EP1128660A2
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EP
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Image processing apparatus
Assignee: Olympus Corp
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Filing: 2001-02-21
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Granted: —
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Expires: 2021-02-21
Abstract
Abstract This invention is an image processing apparatus including a photographing condition estimation unit (13) for estimating a photographing condition of the input image on the basis of photometric information of a photometric evaluation unit (7) and focal information of a focal point detection unit (8); a Y/C separation unit (12) for separating the input image into a luminance signal and a color difference signal; a luminance correction unit (17) for extracting an edge from the luminance signal and correcting the luminance signal by a gradation conversion curve obtained by weighting depending on the photographing condition; a color difference correction unit (18) for performing correction on the color difference signal on the basis of luminance signals obtained before and after the gradation correction and a theoretical limit characteristic of color reproduction; a skin color correction unit (41) for performing skin color correction or the like depending on the photographing condition; a Y/C synthesis unit (19) for synthesizing the luminance signal and the color difference signal obtained after the correction. The image processing apparatus performs gradation correction on the input image such that appropriate hue and saturation are achieved while emphasizing a main object.
Inventors
- 👤 Takao Tsuruoka
- 👤 Kazuhito Horiuchi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 09:58
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/46; H04N1/56; H04N1/60; H04N1/6083; H04N1/40; H04N1/407; H04N1/4072; H04N1/4074; H04N1/6027; H04N1/6086; H04N23/00; H04N23/60; H04N23/61; H04N23/611; H04N23/667; H04N23/70; H04N23/76; H04N25/00; H04N25/50; H04N25/57; H04N25/571; H04N25/575; H04N9/00; H04N9/64; H04N9/643
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
57 words
An image processing apparatus characterized by adjusting
a gradation range of an input image, comprising: photographing condition estimation means for estimating
a photographing condition of the input image; and gradation correction means for performing gradation
correction on the input image on the basis of the photographing
condition to adjust the gradation range to a predetermined
gradation range.
Claim 2
Dependent Claim
135 words
An image processing apparatus characterized by adjusting
a gradation range of an input image, comprising: luminance-color difference separation means for
separating the input image into a luminance signal and a color
difference signal; gradation correction means for performing gradation
correction on the luminance signal to adjust the gradation range
to a predetermined gradation range; color difference correction means for correcting the color
difference signal on the basis of a luminance signal obtained
before the gradation correction and output from the
luminance-color difference separation means, a luminance signal
obtained after the gradation correction and output from the
gradation correction means, and a theoretical limit
characteristic of color reproduction; and luminance-color difference synthesis means for
synthesizing the luminance signal obtained after the gradation
correction and a color difference signal obtained after the
correction into an image signal.
Claim 3
Dependent Claim
159 words
An image processing apparatus characterized by adjusting
a gradation range of an input image, comprising: photographing condition estimation means for estimating
a photographing condition of the input image; luminance-color difference separation means for
separating the input image into a luminance signal and a color
difference signal; gradation correction means for performing gradation
correction of the luminance signal on the basis of the
photographing condition to adjust the gradation range to a
predetermined gradation range; color difference correction means for performing
correction of the color difference signal on the basis of a
luminance signal obtained before the gradation correction and
output from the luminance-color difference separation means,
a luminance signal obtained after gradation correction and output
from the gradation correction means, and a theoretical limit
characteristic of color reproduction; and luminance-color difference synthesis means for
synthesizing an image signal on the basis of the luminance signal
obtained after the gradation correction and a color difference
signal obtained after the correction.
Claim 4
Dependent Claim
110 words
An image processing apparatus characterized by processing
an image group constituted by a plurality of images obtained
by picking up the same object under different exposure conditions
to generate one wide dynamic range image, comprising: photographing condition estimation means for estimating
a photographing condition; extraction means for extracting an appropriate exposure
region on the basis of an image signal level of each image in
the image group; gradation correction means for performing gradation
correction on the appropriate exposure region on the basis of
the photographing condition; and synthesis means for synthesizing appropriate exposure
regions subjected to gradation correction by the gradation
correction means to generate one wide dynamic range image.
Claim 5
Dependent Claim
205 words
An image processing apparatus characterized by processing
an image group constituted by a plurality of images obtained
by picking up the same object under different exposure conditions
to generate one wide dynamic range image, comprising: luminance-color difference separation means for
separating an image signal of each image in the image group into
a luminance signal and a color difference signal; extraction means for extracting an appropriate exposure
region on the basis of a signal level of the luminance signal; gradation correction means for performing gradation
correction on a luminance signal of the appropriate exposure
region; color difference correction means for performing
correction on a color difference signal of the appropriate
exposure region on the basis of a luminance signal obtained before
the gradation correction and output from the luminance-color
difference separation means, a luminance signal obtained after
gradation correction and output from the gradation correction
means, and a theoretical limit characteristic of color
reproduction; luminance-color difference synthesis means for
synthesizing an image signal on the basis of the luminance signal
obtained after the gradation correction and a color difference
signal obtained after the correction; and synthesis means for synthesizing the synthesized image
signal of the appropriate exposure regions to generate one wide
dynamic range image.
Claim 6
Dependent Claim
221 words
An image processing apparatus characterized by processing
an image group constituted by a plurality of images obtained
by picking up the same object under different exposure conditions
to generate one wide dynamic range image, comprising: photographing condition estimation means for estimating
a photographing condition; luminance-color difference separation means for
separating an image signal of each image in the image group into
a luminance signal and a color difference signal; extraction means for extracting an appropriate exposure
region on the basis of a signal level of the luminance signal; gradation correction means for performing gradation
correction on the luminance signal of the appropriate exposure
region on the basis of the photographing condition; color difference correction means for performing
correction on a color difference signal of the appropriate
exposure region on the basis of a luminance signal obtained before
the gradation correction and output from the luminance-color
difference separation means, a luminance signal obtained after
gradation correction and output from the gradation correction
means, and a theoretical limit characteristic of color
reproduction; luminance-color difference synthesis means for
synthesizing an image signal on the basis of the luminance signal
obtained after the gradation correction and a color difference
signal obtained after the correction; and synthesis means for synthesizing the synthesized image
signal of the appropriate exposure regions to generate one wide
dynamic range image.
Claim 7
Dependent Claim
51 words
An image processing apparatus according to claim 1, 3, 4,
or 6, characterized in the photographing condition estimation means estimates
a photographing condition on the basis of at least one piece
of information of focal information, photometric information,
zoom position information, multi-spot photometric information,
line-of-sight input information, and strobe flash information.
Claim 8
Dependent Claim
111 words
An image processing apparatus according to claim 1, 3, 4,
or 6, characterized in the photographing condition estimation means comprises: focal position estimation means for estimating at least
three types of focal positions including a scenic photographing
operation, a portraiture photographing operation, and a close-up
photographing operation from the focal information; object distribution estimation means for estimating at
least three types of object distributions of an entire screen,
a center focus, and a central portion from the photometric
information; and integration means for integrally estimating a
photographing condition by combining the focal position
estimated by the focal position estimation means and the object
distribution estimated by the object distribution estimation
means.
Claim 9
Dependent Claim
104 words
An image processing apparatus according to claim 1, 3, 4,
or 6, characterized in the gradation correction means comprises: selection means for selecting an arrangement of a weight
coefficient on the basis of the photographing condition; characteristic amount calculation means for calculating
a characteristic amount with respect to the input image; histogram generation means for generating a weighting
histogram related to the characteristic amount on the basis of
the arrangement of the weight coefficient; gradation conversion curve calculation means for
calculating a gradation conversion curve on the basis of the
histogram; and conversion means for performing gradation conversion by
using the gradation conversion curve.
Claim 10
Dependent Claim
78 words
An image processing apparatus according to claim 2 or 5,
characterized in the gradation correction means comprises: characteristic amount calculation means for calculating
a characteristic amount related to the luminance signal; histogram generation means for generating a histogram
related to the characteristic amount; gradation conversion curve calculation means for
calculating a gradation conversion curve on the basis of the
histogram; and luminance conversion means for performing gradation
conversion of a luminance signal by using the gradation
conversion curve.
Claim 11
Dependent Claim
99 words
An image processing apparatus according to claim 2, 3, 5,
or 6, characterized in the color difference correction means comprises: first calculationmeans for calculating a first correction
coefficient on the basis of a luminance signal obtained before
the gradation correction and the theoretical limit
characteristic of color reproduction; second calculation means for calculating a second
correction coefficient on the basis of the luminance signal
obtained after the gradation correction and the theoretical limit
characteristic of color reproduction; and color difference conversion means for converting a color
difference signal by using the first correction coefficient and
the second correction coefficient.
Claim 12
Dependent Claim
48 words
An image processing apparatus according to claim 3 or 6,
further comprising: second color difference correction means for correcting
at least one of a hue and a saturation of a specific color in
the color difference signal obtained after the correction on
the basis of the photographing condition.
Claim 13
Dependent Claim
26 words
An image processing apparatus according to claim 1, 2, or
3, characterized in the gradation correction means adjusts a gradation range
by reducing the gradation range.
Claim 14
Dependent Claim
128 words
A recording medium characterized by recording a process
program, executed by a computer, for adjusting a gradation range
of an input image, the process program comprising: the step of separating the input image into a luminance
signal and a color difference signal; the step of performing gradation correction on the
luminance signal to adjust the gradation range to a predetermined
gradation range; the step of performing correction on the color difference
signal on the basis of a luminance signal obtained before the
gradation correction, a luminance signal obtained after the
gradation correction, and a theoretical luminance
characteristic of color reproduction; and the step of synthesizing an image signal on the basis of
the luminance signal obtained after gradation correction and
a color difference signal obtained after the correction.
Claim 15
Dependent Claim
196 words
A recording medium characterized by recording a process
program, executed by a computer, for processing an image group
constituted by a plurality of images obtained by image pickup
performed to the same object under different exposure conditions
to generate one wide dynamic range image, the process program
comprising: the step of separating an image signal of each image in
the image group into a luminance signal and a color difference
signal; the step of extracting an appropriate exposure region on
the basis of a signal level of the luminance signal; the step of performing gradation correction on a luminance
signal of the appropriate exposure region; the step of performing correction on a color difference
signal of the appropriate exposure region on the basis of a
luminance signal obtained before the gradation correction, a
luminance signal obtained after gradation correction, and a
theoretical limit characteristic of color reproduction; the step of synthesizing an image signal on the basis of
the luminance signal obtained after the gradation correction
and a color difference signal obtained after the correction;
and the step of synthesizing the synthesized image signal of
the appropriate exposure regions to generate one wide dynamic
range image.
References Cited (Backward Citations)
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