Method for determining the angular magnitude of imaging acquiring apparatus and vehicle collision warning system using thereof

• US 8,412,480 B2
• Filed: 03/19/2009
• Issued: 04/02/2013
• Est. Priority Date: 12/03/2008
• Status: Active Grant

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Lin, Che-Chung, Wang, Yu-Long, Huang, Dau-Chen, Lin, Chi-Wei, Chang, Yi-Yu
• Primary Examiner(s): Kelley, Christopher S
• Assistant Examiner(s): Jebari, Mohammed
• Application Number:
  US12/407,106
• Publication Number:
  US 20100134265A1
• Time in Patent Office: 1,475 Days
• Field of Search: None
• US Class Current: 702/94
• CPC Class Codes: G01S 11/12 using electromagnetic waves other than radio waves
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/30244 Camera pose
• CPC Class Codes: G06T 2207/30252 Vehicle exterior; Vicinity of vehicle
• CPC Class Codes: G06T 7/80 Analysis of captured images to determine intrinsic or extrinsic camera parameters, i.e. camera calibration

Abstract

The invention provides a method for determining the angular magnitude of an imaging acquiring apparatus, which is capable of obtaining an arranging angular magnitude with respect to the imaging acquiring apparatus in various environments by an iteration algorithm having parameters of position of a calibrating tool with respect to an image coordinate system and characteristic value corresponding to a spatial coordinate system respectively. Meanwhile, the present further provides a vehicle collision warning system which functions to obtain the relative distance between the carrier and objects around according to the image acquired by the imaging acquiring apparatus and the angular magnitude and height of the imaging acquiring apparatus. By means of the method disclosed in the present invention, the procedure to detect the angular magnitude of the image acquiring apparatus is more convenient and accurate such that the convenience for using the vehicle collision warning system is capable of being improved.

Claims

1. A method for determining installed angle of image acquiring apparatus, comprising steps of:

arranging an image acquiring apparatus on a carrier within a predetermined angular range;

acquiring an image of a calibrating tool by the image acquiring apparatus, wherein the image acquiring apparatus is disposed on the carrier by an angular stationary device so that the imaging acquiring apparatus is capable of being installed within the predetermined angular range;

calculating a position of a feature of the image with respect to the calibrating tool according to an image coordinate system and a characteristic value of the feature of the calibrating tool associated with a spatial coordinate system; and

performing an iterative angle-calculating procedure according to the position and the characteristic value for obtaining an installed angle of the image acquiring apparatus, wherein the iterative angle-calculating procedure comprises steps of;

determines a relation between the installed angle and a ratio factor, a focal length of the image acquiring apparatus, the position, the characteristic value, an installed height of the image acquiring apparatus, and vertical pixel numbers of a display unit showing the image acquired by the image acquiring apparatus;

calculating the ratio factor with respect the image acquiring apparatus;

substituting the value of the ratio factor, focal length of the image acquiring apparatus, the position, the characteristic value, installed height of the image acquiring apparatus, and vertical pixel numbers of the display unit showing the image acquired by the image acquiring apparatus into the relation; and

obtaining a convergent installed angle of the image acquiring apparatus by iterating several times;

wherein the characteristic value is a numerical difference derived from the coordinate position of the upper horizontal boundary associated with the calibrating tool and the lower horizontal boundary associated with the calibrating tool, and the relation is defined as;

2. The method of claim 1 wherein an image sensor of the image acquiring apparatus is substantially a charge-coupled device or a complementary metal-oxide semiconductor.

3. The method of claim 1 wherein the image acquiring apparatus is substantially an infrared image-sensing device.

4. The method of claim 1 wherein the angular stationary device further includes a bubble gauge disposed thereon.

5. The method of claim 1 wherein an initial value for iterating is an angular magnitude selected within the predetermined angular range.

6. The method of claim 1 wherein the ratio factor is defined as a ratio of the vertical pixel numbers of the display unit and height of an image sensor of the image acquiring apparatus.

7. The method of claim 1 wherein the carrier is a vehicle.

8. The method of claim 1 wherein the image acquiring apparatus is capable of being disposed at a position selected from a group consisting of the front side of the carrier, the rear side of the carrier, lateral side of the carrier and the combination thereof.

9. The method of claim 1 wherein the iterative angle-calculating procedure further comprises steps of:

determining a relation between the installed angle and a ratio factor, a focal length of the image acquiring apparatus, the position, the characteristic value, an installed height of the image acquiring apparatus, and vertical pixel numbers of a display unit showing the image acquired by the image acquiring apparatus;

substituting the value of the ratio factor, focal length of the image acquiring apparatus, the position, the characteristic value, installed height of the image acquiring apparatus, and vertical pixel numbers of the display unit showing the image acquired by the image acquiring apparatus into the relation; and

obtaining a convergent installed angle of the image acquiring apparatus by iterating several times.

10. The method of claim 9 wherein the ratio factor is defined as a ratio of the vertical pixel numbers of the display unit and height of an image sensor of the image acquiring apparatus.

11. The method of claim 9 wherein an initial value for iterating is an angular magnitude selected within the predetermined angular range.

12. The method of claim 1 wherein the position is substantially a boundary coordinate position of the feature.

13. The method of claim 1 wherein the characteristic value is a width of lateral side of the calibrating tool.

14. A vehicle collision system, comprising:

an image acquiring apparatus for acquiring an image surrounded a vehicle;

an image processing and controlling unit for calculating a position of a feature of the image with respect to the calibrating tool according to an image coordinate system and a characteristic value of the feature of the calibrating tool associated with a spatial coordinate system, performing an iterative angle-calculating procedure according to a relation between the position and the characteristic value for obtaining an installed angle of the image acquiring apparatus, and analyzing a relative distance calculated according to the image, the installed angle and installed height of the image acquiring apparatus, between the vehicle and objectives around the vehicle so as to determine if it is necessary to generate an alarm signal;

a display unit, electrically coupled to the image processing and controlling unit, for displaying the image; and

an alarm unit, electrically coupled to the image processing and controlling unit, for receiving the alarm signal to generate an alarm message;

wherein the characteristic value is a numerical difference derived from the coordinate position of the upper horizontal boundary associated with the calibrating tool and the lower horizontal boundary associated with the calibrating tool, and the relation is defined as;

15. The system of claim 14 wherein an image sensor of the image acquiring apparatus is substantially a charge-coupled device or a complementary metal-oxide semiconductor.

16. The system of claim 14 wherein the image acquiring apparatus is substantially an infrared image-sensing device.

17. The system of claim 14 wherein the image acquiring apparatus is capable of being disposed at a position selected from a group consisting of the front side of the vehicle, the rear side of the vehicle, lateral side of the vehicle and the combination thereof.

18. The system of claim 14 wherein the alarm message is capable of being a sound message, a light, or a vibration.

19. The system of claim 14 further comprising a user operating unit for providing a operating interface whereby for starting the system, and starting to perform the iterative angle-calculating procedure or vehicle tracing and relative distance measuring procedure.

20. The system of claim 14, wherein the image processing and controlling unit further comprises:

an image fetching/decoding unit, coupled to the image acquiring apparatus, for converting information acquired by the image acquiring apparatus into a digital image information;

a digital signal processing/controlling unit, for analyzing and calculating the digital image information so as to obtain the installed angle and the relative distance; and

an image encoding/outputting unit, coupled to the digital signal processing/controlling unit and the displaying unit, for image encoding and thus outputting an output image data to the displaying unit according to a control signal from the digital signal processing/controlling unit.

21. The system of claim 20, wherein the image processing and controlling unit further comprises:

an image random access memory, for storing the digital image information and a processed image data processed by the digital signal processing/controlling unit and providing the digital image information to the digital signal processing/controlling unit and the processed image information to the image encoding/outputting unit; and

a non-volatile programmable memory, for registering the installed angle with respect to the image acquiring apparatus analyzed by the digital signal processing/controlling unit.

22. The system of claim 21, wherein the digital signal processing/controlling unit enables to add information of the installed angle, or the relative distance on the digital image information so as to form a new digital image information and store the new digital image information into the image random access memory.

23. The system of claim 14, wherein the alarm unit enables to generate an alarm image displayed by the display unit for informing driver.