Controllable gated sensor

• US 9,723,233 B2
• Filed: 08/03/2016
• Issued: 08/01/2017
• Est. Priority Date: 04/18/2012
• Status: Active Grant

• Current Assignee: BrightWay Vision Ltd.
• Original Assignee: BrightWay Vision Ltd.
• Inventors: Levi, Eyal, Grauer, Yoav
• Primary Examiner(s): Gaworecki, Mark R
• Application Number:
  US15/226,973
• Publication Number:
  US 20160344965A1
• Time in Patent Office: 363 Days
• CPC Class Codes: H01L 27/1203 the substrate comprising an insulating body on a semiconductor body, e.g. SOI three-dimensional layout H01L27/0688
• CPC Class Codes: H01L 27/14609 Pixel-elements with integrated switching, control, storage or amplification elements scanning details of imagers (circuitry of solid-state image sensors H04N25/00); circuitry of imagers H04N25/70
• CPC Class Codes: H01L 27/14621 Colour filter arrangements
• CPC Class Codes: H01L 27/14627 Microlenses
• CPC Class Codes: H01L 27/14634 Assemblies, i.e. Hybrid structures
• CPC Class Codes: H01L 27/14643 Photodiode arrays; MOS imagers
• CPC Class Codes: H01L 27/14656 Overflow drain structures
• CPC Class Codes: H04N 23/11 for generating image signals from visible and infrared light wavelengths
• CPC Class Codes: H04N 23/56 provided with illuminating means
• CPC Class Codes: H04N 25/131 including elements passing infrared wavelengths
• CPC Class Codes: H04N 25/135 based on four or more different wavelength filter elements
• CPC Class Codes: H04N 25/40 Extracting pixel data from image sensors by controlling scanning circuits, e.g. by modifying the number of pixels sampled or to be sampled
• CPC Class Codes: H04N 25/53 Control of the integration time
• CPC Class Codes: H04N 25/532 by controlling global shutters in CMOS SSIS
• CPC Class Codes: H04N 25/58 involving two or more exposures
• CPC Class Codes: H04N 25/587 acquired sequentially, e.g. using the combination of odd and even image fields
• CPC Class Codes: H04N 25/622 by controlling anti-blooming drains
• CPC Class Codes: H04N 25/623 by evacuation via the output or reset lines
• CPC Class Codes: H04N 25/70 SSIS architectures; Circuits associated therewith

Abstract

A single pixel sensor is provided, comprising a photo sensor configured to convert light into proportional signals; a charge storage configured to accumulate, repeatedly, a plurality of the signals converted by the photosensor; a first transistor coupled between a pixel voltage terminal and the photosensor; a second transistor coupled between the photosensor and the charge storage; and a readout circuit coupled between the charge storage and an output channel, wherein: the single pixel sensor is configured to carry out the repeated accumulations of signals multiple times per each readout by the readout circuit to synchronously convert reflections of light emitted by the illuminator, and to carry out at least one of the repeated accumulations of signals in at least partial overlap with at least one light pulse generated by the pulsed illuminator.

Claims

1. An imaging and/or ranging system comprising a pulsed illuminator and at least one gated imaging array comprising a plurality of single pixel sensors, wherein at least one of the single pixel sensors comprises:

a photosensor configured to convert light into proportional signals;

a charge storage configured to accumulate, repeatedly, a plurality of the signals converted by the photosensor;

a first transistor coupled between a pixel voltage terminal and the photosensor;

a second transistor coupled between the photosensor and the charge storage; and

a readout circuit coupled between the charge storage and an output channel,

wherein the single pixel sensor is configured to carry out the repeated accumulations of signals multiple times per each readout by the readout circuit, to synchronously convert reflections of light emitted by the illuminator, and

wherein the single pixel sensor is further configured such that the period of at least one of the repeated accumulations of signals at least partially overlaps the period of at least one light pulse generated by the pulsed illuminator.

2. The system of claim 1, further configured to generate images of a scene from the readout circuit and to adjust the at least partial overlap to enhance short range image elements.

3. The system of claim 1, further configured to adjust the at least partial overlap according to requirements from an associated advanced driver assistance system (ADAS) and/or autonomous driving functions.

4. The system of claim 1, further configured to apply indirect time of flight (iTOF) algorithms with respect to the at least partial overlap.

5. The system of claim 1, further configured to carry out image processing prior to outputting a video signal.

6. The system of claim 5, wherein the image processing further comprises combining data from at least one of:

one or more image frames, one or more pixel clusters, multiple pixels and image frames captured with different partial overlaps.

7. The system of claim 5, further comprising data storage configured to store the image frames readouts temporarily, wherein the image processing is carried out with respect to stored image frames readouts.

8. The system of claim 1, further configured to synchronize its output according to a predefined video protocol.

9. The system of claim 1, further configured to derive a scene visibility from at least one of the repeated accumulations.

10. The system of claim 9, further configured to adjust operation parameters of the at least one gated imaging array according to the derived scene visibility.

11. The system of claim 9, further configured to adjust the at least partial overlap according to the derived scene visibility.

12. The system of claim 9, wherein the scene visibility comprises an environmental backscattering measure.

13. The system of claim 9, further configured to derive the scene visibility from at least one of the repeated accumulations that at least partially overlaps at least one light pulse.

14. The system of claim 13, further configured to derive the scene visibility at different distances from the illuminator according to a measure of the at least partial overlap between the at least one of the repeated accumulations and the at least one light pulse.

15. The imaging system of claim 14, further configured to determine the at least partial overlap and the at least one overlapped light pulse according to the scene visibility at different distances from the illuminator.

16. The imaging system of claim 1, further configured to determine the at least partial overlap and the at least one overlapped light pulse according to a scene visibility at different distances from the illuminator.

17. The imaging system of claim 1, wherein specified pixel clusters in the at least one gated imaging array are further configured to operate with different durations of the signal accumulations.

18. The imaging system of claim 1, wherein specified pixel clusters in the at least one gated imaging array are further configured to operate with different partial overlap periods and the system is further configured to use at least one of the pixel clusters to collect ambient light, use a plurality of the pixel clusters to collect image signals and derive an image from the collected image signals and the collected ambient light.

19. The imaging system of claim 1, wherein the system is further configured to derive a functionality test result from at least one of the repeated accumulations.

20. The imaging system of claim 1, wherein the first transistor is configured to control a resetting of the photosensor and the first and second transistors are configured to control a transfer of the accumulated signal to the charge storage.

21. The imaging system of claim 1, further comprising a reset transistor coupled between the charge storage and the pixel voltage terminal and configured to reset the charge pixel storage after at least one signal readout and/or at beginnings of signal accumulation periods.

22. The imaging system of claim 1, further comprising a voltage controlling element connected to the charge storage and configured to determine a signal level in the charge storage.

23. The imaging system of claim 1, further configured to operate in SWIR (short wave infrared) and optionally in visible range.

24. A method comprising:

accumulating, repeatedly, in a charge storage of a single pixel sensor, a plurality of signals that are proportionally converted by a photosensor from corresponding light,

controlling a resetting of the photosensor by a first transistor coupled between a pixel voltage terminal and the photosensor,

controlling a transfer of the accumulated signal to the charge storage by a second transistor coupled between the photosensor and the charge storage, and

configuring the single pixel sensor to carry out the repeated accumulations of signals multiple times per each readout of the charge storage by a pixel readout circuit,

wherein the single pixel sensor is configured to synchronously convert reflections of light emitted by an illuminator, and to carry out at least one of the repeated accumulations of signals in a period at least partially overlapping with a period of at least one light pulse generated by the pulsed illuminator.

25. The method of claim 24, further comprising deriving a scene visibility from at least one of the repeated accumulations.

26. The method of claim 24, further comprising adjusting at least one of the accumulating, the controlling and the at least partial overlap according a scene visibility.

27. The method of claim 24, further comprising adjusting different pixel clusters of the sensor to have different at least one of the accumulating, the controlling and the at least partial overlap, and fusing data from pixel readouts from the pixel clusters.

28. The method of claim 24, further comprising:

controlling, by the first transistor, a resetting of the photosensor prior to each signal accumulation period, and

transferring, by the second transistor, at least a portion of the accumulated signal from the photosensor to the charge storage.

29. The method of claim 24, further comprising adjusting the at least partial overlap to enhance short range image elements.

30. The method of claim 24, further comprising adjusting the at least partial overlap according to ADAS and/or autonomous driving functions.

31. The method of claim 24, further comprising applying indirect time of flight algorithms with respect to the at least partial overlap.

32. The method of claim 24, further comprising processing at least one image frame and/or pixel clusters prior to outputting a video signal.

33. The method of claim 32, further comprising storing image frames readout temporarily and synchronizing the output according to a predefined video protocol.