3D vision on a chip

• US 8,102,426 B2
• Filed: 12/18/2006
• Issued: 01/24/2012
• Est. Priority Date: 09/28/1998
• Status: Expired due to Fees

• Current Assignee: Microsoft International Holdings BV (Microsoft Corporation)
• Original Assignee: Microsoft International Holdings BV (Microsoft Corporation)
• Inventors: Yahav, Giora, Iddan, Gavriel Joseph
• Primary Examiner(s): NGUYEN, LUONG TRUNG
• Application Number:
  US11/612,021
• Publication Number:
  US 20070091175A1
• Time in Patent Office: 1,863 Days
• Field of Search: 348/300, 348/301
• US Class Current: 348/207.99
• CPC Class Codes: G01S 17/08 for measuring distance only indirect measurement G01S17/46; active triangulation systems G01S17/48
• CPC Class Codes: G01S 17/14 wherein a voltage or current pulse is initiated and terminated in accordance with the pulse transmission and echo reception respectively, e.g. using counters
• CPC Class Codes: G01S 17/18 wherein range gates are used
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 7/4863 Detector arrays, e.g. charge-transfer gates
• CPC Class Codes: H04N 13/207 using a single 2D image sensor
• CPC Class Codes: H04N 13/254 in combination with electromagnetic radiation sources for illuminating objects
• CPC Class Codes: H04N 23/56 provided with illuminating means
• CPC Class Codes: H04N 25/63 applied to dark current
• CPC Class Codes: H04N 25/76 Addressed sensors, e.g. MOS or CMOS sensors
• CPC Class Codes: H04N 25/77 Pixel circuitry, e.g. memories, A/D converters, pixel amplifiers, shared circuits or shared components
• CPC Class Codes: H04N 5/2226 Determination of depth image, e.g. for foreground/background separation determining depth by image analysis in general G06T7/50; segmentation by image analysis in general G06T7/10

Abstract

A 3D camera for determining distances to regions in a scene comprising: a photosurface having a plurality of pixels each of which comprises a circuit having a light sensitive element that provides a current responsive to light incident thereon, wherein the circuit comprises, at least one amplifier inside the pixel, having an input and an output; at least one feedback capacitor separate from the light sensitive element and connected between the input and output of each of the at least one amplifier; at least one controllable connection through which current flows from the light sensitive element into the input of the at least one amplifier; a light source; and, a controller that, controls the light source to illuminate the scene with light, opens and closes the at least one controllable connection to gate or modulate current from the light sensitive element of a pixel in the photosurface responsive to the time dependence of the gating or modulation of the light, controls the at least one controllable connection to provide a current for correcting biases caused by at least one of background light or dark current, and determines a distance to a region imaged on the pixel responsive to an amount of charge integrated on the feedback capacitor responsive to the gated or modulated current and the corrected biases.

Claims

1. A 3D camera for determining distances to regions in a scene comprising:

a photosurface having a plurality of pixels each of which comprises a circuit having a light sensitive element that provides a current responsive to light incident thereon, wherein the circuit comprises,

at least one amplifier inside each pixel, having an input and an output;

at least one feedback capacitor separate from the light sensitive element and connected between the input and output of each of the at least one amplifier;

at least one controllable connection inside each pixel through which the current flows from the light sensitive element into the input of the at least one amplifier;

a light source; and

a controller that,

controls the light source to illuminate the scene with gated light,

gates or modulates the current from the light sensitive element of each pixel in the photosurface through the at least one controllable connection by opening or closing the at least one controllable connection of each pixel in the photosurface to gate the pixel on and off responsive to the time dependence of the gating or modulation of the light,

controls the at least one controllable connection to correct for biases caused by at least one of background light or dark current, and

determines a distance to a region imaged on a pixel responsive to an amount of charge integrated on the at least one feedback capacitor responsive to the gated or modulated current and the corrected biases.

2. A 3D camera according to claim 1, wherein the at least one amplifier is an operational amplifier.

3. A 3D camera according to claim 2, wherein the circuit comprises at least one data bus and wherein the circuit comprises at least one address switch that connects a data bus of the at least one data bus to an output of one of the at least one amplifiers, either directly or via another switch.

10. A 3D camera according to claim 1, wherein the controller controls the light source to illuminate the scene with a plurality of light pulses, each having a pulse width, and wherein the controller gates the pixels in the photosurface on or off at times coordinated with times at which light pulses of the plurality of light pulses are radiated.

4. A 3D camera for determining distances to regions in a scene comprising:

a photosurface having a plurality of pixels each of which comprises a circuit having a light sensitive element that provides a current responsive to light incident thereon, wherein the circuit for each pixel comprises,

at least one amplifier inside each pixel, having an input and an output, the at least one amplifier being an operational amplifier;

at least one feedback capacitor separate from the light sensitive element and connected between the input and output of each of the at least one amplifier;

at least one controllable connection inside each pixel through which the current flows from the light sensitive element into the input of the at least one amplifier;

a light source; and

a controller that,

controls the light source to illuminate the scene with gated light,

gates or modulates the current from the light sensitive element of each pixel in the photosurface through the at least one controllable connection responsive to the time dependence of the gating or modulation of the light,

controls the at least one controllable connection to correct for biases caused by at least one of background light or dark current, and

determines a distance to a region imaged on a pixel responsive to an amount of charge integrated on the at least one feedback capacitor responsive to the gated or modulated current and the corrected biases;

wherein the at least one controllable connection comprises at least one gate switch and the controller opens and closes the at least one gate switch to gate the pixel on and off and determines the distance to the region imaged on the pixel responsive to an amount of charge integrated on the at least one feedback capacitor of the at least one amplifier during times at which the pixel is gated on.

5. A 3D camera according to claim 4, wherein the at least one gate switch comprises a single gate switch that connects the light sensitive element to the at least one amplifier.

6. A 3D camera according to claim 4, wherein the circuit comprises a reset switch connected to the light sensitive element and wherein when the reset switch is closed, voltage across the light sensitive element is set to a predetermined magnitude.

7. A 3D camera according to claim 6, wherein before the controller gates the pixel of the photosurface on, the controller closes and opens the reset switch of the pixel at least once so that voltage across the light sensitive element is the same each time the pixel is gated on.

8. A 3D camera according to claim 4, wherein the controller gates at least one pixel in the photosurface independently of other pixels in the photosurface.

9. A 3D camera according to claim 8, wherein pixels in the photosurface are grouped into different pixel groups and pixels in a same pixel group are gated on and off by the controller simultaneously and wherein each pixel group is controlled independently of other pixel groups.

11. A 3D camera according to claim 9, wherein at least one pixel in the same pixel group is used for distance measurements to a region in the scene and at least one pixel in the same pixel group is used for imaging the region in the scene, and wherein the at least one pixel used for distance measurements is different from the at least one pixel used for imaging.

12. A 3D camera for determining distances to regions in a scene comprising:

a photosurface having a plurality of pixels each of which comprises a circuit having a light sensitive element that provides a current responsive to light incident thereon, wherein the circuit for each pixel comprises,

at least one amplifier having an input and an output;

at least one feedback capacitor separate from the light sensitive element and connected between the input and output of each of the at least one amplifier;

at least one controllable connection through which current flows from the light sensitive element into the input of the at least one amplifier;

a light source; and

a controller that,

controls the light source to illuminate the scene with gated light,

opens and closes the at least one controllable connection of a pixel in the photosurface to gate the pixel on and off,

controls the at least one controllable connection of the pixel to correct for biases caused by at least one of background light or dark current, and

determines a distance to a region imaged on the pixel responsive to an amount of charge integrated on the at least one feedback capacitor during times when the pixel is gated on.