Comment A few things to consider (Score 4, Interesting) 116
First you can check out How Things Work for the basics.
Second, off the shelf imaging devices are challenging to use for scientific data collection for a number of reasons. The main one being their response is usually designed to replicate the human eye rather than a true spectral response--the difference between photometry and radiometry.
For resolution tests, go to www edmundoptics com and check out the various testing targets available. The cheapest mylar USAF targets are pretty good for testing spatial resolution. Remember that when you get close to the resolution limit of the CCD, aliasing due to misalignment is going to be a factor. Your resolution could be up to a factor of 2X (per axis) better than you can test for, unless you're able to align the target with the pixels.
You should also try to figure out which CCD the device uses. Yahoo!'s Electronics Marketplace is a good place to search for components and there is usally a link to the manufacuter's spec sheet. Some spec sheets are quite detailed and will give you plenty of information regarding sensitivity, dark current, spectral response, etc.
Be skeptical of resolution claims. A flatbed scanner I have claims 9600 dpi or about 2.6e-6 m resolution. In reality, it's no better than about 5e-5 m.
Also, the picture you get out vs the "real" picture is highly dependent on the imager's software & firmware. Autoexposure and color correction functions are usually present and can play havoc with an attempt to figure out what the "real" image is. Again, test targets may help here--if you can control all the other variables in the system, you can do some calibration experiments to figure out what the imager is doing to your image.
Well, I hope this points you in the right direction.
Second, off the shelf imaging devices are challenging to use for scientific data collection for a number of reasons. The main one being their response is usually designed to replicate the human eye rather than a true spectral response--the difference between photometry and radiometry.
For resolution tests, go to www edmundoptics com and check out the various testing targets available. The cheapest mylar USAF targets are pretty good for testing spatial resolution. Remember that when you get close to the resolution limit of the CCD, aliasing due to misalignment is going to be a factor. Your resolution could be up to a factor of 2X (per axis) better than you can test for, unless you're able to align the target with the pixels.
You should also try to figure out which CCD the device uses. Yahoo!'s Electronics Marketplace is a good place to search for components and there is usally a link to the manufacuter's spec sheet. Some spec sheets are quite detailed and will give you plenty of information regarding sensitivity, dark current, spectral response, etc.
Be skeptical of resolution claims. A flatbed scanner I have claims 9600 dpi or about 2.6e-6 m resolution. In reality, it's no better than about 5e-5 m.
Also, the picture you get out vs the "real" picture is highly dependent on the imager's software & firmware. Autoexposure and color correction functions are usually present and can play havoc with an attempt to figure out what the "real" image is. Again, test targets may help here--if you can control all the other variables in the system, you can do some calibration experiments to figure out what the imager is doing to your image.
Well, I hope this points you in the right direction.
