally, if the user, by using this method, suggests the resolution (say 300 DPI), the SDK will try do as suggested.

Here, some restrictions apply:

  • New image size in pixels (Width X Height) cannot exceed 75 MP (Mega Pixels)
  • Each image side (Width or Height), in pixels, cannot exceed 16 bits (65,535)

To achieve that, SDK will iteratively scale down the DPI till both conditions are met.

Returns
  • The current value for DPI.

public boolean getIgnoreExistingText ()

Gets the value IgnoreExistingText from the options object.

Default value is false, so that areas with existing text will be automatically skipped during OCR. Setting to true will cause a pre-existing text to be duplicated with the OCR-ed ones in the PDF document or in GetOCRJsonFromPDF() and getOCRXmlFromPDF() results.

Returns
  • The current value for IgnoreExistingText.

public String getOCREngine ()

Gets the value OCREngine from the options object.

Options include 'default' or 'iris'. Chosen module must be present and correctly licensed.

Returns
  • The current value for OCREngine.

public boolean getUsePDFPageCoords ()

Gets the value UsePDFPageCoords from the options object.

Defines the coordinate system, scaling and units. SDK and OCRModule will refer to this setting while dealing with potential input zone rectangle(s) (ignorable or text) and with the output result as well. The default value is false which corresponds to raster image input.

Here are the meanings for value:

ValueOrigin +Y axis dir.Unit Size Expected input
falsetop-left Downwards Pixel1/DPI inchesImage
true bottom-leftUpwards Point1/72 inches PDF

Note that, OCRModule backend has no notion about the SDK's real input. So, if not explicitelly instructed via this call and value, it will work by default and will report the coordinates as for false. This is important to know for cases when the call for OCR service comes from getOCRJsonFromPDF() or getOCRXmlFromPDF() where the results should be correct in JSON or XML format - and removes the need for user to do additional adjustments.

See also: addIgnoreZonesForPage() addTextZonesForPage() addDPI() getOCRJsonFromImage() getOCRXmlFromImage().

Returns
  • The current value for UsePDFPageCoords.

public OCROptions setAutoRotate (boolean value)

Sets the value for AutoRotate in the options object.

Default value is false. Setting to true will deskew the image before conducting OCR.

Note: This function doesn't apply to IRIS OCR module.

Parameters
value The new value for AutoRotate.
Returns
  • This object, for call chaining.

public OCROptions setIgnoreExistingText (boolean value)

Sets the value for IgnoreExistingText in the options object.

Default value is false, so that areas with existing text will be automatically skipped during OCR. Setting to true will cause a pre-existing text to be duplicated with the OCR-ed ones in the PDF document or in getOCRJsonFromPDF() and getOCRXmlFromPDF() results.

Parameters
value The new value for IgnoreExistingText.
Returns
  • This object, for call chaining.

public OCROptions setOCREngine (String value)

Sets the value for OCREngine in the options object.

Options include 'default' or 'iris'. Chosen module must be present and correctly licensed.

Parameters
value The new value for OCREngine.
Returns
  • This object, for call chaining.

public OCROptions setUsePDFPageCoords (boolean value)

Sets the value for UsePDFPageCoords in the options object.

Defines the coordinate system, scaling and units. SDK and OCRModule will refer to this setting while dealing with potential input zone rectangle(s) (ignorable or text) and with the output result as well. The default value is false which corresponds to raster image input.

Here are the meanings for value:

ValueOrigin +Y axis dir.Unit Size Expected input
falsetop-left Downwards Pixel1/DPI inchesImage
true bottom-leftUpwards Point1/72 inches PDF

Note that, OCRModule backend has no notion about the SDK's real input. So, if not explicitelly instructed via this call and value, it will work by default and will report the coordinates as for false. This is important to know for cases when the call for OCR service comes from getOCRJsonFromPDF() or getOCRXmlFromPDF() where the results should be correct in JSON or XML format - and removes the need for user to do additional adjustments.

See also: addIgnoreZonesForPage() addTextZonesForPage() addDPI() getOCRJsonFromImage() getOCRXmlFromImage().

Parameters
value The new value for UsePDFPageCoords.
Returns
  • This object, for call chaining.