Class

VNRecognizeTextRequest

An image analysis request that finds and recognizes text in an image.

Declaration

@interface VNRecognizeTextRequest : VNImageBasedRequest

Overview

By default, a text recognition request first locates all possible glyphs or characters in the input image, then analyzes each string. To specify or limit the languages sought in the request, set the recognitionLanguages property to an array containing the names of the languages of text you'd like to recognize. Vision returns the result of this request in a VNRecognizedTextObservation object.

Topics

Customizing Recognition Constraints

customWords

An array of strings to supplement the recognized languages at the word recognition stage.

minimumTextHeight

The minimum height of the text expected to be recognized, relative to the image height.

recognitionLevel

A value that determines whether the request prioritizes accuracy or speed in text recognition.

VNRequestTextRecognitionLevel

An enumeration of the tradeoff between fast and accurate text recognition.

Specifying Language

recognitionLanguages

An array of languages to detect, in priority order.

usesLanguageCorrection

A Boolean indicating whether Vision applies language correction during the recognition process.

+ supportedRecognitionLanguagesForTextRecognitionLevel:revision:error:

Requests a list of languages recognized by the specified revision.

Specifying a Revision

VNRecognizeTextRequestRevision1

A constant for specifying revision 1 of the text recognition algorithm.

Relationships

Inherits From

See Also

Text Recognition

VNRecognizedTextObservation

A request that detects and recognizes regions of text in an image.