Asteroid Zoo Talk

Making best use of the color cycling

  • vanrock70 by vanrock70

    I really like the color cycling to help identify things to look at more carefully using the "Play" function. I did a lot of image processing of Xray images years ago, when Silicon Graphics was king. I've noticed a few things that the programmers might want to address:

    1. The images appear to have a standard subtraction to reduce the skyglow noise. Frequently too much is subtracted; less commonly not enough is subtracted.
    2. Some vary widely in basic exposure, making comparison difficult.
    3. Both color cycling and "Play" show a small shift from image to image. It makes everything wiggle and makes real asteroid movement harder to spot.

    I suggest:

    1. Scale the brightness, to match at two points: first, a level at 2-sigma of the skyglow for each; and second the median brightness. Perhaps the median for only those points brighter than 2-sigma of the skyglow would work better; it will take some experimentation.
    2. Black out the points darker than 2-sigma of the skyglow.
    3. Use cross-correlation to exactly register the images on the 10 (or more perhaps) of the centroids of the brightest star dots. Select the centroid within those areas brighter than the median as chosen in the first step above.

    Ideally, these procedures would produce images with just a hint of background flicker, rock-solid star images for all but the dimmest stars visible, and a much more evident rainbow (in color cycling) or dot-shift (in "Play"), leading to a greater detection efficiency.

    An old programmer, AKA vanrock70


  • Dr.Asteroid by Dr.Asteroid scientist, admin

    There are certainly improvements to be made to the image presentation. We're updating some as we go along and will be taking into account the suggestions we receive. We don't want to remove data in play, but the next input will be improved.