---
title: maximumImageDimension
framework: vision
role: symbol
role_heading: Instance Property
path: vision/detectcontoursrequest/maximumimagedimension
---

# maximumImageDimension

The maximum image dimension to use for contour detection.

## Declaration

```swift
var maximumImageDimension: Int
```

## Discussion

Discussion Contour detection is computationally intensive. To improve performance, the framework scales the input image down, while maintaining its aspect ratio, such that its maximum dimension is the value of this property. The framework never scales the image up, so specifying the maximum value ensures that the image processes in its original size and not as a downscaled version. This minimum value supported is 64. The default value is 512.

## See Also

### Configuring a request

- [contrastAdjustment](vision/detectcontoursrequest/contrastadjustment.md)
- [contrastPivot](vision/detectcontoursrequest/contrastpivot.md)
- [detectsDarkOnLight](vision/detectcontoursrequest/detectsdarkonlight.md)