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Deep Image Matting : A machine learning model to perform accurate image matting

This is an introduction to「Deep Image Matting」, a machine learning model that can be used with ailia SDK. You can easily use this model to create AI applications using ailia SDK as well as many other ready-to-use ailia MODELS.


Image matting refers to the problem of extracting interesting targets, usually objects in the foreground, from a static image or a video sequence, which has played an important role in many image and video editing applications.

Deep Image Matting is a machine learning model to perform highly accurate foreground estimation that was announced in April 2017.

Deep Image Matting performs foreground estimation with high accuracy using RGB and TRIMAP images as input, where TRIMAP is an image with value is set to 255 for foreground objects, 0 for the background, and 127 for areas where it is unclear whether it is part of the foreground or the background.

TRIMAPs are usually created manually or from depth cameras, but in recent years they can also be generated by segmentation models.

Input and output of Deep Image Matting

Below is an example of input image.


The corresponding TRIMAP


And the final result image.

Since Deep Image Matting has been trained on 320x320 resolution images, the resolution of the output will also be 320x320.

Usage in ailia SDK

You can run Deep Image Matting in ailia SDK with the following command, which outputs a PNG with an alpha channel by supplying an RGB image and a TRIMAP image as arguments.

python3 -i image.png -t trimap.png

In the ailia SDK, the TRIMAP can also be automatically generated. Provide an empty string as a TRIMAP argument to use Deep Image Matting in conjunction with a segmentation model to automatically generate the TRIMAP.

python3 -i pixaboy.jpg -t “”

Below are the different steps performed internally to generate the TRIMAP on the following input image.


DeeplabV3 is used to perform the automated segmentation.

Below is the result after binarization.

Then the TRIMAP is generated using cv2.erode and cv2.dilate

And the final Deep Image Matting model output.

Related topic

ax Inc. has developed ailia SDK, which enables cross-platform, GPU-based rapid inference.

ax Inc. provides a wide range of services from consulting and model creation, to the development of AI-based applications and SDKs. Feel free to contact us for any inquiry.



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