Calculating the distance between two matrices Matlab

33 views (last 30 days)
I want to calculate the distance between two different DFT results after i performed this code:
I1 = imread('sample1');%read the images
I2 = imread('sample2');
GI1 = rgb2gray(I1) %change it to grayscale
GI2 = rgb2gray(I2)
DftR1 = DFT(GI1) %perform the 2-dimensional DFT(a function that i built it myself)
DftR2 = DFT(GI2)
so far it all worked; however when i want to compare the results of the DFT using this code:
Distance = pdist2(DftR1, DftR2)
I get this particular error: Error using pdist2 (line 224) PDIST2 does not accept complex data for built-in distances.

Accepted Answer

Star Strider
Star Strider on 2 Dec 2014
The DFT that the code you posted previously returns will be complex.
If pdist2 wants only real values,
Distance = pdist2(abs(DftR1), abs(DftR2));
will likely work.
  3 Comments
Star Strider
Star Strider on 2 Dec 2014
Edited: Star Strider on 2 Dec 2014
My pleasure.
The pdist2 function returns a matrix by definition. You can force the matrix to become only value by creating a vector out of it and then performing the operation you believe best suits your application. The mean or standard deviation might be most appropriate:
Dmean = mean(Distance(:));
Dstdv = std(Distance(:));

Sign in to comment.

More Answers (1)

Deepesh B
Deepesh B on 2 Dec 2014
Hi U have to use
abs
before applying
pdist2
because after fft it will have complex numbers

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!