Distinctness of image evaluation method of painted surfaces

摘要

PURPOSE:To evaluate a finish value instantaneously and automatically without contacting the surface of a painted body by inputting a light-dark slit pattern which is prejected on the surface of the painted body as a two-dimensional image, and separating its disorder into plural spatial frequency levels and quantizing the image. CONSTITUTION:The light emitted by a light source 1c is diffused uniformly in box 1a and further passed through a diffusion plate 1d to enable irradiation with slit light having uniform brightness. Then the surface of the painted plate 3 is irradiated with the slit light, its reflected light is inputted by a CCD camera 2 as mapping on the surface of the painted plate 3, and the inputted image information is supplied to an image processor 4. The processor 4 performs A/D conversion into digital information consisting of 512X512 picture elements so that one byte is assigned to one picture element, i.e. with 256 gradations and the information is stored in a frame memory 4b. Then the image information stored in the memory 4b is supplied to an arithmetic part 4c when necessary and quantized by spatial frequencies.