发明名称 Image readout apparatus
摘要 An image readout apparatus for photoelectrically reading an image of an original document which is suitable for use in a facsimile apparatus to transmit and receive the image data of the original document. This apparatus includes: a CCD image sensor to read an image and generate electric data indicative of the image; a reference white plate; a memory to store the reference data obtained by reading the white plate by the image sensor; a correction circuit to correct the image data obtained by reading an original document with the image sensor on the basis of the reference data stored in the memory; and a control circuit for allowing the white plate to be read by the image sensor and allowing the reference data to be stored in the memory even when the original document cannot be read by the image sensor. When the time required to read the original document with the image sensor is above a predetermined time, on the other hand, the control circuit allows the white plate to be read by the image sensor and allows the reference data to be stored in the memory. With this apparatus, the proper slice level is set and a good readout image can be derived.
申请公布号 US4870501(A) 申请公布日期 1989.09.26
申请号 US19870041076 申请日期 1987.04.21
申请人 CANON KABUSHIKI KAISHA 发明人 YOSHIDA, TEKEHIRO
分类号 H04N1/401 主分类号 H04N1/401
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