INTERLINE CHARGE-COUPLED DEVICES

• US 20160344967A1
• Filed: 02/02/2016
• Published: 11/24/2016
• Est. Priority Date: 05/18/2015
• Status: Active Grant

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Analog Devices, Inc.
• Inventors: BARNES, ERIK D., GOLDBERG, JONATHAN
• Granted Patent: US 9,749,565 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01S 17/10 using transmission of interrupted, pulse-modulated waves determination of distance by phase measurements G01S17/32
• CPC Class Codes: G01S 17/36 with phase comparison between the received signal and the contemporaneously transmitted signal
• CPC Class Codes: G01S 17/894 3D imaging with simultaneous measurement of time-of-flight at a 2D array of receiver pixels, e.g. time-of-flight cameras or flash lidar
• CPC Class Codes: G01S 7/4863 Detector arrays, e.g. charge-transfer gates
• CPC Class Codes: H04N 25/713 Transfer or readout registers; Split readout registers or multiple readout registers
• CPC Class Codes: H04N 25/73 using interline transfer [IT]

Abstract

Image capturing systems with interline CCD structures designed to reduce the delay between captures of subsequent image frames are disclosed. Proposed interline CCD structures include two or more sets of storage units associated with a given set of photodetecting elements, where each photodetecting element is associated with one storage unit of each set of storage units in that the charge generated by the photodetecting element during the acquisition of a particular image frame (i.e. during a particular exposure period) may be stored any one of these storage units prior to read-out. Providing multiple sets of storage units allows read-out of charge corresponding to one image frame and stored in one set of storage units while accumulating charge corresponding to another image frame in another set of storage units, thus reducing the delay between captures of different image frames. Consequently, errors and artifacts of the image capturing system can be minimized.

Claims

1. An image acquisition system comprising:

an interline charge-coupled device (CCD) sensor comprising

a plurality of photodetecting elements,

a plurality of first CCD storage units for storing a charge accumulated by the plurality of photodetecting elements during an acquisition of one image frame comprising multiple exposures, and

a plurality of second CCD storage units for storing a charge accumulated by the plurality of photodetecting elements during an acquisition of another image frame comprising multiple exposures; and

a controller configured to ensure that at least a part of the charge accumulated during the acquisition of one image frame is read out during the acquisition of another image frame.

2. The image acquisition system according to claim 1, wherein each photodetecting element of the plurality of photodetecting elements is associated with one first CCD storage unit of the plurality of first CCD storage units and with one second CCD storage unit of the plurality of second CCD storage units.

3. The image acquisition system according to claim 2, wherein the first CCD storage unit associated with the photodetecting element is provided on the same lateral side of the photodetecting element as the second CCD storage unit associated with the photodetecting element.

4. The image acquisition system according to claim 3, wherein said one image frame is a second image frame and said another image frame is a first image frame, and the controller is configured to ensure that:

the plurality of photodetecting elements transfer the charge accumulated by the plurality of photodetecting elements during the acquisition of the first image frame to the plurality of first CCD storage units,

the plurality of first CCD storage units transfer the charge accumulated during the acquisition of the first image frame and obtained from the plurality of photodetecting elements to the plurality of second CCD storage units, and

following the transfer from the plurality of the first CCD storage units to the plurality of second CCD storage units, the plurality of photodetecting elements transfer the charge accumulated by the plurality of photodetecting elements during the acquisition of the second image frame to the plurality of first CCD storage units.

5. The image acquisition system according to claim 2, wherein the first CCD storage unit associated with the photodetecting element is provided on a different lateral side of the photodetecting element as the second CCD storage unit associated with the photodetecting element.

6. The image acquisition system according to claim 5, wherein said one image frame is a first image frame and said another image frame is a second image frame, and the controller is configured to ensure that:

the plurality of photodetecting elements transfer the charge accumulated by the plurality of photodetecting elements during the acquisition of the first image frame to the plurality of first CCD storage units, and

the plurality of photodetecting elements transfer the charge accumulated by the plurality of photodetecting elements during the acquisition of the second image frame to the plurality of second CCD storage units.

7. The image acquisition system according to claim 5, wherein the plurality of first CCD storage units comprises a vertical CCD while the plurality of second CCD storage units comprises a horizontal CCD or vice versa.

8. The image acquisition system according to claim 1, wherein each of the plurality of first CCD storage units and the plurality of second CCD storage units comprises a vertical CCD or each of the plurality of first CCD storage units and the plurality of second CCD storage units comprises a horizontal CCD.

9. The image acquisition system according to claim 1, further comprising an illumination source configured to provide light detected by the plurality of photodetecting elements.

10. The image acquisition system according to claim 9, wherein the light provided by the illumination source comprises pulsed light.

11. The image acquisition system according to claim 10, wherein the image acquisition system is a Time-Of-Flight system, further comprising one or more processors configured to determine distance to one or more objects based on the acquired image frames.

12. A computer-implemented method for controlling an interline charge-coupled device (CCD) sensor comprising a plurality of photodetecting elements, a plurality of first CCD storage units for storing a charge accumulated by the plurality of photodetecting elements during an acquisition of one image frame, and a plurality of second CCD storage units for storing a charge accumulated by the plurality of photodetecting elements during an acquisition of another image frame, the method comprising:

ensuring that at least a part of the charge accumulated during the acquisition of one image frame comprising multiple exposures is read out during the acquisition of another image frame comprising multiple exposures.

13. The computer-implemented method according to claim 12, wherein said one image frame is a second image frame and said another image frame is a first image frame, and the method further comprises:

ensuring that the plurality of photodetecting elements transfer the charge accumulated by the plurality of photodetecting elements during the acquisition of the first image frame to the plurality of first CCD storage units,

ensuring that the plurality of first CCD storage units transfer the charge accumulated during the acquisition of the first image frame and obtained from the plurality of photodetecting elements to the plurality of second CCD storage units, and

ensuring that, following the transfer from the plurality of the first CCD storage units to the plurality of second CCD storage units, the plurality of photodetecting elements transfer the charge accumulated by the plurality of photodetecting elements during the acquisition of the second image frame to the plurality of first CCD storage units.

14. The computer-implemented method according to claim 12, wherein said one image frame is a second image frame and said another image frame is a first image frame, and the method further comprises:

ensuring that the plurality of photodetecting elements transfer the charge accumulated by the plurality of photodetecting elements during the acquisition of the first image frame to the plurality of first CCD storage units, and

ensuring the plurality of photodetecting elements transfer the charge accumulated by the plurality of photodetecting elements during the acquisition of the second image frame to the plurality of second CCD storage units.

15. The computer-implemented method according to claim 12, further comprising:

performing Time-Of-Flight computations to determine distance to one or more objects based on the acquired image frames.

16. A non-transitory computer readable storage medium storing software code portions configured for, when executed on a processor, carrying out a method for controlling an interline charge-coupled device (CCD) sensor comprising a plurality of photodetecting elements, a plurality of first CCD storage units for storing a charge accumulated by the plurality of photodetecting elements during an acquisition of one image frame, and a plurality of second CCD storage units for storing a charge accumulated by the plurality of photodetecting elements during an acquisition of another image frame, the method comprising

ensuring that at least a part of the charge accumulated during the acquisition of one image frame comprising multiple exposures is read out during the acquisition of another image frame comprising multiple exposures.

17. The non-transitory computer readable storage medium according to claim 16, wherein said one image frame is a second image frame and said another image frame is a first image frame, and the software code portions are further configured for:

ensuring that the plurality of photodetecting elements transfer the charge accumulated by the plurality of photodetecting elements during the acquisition of the first image frame to the plurality of first CCD storage units,

ensuring that the plurality of first CCD storage units transfer the charge accumulated during the acquisition of the first image frame and obtained from the plurality of photodetecting elements to the plurality of second CCD storage units, and

ensuring that, following the transfer from the plurality of the first CCD storage units to the plurality of second CCD storage units, the plurality of photodetecting elements transfer the charge accumulated by the plurality of photodetecting elements during the acquisition of the second image frame to the plurality of first CCD storage units.

18. The non-transitory computer readable storage medium according to claim 16, wherein said one image frame is a second image frame and said another image frame is a first image frame, and the software code portions are further configured for:

ensuring that the plurality of photodetecting elements transfer the charge accumulated by the plurality of photodetecting elements during the acquisition of the first image frame to the plurality of first CCD storage units, and

ensuring the plurality of photodetecting elements transfer the charge accumulated by the plurality of photodetecting elements during the acquisition of the second image frame to the plurality of second CCD storage units.

19. The non-transitory computer readable storage medium according to claim 16, wherein the software code portions are further configured for:

performing Time-Of-Flight computations to determine distance to one or more objects based on the acquired image frames.