Vision Basics - Mode Greyscale Processing When the software processes the data from a greyscale image in greyscale mode, it looks at a three-by-three section of pixels and compares the difference in intensity values found in the neighboring pixels to the value of the variable Edge Strength. If the difference found exceeds Edge Strength, the system considers the three-by-three area to be part of an edge. Grey- scale Representation of Sample Matrix shows the edge the system finds in the data from the array in Sample Vision Matrix if Edge Strength is set to 20.
(This figure is somewhat idealized to help illustrate the point.) Greyscale Representation of Sample Matrix The algorithm that ACE Sight uses when looking at the three-by-three neighborhood of pixels allows edges to be located with sub-pixel accuracy. Thus, greyscale processing is gen- erally more accurate than binary processing. Contrast There are two settings that allow you to control the level of contrast in an image. Gain The sensors in the camera report an absolute intensity value.
A camera operating in a low light environment returns values in a limited range at the low end of possible values (0-127) and the image would be very dark (similar to under-exposing a piece of photographic film). If all the objects in the field of view reflect light of a uniform intensity, the values returned are in a very narrow range. If the intensity values were multiplied by a given value, the relative differences between intensity values would increase and edges would be easier to detect. Gain is the ACE Sight parameter that performs this function. ACEUser's Guide, 3.6.x, 18316-000 Rev A Page 310