LPV OCR(Optical Character Recognition) Library, provides classes for character segmentation, recognition and verification. More...

Data Structures
interface	ILFontDatabase
	This interface represents a font database for character recognition. More...

interface	ILOCR
	This interface provide functionalities of character segmentation, recognition and verification. More...

interface	ILOCRChar
	This interface represents a single character and is used to access its properties. More...

interface	ILOCRLine
	This interface represents a single line of text and is used to access its properties. More...

interface	ILOCRResult
	This interface represents a OCR result instance and is used to access its properties. More...

class	LFontDatabase

class	LOCR

class	LOCRChar

class	LOCRLine

class	LOCRResult

Enumerations
enum	LPVOCRDrawFlags { LPVOCRDrawString = 1 , LPVOCRDrawRegion = 2 , LPVOCRDrawCenter = 4 , LPVOCRDrawIndex = 8 , LPVOCRDrawByLine = 16 , LPVOCRDrawDefault = LPVOCRDrawString \| LPVOCRDrawRegion , LPVOCRDrawAll = 0x0f }
	This enumeration represents the flags to control the OCR results' drawing behavior. More...

enum	LPVOCRFeatures { LPVOCRFeaturePixel = 0x0001 , LPVOCRFeatureFGFraction = 0x0002 , LPVOCRFeatureCircularity = 0x0004 , LPVOCRFeatureConvexity = 0x0008 , LPVOCRFeatureConvexityDefects = 0x0010 , LPVOCRFeatureOrientation = 0x0020 , LPVOCRFeatureInertia = 0x0040 , LPVOCRFeatureContourCount = 0x0080 , LPVOCRFeatureHoleCount = 0x0100 , LPVOCRFeatureAspectRatio = 0x0200 , LPVOCRFeatureWidth = 0x0400 , LPVOCRFeatureHeight = 0x0800 , LPVOCRFeatureZoomFactor = 0x1000 , LPVOCRFeatureDefault = LPVOCRFeaturePixel \| LPVOCRFeatureAspectRatio , LPVOCRFeatureAll = 0xffff }
	This enumeration represents the features available for recognition. More...

enum	LPVOCRPixelProjection { LPVOCRPixelProjNone = 0 , LPVOCRPixelProjHorizontal = 1 , LPVOCRPixelProjVertical = 2 , LPVOCRPixelProjHorizontalAndVertical = 3 }
	This enumeration represents the grid projection when calculating the pixel feature. More...

enum	LPVOCRPixelValue { LPVOCRPixelGrayscale = 0 , LPVOCRPixelGrayscaleNormalized = 1 , LPVOCRPixelBinary = 2 , LPVOCRPixelFGFraction = 3 }
	This enumeration represents how the pixel values are calculated in pixel feature. More...

enum	LPVOCRSegmentFlags { LPVOCRSegmentNone = 0x00 , LPVOCRSegmentLigature = 0x01 , LPVOCRSegmentStickyLines = 0x02 , LPVOCRSegmentStrongStickyLines = 0x04 , LPVOCRSegmentTrimUnknownFragments = 0x08 , LPVOCRSegmentDefault = LPVOCRSegmentLigature \| LPVOCRSegmentStickyLines \| LPVOCRSegmentTrimUnknownFragments , LPVOCRSegmentAll = 0xff }
	This enumeration represents the flags to control the line and character segmentation behavior. More...

enum	LPVOCVFlags { LPVOCVShape = 0x01 , LPVOCVGrayscale = 0x02 , LPVOCVMissingPart = 0x04 , LPVOCVGrayScaleMissingPart = 0x08 , LPVOCVAll = 0xff }
	This enumeration represents the verification flags for OCV. More...

Detailed Description

LPV OCR(Optical Character Recognition) Library, provides classes for character segmentation, recognition and verification.

This library provides classes for OCR/OCV tasks. Machine learning technology is involved for prediction. To include the definitions of the library's classes, use the following directive:

Example Code

C++ Snippets: OCRHandWritten.cpp
C# Snippets: OCRHandWritten.cs

Enumeration Type Documentation

◆ LPVOCRDrawFlags

enum LPVOCRDrawFlags

This enumeration represents the flags to control the OCR results' drawing behavior.

Enumerator
LPVOCRDrawString	Draw the recognized text
LPVOCRDrawRegion	Draw the segmentation quadrangle region of the result
LPVOCRDrawCenter	Draw the center point of the result
LPVOCRDrawIndex	Draw the index of the result
LPVOCRDrawByLine	Draw the result by lines or by characters(default).
LPVOCRDrawDefault	Default draw flags, which draws the recognized text and region by characters
LPVOCRDrawAll	Draw the OCR result with all components

◆ LPVOCRFeatures

enum LPVOCRFeatures

This enumeration represents the features available for recognition.

Enumerator
LPVOCRFeaturePixel	Pixel feature, which divides the sample image into grids then uses the averaging grayscale or binary value in individual block as feature
LPVOCRFeatureFGFraction	Foreground fraction feature represents percentage of the foreground pixels(inside the character) in the entire image
LPVOCRFeatureCircularity	Circularity feature, which calculates the circularity property of the character sample's contour, similar as LPVBlobCircularity
LPVOCRFeatureConvexity	Convexity feature, which calculates the convexity property of the character sample's contour, similar as LPVBlobCircularity
LPVOCRFeatureConvexityDefects	Convexity defects features represents the differences between the character sample's contour and its bounding convex hull
LPVOCRFeatureOrientation	Orientation feature, which is the sine value of the major axis of the bounding convex hull of the character sample's contour. Note: this feature is not rotation-invariant.
LPVOCRFeatureInertia	Inertia feature, which calculates the inertia property of the character sample's contour, similar as LPVBlobInertia
LPVOCRFeatureContourCount	Contour-count feature, which uses the count of the character sample's contours as feature, for example, character i has 2 contours.
LPVOCRFeatureHoleCount	Hole-count feature, which uses the count of the character sample's holes as feature, for example, character 8 has 2 holes.
LPVOCRFeatureAspectRatio	Aspect ratio feature, which calculates the aspect ratio of the character's size, similar as LPVBlobAspectRatio
LPVOCRFeatureWidth	Width feature, which use the width of the character as feature. Note: this feature is not scale-invariant.
LPVOCRFeatureHeight	Height feature, which use the width of the character as feature. Note: this feature is not scale-invariant.
LPVOCRFeatureZoomFactor	Zoom factor feature, which represents the scaling factor of the sample image to the unified size. Note: this feature is not scale-invariant.
LPVOCRFeatureDefault	Default recognition features, uses pixel and aspect ratio features
LPVOCRFeatureAll	Use all features

◆ LPVOCRPixelProjection

enum LPVOCRPixelProjection

This enumeration represents the grid projection when calculating the pixel feature.

Enumerator
LPVOCRPixelProjNone	No projection, the pixel feature outputs a @math_eq{columns \times rows} feature vector
LPVOCRPixelProjHorizontal	Horizontal projection, the pixel feature reports averaging in each row which is a @math_eq{rows} feature vector
LPVOCRPixelProjVertical	Vertical projection, the pixel feature reports averaging in each column which is a @math_eq{columns} feature vector
LPVOCRPixelProjHorizontalAndVertical	Horizontal and vertical projection, which is the @math_eq{columns + rows} combination of those two projection.

◆ LPVOCRPixelValue

enum LPVOCRPixelValue

This enumeration represents how the pixel values are calculated in pixel feature.

Enumerator
LPVOCRPixelGrayscale	Averaging the grayscale values of the pixels in the block
LPVOCRPixelGrayscaleNormalized	Averaging the maximum normalized grayscale values of the pixels in the block
LPVOCRPixelBinary	Averaging the binary values in the block, foreground(pixels inside the character) is 1, background is 0
LPVOCRPixelFGFraction	Foreground fraction of individual blocks

◆ LPVOCRSegmentFlags

enum LPVOCRSegmentFlags

This enumeration represents the flags to control the line and character segmentation behavior.

Enumerator
LPVOCRSegmentNone	None
LPVOCRSegmentLigature	Separate the ligatures
LPVOCRSegmentStickyLines	Separate the lines which are sticky but the connection parts are smaller than the stroke width
LPVOCRSegmentStrongStickyLines	Separate the lines which are strongly sticky and the connection parts are larger than the stroke width
LPVOCRSegmentTrimUnknownFragments	Trim the unknown fragments on the head or tail of each line
LPVOCRSegmentDefault	Default segmentation flags
LPVOCRSegmentAll	Enable all segmentations

◆ LPVOCVFlags

enum LPVOCVFlags

This enumeration represents the verification flags for OCV.

Enumerator
LPVOCVShape	The difference between the shape of the character and the samples
LPVOCVGrayscale	The difference between the grayscale of the character and the samples
LPVOCVMissingPart	The fraction of the missing part
LPVOCVGrayScaleMissingPart	The difference between the grayscale of the character's missing part and the samples
LPVOCVAll	Verify all parts

Data Structures

Enumerations