Imaging apparatus, imaging method, integrated circuit, and storage medium
First Claim
1. An imaging apparatus, comprising:
- an optical system operable to adjust an exposure light amount;
an A/D converter operable to receive an analogue signal obtained by the optical system, and convert the analogue signal that is obtained by the optical system to a digital signal;
a dynamic-range increasing unit operable to increase an output value of the digital signal with a dynamic range magnification ratio;
a control unit operable to generate control signals, one for decreasing the exposure light amount and another for increasing the dynamic range magnification ratio;
a dynamic-range compression unit operable to compress the increased value of the digital signal so as to output a value that is within a predetermined range; and
a representative value detection unit operable to detect a representative value of a predetermined portion of image data that is formed using the digital signal,wherein the dynamic-range compression unit compresses the increased value of the digital signal in a manner that a peak value is converted to be a maximum value of the predetermined range, and the control unit generates, in accordance with the maximum value, the signal for decreasing the exposure light amount, which is a signal for adjusting the exposure light amount according to the representative value, and the signal for increasing the dynamic range magnification ratio.
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Accused Products
Abstract
An imaging apparatus captures a large dynamic range image of a scene including a backlit person with a blue sky background in a manner that the person'"'"'s face has an appropriate luminance level without saturating the background sky. An imaging unit obtains analogue image signals through exposure control that prevents a highlight from being saturated, an A/D converter converts the analogue image signals to digital image signals, and a signal processing unit linearly increases the dynamic range of the digital image signals. The image signals with the increased dynamic range are nonlinearly compressed to have a dynamic range of 100% or less through nonlinear dynamic range compression that intensively compresses a highlight portion. The imaging apparatus with this structure first increases the dynamic range of an image and efficiently compresses the increased large dynamic range of the image.
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Citations
15 Claims
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1. An imaging apparatus, comprising:
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an optical system operable to adjust an exposure light amount; an A/D converter operable to receive an analogue signal obtained by the optical system, and convert the analogue signal that is obtained by the optical system to a digital signal; a dynamic-range increasing unit operable to increase an output value of the digital signal with a dynamic range magnification ratio; a control unit operable to generate control signals, one for decreasing the exposure light amount and another for increasing the dynamic range magnification ratio; a dynamic-range compression unit operable to compress the increased value of the digital signal so as to output a value that is within a predetermined range; and a representative value detection unit operable to detect a representative value of a predetermined portion of image data that is formed using the digital signal, wherein the dynamic-range compression unit compresses the increased value of the digital signal in a manner that a peak value is converted to be a maximum value of the predetermined range, and the control unit generates, in accordance with the maximum value, the signal for decreasing the exposure light amount, which is a signal for adjusting the exposure light amount according to the representative value, and the signal for increasing the dynamic range magnification ratio. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An imaging apparatus, comprising:
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an optical system operable to adjust an exposure light amount; an A/D converter operable to receive an analogue signal obtained by the optical system, and convert the analogue signal that is obtained by the optical system to a digital signal; a dynamic-range increasing unit operable to increase an output value of the digital signal with a dynamic range magnification ratio; a control unit operable to generate control signals, one for decreasing the exposure light amount and another for increasing the dynamic range magnification ratio; a dynamic-range compression unit operable to compress the increased value of the digital signal so as to output a value that is within a predetermined range; and a representative value detection unit operable to detect a representative value of a predetermined portion of image data that is formed using the digital signal, wherein the dynamic-range compression unit compresses the increased value of the digital signal in a manner that a peak value is converted to be a maximum value of the predetermined range, and the control unit generates, in accordance with the maximum value, the signal for decreasing the exposure light amount, and the signal for increasing the dynamic range magnification ratio, which is a signal for adjusting the dynamic range magnification ratio according to the representative value.
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11. An imaging method used in an imaging apparatus that includes an optical system operable to adjust an exposure light amount, and an A/D converter operable to receive an analogue signal obtained by the optical system and convert the analogue signal to a digital signal, the imaging method comprising:
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(A) increasing the digital signal with a dynamic range magnification ratio; (B) in accordance with a maximum value of image data formed by the increased digital signal, generating control signals, one for decreasing the exposure light amount and another for increasing the dynamic range magnification ratio; (C) in accordance with the maximum value of image data formed by the increased digital signal, compressing the increased value of the digital signal so as to output a value that is within a predetermined range; and (D) detecting a representative value of a predetermined portion of image data that is formed using the digital signal, wherein the step (C) compresses the increased value of the digital signal in a manner that a peak value is converted to be a maximum value of the predetermined range, and the step (B) generates, in accordance with the maximum value, the signal for decreasing the exposure light amount, which is a signal for adjusting the exposure light amount according to the representative value, and the signal for increasing the dynamic range magnification ratio. - View Dependent Claims (12)
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13. An integrated circuit used in an imaging apparatus that includes an optical system operable to adjust an exposure light amount, and an A/D converter operable to receive an analogue signal obtained by the optical system and convert the analogue signal to a digital signal, the integrated circuit comprising:
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a dynamic-range increasing unit operable to increase the digital signal with a dynamic range magnification ratio; a control unit operable to generate, in accordance with a maximum value of image data formed by the increased digital signal, control signals, one for decreasing the exposure light amount and another for increasing the dynamic range magnification ratio; a dynamic-range compression unit operable to compress, in accordance with the maximum value of image data formed by the increased digital signal, the increased value of the digital signal so as to output a value that is within a predetermined range; and a representative value detection unit operable to detect a representative value of a predetermined portion of image data that is formed using the digital signal, wherein the dynamic-range compression unit compresses the increased value of the digital signal in a manner that a peak value is converted to be a maximum value of the predetermined range, and the control unit generates, in accordance with the maximum value, the signal for decreasing the exposure light amount, which is a signal for adjusting the exposure light amount according to the representative value, and the signal for increasing the dynamic range magnification ratio.
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14. An imaging method used in an imaging apparatus that includes an optical system operable to adjust an exposure light amount, and an A/D converter operable to receive an analogue signal obtained by the optical system and convert the analogue signal to a digital signal, the imaging method comprising:
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(A) increasing the digital signal with a dynamic range magnification ratio; (B) in accordance with a maximum value of image data formed by the increased digital signal, generating control signals, one for decreasing the exposure light amount and another for increasing the dynamic range magnification ratio; (C) in accordance with the maximum value of image data formed by the increased digital signal, compressing the increased value of the digital signal so as to output a value that is within a predetermined range; and (D) detecting a representative value of a predetermined portion of image data that is formed using the digital signal, wherein the step (C) compresses the increased value of the digital signal in a manner that a peak value is converted to be a maximum value of the predetermined range, and the step (B) generates, in accordance with the maximum value, the signal for decreasing the exposure light amount, and the signal for increasing the dynamic range magnification ratio, which is a signal for adjusting the dynamic range magnification ratio according to the representative value. - View Dependent Claims (15)
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Specification