| 摘要 |
<p>PROBLEM TO BE SOLVED: To simply and surely make a focus adjustment characteristic quantitative for a color television receiver or the like. SOLUTION: A pattern generator 2 supplies a focus measurement pattern signal with a pattern consisting of two relative colors arranged as a grid for a prescribed constant period in longitudinal and lateral directions to a color TV 1 being a inspection object. A CCD camera 3 as a photoelectric conversion means photographs a prescribed range of a pattern image displayed on a screen, and the photographing signal is digitized and stored in an address of an image memory 5 depending on a position of the image. An FFT converter 6 calculates a frequency component for each image position from read image data. A focus value calculation means 7 extracts a frequency component of a period of an odd number image among frequency components to calculate a focus value. A CPU 8 displays the focus calculated value on the screen of a display means. The operator adjusts a focus variable resistor of the color TV 1 so as to maximize the focus value displayed on the screen of the display means. Thus, the focus is always adjusted constant independently of the adjustment skill of the operator and the focus inspection characteristic is made quantitative.</p> |
