Suggestions on low light color cameras

[trend]

Low Light cameras?

Wow! Freezing down in GA.. And were suppose to get some more freeeeezing.


Got a question for you'll.. I have been using the CMUcam1 and I haven't been
to impressed because of the lighting it needs. Do you'll have any
suggestions on a low light camera that can preferably do color.

I basically need to be able to look at an object that is on a white
background and be able to to tell what the object is.


Any ideas?.. maybe just getting proper lighting would be an option.. (like
with white leds or somethign).

Here again, this needs to be very small, and relatively inexpensive (under
100bucks).


thanks for any ideas!
Lee

 

[IanP]

Re: Low Light cameras?

Good (but still standard CCTV colur camera will give you 480lines and will be able to operate at light below 1lux. (example Panasonic WV-CP474H https://www.panasonic.ca/English/Broadcast/security/cameras/colour/wvcp474h.asp )
For less than $100 you will not find anything near that. You will be lucky if (regardless of what is stated in data sheets) cameras in this range will have usable picture at 4lux and more.. This also depends on the F-parameter of the lens..

As far as light based on white LEDs is concerned, you will need quite a lot of them bundeled in groups of 10 or more.
I have here swivelling head CCD camera with 24 white LEDs around the lens and, although this camera is 2-lux sensitive, good picture is produced at max 1.5m from the camera.
You will have to think about illuminating the scene as much as you can, maybe you should consider a fluorescent light if the object you wany to see is some meters away..

 

[trend]

Re: Low Light cameras?

actually the camera will be looking down in a white box (5inches by 3inches by 5 inches).

The object will be in there.

Do you think I could get away with LEDs then?


thanks!
Lee

 

[IanP]

Re: Low Light cameras?

Yes, by all means.
There are extra-bright white LEDs on the market and the colour of the picture is really very natural, as white light is the best light (does not contain a lot of red component) for this purpose..

 

[trend]

Low Light cameras?

How many LEDs should I use? Should they all be located at the top?

And should I get the brightest LEDs possible?
What about glare?

You think using the CMUcam with the LED arrangement would be effective?

I am definitly up for buying some and testing them out.. but it sounds like you are very knowledgable.. and I would like to get your take on this.


thanks! Lee

 

[IanP]

Re: Low Light cameras?

Is this your camera?
https://www-2.cs.cmu.edu/~cmucam/home.html

I would estimate that approximately 20 of these extra-brite should be enough..

As far as glare is concerned I don't have this problem with our camera so you should not have this problem either.

 

[trend]

Re: Low Light cameras?

Yes, that is my camera.

I ment glare off the object (it is metal and plastic)

hmm.. should all 20 be located at the top?

thanks!
Lee

Added after 4 minutes:

are there any good led arrays that I should use? or will I have to place them one by one?

thanks-lee

 

[IanP]

Re: Low Light cameras?

If the object is very shiny you will have reflections and depending on the dynamic range of the camera they (reflections) will be more or less unpleasant..
You can spread LED around the camera lens and to do this you can use a vero-board and connect the LEDs in strings of 3 in series and then 7 strings in parallel. This will give you supply volage of 3 x 3.5V @ 7 x 10mA = 10.5V @ 70mA (21 LEDs) or you can use different combination to suit your supply voltage..