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EP0064557A1 Expired / Lapsed EP ⏱️ 0.0 years remaining

Picture signal reading method

Assignee: Fujitsu Ltd
•
Filing: 1981-11-11
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Granted: —
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Expires: 2001-11-11
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Abstract

Abstract A picture signal reading system with step-by-step sub- scanner when the transmitting time for one line is short in facsimile equipment which reads picture information while moving an original (1). When the picture information is read while moving the original (1), the quantity of charge stored in an image sensor (6) becomes insufficient. When the picture signal is identified at a fixed threshold level TH in such a case, an error occurs in the reading. In order to eliminate this problem, a threshold level controlling circuit (14) is provided to move the threshold level in response to the transmitting time for one line divided into blocks. When the transmitting time for the picture signal in one line thus read is short, the threshold level of the next scanning is raised, and when it is long, the threshold level of the next scanning is lowered.

Inventors

  • 👤 Takeshi Amemiya

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-09 22:15
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/41; H04N1/411; H04N1/413; H04N1/415; H04N1/40; H04N1/403

Claims Analysis

Total Claims: 3
Claim 1
Independent Claim 136 words
A picture signal read system where a manuscript paper is fed line by line as much as width of the main scanning in the subscanning direction, the white level and black level of the picture signal obtained by reading the picture data of said manuscript in the main scanning direction are discriminated with reference to the specified threshold level, and only the block including the black level picture signal is sent by detecting the black level picture signal for individual blocks obtained by dividing a scanning line into specified number, thus characterized in that the threshold level in the next scanning is shifted when the number of blocks including said black level picture signal is less than the specified number, and said picture data is read while the manuscript paper is fed in said sub-scanning direction.
Claim 2
Dependent Claim 136 words
A picture signal read system where a manuscript paper is fed line by line as much as width of the main scanning in the subscanning direction, the white level and black level of the picture signal obtained by reading the picture data of said manuscript in the main scanning direction are discriminated with reference to the specified threshold level, and only the block including the black level picture signal is sent by detecting the black level picture signal for individual blocks obtained by dividing a scanning line into specified number, thus characterized in that the threshold level in the next scanning is shifted when the number of blocks including said black level picture signal is less than the specified number, and said picture data is read while the manuscript paper is fed in said sub-scanning direction.
Claim 3
Dependent Claim 74 words
A picture signal read system as claimed in claim 1 where said threshold level shifting means comprises the count means which counts the blocks including said black level signal and the change-over means which changes over the switch circuits connecting resistors having different resistance values in accordance with the signal sent from said count means, thus characterized in that an output of ,said switch circuit is given as the reference signal of the comparator.

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