RANGING MODULE, RANGING SYSTEM, AND METHOD OF CONTROLLING RANGING MODULE

• US 20180348369A1
• Filed: 11/09/2016
• Published: 12/06/2018
• Est. Priority Date: 02/23/2016
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Ohki, Mitsuharu
• Granted Patent: US 10,746,874 B2
• Time in Patent Office: Days
• CPC Class Codes: B60W 30/09 Taking automatic action to avoid collision, e.g. braking and steering
• CPC Class Codes: B60W 30/16 Control of distance between vehicles, e.g. keeping a distance to preceding vehicle
• CPC Class Codes: G01S 17/08 for measuring distance only indirect measurement G01S17/46; active triangulation systems G01S17/48
• 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 17/931 of land vehicles
• CPC Class Codes: G01S 7/4861 Circuits for detection, sampling, integration or read-out
• CPC Class Codes: G01S 7/4914 of detector arrays, e.g. charge-transfer gates
• CPC Class Codes: G01S 7/4915 Time delay measurement, e.g. operational details for pixel components signal extraction and conditioning G01S7/493; Phase measurement
• CPC Class Codes: G01S 7/497 Means for monitoring or calibrating

Abstract

A distance is accurately measured by a ranging system that performs ranging by a ToF method.

A ranging module includes a light receiving unit, a determination unit, and a ranging unit. The light receiving unit receives reflection light from an object and detects a received light quantity of the reflection light within a predetermined detection period every time the predetermined detection period elapses. The determination unit determines whether the object is moved during each of the predetermined detection periods. The ranging unit measures a distance to the object on the basis of received light quantity within a predetermined detection period during which it is determined that the object is not moved.

Claims

1. A ranging module comprising:

a light receiving unit configured to receive reflection light from an object and detect a received light quantity of the reflection light within a predetermined detection period every time the predetermined detection period elapses;

a determination unit configured to determine whether the object is moved during each of the predetermined detection periods; and

a ranging unit configured to measure a distance to the object on the basis of the received light quantity within the predetermined detection period during which it is determined that the object is not moved.

2. The ranging module according to claim 1, wherein

the predetermined detection period includes a first and second detection periods different from each other,

the light receiving unit receives the reflection light and detects first and second received light quantities over predetermined light receiving periods from first and second light reception start timings out of first, second, third, and fourth light reception start timings different from each other during the first detection period, and the light receiving unit receives the reflection light and detects third and fourth received light quantities over the predetermined light receiving periods from the third and fourth light reception start timings during the second detection period, and

the ranging unit measures the distance on the basis of a ratio of a difference between the first and second received light quantities to a difference between the third and fourth received light quantities.

3. The ranging module according to claim 2, further comprising:

a first delay unit configured to delay the first and second received light quantities and output the delayed first and second received light quantities as first and second current received light quantities;

a second delay unit configured to delay the third and fourth received light quantities and output the delayed third and fourth received light quantities as third and fourth current received light quantities; and

a third delay unit configured to delay the third and fourth current received light quantities and output the delayed third and fourth current received light quantities as third and fourth preceding received light quantities,

wherein the determination unit determines whether the object is moved during any one of the first and second detection periods on the basis of a difference between a sum of the first and second current received light quantities and a sum of the third and fourth current received light quantities.

4. The ranging module according to claim 3, wherein

in a case of determining that the object is moved during any one of the first and second detection periods, the determination unit determines whether the object is moved during the first detection period on the basis of a difference between a sum of third and fourth preceding received light quantities and the sum of the first and second current received light quantities, and

in the case where it is determined that the object is moved during the first detection period, the ranging unit measures the distance on the basis of a ratio of a difference between the third and fourth current received light quantities to a difference between the first and second received light quantities next to the first and second current received light quantities.

5. The ranging module according to claim 3, wherein

in a case of determining that the object is moved during any one of the first and second detection periods, the determination unit determines whether the object is moved during the second detection period on the basis of a difference between a sum of the first and second received light quantities next to the first and second current received light quantities and the sum of the third and fourth current received light quantities, and

in a case where it is determined that the object is moved during the second detection period, the ranging unit measures the distance on the basis of a ratio of a difference between the first and second preceding received light quantities to a difference between the first and second current received light quantities.

6. The ranging module according to claim 3, further comprising:

a fourth delay unit configured to delay the first and second received light quantities and output the delayed first and second received light quantities to the first delay unit as next first and second received light quantities; and

a fifth delay unit configured to delay the first and second current received light quantities and output the delayed first and second current received light quantities as first and second preceding received light quantities.

7. The ranging module according to claim 6, wherein

in a case of determining that the object is moved during any one of the first and second detection periods, the determination unit determines whether the object is moved during the second detection period on the basis of a difference between a sum of the first and second preceding received light quantities and a sum of the third and fourth current received light quantities, and

in a case where it is determined that the object is moved during the second detection period, the ranging unit measures the distance on the basis of a ratio of a difference between first and second statistics to a difference between third and fourth preceding received light quantities while defining, as the first statistic, a statistic of the first preceding received light quantity and the first current received light quantity and further defining, as the second statistic, a statistic of the second preceding received light quantity and the second current received light quantity.

8. The ranging module according to claim 6, wherein

in a case of determining that the object is moved during any one of the first and second detection periods, the determination unit determines whether the object is moved during the first detection period on the basis of a difference between a sum of the third and fourth preceding received light quantities and the sum of the first and second current received light quantities, and

in the case where it is determined that the object is moved during the first detection period, the ranging unit measures the distance on the basis of a ratio of a difference between third and fourth statistics to a difference between the next first and second received light quantities while defining, as the third statistic, a statistic of the third current received light quantity and the next third received light quantity and further defining, as the fourth statistic, a statistic of the fourth current received light quantity and the next fourth received light quantity.

9. The ranging module according to claim 1, the light receiving unit including:

a first pixel configured to receive the reflection light and detect first and second received light quantities over predetermined light receiving periods from first and second light reception start timings out of first, second, third, and fourth light reception start timings different from each other during an odd-number-th predetermined detection period, and configured to receive the reflection light and detect third and fourth received light quantities over predetermined light receiving periods from the third and fourth light reception start timings during an even-number-th predetermined detection period; and

a second pixel configured to receive the reflection light and detect third and fourth received light quantities over predetermined light receiving periods from the third and fourth light reception start timings during an odd-number-th predetermined detection period, and configured to receive the reflection light and detect first and second received light quantities over the predetermined light receiving periods from the first and second light reception start timings during an even-number-th predetermined detection period,

wherein the ranging unit measures the distance on the basis of a ratio of the difference between the first and second received light quantities to the difference between the third and fourth received light quantities.

10. The ranging module according to claim 9, wherein the determination unit determines whether the object is moved on the basis of a difference between a sum of the first and second received light quantities and a sum of the third and fourth received light quantities in a focused pixel focused out of the first and second pixels.

11. The ranging module according to claim 10, wherein in a case where it is determined that the object is moved, the ranging unit measures the distance on the basis of a ratio of a difference between received light quantities in the focused pixel to a difference between received light quantities in an adjacent pixel adjacent to the focused pixel out of the first and second pixels.

12. The ranging module according to claim 1, further comprising a light emitting unit configured to irradiate the object with irradiation light.

13. A ranging system comprising:

a light emitting unit configured to irradiate an object with irradiation light;

a light receiving unit configured to receive reflection light from an object and detect a received light quantity of the reflection light within a predetermined detection period every time the predetermined detection period elapses;

a determination unit configured to determine whether the object is moved during each of the predetermined detection periods; and

a ranging unit configured to measure a distance to the object on the basis of the received light quantity within the predetermined detection period during which it is determined that the object is not moved.

14. The ranging system according to claim 13, further comprising an imaging unit configured to capture image data every time the predetermined detection period elapses,

wherein the determination unit determines whether the object is moved on the basis of the image data.

15. A control method for a ranging module, comprising:

a light receiving procedure of receiving reflection light from an object and detecting a received light quantity of the reflection light within a predetermined detection period every time the predetermined detection period elapses;

a determination procedure of determining whether the object is moved during each of the predetermined detection periods; and

a ranging procedure of performing ranging to measure a distance to the object on the basis of the received light quantity within the predetermined detection period during which it is determined that the object is not moved.