| 摘要 |
PROBLEM TO BE SOLVED: To diagnose white turbidity reliably, by detecting dirt of a lens due to white turbidity stably.SOLUTION: An optical signal transmitted through a lens 12 is converted in a photoelectric conversion section 14 into an image signal. An area detection section 20 detects a substantially circular area Rof a predetermined area or more having a luminance value exceeding a predetermined lightness. A luminance gradient calculation section 30 sets a search direction (line) from a predetermined search start point O toward a predetermined direction in the area R, reads the luminance value of pixels on the line thus set, and calculates the luminance gradient g on that line. Furthermore, a white turbidity calculation section 40 calculates the white turbidity U of the lens 12 on the basis of the luminance gradient g. |
