how can I build a function that gives me the average RGB values ​​of a selected region of an image.

Answer 1

[Image Analyst]

Try impixelinfo() to get a live, interactive readout of pixel values. Otherwise, try imfreehand() to draw regions and check out the demos I've attached. If you still can't figure it out, let me know.

[Djeifry Edmilson Cardoso]

Hello! I didn´t understand the term 'numberOfImagesToProcess'.

[Image Analyst]

It means "number of images to process" all in one long word/variable name. Let's say you have 5 PNG images in the folder and 2 BMP images. It counts them all so numberOfImagesToProcess would be 5 + 2 = 7.

[Djeifry Edmilson Cardoso]

Ok. In my case I want to work only with a jpeg image. The program should be changed, right?

[Image Analyst]

Yes, if you have a mixture of file types and want to process just the JPG files, just delete lines calling dir('*.bmp') or whatever extensions you don't want. If you don't have any, then it does no harm to leave in those lines.

[Djeifry Edmilson Cardoso]

I'm finding the program a bit tricky. I want to study the conformity of color in a glass bottle. Can you help me find a simpler program? I am new to Matlab.

[Image Analyst]

Well you're going to have to put work into educating yourself. No 5 line program that's trivial to understand will do the job properly. Color difference is called delta E and is the Euclidean distance between two colors in CIE LAB color space (like my icon to the left). I attach two delta E demos.