The Non-hardware Method of Computer Control of the Amount of Twist of the Thread by Its Image

The paper proposes a non-hardware diffraction method for computer control of the filament twist value using a program of two-dimensional discrete Fourier transform of a digital micro-image of the filament under investigation. The method consists in the sequential application of a two-dimensional Fourier transform. First, using this program, the Fraunhofer diffraction pattern from the micro-image is calculated, then using the same program, the second diffraction pattern is similarly calculated from the image of the first. The second diffraction pattern does not contain speckles, which allows you to calculate the twist of the thread automatically with the output of digital values ??on the display. The efficiency of the method is illustrated on model samples of twisted yarn and samples of industrial synthetic yarns.