how to compare the color image to another color image in directory?

i have a directory of 2500 color images. i want to compare each image with others to know is there in directory similar image with this?

[Walter Roberson]

How do you define "similar image" for this purpose?

[preet]

using compare gray value of R,G,B of each image with other

[preet]

read each image and compare R,G,B component

[preet]

I am try to implement r = corr2(A,B) but this is implement only when both have same size but my images have different sizes .There is one another function that is imshowpair() which may be helpful but worked only in R2012 version of matlab and i am using matlab R2007b. so can you please tell me the solution what should i do before to get new version.I mean any other logic to compare different size of images

Answer 1

[Bjorn Gustavsson]

Well it seems someone's allready done the job for you: http://www.mathworks.se/matlabcentral/fileexchange/42008-content-based-image-retrieval

HTH

[preet]

Bjorn i want very simple logic , defiantly this is used in CBIR but i just need to check whether there is any similar image in the folder or not. actually when i worked on this there are similar images in folder.but i need the single images in folder . This is my training folder of images

Answer 2

[Spandan Tiwari]

One way to compare the images quickly would be compute a structural quality metric such as SSIM between the two images. It is a popular metric and a quick web search can get you all the necessary info.

It is easy to compute and does more than correlation. But you would need to resize one of the images to match the size of the other. You can use IMRESIZE from the Image Processing Toolbox for that. Although IMSHOWPAIR can be helpful if you want to visualize the mismatch between the two images, it won't give you a metric on the amount of mismatch.