An image-analysis request that recognizes text in an image.
This request generates a collection of ``RecognizedTextObservation`` objects that each correspond to a line of text detected in the image.
By default the request will detect English. To detect other languages, set `recognitionLanguages` to an array that contains the languages you want to recognize. To detect any supported language, set `automaticallyDetectsLanguage` to true. Enabling automatic language detection will cause the val
To see the list of supported languages, call `supportedRecognitionLanguages`.
Members (21)
get · iOS 18.0+
minimumTextHeightFraction
TypeScript
get minimumTextHeightFraction(): number
Swift declaration
var minimumTextHeightFraction: Float
The minimum height, relative to the image height, of the text to recognize.
Specify a floating-point number relative to the image height. For example, to limit recognition to text that’s half of the image height, use 0.5. Increasing the size reduces memory consumption and expedites recognition with the tradeoff of ignoring text smaller than the minimum height. The default value is 1/32, or 0.03125.
set · iOS 18.0+
minimumTextHeightFraction
TypeScript
set minimumTextHeightFraction(value: number)
Swift declaration
var minimumTextHeightFraction: Float
The minimum height, relative to the image height, of the text to recognize.
Specify a floating-point number relative to the image height. For example, to limit recognition to text that’s half of the image height, use 0.5. Increasing the size reduces memory consumption and expedites recognition with the tradeoff of ignoring text smaller than the minimum height. The default value is 1/32, or 0.03125.
get · iOS 18.0+
descriptor
TypeScript
get descriptor(): RequestDescriptor
Swift declaration
var descriptor: RequestDescriptor { get }
An enum that identifies the request and request revision.
get · iOS 18.0+
customWords
TypeScript
get customWords(): Array<string>
Swift declaration
var customWords: [String]
An array of strings to supplement the recognized languages at the word-recognition stage.
Custom words take precedence over the standard lexicon. The request ignores this value if `usesLanguageCorrection` is `false`.
set · iOS 18.0+
customWords
TypeScript
set customWords(value: Array<string>)
Swift declaration
var customWords: [String]
An array of strings to supplement the recognized languages at the word-recognition stage.
Custom words take precedence over the standard lexicon. The request ignores this value if `usesLanguageCorrection` is `false`.
get · iOS 18.0+
recognitionLevel
TypeScript
get recognitionLevel(): RecognizeTextRequest_RecognitionLevel
Swift declaration
var recognitionLevel: RecognizeTextRequest.RecognitionLevel
A value that determines whether the request prioritizes accuracy or speed in text recognition.
set · iOS 18.0+
recognitionLevel
TypeScript
set recognitionLevel(value: RecognizeTextRequest_RecognitionLevel)
Swift declaration
var recognitionLevel: RecognizeTextRequest.RecognitionLevel
A value that determines whether the request prioritizes accuracy or speed in text recognition.
get · iOS 18.0+
regionOfInterest
TypeScript
get regionOfInterest(): NormalizedRect
Swift declaration
var regionOfInterest: NormalizedRect
The region of the image in which Vision will perform the request.
The rectangle is normalized to the dimensions of the processed image. Its origin is specified relative to the image's lower-left corner.
By default, the region of interest will be the full image.
set · iOS 18.0+
regionOfInterest
TypeScript
set regionOfInterest(value: NormalizedRect)
Swift declaration
var regionOfInterest: NormalizedRect
The region of the image in which Vision will perform the request.
The rectangle is normalized to the dimensions of the processed image. Its origin is specified relative to the image's lower-left corner.
By default, the region of interest will be the full image.
mutating func setComputeDevice(_ computeDevice: MLComputeDevice?, for computeStage: ComputeStage)
Assigns a compute device for a compute stage.
If the parameter `computeDevice` is `nil`, the framework removes any explicit compute device assignment and allows the framework to select the device.
Configure any compute device for a given compute stage. When performing a request, the system makes a validity check. Use `supportedComputeStageDevices` to get valid compute devices for a request’s compute stages.
- Parameters:
- `computeDevice: `The compute device to assign to the compute stage.
- `computeStage: `The compute stage.
get · iOS 18.0+
supportedRevisions
TypeScript
static get supportedRevisions(): Array<RecognizeTextRequest_Revision>
Swift declaration
static let supportedRevisions: [RecognizeTextRequest.Revision]
The collection of currently-supported revisions for `RecognizeTextRequest`.
get · iOS 18.0+
recognitionLanguages
TypeScript
get recognitionLanguages(): Array<_Foundation_Locale_Language>
Swift declaration
var recognitionLanguages: [Locale.Language]
An array of languages to detect, in priority order.
The order of the languages in the array defines the order in which languages are used during language processing and text recognition.
set · iOS 18.0+
recognitionLanguages
TypeScript
set recognitionLanguages(value: Array<_Foundation_Locale_Language>)
Swift declaration
var recognitionLanguages: [Locale.Language]
An array of languages to detect, in priority order.
The order of the languages in the array defines the order in which languages are used during language processing and text recognition.
get · iOS 18.0+
usesLanguageCorrection
TypeScript
get usesLanguageCorrection(): boolean
Swift declaration
var usesLanguageCorrection: Bool
A Boolean value that indicates whether the request applies language correction during the recognition process.
When this value is `true`, Vision applies language correction during the recognition process. Disabling this property returns the raw recognition results, which provides performance benefits but less accurate results.
set · iOS 18.0+
usesLanguageCorrection
TypeScript
set usesLanguageCorrection(value: boolean)
Swift declaration
var usesLanguageCorrection: Bool
A Boolean value that indicates whether the request applies language correction during the recognition process.
When this value is `true`, Vision applies language correction during the recognition process. Disabling this property returns the raw recognition results, which provides performance benefits but less accurate results.
get · iOS 18.0+
automaticallyDetectsLanguage
TypeScript
get automaticallyDetectsLanguage(): boolean
Swift declaration
var automaticallyDetectsLanguage: Bool
A Boolean value that indicates whether to attempt detecting the language to use the appropriate model for recognition and language correction.
set · iOS 18.0+
automaticallyDetectsLanguage
TypeScript
set automaticallyDetectsLanguage(value: boolean)
Swift declaration
var automaticallyDetectsLanguage: Bool
A Boolean value that indicates whether to attempt detecting the language to use the appropriate model for recognition and language correction.
get · iOS 18.0+
supportedComputeStageDevices
TypeScript
get supportedComputeStageDevices(): NativeMap<ComputeStage, Array<_CoreML_MLComputeDevice>>
Swift declaration
var supportedComputeStageDevices: [ComputeStage : [MLComputeDevice]] { get }
get · iOS 18.0+
supportedRecognitionLanguages
TypeScript
get supportedRecognitionLanguages(): Array<_Foundation_Locale_Language>
Swift declaration
var supportedRecognitionLanguages: [Locale.Language] { get }
The identifiers of the languages that the request supports.
