Further, according to the invention, the Schmitt trigger generator consisting of triodes 175 and 176, resistors 177, v178, 179,207 and 209, ‘capacitors 210 and 211, the inte grator sampling and resetting generator 199, resetting pulse cathode follower 201 associated with resistors 202, V ' 203, 204 and 212, potential pider 194control1ing the noise sensitivity of the integrator and the potential pider 180 biasing the coupling diodes 157 and 158 of channel one, represent a separate control unit common to ‘all amplifying systems each of which is identical to that shown in FIG. 10. The outputs and inputs of the said control unit are tied to many ‘ampli?ers by terminals 213, 214, 215, 216, 217, 218 and 219. The corresponding connections of many amplifying systems can also be con nected to the said terminals, and such amplifying systems do not interact with each other. With the present inven tion, whichever ampli?er system ?rst detects the defect, and which in turn raises the output potential of its cath ode-follower 181 above the mean level of say 225 volts, will switch off all other output cathode-followers ‘paral leled at terminal 218. ' Changes may be made in the above and many ‘appar ently widely different embodiments constructed without departing from the spirit ‘or the essential characteristics of the invention. ' What I claim is: . . 51. In apparatus for detect-ing defects in moving sheet materials having substantially uniform re?ection charac teristics, which senses, by photoelectric means, variations ' in the intensity of light re?ected from the sunface of such a material as it'passes over an inspection surface, an im proved inspection head comprising an ‘aperture plate mounted parallel to said inspection surface, and closely’v adjacent thereto, means de?ning an elongated narrow aperture in said plate extending transversely to the di rection of motion of said material over said inspection . surface, illumination means positioned to each side'of said aperture for illuminating that section ‘of said mate rial passing oversaid surface below said aperture, the in tensity of said illumination from each side of said aper ture being substantially the same over said section of ma terial, photoelectric means positioned adjacent said aper ture responsive only todiifused ?ight re?ected from said section of material passing through said aperture, the di mension of said aperture in the ‘direction of motion of the sheet material being of the same order of magnitude as the diameter of the smallest ‘and most intense defect. Y ‘to be detected, and said aperture having a dimension trans 55 60 65 70 75 versely to the direction of motion of the sheet material substantially greater than the size ‘of the average texture discontinuity of the unblemished sheet material, and of the order of magnitude of the length of the faintest and narrowest defect extending at right angles to said direc tion of motion which produces a variation upon the in tensity of the light re?ected from said surface of said ma terial substantially equivalent to that produced by said smallest and 'most intense defect to be detected. 7 2. In apparatus for detecting defects in moving sheet materials having substantially'unifonm re?ection charac teristics, which senses, by photoelectric means, variations in the intensity of light re?ected from the surface of such a material as it passes over an inspection surface, an im proved inspection head comprising a ‘light-tight housing mounted above said inspection surface [and having a lower surface parallel thereto, an elongated narrow aperture in said lower surface extending transversely to the direction of motion of said material’, over said inspection surface, the dimension of said aperture in the direction of motion of the sheet material \beiug‘of the same order of magnitude ‘ as the diameter of the smallest and most intense defect to be detected, and said aperture having a dimension trans 光电检测与分选机器英文文献和中文翻译(12):http://www.youerw.com/fanyi/lunwen_35843.html