What's wrong with my feature extraction code?

I am getting same descriptors for different images.

I tested it by:

image1 = imread('C:\Users\Explorer\Documents\MATLAB\ASL_signs\A.jpg');

image2 = imread('C:\Users\Explorer\Documents\MATLAB\ASL_signs\B.jpg');

v1=Descrip(image1);

v2=Descrip(image2);

SUM=sum(v1-v2)

_____________________________________________________________________________________

Output :

SUM =

     0

[Explorer]

There is something wrong in Descrip.m because I am getting zero for SUM=sum(v1-v2). Ideally, it should not be zero.

Answer 1

[David Young]

Descrip writes then reads contour.jpg, and then computes the result from that. One way to set about debugging would be to see whether contour.jpg is different for the two images. That will help pin down where the problem lies.

[Explorer]

How can I program it to save figure with different name whenever I run it?

[Explorer]

I created another function having name "Descrip2.m" in which image will be saved with contour2.jpg

And tested again by

image1 = imread('C:\Users\Explorer\Documents\MATLAB\ASL_signs\A.jpg');

image2 = imread('C:\Users\Explorer\Documents\MATLAB\ASL_signs\B.jpg');

v1=Descrip(image1);

v2=Descrip2(image2);

SUM=sum(v1-v2)

__________________________________________________________________________________

Output:

SUM =

     0

____________________________________________________________________________

Still I am getting sum as zero.

[Explorer]

But sum is not equal to equal when I replace "1" with "2" in line # 57 of Descrip.m and Descrip2.m

i.e

________________________________________________________________________

Original

thisBoundary = boundary{1}; % Or whatever blob you want.

________________________________________________________________________

Replaced

thisBoundary = boundary{2}; % Or whatever blob you want.

[David Young]

The idea was that you run Descrip with one input image, look at contour.jpg, run it again with the other input image, and look at contour.jpg again. Are they different?

Answer 2

[Image Analyst]

Don't use image as a variable name - it's the name of a built-in function.

[Explorer]

I have renamed it but still there occur same problem.

[Image Analyst]

What are you using now: Descrip or Descrip2? Doesn't stepping through it with the debugger reveal where the problem is????

[Explorer]

image1 = imread('C:\Users\Explorer\Documents\MATLAB\ASL_signs\A.jpg');

image2 = imread('C:\Users\Explorer\Documents\MATLAB\ASL_signs\B.jpg');

v1=Descrip(image1);

v2=Descrip(image2);

SUM=sum(v1-v2)

___________________________________________________________________________________

Output :

SUM =

     0

_____________________________________________________________________

I think sum should not be zero here. Don't you think so?

[Image Analyst]

If image A equals image B then I think they should be the same. You didn't attach either image so only you can know that. What did stepping through with the debugger reveal to you?

[Walter Roberson]

Watch out for the case where v1 and v2 are being returned as unsigned integers; in that case if v2 > v1 you would get "clipping" at 0 instead of getting a negative number.