Transparent background on iOS



1. Make a mask image.

Acquire mask images using segmentation models such as the DeepLab v3 model distributed by Apple.
Please refer to this article.

2. Make a transparent image.

Create a transparent image with the same size as the original image.
Since the “non-transparent area” is specified in the argument of settingAlphaOne, specify zero to acquire a fully transparent image.

let transparentImage = originalCIImage.settingAlphaOne(in:

3. Synthesize.

Foreground = original image, background = transparent image, mask image = mask image of the object you want to keep, and combine with CIFilter.

let compositeImage = CIFilter(name: "CIBlendWithMask", parameters: [
kCIInputImageKey: originalCIImage,



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