Well, let me ask some questions... 1. Are the images registered and navigated? That is, do you have locations for the pixels in each image in some coordinate system? That's not something that DX does out of the box, although you could add the ability to do so.
2. If 1. is yes, is the coordinate system the same for both images? 3. Are the images the same size? 4. If 1., 2. and 3. are yes, are the images coincident? Here are some things that you could so: If 3. or 4. are yes. You could do pixel-by-pixel operations with Compute from trivial like differencing to complex comparisons. But they may only make sense if 4. is yes. Otherwise the pixels would be of different sizes in physical coordinates. If 1. and 2. are yes and 3 is no, then you can do overlays and interpolation between them, the latter would enable you to do pixel-by-pixel operations. If 2. is no, then you would have transform one to the coordinate system of the other or both to a 3rd coordinate system first. Independently of the above, you have the ability to image processing, coloring, rendering, etc. in each of the images separately. These sorts of problems occur with remotely-sensed images in earth, environmental and space sciences. Most texts on that subject will cover topics of image processing, registration, classification and analysis. Robert Lopez <[EMAIL PROTECTED]>@opendx.watson.ibm.com on 01/17/2002 03:55:39 PM Please respond to [email protected] Sent by: [EMAIL PROTECTED] To: [email protected] cc: Subject: [opendx-users] diff-ing similar images I have been asked to find out what it would take to do a certain project which is essentially extracting the differences between two microscope images. I am way over my head on this request and I will have to learn a lot. I wonder if opendx can be used to do all or some of it. An analogy of the microscope image problem might be easier for me to communicate. Imagine flying an airplane over a city. At a point in the air a photo is taken of a city below. Then a year later flying over again and taking another photo. There would be differences in the photo due to what changed on the earth, but there would also be differences due to other reasons such as weather, different airplane positions, different camera settings etc. So there would first have to be some manipulations just to get the two images to overlay correctly. Then some lighting artifacts from the weather have to be removed. Then everything in the first image that is also in the second image would have to be removed. The remaining changes are all that should appear in the final image; with perhaps some other coordinate information to determine where the differences are in the city. I am also interested in references to the literatures which cover ways to do this. Thanks.
