| 摘要 |
PURPOSE:To reliably decide a defect part of a fine signal, by a method wherein a delay differentiation of a photographing signal is conducted 2 times, the obtained signal is binary-codes to store it in a memory, and a processing takes place based on a content thereof. CONSTITUTION:A signal (a) from a camera 1 is amplified, and it produces a signal as shown in (b) which is inputted to a differential amplifier 4 and a delay circuit 3. The delay circuit 3 applies a signal (c), delaying by some time, to the differential amplifier 4, and a difference between the signal (c) and the signal (b) is found to perform a first delay differentiation. Then, a good product inclines to some extent, and if a contamination of a defect is present, it is formed into a wave-form which changed in the middle of the inclination. A signal (d), which is delay-differentiated once, is inputted to a differential amplifier 6 and a delay circuit 5, and a second delay differentiation takes place through addition of a delayed signal (e). A signal, on which a delay-differentiated is made two times, is applied to a comparator 7, a negative reference level (g) is added for comparison, and in the case of a good product, the binary-coded signal produces a pulse, and in the case of a bad product, it produces 2 pulses. A signal (h) is inputted to a counter 9 to store it in a memory 11. Meanwhile, an output (f) of the differential amplifier 6 is compared with a reference level (k) by a comparator 8, and an output (l) is stored in a memory 12 to decide a deciding circuit 13. |
