Maps of distances from range finders?

June 3, 2009
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I’ve been doing homework with lots of search strategies, but still looking for some answers.
I would like a range finder to draw a two-dimensional map that represents the distances of everything within its field of view. It would look as if you were using a video/still camera, shooting what’s in front of, say, my robot, but the picture would not be displaying the varying brightness of light reflected from objects. Rather, there would be, perhaps, a gray-scale image based on distances observed by a range finder.
This would probably require a scanning of the scene (as a video camera would do) rather than the single horizontal line that (I believe) a typical range finder would yield.
Anybody work with such concepts or have suggestions? I’ve been searching literature on surveying, photogrammetry (!), autonomous vehicle navigation, and the like. I’m just hoping to find a relatively simple solution; somebody must have done this before.
Les Bradley

— LesBradley

2 Responses to “Maps of distances from range finders?”

  • Kelly » Posted 39 weeks ago.

    The problem with using range finders like IR and Ultrasonic is that their detection area is conical so it would pick up the closest of two objects within its field. Also range finders tend to have a zone where they work: either near (a few feet or inches) or far (several yards) You might look into how 3D scanners work. They usually use a linear laser (like a laser level) and a camera.
    The camera image is analyzed for displacement from a known distance. For instances if an object that is five feet away places the laser in the center of the image, a near object might show the laser beam more to the left and a far object more to the right. The laser usually pans across the image so a number of images would have to be analyzed to get a set of points of varying distance. Resulting in an image.
    I know there is a 3D imaging company hear in Maryland that does some work creating 3D models of accidents scenes but I can’t remember their name.

  • Les » Posted 38 weeks ago.

    Kelly,
    I have extracted the sonar transducer and board from a Polaroid 660 and reading up on accessing this. I see the problem of covering a range of different distances and the need to adjust the sensitivity/intensity of the signal to accommodate for this range.

    I will pursue some of your suggestions. I suspect laser will be the route to take.

    I will bring my dissasembled Polaroid to tonight’s meeting.

    Thanks, Les