| 摘要 |
PURPOSE:To secure an accurate convergence compensated variable, by compensating a pattern picture signal to be outputted out of a light receiving element by a correction factor dependent upon a spectral light emitting characteristic of a phosphor in a color cathode-ray tube to be measured, and a spectral sensitivity characteristic of each light receiving element for red, green and blue colors of a color TV camera picking up a measuring pattern of the picture tube. CONSTITUTION:Each output of light receiving elements for red, green and blue colors for a camera picking up a white color pattern on a color cathode-ray tube is compensated by a correction factor dependent upon a spectral light emitting characteristic of a phosphor of the color cathode-ray tube and a spectral sensitivity characteristic of a light receiving element at the camera side. Accordingly, each light receiving element output after compensation, that is, the pattern image signal divided into three primary colors comes to a unicolorous pattern image signal of red, green and blue each. With this constitution, luminance center-of-gravity of the pattern image of each color such as red, green and blue can be accurately found out, so that a convergence compensated variable is also accurately findable.
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