Adaptive Multi-Level Threshold for image

Dear All;

I have an image with non-uniform illumination , i need to use adaptive threshold to compensate for that , then use multi level threshold to segment the image into Three regions, what is the best way to do that

Answer 1

[Image Analyst]

Try adapthisteq(). How you classify into 3 classes after that depends on how easy it is to find the thresholds. Write a script to flatten your image with adapthisteq() and then take the histogram and show it to us.

[mustafa alnasser]

Thank you very much for help.

in fact, Adaptive threshold makes it worse .

You can check the link below for the video source to undersatnd the situation http://www.youtube.com/watch?v=IjHZ4aEaCaE

What i am looking for is to segment the image into three area( Liquid, Gas, and Mix region at the border) I would like to combine both adaptive thresholding and multithresholding

[Image Analyst]

I didn't say anything about adaptive threshold, just adaptive histogram equalization. But your idea might work. Give it a try.

[Rizwan Chughtai]

@image analyst, my question is a little off topic but i need your help on this.

i have two images (as uploaded s1 & s2), one is having the boxes in x-axis direction and second is having the boxes in y-axis direction.

Question 1: how we can find that the boxes is in x-axis direction OR in y-axis direction?

Question 2:after finding the direction, extract/separate the boxes from that image?

[Rizwan Chughtai]

@image analyst, my question is a little off topic but i need your help on this.

i have two images (as uploaded s1 & s2), one is having the boxes in x-axis direction and second is having the boxes in y-axis direction.

Question 1: how we can find that the boxes is in x-axis direction OR in y-axis direction?

Question 2:after finding the direction, extract/separate the boxes from that image?

(first see the imges 's1' & 's2')

[Image Analyst]

Use regionprops() to get the bounding box and look at the width and height of it.

Answer 2

[Anand]

Have you tried using multithresh after adapthisteq? multithresh does multi-level thresholding using Otsu's method.

thresh = multithresh(I,2);
segI = imquantize(I,thresh);

[mustafa alnasser]

thank you for the answer

Asi explainred, i need first to remove the non uniform illumination then use multi threshold , Non uniform illumanation function deose not works well for all cases that why I switch to adaptive thresholding but this one will give me binary image , my question how to combine both ?

Answer 3

[mustafa alnasser]

Thank you very much for help.

in fact, Adaptive threshold makes it worse .

You can check the link below for the video source to undersatnd the situation http://www.youtube.com/watch?v=IjHZ4aEaCaE

What i am looking for is to segment the image into three area( Liquid, Gas, and Mix region at the border) I would like to combine both adaptive thresholding and multithresholding