JPH0417371B

An apparatus for detecting the presence of a foreign matter on each solid drug by scanning the surface of the solid drug with the use of a television camera and generating a pulse signal when the level of a scanning signal thereof exceeds a predetermined value. The apparatus comprises a shift register for temporarily storing, for each address, the pulse signal per scan line of the camera and for outputing the same sequentially for each address during the next succeeding scan, an OR gate for receiving both an address output from the shift register and the next succeeding address output, an AND gate for receiving both an output from the OR gate and an output at the address corresponding to the address output at the next succeeding scan line, a counter for counting pulse signals fed from the AND gate, and an output circuit for generating a detection signal indicative of the detection of foreign matter when the count of the counter is greater than a predetermined value, whereby a pulse signal bridging between the neighboring addresses and also between the adjoining scan lines can be taken out by the counter so that foreign matter of a length and width corresponding to the output thereof can be detected.