org.safs.tools.ocr

Class OCREngine

java.lang.Object

org.safs.tools.ocr.OCREngine

Direct Known Subclasses:

GOCREngine, TesseractOCREngine

public abstract class OCREngine
extends java.lang.Object

An abstract class to define common behaviors of OCR engines. The concrete OCR engines need to derive from this class, and implement the common behaviors in it.

Author:

Junwu Ma
DEC 14, 2009 Original Release
DEC 22, 2009 (JunwuMa) Updates to make it work for GOCR newly introduced.
JAN 27, 2009 (JunwuMa) Add method runCommandLine(String).
JAN 29, 2009 (JunwuMa) Updates to use BICUBIC interpolation to resize images for better effect.
FEB 25, 2010 (JunwuMa) Refactoring for OCR keywords.
APR 20, 2010 (Lei Wang) Add static method getOCREngine(): get the OCREngine instance according to the given engine name (by parameter or STAF variable). Add static method getOCREngineKey(), setOCREngineKey(), getOCRLanguageCode(), setOCRLanguageCode(): get or set STAF variables

See Also:

TesseractOCREngine, GOCREngine

Field Summary

Fields

Modifier and Type	Field and Description
float	defaultZoomScale
static java.lang.String	OCR_DEFAULT_ENGINE_CLAZZ
static java.lang.String	OCR_DEFAULT_ENGINE_KEY
static java.lang.String	OCR_G_ENGINE_CLAZZ
static java.lang.String	OCR_G_ENGINE_KEY
static java.lang.String	OCR_T_ENGINE_CLAZZ
static java.lang.String	OCR_T_ENGINE_KEY
static java.lang.String	STAF_OCR_ENGINE_VAR_NAME
static java.lang.String	STAF_OCR_LANGUAGE_ID_VAR_NAME

Constructor Summary

Constructors

Constructor and Description
OCREngine()

Method Summary

Modifier and Type	Method and Description
java.awt.Rectangle	findTextRectFromImage(java.lang.String searchtext, int index, java.awt.image.BufferedImage image, java.lang.String stdlangId, java.awt.Rectangle subarea, float zoom)
float	getdefaultZoomScale()
static OCREngine	getOCREngine(java.lang.String ocrNameKey, STAFHelper staf) Note: This method first try to get OCR engine corresponding to ocrNameKey; If not found, try to get the OCR engine defined by STAF variable STAF_OCR_ENGINE_VAR_NAME; If there is no OCR engine defined in STAF variable, then use the default engine defined by OCR_DEFAULT_ENGINE_KEY.
static java.lang.String	getOCREngineKey(STAFHelper staf) Note: This method will get the value of STAF variable STAF_OCR_ENGINE_VAR_NAME
static java.lang.String	getOCRLanguageCode(STAFHelper staf) Note: This method will get the value of STAF variable STAF_OCR_LANGUAGE_ID_VAR_NAME
protected java.lang.String	getSelfDefinedLangId(java.lang.String langId) Translate the standard language code to OCR specific language code.
java.lang.String	imageToText(java.awt.image.BufferedImage image, java.lang.String langId, java.awt.Rectangle subarea)
java.lang.String	imageToText(java.awt.image.BufferedImage image, java.lang.String langId, java.awt.Rectangle subarea, float zoom) Convert buffered image to text using OCR technology.
static void	main(java.lang.String[] args) Usage: java OCREngine imageFile [-e engine] [-l languageID] [-z scale]
protected java.lang.String	runCommandLine(java.lang.String cmdline)
void	setdefaultZoomScale(float value)
static boolean	setOCREngineKey(STAFHelper staf, java.lang.String engineKey) Note: This method will set the value to STAF variable STAF_OCR_ENGINE_VAR_NAME
static boolean	setOCRLanguageCode(STAFHelper staf, java.lang.String languageCode) Note: This method will set the value to STAF variable STAF_OCR_LANGUAGE_ID_VAR_NAME
java.lang.String	storedImageToText(java.lang.String imagefile, java.lang.String langId, java.awt.Rectangle subarea)
java.lang.String	storedImageToText(java.lang.String imagefile, java.lang.String langId, java.awt.Rectangle subarea, float zoom) Convert an image file to text using OCR technology.
java.awt.image.BufferedImage	zoomImageWithType(java.awt.image.BufferedImage image, int imageType, java.awt.Rectangle subarea, float zoomValue)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

STAF_OCR_ENGINE_VAR_NAME

public static java.lang.String STAF_OCR_ENGINE_VAR_NAME

STAF_OCR_LANGUAGE_ID_VAR_NAME

public static java.lang.String STAF_OCR_LANGUAGE_ID_VAR_NAME

OCR_T_ENGINE_KEY

public static java.lang.String OCR_T_ENGINE_KEY

OCR_G_ENGINE_KEY

public static java.lang.String OCR_G_ENGINE_KEY

OCR_T_ENGINE_CLAZZ

public static java.lang.String OCR_T_ENGINE_CLAZZ

OCR_G_ENGINE_CLAZZ

public static java.lang.String OCR_G_ENGINE_CLAZZ

OCR_DEFAULT_ENGINE_KEY

public static java.lang.String OCR_DEFAULT_ENGINE_KEY

OCR_DEFAULT_ENGINE_CLAZZ

public static java.lang.String OCR_DEFAULT_ENGINE_CLAZZ

defaultZoomScale

public float defaultZoomScale

Constructor Detail

OCREngine

public OCREngine()

Method Detail

getdefaultZoomScale

public float getdefaultZoomScale()

setdefaultZoomScale

public void setdefaultZoomScale(float value)

imageToText

public java.lang.String imageToText(java.awt.image.BufferedImage image,
                                    java.lang.String langId,
                                    java.awt.Rectangle subarea)
                             throws SAFSException

Throws:

SAFSException

imageToText

public java.lang.String imageToText(java.awt.image.BufferedImage image,
                                    java.lang.String langId,
                                    java.awt.Rectangle subarea,
                                    float zoom)
                             throws SAFSException

Convert buffered image to text using OCR technology. It needs to be implemented in its derived class.

Parameters:

image, - an input BufferedImage for converting to text, supposed to be those images displayed on computer CRT. These 'screen-captured' images are at low DPI (75). It needs to be resized for using in OCR engine. Tesseract uses images with 300DPI.

langId, - language id representing the language that OCR intends to convert to.

subarea, - area of the input image for convert. NULL stands for whole area of the image.

zoom, - float, it is an optional parameter representing zoom value. SAFS uses a simple way -- resizing the image to fit 300DPI that is required by OCR for better text recognition. Normal screen-captured images are at low DPI-- (75~90). A value between 0 and 1, stands for the size of zooming out the source image to fit 300DPI for text recognition. A value bigger than 1, stands for the size of zooming in the source image to fit GOCR's requirement. User may give a proper zoom value for the text in a image to be fit in and recognized.

Returns:

String, converted from the input image. NULL if fails to convert.

Throws:

SAFSException - if meets any Exception

storedImageToText

public java.lang.String storedImageToText(java.lang.String imagefile,
                                          java.lang.String langId,
                                          java.awt.Rectangle subarea)
                                   throws SAFSException

Throws:

SAFSException

getSelfDefinedLangId

protected java.lang.String getSelfDefinedLangId(java.lang.String langId)

Translate the standard language code to OCR specific language code. It should be overridden in derived classes. Refer to Locale.ENGLISH.getLanguage() for input langid. For example: 'en' -- English

Parameters:

langId, - standard language code

Returns:

findTextRectFromImage

public java.awt.Rectangle findTextRectFromImage(java.lang.String searchtext,
                                                int index,
                                                java.awt.image.BufferedImage image,
                                                java.lang.String stdlangId,
                                                java.awt.Rectangle subarea,
                                                float zoom)
                                         throws SAFSException

Throws:

SAFSException

storedImageToText

public java.lang.String storedImageToText(java.lang.String imagefile,
                                          java.lang.String langId,
                                          java.awt.Rectangle subarea,
                                          float zoom)
                                   throws SAFSException

Convert an image file to text using OCR technology.

Parameters:

imagefile, - image file with formats BMP,GIF,JPEG,PNG and TIFF

langId, - if useful, it represents the language that OCR intends to convert to. NULL means OCR doesn't care languages.

subarea, - area of the input image for convert. NULL stands for whole area of the image.

zoom, - float, it is an optional parameter representing zoom value. SAFS uses a simple way -- resizing the image to fit 300DPI that is required by OCR for better text recognition. Normal screen-captured images are at low DPI-- (75~90). A value between 0 and 1, stands for the size of zooming out the source image to fit 300DPI for text recognition. A value bigger than 1, stands for the size of zooming in the source image to fit GOCR's requirement. User may give a proper zoom value for the text in a image to be fit in and recognized.

Returns:

String, converted from the input image. NULL if fails to convert.

Throws:

SAFSException - if meets any Exception

zoomImageWithType

public java.awt.image.BufferedImage zoomImageWithType(java.awt.image.BufferedImage image,
                                                      int imageType,
                                                      java.awt.Rectangle subarea,
                                                      float zoomValue)
                                               throws SAFSException

Parameters:

image - an BufferedImage for zooming.

imageType - image type of the zoomed image for the BufferedImage returned. Usually use BufferedImage.TYPE_BYTE_GRAY in 8 BitPerPixel.

subarea, - area of the input image for convert. NULL stands for whole area of the image.

zoomValue, - a float, means the size of zoom-in if between 0 and 1; means the size of zoom-out if bigger than 1.

Returns:

BufferedImage, a resized image in imageType.

Throws:

SAFSException

runCommandLine

protected java.lang.String runCommandLine(java.lang.String cmdline)
                                   throws SAFSException

Throws:

SAFSException

getOCREngine

public static OCREngine getOCREngine(java.lang.String ocrNameKey,
                                     STAFHelper staf)
                              throws SAFSException

Note:
This method first try to get OCR engine corresponding to ocrNameKey;
If not found, try to get the OCR engine defined by STAF variable STAF_OCR_ENGINE_VAR_NAME;
If there is no OCR engine defined in STAF variable, then use the default engine defined by OCR_DEFAULT_ENGINE_KEY.

Parameters:

ocrNameKey - The name of OCR engine. It can be constant OCR_T_ENGINE_KEY or OCR_G_ENGINE_KEY. It can be null, in this case, we try to get OCR engine defined by STAF variable STAF_OCR_ENGINE_VAR_NAME.

staf -

Returns:

An OCREngine

Throws:

SAFSException

getOCREngineKey

public static java.lang.String getOCREngineKey(STAFHelper staf)

Note:
This method will get the value of STAF variable STAF_OCR_ENGINE_VAR_NAME

Parameters:

staf -

Returns:

setOCREngineKey

public static boolean setOCREngineKey(STAFHelper staf,
                                      java.lang.String engineKey)

Note:
This method will set the value to STAF variable STAF_OCR_ENGINE_VAR_NAME

Parameters:

staf -

engineKey -

Returns:

getOCRLanguageCode

public static java.lang.String getOCRLanguageCode(STAFHelper staf)

Note:
This method will get the value of STAF variable STAF_OCR_LANGUAGE_ID_VAR_NAME

Parameters:

staf -

Returns:

setOCRLanguageCode

public static boolean setOCRLanguageCode(STAFHelper staf,
                                         java.lang.String languageCode)

Note:
This method will set the value to STAF variable STAF_OCR_LANGUAGE_ID_VAR_NAME

Parameters:

staf -

languageCode -

Returns:

main

public static void main(java.lang.String[] args)

Usage: java OCREngine imageFile [-e engine] [-l languageID] [-z scale]

Parameters:

args -