RU2013119356A - METHOD FOR DETERMINING THREAD ANGLE - Google Patents

Abstract

The method for determining the twist angle of the thread, which consists in analyzing the angular diagram of the distribution of light flux in the diffraction pattern observed from the material under study by illuminating the surface of the thread with a parallel beam of monochromatic coherent light with a circular cross section, and the magnitude of the desired twist angle is judged by the angle measured between the direction to the maximum in the angular diagram of the light flux in the diffraction pattern and the perpendicular to the filament drawn in the plane of the picture from its center, It means that they study a computer microimage of the studied filament, the diffraction pattern of which is calculated for such lighting using a fast two-dimensional Fourier transform, and the angular distribution diagram of the light flux in the diffraction pattern is judged by the angular distribution diagram of the average total pixel illumination intensity, which is calculated in a ring defined by the radii R and R relative to the center of the diffraction pattern in the polar coordinate system for each angle φ in the range of values 0-2π according to the formula, where ΔS is the area of the sector of the ring bounded by the angle Δφ; the numerator is the sum of the intensities of the image pixels i that fall into the selected sector ΔS; N is the number of pixels in ΔS.

Claims (1)

The method for determining the twist angle of the thread, which consists in analyzing the angular diagram of the distribution of light flux in the diffraction pattern observed from the material under study by illuminating the surface of the thread with a parallel beam of monochromatic coherent light with a circular cross section, and the magnitude of the desired twist angle is judged by the angle measured between the direction to the maximum in the angular diagram of the light flux in the diffraction pattern and the perpendicular to the filament drawn in the plane of the picture from its center, ayuschiysya that examined computer microimage investigated the filament, from which the diffraction pattern for this coverage is calculated using the two-dimensional fast Fourier transform, and an angular distribution diagram of the light flux in the diffraction pattern is judged by the average angular distribution diagram of the total intensity of illumination of pixels $$I_{\Delta S}(\varphi )$$

, which is calculated in a ring defined by the radii R ₁ and R ₂ relative to the center of the diffraction pattern in the polar coordinate system for each value of the angle φ in the range of values 0-2π according to the formula $$I_{\Delta S}(\varphi )=\frac{{\displaystyle \sum _{n=\mathrm{one}}^N{i}_{p_n}}}{N}$$

, where ΔS is the area of the sector of the ring bounded by the angle Δφ; the numerator is the sum of the intensities of the image pixels i _p that fall into the selected sector ΔS; N is the number of pixels in ΔS.