dan@rna.UUCP (Dan Ts'o) (05/24/90)
Although the actual application involves a video camera and video digitizer (frame grabber), I don't think it matters for the question... CAMERA --> DIGITIZER I wish to test several cameras for their respective signal/noise characteristics (S/N). The only DIGITIZER I have at the moment is spec'd at 8-bits (and only provides 8-bits output). I wish to infer the S/N of the CAMERA, which may or may not be better than 48db (8-bits). What is a good procedure ? For example: CAMERA1 may have an S/N of 48db. CAMERA2 may have an S/N of 60db. What test can I devise to measure the CAMERA's S/N, given an 8-bit digitizer ? Cheers, Dan Ts'o 212-570-7671 Dept. Neurobiology dan@rna.rockefeller.edu Rockefeller Univ. ...cmcl2!rna!dan 1230 York Ave. rna!dan@nyu.edu NY, NY 10021 tso@rockefeller.arpa tso@rockvax.bitnet
lewis@saint (Keith Lewis) (05/25/90)
In article <1022@rna.UUCP> dan@rna.UUCP (Dan Ts'o) writes: > > I wish to test several cameras for their respective signal/noise >characteristics (S/N). The only DIGITIZER I have at the moment is spec'd >at 8-bits (and only provides 8-bits output). I wish to infer the S/N of >the CAMERA, which may or may not be better than 48db (8-bits). What is a >good procedure ? > This test depends on the digitizer being up to spec. Point the camera at something with a smooth intensity countour. A shadeless lamp 1 foot away from a SMOOTH white wall will do (keep the lamp itself out of the frame). Grab a few frames in exactly the same position. Without noise, the frames would be identical, right? In reality, if the camera IS better than the digitizer, there will be bands where all the frames agree exactly and bands where they often differ. The thinner the differing bands are, the better the S/N of the camera. - - - - Keith Lewis lewis@saint.mitre.org, klewis@mitre.arpa engineer-musician-network_manager-agitator-peacemaker-lover-philosopher (703)883-5873 Disclaimer: These opinions are not mine; I found them. If they are yours, you may claim them within 30 days.