Determining distance of a pixel to the camera

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VirgilVox

Determining distance of a pixel to the camera

in General Discussion • Other • 2 months ago

Hi everyone, I've been lurking the forums for awhile whenever I needed an answer and I thank the community for that. However, I have question I haven't found a clear answer for, figured I'd finally create an account.

What is the best way to determine the distance of a pixel in an image or frame of video to the camera. I know there is some sort of math that helps with this, I'm just looking for the simplest solution.

I am writing laser scanning software. Trying to get the simplest method down I need to first figure out how to determine the distance of each point of the laser line to the camera. So there would be a red curve in each frame.

Has anyone tried this and figured it out? Do you know of a method that might be useful? Is there a specific term or concept I should research that might be beneficial? Anything helps.

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PhiLho

Re: Determining distance of a pixel to the camera

2 months ago

Sorry, but I fail to understand what you mean by distance of a pixel to the camera. Pixels are point on a flat surface, the screen (or a virtual plane for off-screen pixels), so how can they be far or close of some camera? A real device or the concept used in 3D imaging to compute a perspective?

And how all this relates to a laser scanning software?

I can make speculations (void if I am far off your intent). Perhaps you mean to compute the distance of a physical point highlighted by a laser from its image captured by a camera.

I am not a specialist, but the answer is probably "you cannot". At best, you project a grid on an object and using some advanced maths (no idea what they are), you deduce the depths from the deformations of the grid.

Not an easy task, unless you find a Java library able to do that.

Perhaps it is also possible from a single line, if it is made of dots (not continuous): the visible distance between points can be used to compute a relative depth. Note that these give relative depths (of a location to the next one), not an absolute distance (x centimeters from the camera). Although computing the size (of squares, or distance between dots) on a flat, perpendicular surface can be used to compute this distance.

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