Camera suggestions for monochrome LCD

[tonye]

I am in need of a camera for testing a small monochrome LCD, like the kind found on corporate desktop phones. I will need to test various checkerboard patterns and some fixed messages that will appear on the screen.

Can anyone suggest a cost effective camera for this application? The LCD itself is about 6" wide and 1.5" tall with two rows of text available.

Thanks,

~tony

[Robert_Eastlund]

Dear Tony,

I would be happy to help you select a camera and lens.

1) Will the LCD display be backlit during testing?

2) Are there any space constraints regarding the positioning of the camera/lens assembly?

-Robert Eastlund

[muks]

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Can anyone suggest a cost effective camera for this application?

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Cost effective is very generic term.Can you give us an idea of the price range that you are looking at?In addition to roberts question also letus know the shutter speed and resolution u r looking at. 

[tonye]

Thanks for the replies.

Yes, the LCD is backlit. I've got a decent amount of room to position the camera/Lens in relation to the unit under test (can be up to 6" away without a problem).

In relation to shutter speed, the images I will be gathering are static, meaning the UUT will keep the pattern of interest displayed for as long as I require. On the resolution side I'm not sure what number to propose. Since it's a fairly small display and I'm not looking to detect pixel level errors, mostly character level (like OCR) or gross pattern errors like a missing column or row.

Thanks,

~tony

[muks]

Why not use a webcam for this application?

[BruceAmmons]

What is the number of pixels across the screen?  Alternatively, what is the number of characters across and how many pixels are in each character?

I would recommend at least 2 camera pixels per LCD pixel.  That would give you the minimum horizontal resolution for your camera.

Bruce

[muks]

But bruce his application is ocr and no measurement involved

[tonye]

I'm new to the Vision side of automation, so would a webcam work? I assume that it would grab a picture and then I would use the vision software to analyze that? I suspect that a webcam might not have the resolution I was after but I could be way wrong on that.

Thanks.

[tonye]

I do need to make minor measurements besides OCR such as detecting when the display intensity has been lowered. I'll be measuring when its at it lowest, darkest and in the middle. I will get the character count and pixel per character later (the specs and unit are not in front of me.

[BruceAmmons]

I have done OCR, and I stand by my recommendation.  I would actually prefer about 3 pixels per pixel, but 2 will work okay.

You have to have enough detail to examine every pixel even if you are just looking for missing vertical lines, etc.  It is still pixel level details.

Bruce