An automated pharmaceutical plant uses image processing in measuring the shapes of medicat...

An automated pharmaceutical plant uses image processing in measuring the shapes of medication tablets for the purpose of quality control. The segmentation stage of the system is based on Otsu’s method. The speed of the inspection lines is so high that a very high rate flash illumination is required to “stop” motion. When new, the illumination lamps project a uniform pattern of light. However, as the lamps age, the illumination pattern deteriorates as a function of time and spatial coordinates according to the equation

where (M/2, N/2)is the center of the viewing area and t is time measured in increments of months. The lamps are experimental and the behavior of A(t)is not fully understood by the manufacturer. All that is known is that, during the life of the lamps, A(t)is always greater than the negative component in the preceding equation because illumination cannot be negative. It has been observed that Otsu’s algorithm works well when the lamps are new, and their pattern of illumination is nearly constant over the entire image. However, segmentation performance deteriorates with time. Being experimental, the lamps are exceptionally expensive, so you are employed as a consultant to help solve the problem computationally and thus extend the useful life of the lamps. You are given flexibility to install any special markers or other visual cues near the edges of the viewing area of the imaging cameras. Propose a solution in sufficient detail that the engineering plant manager can understand your approach. (Hint: Review the image model discussed in Section 2.3.4 and consider using a small target of known reflectivity.)