binary mask of RGB image

Hello everyone,

I'm new to matlab

I'm wondering if is there is a function that can help me in performing the followings:

I have an RGB image, I'm gonna spicify a range of values for every RGB component.

so I have three ranges of values.

then, the values in the image that in these ranges, I want them to be white

values outside the range will be black.

How can I write a code perform this?

Thank you

Answer 1

[Image Analyst]

Try this:

% Extract the individual red, green, and blue color channels.
redChannel = rgbImage(:, :, 1);
greenChannel = rgbImage(:, :, 2);
blueChannel = rgbImage(:, :, 3);
redMask = redChannel >= redMin & redChannel <= redMax;
greenMask = greenChannel >= greenMin & greenChannel <= greenMax;
blueMask = blueChannel >= blueMin & blueChannel <= blueMax;
finalMask = redMask | greenMask | blueMask;

[Lamya Mohammad]

Thank so much! That was usefull

[Imran Riaz]

Can you share the complete code and its output? What u got? I have almost same problem.

[Image Analyst]

@Imran Riaz try using the Color Thresholder app on the Apps tab of the tool ribbon.

[Imran Riaz]

But how to automate it for whole dataset?

[Image Analyst]

@Imran Riaz you can write a program where you loop over the whole dataset. Hopefully the thresholds don't change from image to image. If they need to, then you'll have to come up with some algorithm that decides upon the thresholds. Obviously I don't know that since there is no one automatic thresholding algorithm that works for all images. You need to come up with a custom algorithm that works for your particular kind of images. Hopefully they're all fairly similar, just perhaps with slight changes in brightness or contrast.

[Imran Riaz]

Yes, Image size is same, difference is only brightness of fingers. Some people have white color fingers, some have brown and some have blackish color. So how to adjust the channel value that output come free from noise and image is well for further feature extraction. I share 3 different images.

[Imran Riaz]

Can you recommend any other way to remove the background automatically, bcz I have more that 4500 images.

[Image Analyst]

I'd convert to HSV and look for Saturation values below and above 0.25. Below will be white/gray, and above will be colored/skin. Use the Color Thresholder on the Apps tab.