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EP0481808A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Image processing device and image processing method

Assignee: Fujitsu Ltd
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Filing: 1991-10-18
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Granted: —
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Expires: 2011-10-18
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Abstract

Abstract Prior to a binary conversion process on a gray-scale image, a user predetermines a binary conversion threshold corresponding to original image density data and stores it in a binary conversion threshold storage unit. In the binary conversion process, the user applies the original image density data to an image processing unit. A binary conversion threshold setter reads a corresponding binary conversion threshold from the binary conversion threshold storage unit based on the original image density data, and the binary conversion processing unit performs a binary conversion process of the original density data based on the minimized average error method using the binary conversion threshold. Thus, the present invention enables desirable reproduction of drawings including characters, eliminating grain noises, and obtaining a high quality image both in drawings and gray-scale portions. The operational error reducer reduces operational errors generated in an average error operation performed in the minimized average error method, and minimizes the deterioration in gradation caused by an operational error.

Inventors

  • 👤 Seiichi Itoh

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-09 12:33
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/405; H04N1/4051; H04N1/4052; H04N1/4053; H04N1/403

Claims Analysis

Total Claims: 9
Claim 1
Independent Claim 56 words
An image processing device comprising: a quantizing means for quantizing image input; a binary conversion processing means utilized in a minimized average error method for binary-conversion processing a gray-scale image using the minimized average error method; and a binary conversion threshold storing means for storing a binary conversion threshold corresponding to quantized original image density data.
Claim 2
Dependent Claim 86 words
An image processing device comprising: a quantizing means for quantizing image input; a binary-conversion processing means utilized in a minimized average error method for binary-conversion processing a gray-scale image using the minimized average error method; and a binary conversion threshold setting means for obtaining a corresponding binary conversion threshold from said binary conversion threshold storing means using quantized original image density data received from said binary-conversion processing means in said minimized average error method, and for sending the binary conversion threshold to said binary-conversion processing means.
Claim 3
Dependent Claim 103 words
An image processing device comprising: a quantizing means for quantizing image input; a binary-conversion processing means utilized in a minimized average error method for binary-conversion processing a gray-scale image using the minimized average error method; a binary conversion threshold storing means for storing a binary conversion threshold corresponding to quantized original image density data; and a binary conversion threshold setting means for obtaining a corresponding binary conversion threshold from said binary-conversion threshold storing means using quantized original image density data received from said binary-conversion processing means utilized in said minimized average error method, and for sending the binary-conversion threshold to said binary-conversion-processing means.
Claim 4
Dependent Claim 40 words
An image processing device according to Claim 3, wherein said binary conversion threshold setting means obtains said binary conversion threshold using quantized original image density data on each picture element to perform a binary conversion process on said picture element.
Claim 5
Dependent Claim 58 words
An image processing device according to Claim 3, wherein said binary conversion threshold setting means obtains said binary conversion threshold using an average value of quantized original image density data of a target picture element and a plurality of specified picture elements surrounding said targert picture element to perform a binary conversion process on a single picture element.
Claim 6
Dependent Claim 34 words
An image processing unit according to Claim 3, wherein said binary-conversion processing means in said minimized average error method comprises an operational error reducing means for reducing operational errors associated with average error operation.
Claim 7
Dependent Claim 62 words
An image processing device comprising: a quantizing means for quantizing image input; and a binary-conversion processing means utilized in a minimized average error method for binary-conversion processing a gray-scale image using the minimized average error method, said binary-conversion processing means utilized in a minimized average error method comprising an operational error reducing means for reducing operational errors associated with average error operation.
Claim 8
Dependent Claim 48 words
An image processing method comprising obtaining: a step for obtaining a predetermined binary conversion threshold using quantized original image density data; and a step for performing a binary process on a picture element in the minimized average error method using the obtained binary conversion threshold as a threshold.
Claim 9
Dependent Claim 35 words
An image processing method for binary-conversion processing density information of each picture element of an original image in the minimized average error method, comprising: a step for reducing operational errors associated wiht average error operation.

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