Distance measuring system

• US 8,379,930 B2
• Filed: 06/30/2010
• Issued: 02/19/2013
• Est. Priority Date: 12/30/2009
• Status: Active Grant

• Current Assignee: Hon Hai Precision Industry Co., Ltd.
• Original Assignee: Hon Hai Precision Industry Co., Ltd.
• Inventors: Chang, Jen-Tsorng
• Primary Examiner(s): Lu, Tom Y
• Application Number:
  US12/826,675
• Publication Number:
  US 20110158481A1
• Time in Patent Office: 965 Days
• Field of Search: None
• US Class Current: 382/106
• CPC Class Codes: G01S 17/08 for measuring distance only indirect measurement G01S17/46; active triangulation systems G01S17/48

Abstract

A distance measuring system includes a light source module, an image capturing device, a signal processing unit, a selecting unit, and a distance calculating unit. The light source module is configured for emitting a first and a second infrared light beams in an asynchronous manner. The first infrared light beam has a same intensity with the second infrared light beam. The image capturing device is configured for capturing images of the first and second infrared light beams reflected by a measurement object. The signal processing unit is configured for analyzing the images of the first and second infrared light beams reflected by the measurement object to determine intensities thereof. The selecting unit is configured for selecting one of the first and second reflected infrared light beams whichever has a greater intensity. The distance calculating unit is configured for calculating a distance to the object from to the distance measuring system.

Claims

1. A distance measuring system, comprising:

a light source module for emitting a first infrared light beam and a second infrared light beam in an alternating manner to a measurement object, the first infrared light beam having a first central wavelength, the infrared light beam having a second central wavelength, the first infrared light beam having a same intensity with the second infrared light beam;

an image capturing device configured for capturing images of the first and second infrared light beams reflected by the measurement object;

a signal processing unit configured for analyzing the images of the first and second infrared light beams reflected by the measurement object to determine intensities thereof;

a selecting unit configured for selecting one of the first and second reflected infrared light beams whichever has a greater intensity;

a distance calculating unit configured for calculating a distance to the object from to the distance measuring system according to the intensity of the selected one of the first and second reflected infrared light beams.

2. The distance measuring system of claim 1, further comprising a control unit wherein the image capturing device is configured for generating detection signals associated with images of the first and second reflected infrared light beams, the signal processing unit is configured for generating processing signals associated with the intensities of the first and second reflected infrared light beams, and the control unit is configured for controlling the signal processing unit to store the detection signals and to output the processing signals to the selecting unit.

3. The distance measuring system of claim 2, wherein the control unit is configured to control the light source module to emit the first and second infrared light beams in the form of continuous amplitude modulated mode.

4. The distance measuring system of claim 1, wherein the image capturing device comprises an infrared sensitive image sensor and an infrared pass filter having two passbands for only allowing the first and the second infrared light beams to pass therethrough.

5. The distance measuring system of claim 2, wherein the control unit is configured to control the light source module to emit the first and second infrared light beams in an alternate fashion.

6. The distance measuring system of claim 4, wherein the image capturing device comprises an optical lens for focusing the first and second infrared light beams on the image sensor.

7. The distance measuring system of claim 4, wherein the image sensor is a monochromatic sensor.

8. The distance measuring system of claim 1, wherein the light source module comprises first and second infrared emitting diodes for respectively emitting the first and second infrared light beams.

9. The distance measuring system of claim 1, wherein the wavelength of each of the first and second infrared light beams is in a range from 680 nm to 1050 nm.

10. The distance measuring system of claim 1, further comprising a display device for displaying the value of the distance to the measurement object.

11. A distance measuring system, comprising:

a first light source configured for emitting a first pulsed infrared light beam of a first central wavelength toward an object;

a second light source configured for emitting a second pulsed infrared light beam of a second central wavelength different from the first central wavelength toward the object, and an intensity of the first infrared light beam being equal to an intensity of the second infrared light beam;

a control unit configured for controlling the first and the second light sources to alternately emit the respective first and second pulsed infrared light beams;

an image capturing device configured for capturing images of the first and the second pulsed infrared light beams reflected by the object and generating two respective detection signals associated therewith, the image capturing device comprising an infrared sensitive image sensor and an infrared pass filter having two passbands for only allowing the first and second pulsed infrared light beams to pass therethrough;

a signal processing unit configured for determining intensities of the first and the second infrared light beams based on the respective detection signals and generating processing signals associated with the intensities of the respective first and second reflected pulsed infrared light beams;

a selecting unit configured for selecting one of the first and second reflected pulsed infrared light beams whichever has a greater intensity;

a distance calculating unit configured for calculating a distance to the object from the distance measuring system according to the intensity of the selected one of the first and second reflected pulsed infrared light beams.

12. The distance measuring system of claim 11, wherein the control unit is configured for controlling the signal processing unit to store the detection signals and to output the processing signals to the selecting unit.

13. The distance measuring system of claim 11, wherein the control unit is configured to control the first and second light sources to respectively emit the first and second infrared light beams in the form of continuous amplitude modulated mode.

14. The distance measuring system of claim 11, wherein the control unit is configured to control the first and second light sources to emit the first and second infrared light beams in an alternate fashion.

15. The distance measuring system of claim 11, wherein the image capturing device comprises an optical lens for focusing the first and second infrared light beams on the image sensor.

16. The distance measuring system of claim 11, wherein the image sensor is a monochromatic sensor.

17. The distance measuring system of claim 11, wherein the first light source comprises a first infrared emitting diode for emitting the first pulsed infrared light beams, and the second light source comprises a second infrared emitting diode for emitting the second pulsed infrared light beams.

18. The distance measuring system of claim 11, wherein the central wavelength of each of the first and second pulsed infrared light beams is in a range from 680 nm to 1050 nm.

19. The distance measuring system of claim 11, further comprising a display device for displaying a value of the distance.

20. A distance measuring system, comprising:

a first light source configured for emitting a first pulsed infrared light beam of a first central wavelength;

a second light source configured for emitting a second pulsed infrared light beam of a second central wavelength different from the first central wavelength toward an object, with an intensity of the first pulsed infrared light beam being equal to an intensity of the second pulsed infrared light beam,

a control unit configured for controlling the first and second light sources to alternately emit the first and second pulsed infrared light beams;

an image capturing device configured for capturing images of the first pulsed infrared light beam reflected by the object and generating first detection signals associated with light intensities of the first pulsed infrared light beam at different pulse periods thereof, and for capturing images of the second pulsed infrared light beam reflected by the object and generating second detection signals associated with light intensities of the second pulsed infrared light beam at different pulse periods thereof, and the image capturing device comprising an infrared sensitive image sensor and an infrared pass filter having two passbands for only allowing the first pulsed infrared light beam and the second pulsed infrared light beam to pass therethrough;

a signal processing unit configured for analyzing the intensities of the first pulsed infrared light beam based on the first detection signals and generating a first processing signal associated an average intensity of the first pulsed infrared light beam captured by the image capturing device, and for analyzing the intensities of the second pulsed infrared light beam based on the second detection signals and generating a second processing signal associated an average intensity of the second pulsed infrared light beam captured by the image capturing device;

a selecting unit configured for selecting one of the first and the second pulsed infrared light beams captured by the image capturing device whichever has a greater average intensity; and

a distance calculating unit configured for calculating a distance of the object relative to the distance measuring system according to the average intensity of the selected one of the first and the second pulsed infrared light beams captured by the image capturing device.