Topic: Multiband images

rperroy from COSI-Corr has sent you a message.

The message reads as follows:

Hello from UCSB!

I just signed up for the discussion group and would like to post a question I had regarding aerial images.  In order to orthorectify a 3-band aerial image, is there any way to process all 3 bands at once?  So far I have been generating a mapping matrix and associated files for a single band, then using those same files for the additional bands but don't know if this is the best way to go about it.

Thank you very much for your software, my results so far are beautiful!

Ryan Perroy



Re: Multiband images

Dear Ryan,

It all depends on your imaging system.

If the 3 bands are acquired using the same sensor (Bayer matrix or color film?), or if you can consider the 3 bands to be EXACTLY co-registered in the focal plane, then it is enough to derive the transformation matrices for one particular band, and then resample successively each of the 3 bands according to the same transformation matrices. In this case, it is true that COSI-Corr is not yet fully user friendly, and you will have to call the resampling process 3 times. However, note that you can use the batch processing feature (the Queue option), and batch the 3 resampling together. Then you don't have to wait for each process to end to start the next one...

If the bands are not well co-registered in the focal plane (e.g., because the imaging system uses 3 CCDs with a beam splitter and uneven defects, or it is a pusbroom system, etc...), then a particular band has to be ortho-rectified first, and the other bands should be ortho-rectified taking this first ortho as a reference. Then, in this case, you would have to optimize GCP and construct transformation matrices for each band. You can also get some help from the queue manager.

If I understand you correctly, your answer should be in my first paragraph.



Re: Multiband images

Dear Sebastien,

Yes, in this case the image is a color film.  Thank you for answering my question!