---
title: VNImageAlignmentObservation
framework: vision
role: symbol
role_heading: Class
path: vision/vnimagealignmentobservation
---

# VNImageAlignmentObservation

The abstract superclass for image-analysis results that describe the relative alignment of two images.

## Declaration

```swift
class VNImageAlignmentObservation
```

## Overview

Overview This abstract superclass forms the basis of image alignment or registration output. You receive its subclasses, such as VNImageTranslationAlignmentObservation and VNImageHomographicAlignmentObservation, by performing specific registration requests. Don’t create one of these classes yourself.

## Relationships

### Inherits From

- [VNObservation](vision/vnobservation.md)

### Inherited By

- [VNImageHomographicAlignmentObservation](vision/vnimagehomographicalignmentobservation.md)
- [VNImageTranslationAlignmentObservation](vision/vnimagetranslationalignmentobservation.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)
- [VNImageTranslationAlignmentObservation](vision/vnimagetranslationalignmentobservation.md)
- [VNImageHomographicAlignmentObservation](vision/vnimagehomographicalignmentobservation.md)