Extract complex image from a solid-colored background
by Kirk Smith on Feb 21, 2012 at 3:57:37 pm
I'm trying to render a complex image and remove the background, which is a solid color (RGB 127, 127 127). The image is a screenshot taken from the preview window of a game tool, so I know that the background color IS solid and doesn't have little variations. Now, I've tried the Magic Eraser and the Select Color Range tools, but since the image is complex (has semi-transparent parts) the result is not acceptable. Unfortunately I'm not able to change the background color in the preview window, I have a feeling that extracting the image would be easier if I could, but alas.
So my question is, can anyone think of a good way to do this? Knowing that the background color will always be a solid gray?
What I tried was semi-successful and looked ok on a black or white background, but for some reason looked horrible on a background the same shade of gray as the original image. Basically I copied the red/green/blue channels into their own grayscale documents and created a new layer with the same shade of gray as the background, placed it at the bottom of the stack and set the top layer's blending mode to Difference. This worked in making the colors that were the same (the shade of gray) black and pixels that were different showed through as a shade of gray or white. I then copied these grayscale images into their own alpha channels in the main document, ctrl+shift+clicked each of the thumbnails to make a composite selection and added that selection as a layer mask to the original image. Like I said, the result was decent on certain background colors, but looked terrible on the gray background.
So, does anyone have any tips? Also, here is an example image:
Re: Extract complex image from a solid-colored background by Kirk Smith on Feb 21, 2012 at 6:18:51 pm
Sorry for the double post, it wouldn't let me edit. I figured this out. The answer was the Background Eraser tool, with a huge brush size (enough to cover the entire image with one click, I set it to 2500px), Sample Once, Discontiguous, 40% tolerance, and protect foreground unchecked. Click anywhere on the gray portion and it removes it all, leaving the part I wanted intact.