Vision

Performing Requests 18

The handlers and base request types that execute computer-vision analysis on still images and video sequences.

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  VNImageRequestHandleriOS 11.0+

  @brief Performs requests on a single image.
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  VNSequenceRequestHandleriOS 11.0+

  @brief Performs requests on a sequence of images.
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  VNVideoProcessoriOS 14.0+

  @abstract A controller object that is used to perform one or more requests on a video stream.
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  VNRequestiOS 11.0+

  @class VNRequest
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  VNImageBasedRequestiOS 11.0+

  @brief A request that will process the contents of a reference image.
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  VNTargetedImageRequestiOS 11.0+

  @brief A request that requires an initial image as a starting point for its work.
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  VNStatefulRequestiOS 14.0+

  @brief A request that builds evidence over time by being reused on multiple images.
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  ImageRequestHandleriOS 18.0+

  A Swift handler that performs analysis requests on a single image.
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  TargetedImageRequestHandleriOS 18.0+

  A Swift handler that performs requests comparing an analyzed image to a target image.
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  VideoProcessoriOS 18.0+

  A Swift object that runs analysis requests over the frames of a video.
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  VisionRequestiOS 18.0+

  A protocol for Vision analysis requests.
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  ImageProcessingRequestiOS 18.0+

  An image analysis request that operates on a region of interest and produces observations.
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  TargetedRequestiOS 18.0+

  A request that can be used with a `TargetedImageHandler` to analyze two images together.
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  StatefulRequestiOS 18.0+

  A request type that builds evidence of a condition over time.
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  DownloadableAssetsRequestiOS 27.0+

  A protocol for requests whose models require downloadable assets.
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  DownloadableAssetsProgress

  A value that reports the download progress of a request's model assets.
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  DownloadableAssetsRequestStatusiOS 27.0+

  Constants that describe the download status of a request's model assets.
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  RequestDescriptoriOS 18.0+

  A descriptor that identifies a request type and its supported revisions.

Face and Body Detection 18

Requests and observations for detecting faces, facial landmarks, capture quality, and human regions.

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  VNDetectFaceRectanglesRequestiOS 11.0+

  @brief A request that will detect faces in an image.
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  VNDetectFaceLandmarksRequestiOS 11.0+

  @brief A request that will produce face landmark information.
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  VNDetectFaceCaptureQualityRequestiOS 13.0+

  @brief A request that will produce or update a VNFaceObservation's property faceCaptureQuality with a float value.
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  VNDetectHumanRectanglesRequestiOS 13.0+

  @brief A request that will detect human Torsos in an image.
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  VNFaceObservationiOS 11.0+

  @class VNFaceObservation
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  VNHumanObservationiOS 15.0+

  @class VNHumanObservation
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  VNFaceLandmarksiOS 11.0+

  @class VNFaceLandmarks
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  VNFaceLandmarks2DiOS 11.0+

  @class VNFaceLandmarks2D
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  VNFaceLandmarkRegioniOS 11.0+

  @class VNFaceLandmarkRegion
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  VNFaceLandmarkRegion2DiOS 11.0+

  @class VNFaceLandmarkRegion2D
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  DetectFaceRectanglesRequestiOS 18.0+

  A request that finds faces within an image.
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  DetectFaceLandmarksRequestiOS 18.0+

  An image analysis request that finds facial features like eyes and mouth in an image.
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  DetectFaceCaptureQualityRequestiOS 18.0+

  A request that determines the capture quality of faces in a photo.
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  DetectHumanRectanglesRequestiOS 18.0+

  A request that finds rectangular regions that contain people in an image.
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  FaceObservationiOS 18.0+

  A Swift observation describing a detected face and its attributes.
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  HumanObservationiOS 18.0+

  An object that represents a person that the request detects.
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  VNFaceObservationAcceptingiOS 11.0+

  @brief A protocol that allows a user to provide an input collection of VNFaceObservations as part of a request. The protocol can be adopted by request objects that request additional information about
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  VNRequestFaceLandmarksConstellation

  @brief Constellation type defines how many landmark points are used to map a face. Revisions 1, 2, and 3 support 65 points, where Rev3 also supports 76 points.

Pose Estimation 21

Requests and observations that estimate human body, hand, and animal poses in two and three dimensions.

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  VNDetectHumanBodyPoseRequestiOS 14.0+

  @brief Detects specific landmark points on human bodies.
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  VNDetectHumanBodyPose3DRequestiOS 17.0+

  @brief A request that detects specific landmark points on human bodies in 3D space relative to the camera.
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  VNDetectHumanHandPoseRequestiOS 14.0+

  @brief Detects specific landmark points on human hands.
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  VNDetectAnimalBodyPoseRequestiOS 17.0+

  @brief Detects specific landmark points on animal bodies.
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  VNHumanBodyPoseObservationiOS 14.0+

  An observation that describes the detected joint positions of a human body pose.
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  VNHumanBodyPose3DObservationiOS 17.0+

  An observation that describes a human body pose in three-dimensional space.
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  VNHumanHandPoseObservationiOS 14.0+

  An observation that describes the detected joint positions of a human hand pose.
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  VNAnimalBodyPoseObservationiOS 17.0+

  An observation that describes the detected joint positions of an animal body pose.
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  VNHumanBodyRecognizedPoint3DiOS 17.0+

  @brief
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  DetectHumanBodyPoseRequestiOS 18.0+

  A request that detects a human body pose.
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  DetectHumanBodyPose3DRequestiOS 18.0+

  A request that detects a human body pose.
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  DetectHumanHandPoseRequestiOS 18.0+

  A request that detects a human hand pose.
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  DetectAnimalBodyPoseRequestiOS 18.0+

  A request that detects an animal body pose.
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  HumanBodyPoseObservationiOS 18.0+

  An observation that provides the body points the analysis recognized.
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  HumanBodyPose3DObservationiOS 18.0+

  An observation that provides the three-dimensional body points the request recognizes.
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  HumanHandPoseObservationiOS 18.0+

  An observation that provides the hand points the analysis recognized.
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  AnimalBodyPoseObservationiOS 18.0+

  An observation that provides the animal body points the analysis recognizes.
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  JointiOS 18.0+

  A body pose joint represented as a normalized point in an image, along with a joint name label and a confidence value.
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  Joint3DiOS 18.0+

  A named three-dimensional joint within a detected pose.
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  ChiralityiOS 18.0+

  Constants that specify the left or right handedness of a detected hand.
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  PoseProvidingiOS 18.0+

  An observation that provides a collection of joints that make up a pose.

Detecting Shapes and Trajectories 17

Requests and observations that locate rectangles, contours, the horizon, and moving objects in a scene.

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  VNDetectRectanglesRequestiOS 11.0+

  @brief A request that will detect rectangles in an image.
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  VNDetectContoursRequestiOS 14.0+

  @brief A request that will detect the contours for the edges in an image.
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  VNDetectHorizonRequestiOS 11.0+

  @brief Determine what the horizon tilt of an image is.
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  VNDetectTrajectoriesRequestiOS 14.0+

  @brief A request that detects trajectories of shapes (even small ones) that follow a parabolic path in a sequence of images.
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  VNRectangleObservationiOS 11.0+

  @class VNRectangleObservation
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  VNContoursObservationiOS 14.0+

  An observation that contains the detected contours of an image.
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  VNContouriOS 14.0+

  @brief The VNContour class describes a contour provided by a VNContoursObservation.
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  VNHorizonObservationiOS 11.0+

  @class VNHorizonObservation
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  VNTrajectoryObservationiOS 14.0+

  @class VNTrajectoryObservation
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  DetectRectanglesRequestiOS 18.0+

  An image-analysis request that finds projected rectangular regions in an image.
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  DetectContoursRequestiOS 18.0+

  A request that detects the contours of the edges of an image.
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  DetectHorizonRequestiOS 18.0+

  An image analysis request that determines the horizon angle in an image.
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  DetectTrajectoriesRequestiOS 18.0+

  An image analysis request that determines the horizon angle in an image.
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  RectangleObservationiOS 18.0+

  An object that represents the four vertices of a detected rectangle.
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  ContoursObservationiOS 18.0+

  An observation that provides all of the detected contours in an image.
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  HorizonObservationiOS 18.0+

  The horizon angle information that an image analysis request detects.
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  TrajectoryObservationiOS 18.0+

  An observation that describes a detected trajectory.

Reading Text, Barcodes, and Documents 26

Requests and observations for recognizing text, scanning barcodes, segmenting documents, and detecting lens smudges.

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  VNRecognizeTextRequestiOS 13.0+

  @brief A request that will detect regions of text and recognize the containing text in an image.
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  VNDetectTextRectanglesRequestiOS 11.0+

  @brief A request that will detect regions of text in an image.
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  VNDetectBarcodesRequestiOS 11.0+

  @brief A request that detects barcodes in an image.
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  VNDetectDocumentSegmentationRequestiOS 15.0+

  @brief Performs document detection and segmentation in an image.
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  VNRecognizedTextiOS 13.0+

  @class VNRecognizedText
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  VNRecognizedTextObservationiOS 13.0+

  @class VNRecognizedTextObservation
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  VNTextObservationiOS 11.0+

  @class VNTextObservation
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  VNBarcodeObservationiOS 11.0+

  @class VNBarcodeObservation
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  RecognizeTextRequestiOS 18.0+

  An image-analysis request that recognizes text in an image.
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  DetectTextRectanglesRequestiOS 18.0+

  An image analysis request that finds regions of visible text in an image.
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  DetectBarcodesRequestiOS 18.0+

  A request that detects barcodes in an image.
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  DetectDocumentSegmentationRequestiOS 18.0+

  A request that detects rectangular regions that contain text in the input image.
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  RecognizeDocumentsRequestiOS 26.0+

  An image-analysis request to scan an image of a document and provide information about its structure.
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  RecognizedTextiOS 18.0+

  The recognized text string and confidence for a detected text region.
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  RecognizedTextObservationiOS 18.0+

  A Swift observation containing recognized text candidates for a text region.
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  TextObservationiOS 18.0+

  A Swift observation locating a region of text without recognizing its contents.
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  BarcodeObservationiOS 18.0+

  A Swift observation describing a detected barcode and its decoded payload.
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  DetectedDocumentObservationiOS 18.0+

  An observation that contains a detected document.
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  DocumentObservationiOS 26.0+

  Information about the sections of content that an image-analysis request detects in a document.
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  DetectLensSmudgeRequestiOS 26.0+

  A request that detects a smudge on a lens from an image or video frame capture.
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  SmudgeObservationiOS 26.0+

  An observation that provides a confidence score indicating the presence of a smudge in an image or video frame capture.
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  BarcodeReaderTool

  A tool that scans machine-readable codes in an image.
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  OCRTool

  A tool that recognizes text in an image.
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  VNBarcodeSymbology

  @brief Barcode symbologies that are supported by the Vision framework.
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  BarcodeSymbologyiOS 18.0+

  Constants that identify the barcode symbologies Vision can detect.
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  VNRequestTextRecognitionLevel

  @brief Text recognition level options to favor speed over recognition accuracy. The VNRequestTextRecognitionLevelAccurate is the default option used by VNRecognizeTextRequest.

Classification and Core ML 23

Requests, models, and observations for classifying images, recognizing animals, and running custom Core ML models.

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  VNClassifyImageRequestiOS 13.0+

  @brief A request for classifying an image.
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  VNRecognizeAnimalsRequestiOS 13.0+

  @brief A request that will recognize various animals in an image. The list of animals supported by the recognition algorithm can be queried by -supportedIdentifiersAndReturnError:
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  VNCoreMLRequestiOS 11.0+

  @brief The VNCoreMLRequest uses a VNCoreMLModel, that is based on a CoreML MLModel object, to run predictions with that model. Depending on the model the returned
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  VNCoreMLModeliOS 11.0+

  @brief The VNCoreMLModel uses an CoreML based model and prepares it for use with VNCoreMLRequests.
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  VNClassificationObservationiOS 11.0+

  @class VNClassificationObservation
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  VNRecognizedObjectObservationiOS 12.0+

  @class VNRecognizedObjectObservation
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  VNCoreMLFeatureValueObservationiOS 11.0+

  @class VNCoreMLFeatureValueObservation
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  VNDetectedObjectObservationiOS 11.0+

  @class VNDetectedObjectObservation
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  VNGenerateImageFeaturePrintRequestiOS 13.0+

  @brief A request for generating a feature print of an image.
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  VNFeaturePrintObservationiOS 13.0+

  An observation that contains a feature-print descriptor for comparing images.
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  ClassifyImageRequestiOS 18.0+

  A request to classify an image.
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  RecognizeAnimalsRequestiOS 18.0+

  A request that will recognize various animals in an image.
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  CoreMLRequestiOS 18.0+

  An image analysis request that uses a Core ML model to process images.
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  CoreMLModelContaineriOS 18.0+

  A model container to use with an image analysis request.
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  ClassificationObservationiOS 18.0+

  An object that represents classification information that an image analysis request produces.
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  RecognizedObjectObservationiOS 18.0+

  An observation with an array of classification labels that classify the recognized object.
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  CoreMLFeatureValueObservationiOS 18.0+

  A Swift observation wrapping a Core ML feature value produced by a model.
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  DetectedObjectObservationiOS 18.0+

  An observation that provides the position and extent of an image feature that an image analysis request detects.
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  GenerateImageFeaturePrintRequestiOS 18.0+

  An image-based request to generate feature prints from an image.
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  FeaturePrintObservationiOS 18.0+

  An observation that provides the recognized feature print.
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  VNAnimalIdentifier

  Constants that identify the kinds of animals Vision can recognize.
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  VNImageCropAndScaleOption

  Constants that specify how an image is cropped and scaled before analysis.
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  ImageCropAndScaleActioniOS 18.0+

  Constants that specify how an image is cropped and scaled before analysis.

Segmentation, Saliency, and Aesthetics 24

Requests and observations that generate segmentation masks, saliency and optical-flow maps, and aesthetics scores.

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  VNGeneratePersonSegmentationRequestiOS 15.0+

  @brief Performs person segmentation on an image generating a mask.
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  VNGeneratePersonInstanceMaskRequestiOS 17.0+

  @brief A request that generates an instance mask of individual people found in the image.
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  VNGenerateForegroundInstanceMaskRequestiOS 17.0+

  @brief A request that generates an instance mask of salient objects that can be separated from the background.
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  VNGenerateAttentionBasedSaliencyImageRequestiOS 13.0+

  @brief Generates an image that identifies which part(s) of a given image is most interesting (i.e. something that a human is likely to look at - hence attention based).
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  VNGenerateObjectnessBasedSaliencyImageRequestiOS 13.0+

  @brief Generates an image that identifies which part(s) of a given image are most likely to be objects (i.e. something that a human is likely to see as an object).
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  VNGenerateOpticalFlowRequestiOS 14.0+

  @brief VNGenerateOpticalFlowRequest will determine directional change vectors for each pixel in the targeted image to transform it into the image processed
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  VNCalculateImageAestheticsScoresRequestiOS 18.0+

  @brief Analyzes an image for aesthetically pleasing attributes and returns a VNImageAestheticsScoresObservation.
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  VNSaliencyImageObservationiOS 13.0+

  @class VNSaliencyImageObservation
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  VNInstanceMaskObservationiOS 17.0+

  @brief An observation resulting from an instance mask generation request. It contains an instance mask that labels instances in the mask that labels per pixel an instance.
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  VNPixelBufferObservationiOS 11.0+

  @class VNPixelBufferObservation
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  VNImageAestheticsScoresObservationiOS 18.0+

  @class VNImageAestheticsScoresObservation
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  GeneratePersonSegmentationRequestiOS 18.0+

  A request that produces a matte image for a person it finds in the input image.
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  GeneratePersonInstanceMaskRequestiOS 18.0+

  Generates an instance mask of individual people found in the image.
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  GenerateForegroundInstanceMaskRequestiOS 18.0+

  A request that generates an instance mask of noticeable objects to separate from the background.
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  GenerateSelectedObjectSegmentationRequest

  Generates a segmentation mask based on the provided points, rectangle, mask or scribble
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  GenerateIterativeSegmentationRequest

  Generates a segmentation mask based on the provided points, rectangle, or scribble
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  GenerateAttentionBasedSaliencyImageRequestiOS 18.0+

  An object that produces a heat map that identifies the parts of an image most likely to draw attention.
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  GenerateObjectnessBasedSaliencyImageRequestiOS 18.0+

  A request that generates a heat map that identifies the parts of an image most likely to represent objects.
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  CalculateImageAestheticsScoresRequestiOS 18.0+

  A request that analyzes an image for aesthetically pleasing attributes.
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  SaliencyImageObservationiOS 18.0+

  An observation that contains a grayscale heat map of important areas across an image.
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  InstanceMaskObservationiOS 18.0+

  An observation that contains an instance mask that labels instances in the mask.
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  PixelBufferObservationiOS 18.0+

  An object that represents an image that an image analysis request produces.
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  OpticalFlowObservationiOS 18.0+

  An object that represents an optical flow that an image analysis request produces.
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  ImageAestheticsScoresObservationiOS 18.0+

  A Swift observation reporting the computed aesthetics score for an image.

Tracking and Image Registration 20

Requests and observations for tracking objects across frames and aligning images by translation or homography.

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  VNTrackingRequestiOS 11.0+

  @abstract A base class for all tracking requests.
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  VNTrackObjectRequestiOS 11.0+

  @brief VNTrackObjectRequest tracks an object in a sequence of images.
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  VNTrackRectangleRequestiOS 11.0+

  @brief VNTrackRectangleRequest tracks a rectangle in a sequence of images.
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  VNTrackOpticalFlowRequestiOS 17.0+

  @brief `VNTrackOpticalFlowRequest` will determine directional change vectors for each pixel from a previous to current image, reporting this result with a single `VNPixelBufferObservation`.
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  VNImageRegistrationRequestiOS 11.0+

  @brief A request that will calculate a transformation for morphing a "floating" image onto an unchanging "reference" image.
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  VNTranslationalImageRegistrationRequestiOS 11.0+

  @brief An image registration request that will calculate a translational transformation for morphing a "floating" image onto an unchanging "reference" image.
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  VNHomographicImageRegistrationRequestiOS 11.0+

  @brief An image registration request that will calculate a homographic transformation for morphing a "floating" image onto an unchanging "reference" image.
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  VNTrackTranslationalImageRegistrationRequestiOS 17.0+

  @brief An image registration request that will produce a translational transformation which will morph one image to another.
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  VNTrackHomographicImageRegistrationRequestiOS 17.0+

  @brief An image registration request that will produce a homographic transformation that can morph one image to another.
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  VNImageAlignmentObservationiOS 11.0+

  @class VNImageAlignmentObservation
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  VNImageTranslationAlignmentObservationiOS 11.0+

  @class VNImageTranslationAlignmentObservation
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  VNImageHomographicAlignmentObservationiOS 11.0+

  @class VNImageHomographicAlignmentObservation
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  TrackObjectRequestiOS 18.0+

  An image analysis request that tracks the movement of a previously identified object across multiple images or video frames.
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  TrackRectangleRequestiOS 18.0+

  An image analysis request that tracks movement of a previously identified rectangular object across multiple images or video frames.
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  TrackOpticalFlowRequestiOS 18.0+

  This request generates an OpticalFlowObservation object that describes the directional change from image to image.
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  TrackTranslationalImageRegistrationRequestiOS 18.0+

  An image analysis request, as a stateful request you track over time, that determines the affine transform necessary to align the content of two images.
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  TrackHomographicImageRegistrationRequestiOS 18.0+

  An image analysis request, as a stateful request you track over time, that determines the perspective warp matrix necessary to align the content of two images.
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  ImageTranslationAlignmentObservationiOS 18.0+

  Affine transform information that an image alignment request produces.
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  ImageHomographicAlignmentObservationiOS 18.0+

  An object that represents a perspective warp transformation.
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  VNRequestTrackingLevel

  @brief Tracking level options to favor speed or location accuracy. The VNRequestTrackingLevelFast is the default option used by trackers.

Geometry and Points 17

Value and geometry types describing points, vectors, circles, and recognized landmark coordinates.

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  VNPointiOS 14.0+

  @class VNPoint
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  VNPoint3DiOS 17.0+

  @class VNPoint3D
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  VNVectoriOS 14.0+

  @class VNVector
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  VNCircleiOS 14.0+

  @class VNCircle
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  VNDetectedPointiOS 14.0+

  @class VNDetectedPoint
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  VNRecognizedPointiOS 14.0+

  @class VNRecognizedPoint
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  VNRecognizedPoint3DiOS 17.0+

  @class VNRecognizedPoint3D
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  VNGeometryUtilsiOS 14.0+

  A set of utilities for computing geometric measurements on detected contours.
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  VNRecognizedPointsObservationiOS 14.0+

  @class VNRecognizedPointsObservation
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  VNRecognizedPoints3DObservationiOS 14.0+

  @class VNRecognizedPoints3D
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  NormalizedPointiOS 18.0+

  A 2D point with x and y coordinates in the range [0, 1].
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  NormalizedRectiOS 18.0+

  A rectangle with normalized coordinates in the range [0, 1].
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  NormalizedCircleiOS 18.0+

  A circle defined in normalized image coordinates.
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  CoordinateOriginiOS 18.0+

  Constants that specify the origin used for normalized coordinates.
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  BoundingBoxProvidingiOS 18.0+

  A protocol for objects that have a bounding box.
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  BoundingRegionProvidingiOS 26.0+

  A protocol for observations that expose a bounding region in an image.
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  QuadrilateralProvidingiOS 18.0+

  An protocol for objects that have a bounding quadrilateral.

Observation Base Types 4

The root observation type and protocols shared by the results that Vision requests produce.

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  VNObservationiOS 11.0+

  @class VNObservation
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  VisionObservationiOS 18.0+

  A protocol that defines the common interface for Vision analysis results.
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  VNRequestProgressProvidingiOS 13.0+

  A protocol for requests that report incremental progress during analysis.
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  VNRequestRevisionProvidingiOS 12.0+

  A protocol for types that report the algorithm revision used to produce a result.

Options, Keys, and Errors 11

Configuration options, dictionary keys, identifiers, and error types used throughout the framework.

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  VNImageOption

  @brief Options keys passed into the VNImageRequestHandler creations or requests that take an auxiliary image. These are options that either describe specific properties of an image like the VNImageOpt
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  VNVideoProcessingOption

  Keys that configure how a video processor runs analysis requests.
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  VNComputeStageiOS 17.0+

  Constants that identify the compute stages a request can run on.
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  ComputeStageiOS 18.0+

  Types that represent the compute stage.
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  VNRecognizedPointKey

  Constants that identify individual recognized points such as body joints.
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  VNRecognizedPointGroupKey

  Constants that identify groups of related recognized points.
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  VNElementTypeiOS 13.0+

  Constants that specify the element data type of an observation's results.
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  ElementTypeiOS 18.0+

  An enumeration of the type of element in feature print data.
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  VNErrorCode

  Error codes that Vision reports when a request fails.
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  VisionErroriOS 18.0+

  An error type that describes failures encountered while performing Vision requests.
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  VisionResultiOS 18.0+

  A type that represents the outcome of a Vision request.

Enumerations 3

• En
  VNChiralityiOS 15.0+
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  VNPointsClassificationiOS 16.0+
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  VNBarcodeCompositeTypeiOS 17.0+

Type Aliases 6

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  VNRequestCompletionHandler

  @abstract A block that is executed at the completion of a request.
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  VNRequestProgressHandler

  @abstract A block that is executed at intervals during the processing of a request.
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  VNConfidence
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  VNAspectRatio
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  VNDegrees
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  NormalizedRegion

Extends 3