Imaging apparatus, imaging method, integrated circuit, and storage medium

An imaging apparatus comprising:

• an optical system operable to focus light from a subject;
• a light amount adjustment unit operable to adjust an amount of light that is incident on the optical system;
• an imaging unit operable to read an optical image of the subject that is formed with the light focused by the optical system, and output the read optical image as an image signal that is used to form an image including pixels;
• an A/D converter operable to convert an analogue image that is output from the imaging unit to a digital image;
• a drive unit operable to drive the imaging unit in a manner that the imaging unit obtains a plurality of analogue images through a plurality of sequential divisional exposures each of which is performed for an identical exposure time, a total exposure time of the divisional exposures being equal to a predetermined exposure time;
• and
• a dynamic-range increasing unit operable to increase a dynamic range of corresponding pixels of a plurality of digital images resulting from conversion of the plurality of analogue images performed by the A/D converter and add up the corresponding pixels of the digital images to form an image with an increased dynamic range, and output the image with the increased dynamic range.

An imaging apparatus comprising:

• an optical system operable to focus light from a subject;
• a light amount adjustment unit operable to adjust an amount of light that is incident on the optical system;
• an imaging unit operable to read an optical image of the subject that is formed with the light focused by the optical system, and output the read optical image as an image signal that is used to form an image including pixels;
• an A/D converter operable to convert an analogue image that is output from the imaging unit to a digital image;
• a drive unit operable to drive the imaging unit in a manner that the imaging unit obtains a plurality of analogue images through a plurality of sequential divisional exposures that are performed to prevent an output of the A/D converter from being saturated;
• and
• a dynamic-range increasing unit operable to increase a dynamic range of corresponding pixels of a plurality of digital images resulting from conversion of the plurality of analogue images performed by the A/D converter and add up the corresponding pixels of the digital images to form an image with an increased dynamic range, and output the image with the increased dynamic range.

An imaging method used in an imaging apparatus that includes an optical system operable to focus light from a subject, a light amount adjustment unit operable to adjust an amount of light that is incident on the optical system, an imaging unit operable to read an optical image of the subject that is formed with the light focused by the optical system and output the read optical image as an image signal that is used to form an image including pixels, an A/D converter operable to convert an output of the imaging unit through analogue-to-digital conversion, and a digital signal processing unit operable to adjust an output value of the A/D converter,

• the imaging method comprising:
• decreasing the amount of light using the light amount adjustment unit;
• and
• linearly increasing a dynamic range of an output of the A/D converter with an increase that is set according to the decreased amount of light using the digital signal processing unit.

A computer-readable storage medium that stores a program executed by a control unit of an imaging apparatus that includes an optical system operable to focus light from a subject, a light amount adjustment unit operable to adjust an amount of light that is incident on the optical system, an imaging unit operable to read an optical image of the subject that is formed with the light focused by the optical system and output the read optical image as an image signal that is used to form an image including pixels, an A/D converter operable to convert an output of the imaging unit through analogue-to-digital conversion, a digital signal processing unit operable to adjust an output value of the A/D converter, and the control unit operable to control the light amount adjustment unit and the digital signal processing unit,

• the program enabling the control unit to:
• generate a signal for decreasing the light amount using the light amount adjustment unit;
• and
• linearly increase a dynamic range of an output of the A/D converter with an increase that is set according to the decreased amount of light using the digital signal processing unit.

A computer-readable storage medium that stores a program executed by a control unit of an imaging apparatus that includes an optical system operable to focus light from a subject, a light amount adjustment unit operable to adjust an amount of light that is incident on the optical system, an imaging unit operable to read an optical image of the subject that is formed with the light focused by the optical system and output the read optical image as an image signal that is used to form an image including pixels, an A/D converter operable to convert an analogue image output from the imaging unit to a digital image, a digital signal processing unit operable to adjust an output value of the A/D converter, and the control unit operable to control the light amount adjustment unit, the imaging unit, and the digital signal processing unit,

• the program enabling the control unit to:
• drive the imaging unit in a manner that the imaging unit obtains a plurality of analogue images through a plurality of sequential divisional exposures each of which is performed for an identical exposure time, a total exposure time of the divisional exposures being equal to a predetermined exposure time;
• and
• increase a dynamic range of corresponding pixels of a plurality of digital images resulting from conversion of the plurality of analogue images performed by the A/D converter and add up the corresponding pixels of the digital images to form an image with an increased dynamic range, and output the image with the increased dynamic range.

An integrated circuit used together with an optical system that focuses light from a subject, the integrated circuit comprising:

• a light amount adjustment unit operable to adjust an amount of light that is incident on the optical system;
• an imaging unit operable to read an optical image of the subject that is formed with the light focused by the optical system and output the read optical image as an image signal that is used to form an image including pixels;
• an A/D converter operable to convert an analogue image output from the imaging unit to a digital image;
• a drive unit operable to drive the imaging unit in a manner that the imaging unit obtains a plurality of analogue images through a plurality of sequential divisional exposures each of which is performed for an identical exposure time, a total exposure time of the divisional exposures being equal to a predetermined exposure time;
• and
• a dynamic-range increasing unit operable to increase a dynamic range of corresponding pixels of a plurality of digital images resulting from conversion of the plurality of analogue images performed by the A/D converter and add up the corresponding pixels of the digital images to form an image with an increased dynamic range, and output the image with the increased dynamic range.

For an imaging apparatus equipped with an optical system, a computer logic device comprising:

• a two-dimensional lookup table;
• a computer logic storage device readable by a digital processing system;
• and instructions embodied in the logic storage device, the instructions being executable by the digital processing system for performing method steps for undertaking a soft decision, the method steps comprising:
• increasing a dynamic range of an output value of a signal resulting from analogue-to-digital conversion with a dynamic range increase ratio,
• adjusting the output value according to a peak value of image data that is formed using the signal whose dynamic range has been magnified, and
• obtaining an output value using a conversion characteristic stored in the two-dimensional lookup table according to the adjusted image signal and a vicinity luminance value of the image signal.