DLPLCR4500EVM: Optimum HW setups for structured light

John Traynor

Part Number: DLPLCR4500EVM

Hi all,

Just interested to hear from people on what physical setups gave the best results for structured light / point cloud generation

So for example lets say you had the 4500EVM 400mm from the target device you wanted to inspect. Lets say the device is a 100mm cube. Is their an optimal placement of the camera + lens relative to the projector lens in both the horizontal and vertical distance. What impact does the angle of the camera have? Can this be worked out mathematically with some formula?

Thanks in advance

John

over 5 years ago

0 Philippe Dollo over 5 years ago

TI__Mastermind 28005 points

John,

The distance between the projector and camera does have an impact. For instance, a wider angle will make distortion easier to detect, but also distort the point cloud of the object itself.

I'll see if I can find some more detailed material to assist you and get back to you in a few days.

Best Regards,
Philippe Dollo

0 John Traynor over 5 years ago in reply to Philippe Dollo

Intellectual 885 points

Hi Philippe,

Thanks for the reply.

We have performed numerous setups at different angle and distances and we just wanted to know if there was a more scientific approach to the physical setup, so any information you can share would be greatly appreciated

Thanks

John

0 Pablo Figueredo over 5 years ago in reply to John Traynor

Prodigy 85 points

Hello, at the optimum angle between camera and projector is 15 degrees.

regards

Paul

0 John Traynor over 5 years ago in reply to Pablo Figueredo

Intellectual 885 points

Hi Paul,

Thanks for your reply

Interesting to hear what worked well in your experience. Was the 15 figure arrive at through trial and error or Mathematically?

Many thanks

John

0 Pablo Figueredo over 5 years ago in reply to John Traynor

Prodigy 85 points

In forums of scanning recommend 25 to 30 degrees of angle between cameras, to scanner with 2 cameras. Therefore, the angle between a camera and a projector is 15.

In any case, the cocept is the following: less angle will give more field of vision and less precision. More angle will give less field of vision and more precision.

I could do the test with some object or of known dimensions and compare the results obtained at 15 degrees and at 45.

regards

0 John Traynor over 5 years ago in reply to Pablo Figueredo

Intellectual 885 points

Many thanks. We did similar tests and we couldn't necessarily say the results were better at a wider angle - just different. It was hard to quantify so I was trying to put some formula behind it

0 Pablo Figueredo over 5 years ago in reply to John Traynor

Prodigy 85 points

your scanner is 1 or 2 cameras?
As a general rule it is taken that the distance between cameras (for a scanner of 2 cameras) is half the distance from the scanner to the object. this gives approximately an angle of 30 degrees between cameras.

0 John Traynor over 5 years ago in reply to Pablo Figueredo

Intellectual 885 points

1 at the moment but will probably end up being 2 I think

Very helpful

Thanks

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DLPLCR4500EVM: Optimum HW setups for structured light