---
title: VNRequestRevisionProviding
framework: vision
role: symbol
role_heading: Protocol
path: vision/vnrequestrevisionproviding
---

# VNRequestRevisionProviding

A protocol for specifying the revision number of Vision algorithms.

## Declaration

```swift
protocol VNRequestRevisionProviding
```

## Overview

Overview Subclasses of VNRequest should adopt this protocol to specify which revision of an algorithm the Vision framework uses to generate requests.

## Topics

### Specifying Revision Number

- [requestRevision](vision/vnrequestrevisionproviding/requestrevision.md)

### Determining Revision Type

- [VNRequestRevisionUnspecified](vision/vnrequestrevisionunspecified.md)
- [VNDetectRectanglesRequestRevision1](vision/vndetectrectanglesrequestrevision1.md)
- [VNTrackRectangleRequestRevision1](vision/vntrackrectanglerequestrevision1.md)
- [VNTrackObjectRequestRevision1](vision/vntrackobjectrequestrevision1.md)
- [VNDetectFaceRectanglesRequestRevision2](vision/vndetectfacerectanglesrequestrevision2.md)
- [VNDetectFaceRectanglesRequestRevision1](vision/vndetectfacerectanglesrequestrevision1.md)
- [VNDetectFaceLandmarksRequestRevision3](vision/vndetectfacelandmarksrequestrevision3.md)
- [VNDetectFaceLandmarksRequestRevision2](vision/vndetectfacelandmarksrequestrevision2.md)
- [VNDetectFaceLandmarksRequestRevision1](vision/vndetectfacelandmarksrequestrevision1.md)
- [VNRecognizeTextRequestRevision1](vision/vnrecognizetextrequestrevision1.md)
- [VNDetectTextRectanglesRequestRevision1](vision/vndetecttextrectanglesrequestrevision1.md)
- [VNDetectBarcodesRequestRevision1](vision/vndetectbarcodesrequestrevision1.md)
- [VNDetectHorizonRequestRevision1](vision/vndetecthorizonrequestrevision1.md)
- [VNTranslationalImageRegistrationRequestRevision1](vision/vntranslationalimageregistrationrequestrevision1.md)
- [VNHomographicImageRegistrationRequestRevision1](vision/vnhomographicimageregistrationrequestrevision1.md)
- [VNCoreMLRequestRevision1](vision/vncoremlrequestrevision1.md)
- [VNGenerateAttentionBasedSaliencyImageRequestRevision1](vision/vngenerateattentionbasedsaliencyimagerequestrevision1.md)
- [VNGenerateObjectnessBasedSaliencyImageRequestRevision1](vision/vngenerateobjectnessbasedsaliencyimagerequestrevision1.md)
- [VNClassifyImageRequestRevision1](vision/vnclassifyimagerequestrevision1.md)
- [VNGenerateImageFeaturePrintRequestRevision1](vision/vngenerateimagefeatureprintrequestrevision1.md)
- [VNDetectFaceCaptureQualityRequestRevision1](vision/vndetectfacecapturequalityrequestrevision1.md)
- [VNDetectHumanRectanglesRequestRevision1](vision/vndetecthumanrectanglesrequestrevision1.md)

## Relationships

### Conforming Types

- [VNAnimalBodyPoseObservation](vision/vnanimalbodyposeobservation.md)
- [VNBarcodeObservation](vision/vnbarcodeobservation.md)
- [VNClassificationObservation](vision/vnclassificationobservation.md)
- [VNContour](vision/vncontour.md)
- [VNContoursObservation](vision/vncontoursobservation.md)
- [VNCoreMLFeatureValueObservation](vision/vncoremlfeaturevalueobservation.md)
- [VNDetectedObjectObservation](vision/vndetectedobjectobservation.md)
- [VNFaceLandmarkRegion](vision/vnfacelandmarkregion.md)
- [VNFaceLandmarkRegion2D](vision/vnfacelandmarkregion2d.md)
- [VNFaceLandmarks](vision/vnfacelandmarks.md)
- [VNFaceLandmarks2D](vision/vnfacelandmarks2d.md)
- [VNFaceObservation](vision/vnfaceobservation.md)
- [VNFeaturePrintObservation](vision/vnfeatureprintobservation.md)
- [VNHorizonObservation](vision/vnhorizonobservation.md)
- [VNHumanBodyPose3DObservation](vision/vnhumanbodypose3dobservation.md)
- [VNHumanBodyPoseObservation](vision/vnhumanbodyposeobservation.md)
- [VNHumanHandPoseObservation](vision/vnhumanhandposeobservation.md)
- [VNHumanObservation](vision/vnhumanobservation.md)
- [VNImageAestheticsScoresObservation](vision/vnimageaestheticsscoresobservation.md)
- [VNImageAlignmentObservation](vision/vnimagealignmentobservation.md)
- [VNImageHomographicAlignmentObservation](vision/vnimagehomographicalignmentobservation.md)
- [VNImageTranslationAlignmentObservation](vision/vnimagetranslationalignmentobservation.md)
- [VNInstanceMaskObservation](vision/vninstancemaskobservation.md)
- [VNObservation](vision/vnobservation.md)
- [VNPixelBufferObservation](vision/vnpixelbufferobservation.md)
- [VNRecognizedObjectObservation](vision/vnrecognizedobjectobservation.md)
- [VNRecognizedPoints3DObservation](vision/vnrecognizedpoints3dobservation.md)
- [VNRecognizedPointsObservation](vision/vnrecognizedpointsobservation.md)
- [VNRecognizedText](vision/vnrecognizedtext.md)
- [VNRecognizedTextObservation](vision/vnrecognizedtextobservation.md)
- [VNRectangleObservation](vision/vnrectangleobservation.md)
- [VNSaliencyImageObservation](vision/vnsaliencyimageobservation.md)
- [VNTextObservation](vision/vntextobservation.md)
- [VNTrajectoryObservation](vision/vntrajectoryobservation.md)

## See Also

### Determining the Revision

- [currentRevision](vision/vnrequest/currentrevision.md)
- [defaultRevision](vision/vnrequest/defaultrevision.md)
- [supportedRevisions](vision/vnrequest/supportedrevisions.md)