I would like to determine the average of a region of pixels within an image and quantify it automatically. How can I do that?

Hello,

I have an .lsm image and with a single color channel. Each image has a couple of regions of pixels that I would like to calculate the mean. Is there a function that can identify these regions of interest and quantify its mean automatically?

Also is there a function in Matlab that could count the regions within an iamge based on its RGB?

Thank you!!

Kind wishes,

Neo

Answer 1

[Image Analyst]

You need to create a binary image and then use regionprops

In short it's

props = regionprops(binaryImage, grayScaleImage, 'MeanIntensity');
allMeanIntensities = [props.MeanIntensity]

See my Image Processing Tutorial in my File Exchange:

Image Analyst's File Exchange

[Neo]

I will try this. What about the second part of the question?

>> Also is there a function in Matlab that could count the number of regions within an image based on its RGB? i.e. if some regions are blue or red does matlab have a function that can qunatify the number of regions that are red or blue?

Thanks

[Image Analyst]

You can take the 3-D histogram and find all unique colors. There could be up to 16 million colors. The number of unique colors is then nnz(colorHistogram). To find out how many regions there are you'd have to try each color one at a time and that could take days.

If you have certain ranges that you'd like, like red-ish or blue-ish, then you can use the Color Thresholder on the Apps tab of the tool ribbon to create masks for those particular color ranges.

[Neo]

Thanks I will try this!

[Neo]

Hey Image Analyst, as a follow up question: I have an image that has small red or green circles per image. Each image could have up to 30 or so red or green circles per image. I have to count them manually in order to quantify them and it can be tedious with more than 50 images. Is there a way to classify the circles as red or green and then quantify them by color automatically? Thanks!

[Image Analyst]

Yes, use the Color Thresholder app on the Apps tab of the tool ribbon.

Look for examples if you search for the "color segmentation" tag.

[Neo]

The color thresholder app was great, for future learners it helped to create a mask based on the predetermined settings that I set.

Thanks!

[Neo]

@Image Analyst in case you did not see earlier, thank you!!

[Image Analyst]

@Neo, glad it worked for you. Thanks for accepting the answer.