Image measuring instrument, three, stages_three stages of image measuring instrument information processing

Starting from the vision theory, Marr divides the image measurement process into top-down stages, that is, the visual information goes from the initial raw data (two-dimensional image data) to the final representation of the three-dimensional environment. The processing of the stage is shown in Figure 1-4. The three stages of image measuring instrument information processing. The first stage is early visual processing, which extracts basic features such as corners, edges, textures, lines, borders, etc. from the input two-dimensional original image. The collection of these features is called primitives Figure (Primitivesketch). The second stage is mid-term visual processing, which is to restore the depth, normal direction, contour, etc. of the visible part of the scene from the input map and primitive map in the observer-centered coordinate system. This information contains depth information, but is not a true three-dimensional representation of the object, so it is called a 2.5-dimensional sketch. 2.5-dimensional description is a vivid term that means a partial and incomplete description of three-dimensional information. When the human eye or camera observes objects in the surrounding environment, the observer initially describes the three-dimensional object in its own coordinate system. In addition, we can only observe the part of the object (other... part is The back of the object or the part obscured by other objects). The third stage is post-visual processing, which is the process of restoring, representing and recognizing three-dimensional objects from the input image, primitive image, and 2.5-dimensional image in the object-centered coordinate system. This three-dimensional shape description has nothing to do with the observer's perspective. Table 1-2 summarizes the purpose and characteristics of the three stages of visual information processing. Table 1-2 The frame of replying shape information from image