Image analysis – Histogram processing – For setting a threshold
Patent
1984-05-25
1987-09-01
Kreitman, Stephen A.
Image analysis
Histogram processing
For setting a threshold
G06K 936
Patent
active
046913653
ABSTRACT:
An image reading apparatus has a CCD for reading an original image, a standard white plate for providing a standard image signal, a control circuit for controlling light amount and temperature of a fluorescent lamp as a light source, a CPU for controlling the operation sequence of the overall apparatus, a RAM for storing a standard image signal corresponding to the standard white plate, a ROM storing a control program for the CPU, and a display for displaying an error. An image signal of an original read by the CCD is corrected in accordance with the standard image signal. For example, an average value of a block of four pixel image signals, for example, is calculated and is compared with an average value of the standard image signals obtained by reading the standard surface a plurality of times. An abnormal pixel signal is replaced with an immediately preceding normal pixel signal or a predetermined signal pattern. An abnormal light amount or temperature of the fluorescent lamp is detected in accordance with the standard signal corresponding to the standard surface exposed by the lamp.
REFERENCES:
patent: 4314281 (1982-02-01), Wiggins et al.
patent: 4408231 (1983-10-01), Bushaw et al.
patent: 4430748 (1984-02-01), Tuhro et al.
patent: 4464789 (1984-08-01), Sternberg
patent: 4541116 (1985-09-01), Lougheed
Canon Kabushiki Kaisha
Kreitman Stephen A.
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