Matlab: Comparing 2 images with different dimension and pixel size -

i have 2 images need compare:

image 1: size [512 x 512] pixel dimension: 0.41 mm

image 2: size [210 x 210] pixel dimension 1 mm tried use: imresize

imresize(image_1, [210 210]) % change size/pixel 

however reduce resolution , image not clear @ all. suggestion welcome!

you have problem comparing 2 images of different resolutions. pre-processing of images make them comparable, maybe more making them of same size. pre-processing depends on images.

anyway, perhaps better re-size smaller 1 larger version using 1 of methods mentioned here: http://www.mathworks.com/help/images/ref/imresize.html , compare them. example, enlarge smaller image using 'lanczos3' method.

imresize(image_2,[512 512],'lanczos3');