How do i generate hash value from an image file ?

Hi, I'm writing a project which involves the generation of MD5 Hash values from an image, i have analysed the image using MATLAB. I have also gotten to the point of finding a ROI (Region of Interest) but i dont know how i can be able to generate hash values from there.

Please any help will be appreciated.

this is the code i have so far..

clear all;
k=input ('Enter the file name:' , 's');
I = imread(k);
background = imopen(I,strel('disk',15));
figure, surf(double(background(1:8:end,1:8:end))),zlim([0 255]);
set(gca,'ydir','reverse');
I2 = I - background;
I3 = imadjust(I2);
level = graythresh(I3);
bw = im2bw(I3,level);
bw = bwareaopen(bw, 50);
I4 = imshow(I);
e = imellipse(gca,[65 109 48 48]);
BW = createMask(e,I4);

img = double(I4);

[SP_POINTS] = MakeFeatures(img);

%Show feature points
out = 1- SP_POINTS;
out = im2uint8(out);

hashVec = createstruct(out);

figure, imshow(I);
figure, imshow(I2);
figure, imshow(I3);
figure, imshow(bw);
cc = bwconncomp(bw, 4)
cc.NumObjects

[Institute Jassim]

Hi Freind, I am wotking on the watermarking by using wavelet algorith. I need to create a hash function in matlab language for an image in order to embed it as a watermark.

Answer 1

[Jan]

There are some tools in the FEX: computehash, CalcMD5

See also: MATLAB Answers:hash-function-for-matlab-struct

Answer 2

[Walter Roberson]

imshow() returns the handle-graphics handle to the image object created in the tool figure. A handle-graphics handle is already of class double, so I am having difficulty figuring out what you are expecting your line

img = double(I4);

to do ?

MakeFeatures does not appear to be a Mathworks routine, and createstruct() does not appear to be either.

If you were to use

roiPixels = I(repmat(logical(BW),1,1,size(I,3)));

then that would extract the pixel values only at the masked locations. Be careful, though: if your original image is RGB then all of the information for R would appear before all of the information for G which in turn would appear before all of the information for B.

Answer 3

[shivu P]

Enter the file name:c.jpg
Undefined function 'MakeFeatures' for input arguments of type 'double'.
Error in MD5 (line 25) [SP_POINTS] = MakeFeatures(img);  >>  >>

I am getting this error after executing this code..........any help to resole this would be more appreciable

[Walter Roberson]

http://users.ece.utexas.edu/~bevans/projects/hashing/toolbox/index.html