Abstract: An optical reader system includes a plurality of sensor elements for providing a picture signal. Before initiating an actual reading operation, a white background plate is scanned to obtain reference information. The white background plate data is reversed to obtain a reciprocal of the white level and the thus obtained reciprocal is memorized in a memory. In an actual reading operation, the picture signal derived from the sensor elements is multiplied by the reciprocal memorized in the memory to compensate for the nonuniformity of the sensor outputs.

Abstract: An optical image reading apparatus comprises a solid state image sensor having a plurality of blocks, means for generating video signals correponding to an object to be read out by the solid state image sensor, means for determining respective mean values of the video signals concerning the blocks, means for storing the mean values in digital information, means for reading out the stored mean value and converting the digital information to analog information, and means for determining a corrected slice level in each of the blocks.

Abstract: An image sensor output correcting system wherein a correcting region of an object being read is scanned in advance by means of a sensor array, thereby to provide a correcting signal based on the signal obtained in the scanning operation for correcting the scanning video signal of the region being read, characterized in that the video signal obtained during the scanning operation of the correcting region is sampled with a predetermined interval, the video signals of the sensor corresponding to a plurality of scanning lines are compared, and the maximum value is stored as the correcting signal, whereby high speed scanning can be made without degrading the correcting function as compared with a system where the outputs of the respective sensors of the sensor array are analog to digital converted to generate the correcting signal.

Abstract: An image information reading apparatus, wherein another comparator having a deep slice level is provided apart from a usual comparator having an ordinary slice level, and determination is made continuously as to whether a white portion of a small area is included in the black background being scanned and either of the said two comparators is enabled as a function of the determination, whereby a clear reproduced image is obtained with ease.

Abstract: Optical information on a card is read by an image sensor and then converted to a video signal represented by a digital signal of several bits through the use of an amplifier and an A - D converter. A reference level is determined by scanning a reference portion which is preferably provided along one edge of the card. The video signal is quantized by comparing with three sliced levels corresponding to 0.5, 0.75 and 0.85 times the reference level. The quantized information is applied to a recognition station.