You are here: Start » Function Reference » Optical Character Recognition » ExtractText

ExtractText

Ready-to-use tool for extracting and splitting character to single characters.

Syntax

void avl::ExtractText
(
	const avl::Image& inImage,
	const avl::Rectangle2D& inRoi,
	const avl::CoordinateSystem2D& inRoiAlignment,
	const avl::TextSegmentation& inSegmentationModel,
	atl::Array<avl::Region>& outCharacters,
	avl::Region& diagTextRegion,
	atl::Array<avl::Region>& diagAlignedCharacters,
	avl::Rectangle2D& diagAlignedRoi
)

void ExtractText
(
	Image inImage,
	Rectangle2D inRoi,
	CoordinateSystem2D inRoiAlignment,
	TextSegmentation inSegmentationModel,
	out Region[] outCharacters,
	out Region diagTextRegion,
	out Region[] diagAlignedCharacters,
	out Rectangle2D diagAlignedRoi
)

Parameters

Name	Type	Description
inImage	const Image&	An input image with text
inRoi	const Rectangle2D&	Location of the text
inRoiAlignment	const CoordinateSystem2D&	Adjusts the region of interest to the position of the inspected object
inSegmentationModel	const TextSegmentation&	Model used for separating text from background
outCharacters	Array<Region>&	Split characters aligned to ROI
diagTextRegion	Region&	Region of text after extraction
diagAlignedCharacters	Array<Region>&	Character regions preserving original image orientation
diagAlignedRoi	Rectangle2D&	ROI rectangle after alignment

Description

This filter distinguish characters from the background using a set of algorithms. This filter performs two steps: text extraction and text segmentation:

Text extraction – in this step filter uses some basic thresholding methods to get a characters region from the image.
Text segmentation – split previously found region into separate regions contains character.

Input inRoi should contains only a single line of text.

Hints

If the object location is variable, pass an appropriate local coordinate system to inRoiAlignment.
Before defining inSegmentationModel first specify inRoi – the rectangle in which characters will be extracted.

Remarks

To read more about how to use OCR technique, refer to Machine Vision Guide: Optical Character Recognition

Errors

Error type	Description
DomainError	Invalid thresholding algorithm in ExtractText.
DomainError	Invalid splitting algorithm in ExtractText.