THE TEST

A STRAIGHTFORWARD LOOK AT THE EFFECTS OF MOTION BLUR

    We could continue to discuss the effects of motion blur.  We could spend much time trying to describe the distortions caused when the shading of the nearby terrain is blended with the craters as they are smeared.  This could be debated endlessly because of the variables and uncertainties involved when we have varying degrees of experience with the interplay of the various shades of gray when they are mixed.

    The best way to address the question of motion blur is to impose it upon an image that is otherwise clear and undistorted.  This would put the arguments for and against motion blur to a real-world test.  But how should such a test be executed?  The test must be repeatable in a way that would be straightforward enough that most people could do it easily.  The best and most straightforward way that I can think of is to use a tool easily accessible to all, and applying a technique easily applied by all.

    Fortunately the tool exists on the internet and can be downloaded by anyone with a modem.  The tool of choice is Paint Shop Pro 5, and the technique simply involves the application of the "Motion Blur" filter.

This is the normal appearance of the surface of the Moon as seen in the average Lunar Orbiter image.  This was not an oblique view, so to approximate the images with the doubles, this image was compressed vertically.
This is the same image as above, after the "Motion Blur" filter was applied.  The similarity to the images of the double craters are immediately apparent.

    The lower image is the result of lateral motion blur for a distance of twenty pixels.  The three craters indicated are each about twenty pixels across in the upper image, allowing for a bit of overlap of the "leading" and "trailing" walls.  This overlap results in the "dividing wall" seen in the high-res frames of LO3-85, 123, and 214.  As in those images, here the doubles only occur if the original craters are within a certain limited size range.  Smaller craters simply appear as elongated trenches.

    At this point we should revisit the arguments in favor of artificiality:

    THE CENTRAL 'WALL' MUST MATCH ONE OF THE SIDE WALLS OF THE CRATER - As can be seen with crater C above, this is faulty reasoning. In this test it is obvious that the "leading" and "trailing" walls have merged together to form a new "wall" different from either of the two true walls of the craters.

    THE TWO HALVES MUST BE ALIKE - This, too, is shown to be faulty reasoning, but this is an understandable error to make.  If the area surrounding the original crater was shaded evenly, both halves would indeed be equal.  But as can be clearly seen with the crater marked "C", the uneven shading factors in to create two halves with different appearances.  In the blurred crater "C" the halves are not even of the same size, not to mention the same appearance.

    SMEARING MUST BE IN THE DIRECTION OF THE SPACECRAFT MOTION - That is, all features must appear to be smeared in exactly the same direction.  Another erroneous but understandable assumption. Look again at the blurred crater "C".  Though the motion blur is exactly horizontal, this "pair" is tilted slightly, as are some of the small "trench craters" to the immediate right in the larger image.

    The obvious result of this test is that all the effects seen in the Lunar Orbiter "double crater" frames can easily be accounted for by the simple blurring of the image due to motion of the camera during exposure.

    For those who want to try this test themselves, the settings of the Motion Blur filter in Paint Shop Pro 5 are Direction 90 and  Intensity 20.  The above image can also be downloaded in JPEG format.

Author: MikeLomax@aol.com