How can i compare two images by its contents?

I need to compare two images by the contents in those images. If the objects in the images are same then the comparison result should be same and if not then the result be different.

[Walter Roberson]

How would you like to define "the same" between two visual objects? For example if you have a picture of a Balsam Fir tree, and a picture of a Christmas Tree (not the same tree) all decorated, then does the algorithm have to be able to figure out that the Christmas Tree is of the same species as the sample Balsam Fir image? Or given a picture of a chrysalis, does it have to be able to match with the corresponding butterfly ?

Answer 1

[Image Analyst]

I suggest you do a Google search on "CBIR" (Content Based Image Retrieval) and see what pops up. They're making tremendous advances recently.