Image scanner

Assignee: Konica Minolta Inc

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Filing: 1990-12-24

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Granted: —

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Expires: 2010-12-24

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Abstract

Abstract This invention relates to an image scanning apparatus and more particularly to the scanning apparatus for use in a digital copier which obtains a negative image from an image of an original. A color image signal is generated from an image sensor by sensing a reflected light from an original through a scanner and an optical filter, and is converted to an image data consisting of a color code and a luminance data. Color histograms and summarised histogram are produced from the image data, which represent luminance distributions for each color code and a total luminance distribution. A pattern class for each histogram is identified by checking histogram shape, and coefficient data of mutual transfer function and gamma data are selected from data tables according to the identified pattern class. The luminance data are corrected in accordance with the selected coefficient data and gamma data.

Inventors

👤 Toshiro Fujimori

Bibliographic Details

Application Number —

Jurisdiction EP

Data Source google_patents

Last Synchronized 2026-11-09 13:40

CPC Classifications

H; H04; H04N; H04N1/00; H04N1/40; H04N1/407; H04N1/4072; H04N1/4074; H04N1/46; H04N1/56; H04N1/60; H04N1/6027

Claims Analysis

Total Claims: 5

Claim 1

Independent Claim 191 words

An image scanning apparatus comprising: means for generating a color image signal in response to a reflected light from an original; means for converting the color image signal into image data having a color code data and a luminance data; means for generating a marker signal based on the image data to indicate a marker position in a line of a scanning; means for converting the luminance data into negative image luminance data in accordance with the marker signal; means for producing color histograms and a summarised histogram from the image data, wherein each of the color histograms represents a luminance distribution of the image data having same color code and the summarised histogram represents a total luminance distribution of the color histograms; means for recognizing shape of each of the color and summarised histograms and identifying a pattern class of each of the color and summarised histograms in accordance with the recognized shape; gamma-selecting means for selecting a predetermined gamma data from a plurality of stored gamma data in accordance with the identified pattern class; and gamma-correcting means for correcting the luminance data in accordance with the selected gamma data.

Claim 2

Dependent Claim 34 words

The image scanning apparatus of Claim 1, wherein the color image signal generating means comprises means for color-separating the reflected light whereby the color image signal is generated in accordance with the color-separated light.

Claim 3

Dependent Claim 16 words

The image scanning apparatus of Claim 1, further comprising means for correcting the color code data.

Claim 4

Dependent Claim 44 words

The image scanning apparatus of Claim 1, further comprising: coefficient-selecting means for selecting a set of coefficient data for modulation transfer function in accordance with the identified pattern class; and gradation-correcting means for correcting the luminance data in accordance with the selected coefficient data.

Claim 5

Dependent Claim 205 words

An image scanning apparatus comprising: means for generating a color image signal in response to a reflected light from an original: means for converting the color image signal into image data having a color code data and a luminance data; means for generating a marker signal based on the image data to indicate a marker position in a line of a scanning; means for converting the luminance data into negative image luminance data in accrdance with the marker signal; means for producing color histograms and a summarised histogram in accordance with the color code data and the luminance data of the image data, wherein each of the color histograms represents a luminance distribution of luminance data with each color code and the summarised histogram represents a total luminance distribution; means for recognizing shape of each of the color and summarised histograms and identifying a pattern class of each of the color and summarised histograms in accordance with the recognized shape; coefficient-selecting means for selecting a set of coefficient data for modulation transfer function from a plurality of sets of stored coefficient data in accordance with the selected pattern class; and gradation correcting means for correcting the luminance data in accordance with the selected coefficient data.

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