Dot Matrix Display Testing

[Gops]

Hello,

I have a requirement to test a dot matrix led display (At pixel level). The system needs to detect the display contents and check whether the appropriate dots are ON for different context. The display is 40 square dots X 300 Square dots.

Is it possible to use the vision module to detect the details at pixel level and test?

Regards

Gopal

[chris.b]

Hi Gopal!

The smallest detail the system will be able to detect will depend on a number of factors, including your camera's sensor resolution and and your lens' field of view.

If you do not have a camera and lens yet, make sure they will provide you with adequate resolution and focal length.  A document entitled Calculating Camera Sensor Resolution and Lens Focal Length on our website details the steps to find the required camera and lens specs.

To find the needed sensor resolution, use the following equation:
sensor resolution (S) = (FOV / resolution) x 2 = (FOV / size of smallest feature) x 2

To find the needed focal length, use the following equation:
focal length x FOV = sensor size x working distance

If your camera and lens are up to the task, you will be able to test your display with Vision Development Module.

[BruceAmmons]

To give you a number, I would probably select a camera with a horizontal resolution of 1000 pixels or so.  That would give you 3 camera pixels per LCD pixel.  It would be pretty easy to determine which ones are on or off.

Bruce

[chris.b]

Thanks Bruce!  I should have mentioned that as well.

[muks]

What is the camera u r plannin to use.

[Gops]

Hello,

I thank you for the response. Iam planning to use a Sony DFW90 fire wire camera. Right now I dont have the specification of the lens. I have understand from the camera specification it can capture a image of size 1280x960. Iam not sure about the lens specification for this camera.

I tired to capture the image of my DUT with this camera. I need to place the camera atleast 1 feet from the DUT to get the complete view of the LCD.

Iam trying to evaluate whether this picture would be sufficient for the pixel analysis in the product.

Regards

Gopal

[muks]

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I tired to capture the image of my DUT with this camera. I need to place the camera atleast 1 feet from the DUT to get the complete view of the LCD.

Iam trying to evaluate whether this picture would be sufficient for the pixel analysis in the product.

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You neednt fix the working distance at 1 feet if you dont have any mechanical constraints.U can change the focal lenght of the lens (Like 8mm or lower) and get a good view of the image.

[chris.b]

I believe this set-up should work well.

Resolution of the DUT: 300 x 40
Resolution of the captured image: 1280 x 960

Assuming the DUT fits in the image in the long (300 px) direction, you will have more than 4 pixels of camera resolution per each DUT pixel (~1280 / 300).  This should work great for pixel analysis.

[muks]

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Hi Gopal!

The smallest detail the system will be able to detect will depend on a number of factors, including your camera's sensor resolution and and your lens' field of view.

If you do not have a camera and lens yet, make sure they will provide you with adequate resolution and focal length.  A document entitled Calculating Camera Sensor Resolution and Lens Focal Length on our website details the steps to find the required camera and lens specs.

To find the needed sensor resolution, use the following equation:
sensor resolution (S) = (FOV / resolution) x 2 = (FOV / size of smallest feature) x 2

To find the needed focal length, use the following equation:
focal length x FOV = sensor size x working distance

If your camera and lens are up to the task, you will be able to test your display with Vision Development Module.

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I feel it is a good suggestion.Y  1 star ?Here i  toss u a five

[chris.b]

well thank you very much!