Patent EP0713342A2 successfully refreshed from Google Patents.
EP0713342A2
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Color image sensing apparatus and method of expanding dynamic range
Assignee: Canon Inc
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Filing: 1995-11-17
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Granted: —
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Expires: 2015-11-17
Abstract
Abstract Disclosed is an image processing method of expanding the dynamic range by determining a saturated or noise region in an image signal and replacing the image signal with a proper image signal. A threshold value (step S4) is set in units of colors on the basis of a standard image signal for each color, which is obtained upon sensing an image in a standard exposure, and a non-standard image signal for each color, which is obtained upon sensing the image in a non-standard exposure. A saturated or noise region is determined by applying the threshold value set in units of colors to the standard image signal. A region determined as a saturated or noise region is replaced with the non-standard image signal.
Inventors
- 👤 Eiichiro c/o Canon K.K. Ikeda
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 17:25
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/64; H04N9/646; H04N23/00; H04N23/70; H04N23/80; H04N23/84; H04N23/843; H04N25/00; H04N25/10; H04N25/11; H04N25/13; H04N25/133; H04N25/135; H04N25/136; H04N2209/00; H04N2209/04; H04N2209/041; H04N2209/042; H04N2209/045; H04N2209/046
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
84 words
An image processing method of determining whether an image signal output from an image sensing device through a predetermined color filter is improper, characterized by comprising: the threshold value setting step (S4, S13) of setting a threshold value in correspondence with a color filter of said image sensing device; and the determination step (S5, S13) of determining, in units of colors, whether each chrominance signal output from said image sensing device and color-separated is improper by using the threshold value corresponding to each color.
Claim 2
Dependent Claim
138 words
An image processing method of determining whether an image signal output from an image sensing device through a predetermined color filter is improper, characterized by comprising: the threshold value setting step (S4, S13) of setting a threshold value in correspondence with each filter of said image sensing device; the sensing step of sensing an image in advance by said image sensing device in a standard exposure and in a non-standard exposure to obtain a standard image signal and a non-standard image signal corresponding to each color; the determination step (S5, S13) of determining whether the standard image signal of one color is improper by using the threshold value set in correspondence with the color; and the replacement step (S5, S15) of replacing the standard image signal determined as an improper image signal with the corresponding non-standard image signal.
Claim 3
Dependent Claim
37 words
The method according to claim 2, wherein the threshold value setting step includes the step of determining the threshold value corresponding to the color on the basis of the standard image signal and the non-standard image signal.
Claim 4
Dependent Claim
49 words
The method according to claim 2, wherein the threshold value setting step includes the step of determining the threshold value corresponding to one color depending on whether a degree of change in non-standard image signal with respect to the standard image signal obtained in the sensing step is large.
Claim 5
Dependent Claim
49 words
The method according to claim 2, wherein the threshold value setting step includes the step of obtaining the non-standard image signal in an exposure amount smaller than a standard exposure amount when it is to be determined whether the image signal obtained from said image sensing device is saturated.
Claim 6
Dependent Claim
49 words
The method according to claim 2, wherein the threshold value setting step includes the step of obtaining the non-standard image signal in an exposure amount larger than a standard exposure amount when it is to be determined whether the image signal obtained from said image sensing device is dark-noisy.
Claim 7
Dependent Claim
81 words
An image processing method of determining a saturated region of an image signal output from an image sensing device through a predetermined color filter, characterized by comprising: the threshold value setting step (S13) of setting a threshold value in units of colors in correspondence with a color filter of said image sensing device; and the determination step (S13) of determining the saturated region in each chrominance signal output from said image sensing device and color-separated by using a minimum threshold value.
Claim 8
Dependent Claim
76 words
The method according to claim 7, wherein the threshold value setting step includes the steps of sensing an image in advance by said image sensing device in a standard exposure and in a non-standard exposure to obtain a standard image signal and a non-standard image signal corresponding to each color; and setting the threshold value for the color on the basis of the obtained standard image signal and the non-standard image signal of a certain color.
Claim 9
Dependent Claim
91 words
The method according to claim 7, wherein the threshold value setting step comprises: the step of sensing an image in advance by said image sensing device in a standard exposure to obtain a standard image signal of one color; the step of sensing the image in advance by said image sensing device in a non-standard exposure to obtain a non-standard image signal of the color; and the step of determining the threshold value corresponding to the color on the basis of the obtained standard image signal and the non-standard image signal.
Claim 10
Dependent Claim
42 words
The method according to claim 9, wherein the threshold value setting step includes the step of calculating the threshold value corresponding to one color by using an average value of a difference between the standard image signal and the non-standard image signal.
Claim 11
Dependent Claim
44 words
The method according to claim 9, wherein the threshold value setting step includes the step of determining the threshold value corresponding to one color depending on whether a degree of change in non-standard image signal with respect to the standard image signal is large.
Claim 12
Dependent Claim
81 words
An image processing method of determining a noise region of an image signal output from an image sensing device through a predetermined color filter, characterized by comprising: the threshold value setting step (S13) of setting a threshold value in units of colors in correspondence with a color filter of said image sensing device; and the determination step (S13) of determining the noise region in each chrominance signal output from said image sensing device and color-separated by using a maximum threshold value.
Claim 13
Dependent Claim
76 words
The method according to claim 12, wherein the threshold value setting step includes the steps of sensing an image in advance by said image sensing device in a standard exposure and in a non-standard exposure to obtain a standard image signal and a non-standard image signal corresponding to each color, and setting the threshold value for the color on the basis of the obtained standard image signal and the non-standard image signal of a certain color.
Claim 14
Independent Claim
40 words
The method according to any one of claims 1, 2 or 12, wherein the determination step includes the step of determining the image signal as improper when the image signal is an image signal from a saturated image sensing device.
Claim 15
Independent Claim
40 words
The method according to any one of claims 1, 2 or 12, wherein the determination step includes the step of determining the image signal as improper when the image signal is an image signal from a low-sensitivity image sensing device.
Claim 16
Independent Claim
48 words
The method according to any one of claims 1, 2 or 12, wherein the determination step includes the step of applying the threshold value set in the threshold value setting step to a signal of a standard image sensed by said image sensing device in a standard exposure.
Claim 17
Independent Claim
97 words
The method according to any one of claims 1, 2 or 13, wherein the threshold value setting step comprises: the step of sensing an image in advance by said image sensing device in a standard exposure to obtain a standard image signal of one color; the step of sensing an image in advance by said image sensing device in a non-standard exposure to obtain a non-standard image signal of the color; and the step of determining the threshold value corresponding to the color on the basis of the obtained standard image signal and the non-standard image signal.
Claim 18
Dependent Claim
42 words
The method according to claim 17, wherein the threshold value setting step includes the step of calculating the threshold value corresponding to one color by using an average value of a difference between the standard image signal and the non-standard image signal.
Claim 19
Dependent Claim
44 words
The method according to claim 17, wherein the threshold value setting step includes the step of determining the threshold value corresponding to one color depending on whether a degree of change in non-standard image signal with respect to the standard image signal is large.
Claim 20
Dependent Claim
49 words
The method according to claim 17, wherein the threshold value setting step includes the step of obtaining the non-standard image signal in an exposure amount smaller than a standard exposure amount when it is to be determined whether the image signal obtained from said image sensing device is saturated.
Claim 21
Dependent Claim
49 words
The method according to claim 17, wherein the threshold value setting step includes the step of obtaining the non-standard image signal in an exposure amount larger than a standard exposure amount when it is to be determined whether the image signal obtained from said image sensing device is dark-noisy.
Claim 22
Dependent Claim
38 words
The method according to claim 7, further comprising the steps of obtaining a non-standard signal in a non-standard exposure, and replacing the image signal determined as the saturated region in the determination step with the non-standard image signal.
Claim 23
Dependent Claim
38 words
The method according to claim 12, further comprising the steps of obtaining a non-standard signal in a non-standard exposure, and replacing the image signal determined as the saturated region in the determination step with the non-standard image signal.
Claim 24
Dependent Claim
18 words
The method according to claim 22, further comprising the step of performing smoothing processing of the replaced image.
Claim 25
Dependent Claim
18 words
The method according to claim 23, further comprising the step of performing smoothing processing of the replaced image.
Claim 26
Dependent Claim
82 words
An image processing apparatus which determines whether an image signal output from an image sensing device through a predetermined color filter is improper, characterized by comprising: threshold value setting means (S4, S13) for setting a threshold value in correspondence with a color filter of said image sensing device; and determination means (S5, S13) for determining, in units of colors, whether each chrominance signal output from said image sensing device and color-separated is improper by using the threshold value corresponding to each color.
Claim 27
Dependent Claim
135 words
An image processing apparatus which determines whether an image signal output from an image sensing device through a predetermined color filter is improper, characterized by comprising: threshold value setting means (S4, S13) for setting a threshold value in correspondence with a color filter of said image sensing device; sensing means for sensing an image in advance by said image sensing device in a standard exposure and in a non-standard exposure to obtain a standard image signal and a non-standard image signal corresponding to each color; determination means (S5, S13) for determining whether the standard image signal of one color is improper by using the threshold value set in correspondence with the color; and replacement means (S5, S15) for replacing the standard image signal determined as an improper image signal with the corresponding non-standard image signal.
Claim 28
Dependent Claim
79 words
An image processing apparatus for determining a saturated region of an image signal output from an image sensing device through a predetermined color filter, characterized by comprising: threshold value setting means (S13) for setting a threshold value in units of colors in correspondence with a color filter of said image sensing device; and determination means (S13) for determining the saturated region in each chrominance signal output from said image sensing device and color-separated by using a minimum threshold value.
Claim 29
Dependent Claim
79 words
An image processing apparatus for determining a noise region of an image signal output from an image sensing device through a predetermined color filter, characterized by comprising: threshold value setting means (S13) for setting a threshold value in units of colors in correspondence with a color filter of said image sensing device; and determination means (S13) for determining the noise region in each chrominance signal output from said image sensing device and color-separated by using a maximum threshold value.
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