OpenCV Features2d.drawMatches set transparent matchColor [closed]

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I am working on one OpenCV Android Project in which i want to compare one stored image with the frame detected in camera and thus showing matched and difference keypoints from both images. And Here i am getting both the matched and differences keypoints in the app currently between 2 images but i need to make the matched keypoints color transparent in below method call:

Scalar GREEN = new Scalar(0, 255, 0, 128);

Features2d.drawMatches(img1, keypoints1, aInputFrame, keypoints2, goodMatches, outputImg, GREEN, RED, drawnMatches, Features2d.DRAW_RICH_KEYPOINTS);

I want to make the GREEN color as transparent so as to display only difference keypoints in the App between two images.

Hope to get quick response from everyone of you.

Regards - Kudoss!!!