Abstract: A light-measuring device is disclosed for continuously and accurately measuring the intensity of light beams of from low intensity to high intensity. The intensity of a light beam to be measured is measured by a photodiode. A bias voltage is applied to the photodiode by a bias power source to improve the saturation characteristic. When the measured light beam is of high intensity, an analog switch and a photo MOS relay are switched on. When measuring a light beam with medium intensity, only the analog switch is turned off and a bias voltage is not applied to the photodiode. When measuring a light beam with low intensity, the bias voltage is not applied to the photodiode by switching off the photo MOS relay.

Abstract: A boundary or line-detecting process using image-filtering is used to detect fabric faults in moving textile fabric webs. A double-slit mask or an electrical equivalent thereof is used as a filter. The output signal of the filter is formed from the difference between the two luminosity values averaged across each slit of the filter mask. The image-filtering system is realized either by non-coherent optical spatial filters or by means of digital electronic circuits. The surface of the fabric web generally has a certain texture which already contains boundary and line elements. These basic values are used to derive fabric-specific parameters from which the boundary or line elements due to fabric faults are deducted. The boundary or line elements which remain, owing to their increased contrast, unambiguously indicate faults in the fabric web.