Figure 4. Absolute Value Difference Grayscale Map and Difference Grayscale Map
(a) (b)
Figure 5. Three dimensional gray distribution of absolute value difference gray map, and three dimensional gray distribution of difference gray map
It is obvious that there is more image information in 4a, but most of them are interference pixels. Its two-dimensional gray-scale histogram shows multi peak characteristics, and its three-dimensional gray-scale distribution diagram 5a shows highly consistent with the information in Figure 4a. The method proposed in this article is used to construct a differential grayscale image. Figure 4b shows that the grayscale values in the area where the crane grasps the boom are brighter than the surrounding environment, and are highlighted to achieve the purpose of constructing differences. Figure 6b 2D gray histogram shows that the gray value of more than 90% of the pixels in the whole image is 0, with obvious peaks and troughs, showing a bimodal distribution.