Removing green color edges around the avatar

Hi Team

I generated an MP4 avatar video with a green background (#008000), using the chroma keying technique I tried to remove the background color but the edges still have the green color (added a sample image and snippet of code that sets the green color pixel opacity to zero below)

Could you suggest a way to remove the green color along the edges?

// If this is true setting the opacity to zero
if (g > 90 && r < 90 && b < 90) {
    imageFrame.data[i + 3] = 0;
}