In an apparatus for reading-out features such as characters and marks recorded on an object such as labels, boxes and cards, the object is scanned by a linear CCD array to produce a video signal and a background level is detected from the video signal on the basis of an edge signal derived from the video signal. A plurality of slice levels having span and pitch adjusted according to said background level are generated and the video signal is compared with the slice levels to produce an output video signal. Even if the level of the video signal changes abruptly, it is possible to obtain more accurate output video signal and to remove error in pattern recognition. In another preferred embodiment, an amplitude of the video signal is adjusted by a variable attenuator in accordance with the detected background level.

Reading-out apparatus

An apparatus for converting an analog input signal to a binary output signal, particularly for use in a facsimile system. The apparatus includes a reference level generator having its input terminal supplied with the analog input signal, a signal dividing circuitry connected between the input and output terminals of the reference level generator, an integrator having one end connected with the dividing output terminal of the signal dividing circuitry and the other end connected with a common potential level point in the apparatus and a comparator having one input terminal connected with the signal dividing output terminal of the dividing circuitry and the other input terminal connected with the input terminal of the reference level generator. The reference level on the basis of which the analog input signal is converted to a binary signal is thus adjusted for satisfactory conversion of the signal.

Apparatus for converting an analog signal to a binary signal

An apparatus for processing video signals received from an optical scanner is described. A comparator means is used for comparing the video signals with a dynamic threshold voltage. This threshold voltage is generated by a peak detector circuit which also receives the video signals. The peak detector circuit includes decay means for decaying signals representative of the detected peaks at a predetermined rate. This thresholding technique provides compensation for a wide dynamic range of video signals received from a photodiode array.

William R. Smith

Papers

Apparatus for processing video signals received from an optical scanner