---
title: VNImageHomographicAlignmentObservation
framework: vision
role: symbol
role_heading: Class
path: vision/vnimagehomographicalignmentobservation
---

# VNImageHomographicAlignmentObservation

An object that represents a perspective warp transformation.

## Declaration

```swift
class VNImageHomographicAlignmentObservation
```

## Overview

Overview This type of observation results from a VNHomographicImageRegistrationRequest, informing the warpTransform performed to align the input images.

## Topics

### Accessing the Transform

- [warpTransform](vision/vnimagehomographicalignmentobservation/warptransform.md)

## Relationships

### Inherits From

- [VNImageAlignmentObservation](vision/vnimagealignmentobservation.md)

### Conforms To

- [CVarArg](swift/cvararg.md)
- [CustomDebugStringConvertible](swift/customdebugstringconvertible.md)
- [CustomStringConvertible](swift/customstringconvertible.md)
- [Equatable](swift/equatable.md)
- [Hashable](swift/hashable.md)
- [NSCoding](foundation/nscoding.md)
- [NSCopying](foundation/nscopying.md)
- [NSObjectProtocol](objectivec/nsobjectprotocol.md)
- [NSSecureCoding](foundation/nssecurecoding.md)
- [VNRequestRevisionProviding](vision/vnrequestrevisionproviding.md)

## See Also

### Image alignment

- [Aligning Similar Images](vision/aligning-similar-images.md)
- [VNTargetedImageRequest](vision/vntargetedimagerequest.md)
- [VNImageRegistrationRequest](vision/vnimageregistrationrequest.md)
- [VNTranslationalImageRegistrationRequest](vision/vntranslationalimageregistrationrequest.md)
- [VNTrackTranslationalImageRegistrationRequest](vision/vntracktranslationalimageregistrationrequest.md)
- [VNHomographicImageRegistrationRequest](vision/vnhomographicimageregistrationrequest.md)
- [VNTrackHomographicImageRegistrationRequest](vision/vntrackhomographicimageregistrationrequest.md)
- [VNImageAlignmentObservation](vision/vnimagealignmentobservation.md)
- [VNImageTranslationAlignmentObservation](vision/vnimagetranslationalignmentobservation.md)