regionprops

I would like someone to give me a good example to understand the use of regionprops with 'PixelList' as a parameter

[Right Grievous]

Thank you all, but I don't have the image processing toolbox (hence my problem) otherwise I would have figured out how to use regionprops myself.

I suspect the reason I can't find a solution to this is because there is a toolbox function.

Is there any way to do it without the image processing toolbox?

Thanks,

Rod.

[Walter Roberson]

Rod, you have not indicated what your question is.

Note: the Image Processing Toolbox is included with the Student Version license, but is not necessarily installed by default.

[Amit Kumar]

You can use Online MATLAB for assessing Image Processing Toolbox. Even I was not having it, but on Online MATLAB platform its available.

Answer 1

[David Young]

Try this for a start:

img = zeros(5,5);
img(2:4, 2:4) = 1;
props = regionprops(img, 'PixelList');
disp(img);
disp(props.PixelList);

You can change the pattern of ones in img until you're clear about how the result is structured. Another simple but informative example:

img = zeros(5,5);
img(2,2) = 1;
img(4,4) = 2;
props = regionprops(img, 'PixelList');
disp(props(1).PixelList);
disp(props(2).PixelList);

[Gopika Babu]

i have some doubt

Answer 2

[Saneem Ahmed]

regionprops is a function which is used on a labeled image. If we are having an image im. let it be a black and white image( values are either 1's or 0's). Now apply bwlabel to label image for this image.

[label n]=bwlabel(im); %n gives number of clusters, no.of groups of 1's. 0's are considered to be background.

now the label image can be put as input to regionprops to find certain characteristics about each clusters in the image. regionprops can give us area, bounding box, centroid, eccentricity etc of each cluster. 'PixelList' in regionprops will return pixel co-ordinates of each element in cluster. code can be like...

pix = regionprops(label.'PixeList');

list1=pix(1).PixelList; % we have to access like this coz regionprops gives output as a structure. similarly we can access every cluster.

listn=pix(n).PixelList;

[Sean de Wolski]

It's also to be used with BWCONNCOMP, a much more powerful function.