how can i find t closest image in many images?

when i have a original image, which function can help me to find closest image in database?

i want to find the most similar one.

Answer 1

[Image Analyst]

Other than RMS, there is also SSIM, PSNR, and MD or relative MD. There are functions for psnr() and ssim() in the Image Processing Toolbox.

[heo jaemu]

if 2 images have different angle(but, similar angle and view), I want to find features that prove 2 images are equal. ex) distinct corners

[Image Analyst]

Well the images won't be equal if something is different, angle or view. But you can find parts of the image that may be similar or in different locations with functions in the Computer Vision System Toolbox: http://www.mathworks.com/products/computer-vision/features.html#object-detection-and-recognition

Answer 2

[Thorsten]

Well, there is lots of research devoted to this question. One simple way would be to compute the RMS (root mean squared) difference between the images:

   D = sqrt(mean((im2double(I1(:)) - im2double(I2(:))).^2));

This works only if the images have the same size.