Hi all,
I'd want to test a few cameras but I'm not so expert on how to perform it well.
I've built a sort of test box (4m long, 1m wide, 0.8m high) where I will install my camera and do all the tests.
On one side of this box I fixed a test chart that I bought from vidilabs.com. The camera, on the other hand, can be placed anywhere along all the lenght of the box.
I illuminate the chart with 4 tungsten lights (that i can move along the box) controlled by a light dimmer. At approx 0.5m from the chart, I fixed 4 fluorescent lights on both side of the box (2 per side). There is no external light.
In this way I can test the cameras' quality at different light conditions (eg. fluorescent/tungsten lights, 1000 lux, 400 lux, low light conditions). Illumination is measured (using a lux meter) in the centre of the chart as close as possible to and parallel to the chart plane.
The videosignal can be analyzed using a Video Measurement Set (Tektronix VM700T).
Now I know that I can measure the performance of the camera and compare different cameras if I do the measures with the same light conditions and recording the same chart.
In this way I can objectively measure:
Resolution, S/N, color output. Anything else?
Furthermore, looking at the details on the chart, I can measure:
reflection, licence plates recognition capability, face recognition capability, intrusion detection capability.
But i guess that for these measures I can just give a subjective value for example using a scale from 1 to 10. Am I right? If not, please suggest me how i can perform an accurate measure of these features.
Anyway, I have several doubt regarding how to perform these tests:
Lights:
Should i care about light temperature?
is there a "recommended" light (and lux level on the chart) to use for the objective measures i mentioned above?
Should i fix the tungsten light in a stable position (e.g. 3m from the chart)?
Camera settings:
For varifocal cameras, should i set the lens at minimum, middle or maximum focal lenght?
When possible, should i switch off all the video processing features of the camera (AGC, BLC, etc)?
Hope you can help me!
Thanks in advance!
Mario