Background Subtraction

Hello!

I have an image of some fluorescent samples http://imageshack.us/photo/my-images/440/washingexp.png and I need to get a "intensity" reading from them. All is good except for the background subtraction in the image. I want to sum up my samples only and not the background and I am having trouble doing this.

Does anyone have any tips on background subtracting? Every time I do it MatLab cuts out from my samples. I really want to single out my samples but not lose them! :)

Thank you!

I'm doing something like

I =imread('washingexp.tif');

for r=1:1024
    for C=1:1360
        B(r,C)=I(r,C)-88;
    end
end

[Ryan]

Do you have the image processing toolbox.

[Walter Roberson]

It is not immediately clear which parts are background or not? In particular it is not clear if the bright dots are part of the background or the foreground

Answer 1

[Ryan]

There are various methods to better segment your image and most are best dealt with on a case by case basis.

Check out Image Analyst's tutorials on the file exchange: http://www.mathworks.com/matlabcentral/fileexchange/authors/31862

In particular this should be of help: http://www.mathworks.com/matlabcentral/fileexchange/25157-image-segmentation-tutorial-blobsdemo

[Ryan]

If you have the image processing toolbox:

I = imread('imagefile.png");

BW = im2bw(I,graythresh(I)); % "graythresh(I)" is Otsu's method for finding the optimal intensity level for performing an image threshold.

BW2 = imfill(BW,'holes');

Labels = bwlabel(BW2,8);

Properties = regionprops(Labels,'all');

help regionprops

[Ryan]

use bwareaopen(Image,'200 or some other "area" value) to eliminate the glares if you need to.