Imaging device, imaging system, and imaging method

• US 8,212,912 B2
• Filed: 04/07/2009
• Issued: 07/03/2012
• Est. Priority Date: 04/10/2008
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Iijima, Tomokuni, Tamaki, Satoshi
• Primary Examiner(s): Ho, Tuan
• Assistant Examiner(s): Trehan, Akshay
• Application Number:
  US12/598,292
• Publication Number:
  US 20100128140A1
• Time in Patent Office: 1,183 Days
• Field of Search: 348/222.1, 348/263, 348/265, 348/335
• US Class Current: 348/335
• CPC Class Codes: H04N 23/55 Optical parts specially adapted for electronic image sensors; Mounting thereof
• CPC Class Codes: H04N 23/57 Mechanical or electrical details of cameras or camera modules specially adapted for being embedded in other devices
• CPC Class Codes: H04N 25/61 the noise originating only from the lens unit, e.g. flare, shading, vignetting or "cos4"
• CPC Class Codes: H04N 25/63 applied to dark current
• CPC Class Codes: H04N 25/633 by using optical black pixels
• CPC Class Codes: H04N 25/673 by using reference sources

Abstract

The number of thermal sensors in an imaging device that requires temperature measurement is reduced. The imaging device includes: a lens array (112) including lenses; an imaging element (122) provided at a predetermined distance from the lens array (112) and having imaging areas respectively corresponding to the lenses; a light-shielding wall (113) which partitions a space between the lens array and the imaging element so as to prevent light entering each of the lenses from reaching the imaging areas different from a corresponding one of the imaging areas; an imaging signal input unit (133) configured to generate an imaging signal by digitalizing an electric signal provided by the imaging element; and a temperature estimation unit (143) configured to calculate, from the imaging signal, a length of an image of the light-shielding wall projected on an imaging plane of the imaging element, and to estimate a temperature using the calculated length of the image of the light-shielding wall.

Claims

1. An imaging device for taking an image of an object, said imaging device comprising:

a lens array including a plurality of lenses;

an imaging element provided at a predetermined distance from said lens array and having a plurality of imaging areas respectively corresponding to said plurality of lenses;

a light-shielding wall which partitions a space between said lens array and said imaging element so as to prevent light entering each of said plurality of lenses from reaching said plurality of imaging areas different from a corresponding one of said plurality of imaging areas;

an imaging signal input unit configured to generate an imaging signal by digitalizing an electric signal provided by said imaging element; and

a temperature estimation unit configured to calculate, from the imaging signal, a length of an image of said light-shielding wall projected on an imaging plane of said imaging element, and to estimate a first temperature using the calculated length of the image of said light-shielding wall.

2. The imaging device according to claim 1, further comprising:

a thermal sensor which is provided near said lens array and detects a second temperature; and

a reliability calculation unit configured to calculate a reliability value of the second temperature based on the first temperature and the second temperature.

3. The imaging device according to claim 2,

wherein said reliability calculation unit is configured to calculate the reliability value such that a reliability of the second temperature is lower when a difference between the first temperature and the second temperature is larger.

4. The imaging device according to claim 2, further comprising:

a temperature compensation operation unit configured to estimate an amount of change in distance between optical axes of said plurality of lenses caused by a change in temperature from a predetermined temperature to the second temperature, and to correct, using the estimated amount of change, data obtained from the imaging signal; and

a distance calculation unit configured to calculate a disparity between images taken on said plurality of imaging areas, and a distance to the object using the data corrected by said temperature compensation operation unit.

5. The imaging device according to claim 2, further comprising

a notification unit configured to generate notification data for external notification when a reliability of the second temperature is determined to be low because the reliability value calculated by said reliability calculation unit exceeds a predetermined value.

6. The imaging device according to claim 1, further comprising

a lens tube of a tubular shape provided between said lens array and said imaging element to surround said light-shielding wall, wherein said lens tube includes at least a pair of grooves in an inner surface,

wherein said light-shielding wall is a platy member of a rectangular shape extending in a direction from the imaging plane of said imaging element to said lens array, and includes side edges fitted into said grooves of said lens tube so as to set said light-shielding wall in place, and at least two protruding portions protruding from a same plate surface of said platy member, and

wherein said temperature estimation unit is configured to estimate the first temperature using a length of an image between said protruding portions.

7. The imaging device according to claim 1, further comprising

a lens tube of a tubular shape provided between said lens array and said imaging element to surround said light-shielding wall, wherein said lens tube includes at least a pair of grooves in an inner surface,

wherein said light-shielding wall is a platy member extending in a direction from the imaging plane of said imaging element to said lens array, and includes a first plate portion having side edges fitted into said grooves of said lens tube, and a second plate portion protruding from said first plate portion toward the imaging plane, and

wherein said temperature estimation unit is configured to estimate the first temperature using a length of an image of said second plate portion.

8. An imaging system comprising:

said imaging device according to claim 4; and

a system control unit configured to perform predetermined control based on the distance to the object and the reliability value which are calculated by said imaging device.

9. An imaging method for use in an imaging device,

wherein the imaging device includes:

a lens array including a plurality of lenses;

an imaging element provided at a predetermined distance from the lens array and having a plurality of imaging areas respectively corresponding to the plurality of lenses; and

a light-shielding wall which partitions a space between the lens array and the imaging element so as to prevent light entering each of the plurality of lenses from reaching the plurality of imaging areas different from a corresponding one of the plurality of imaging areas, and

said imaging method comprises;

generating an imaging signal by digitalizing an electric signal provided by the imaging element; and

calculating, from the imaging signal, a length of an image of the light-shielding wall projected on an imaging plane of the imaging element, and estimating a temperature using the calculated length of the image of the light-shielding wall.

10. A non-transitory computer-readable medium having a computer program recorded thereon for execution by an imaging device,

wherein the imaging device includes:

a lens array including a plurality of lenses;

an imaging element provided at a predetermined distance from the lens array and having a plurality of imaging areas respectively corresponding to the plurality of lenses; and

a light-shielding wall which partitions a space between the lens array and the imaging element so as to prevent light entering each of the plurality of lenses from reaching the plurality of imaging areas different from a corresponding one of the plurality of imaging areas, and

said program, when executed, causes the imaging device to perform an imaging method comprising;

generating an imaging signal by digitalizing an electric signal provided by the imaging element; and

calculating, from the imaging signal, a length of an image of the light-shielding wall projected on an imaging plane of the imaging element, and estimating a temperature using the calculated length of the image of the light-shielding wall.