Method for estimating distance, and system and computer-readable medium for implementing the method

Patent metadata

Field	Value
Publication number	US-2016189361-A1
Application number	US-201514852963-A
Country	US
Kind code	A1
Filing date	Sep 14, 2015
Priority date	Dec 24, 2014
Publication date	Jun 30, 2016
Grant date	—

Abstract

A method for estimating a distance between a first target and a second target in an image is to be implemented using a distance estimation system that includes a processor module. In the method, the processor module is programmed to: generate an image depth map associated with the image; generate first position information associated with a first position which corresponds to the first target in the image, and second position information associated with a second position which corresponds to the second target in the image; and compute an estimate of a distance between the first target and the second target based on at least the image depth map, the first position information, and the second position information.

First claim

What is claimed is:

1 . A method for estimating a distance between a first target and a second target in an image, the method to be implemented using a distance estimation system that includes a processor module, the method including the steps of:
a) generating, by the processor module, an image depth map associated with the image; b) generating, by the processor module, first position information associated with a first position which corresponds to the first target in the image, and second position information associated with a second position which corresponds to the second target in the image; and c) computing, by the processor module, an estimate of a distance between the first target and the second target based on at least the image depth map, the first position information and the second position information.

2 . The method of claim 1 , the distance estimation system further including an image capturing module for capturing the image, the image capturing module including a lens and an image sensor, wherein step c) includes the sub-steps of:
c-1) estimating, by the processor module, a first target distance between the first target and the lens based on the first position information, the image depth map, a focus length of the lens for capturing the image, and a pixel size of the image sensor; and c-2) computing, by the processor module, the estimate of the distance between the first target and the second target, based on at least the first target distance, the first position information, the second position information, and the focus length of the lens.

3 . The method of claim 2 , the distance estimation system further including a sensor module for detecting a tilt angle of the image sensor with respect to an imaginary vertical line, wherein, in sub-step (c-2), the processor module executes the sub-steps of:
obtaining a first pixel position and a second pixel position on the image sensor based respectively on the first position information and the second position information, the first and second pixel positions corresponding to the first and second positions in the image, respectively; calculating a distance between the first pixel position and the second pixel position on the image sensor; and computing the estimate of the distance (h 1 ) between the first target and the second target using the following equation:

h
11

·

sin


(
A
)

+

f
·

sec


(
A
)

d
1

=

h
11

·

cos


(
A
)

h
1

where (h 11 ) represents the distance between the first and second pixel positions on the image sensor, (A) represents the tilt angle, (f) represents the focus length of the lens, and (d 1 ) represents the first target distance.

4 . The method of claim 1 , the distance estimation system further including an image capturing module for capturing the image, the image capturing module including a lens and an image sensor, wherein step c) includes the sub-steps of:
c-1) estimating, by the processor module, a first target distance between the first target and the lens and a second target distance between the second target and the lens based on the first position information, the second position information, the image depth map, a focus length of the lens for capturing the image, and a pixel size of the image sensor; and c-2) computing, by the processor module, the estimate of the distance between the first target and the second target based on at least the first target distance, the second target distance, the first position information, the second position information, and the focus length of the lens.

5 . The method of claim 4 , wherein, in sub-step (c-2), the processor module executes the sub-steps of:
obtaining a first pixel position and a second pixel position on the image sensor based respectively on the first position information and the second position information, the first and second pixel positions corresponding to the first and second positions in the image, respectively; calculating a distance between the first pixel position and the second pixel position on the image sensor; and computing the estimate of the distance (h 2 ) between the first target and the second target using the following equations:

h
2

=

d
1
2

+

d
2
2

-

2
·

d
1

·

d
2

·

cos


(
K
)

K
=

h
33

f

where (d 1 ) represents the first target distance, (d 2 ) represents the second target distance, (h 33 ) represents the distance between the first and second pixel positions, and (f) represents the focus length of the lens.

6 . The method of claim 4 , the distance estimation system further including a sensor module for detecting a tilt angle of the image sensor with respect to an imaginary vertical line, the image being captured when the tilt angle of the sensor module is equal to zero degree, wherein, in sub-step (c-2), the processor module executes the sub-steps of:
obtaining a first pixel position and a second pixel position on the image sensor based respectively on the first position information and the second position information, the first and second pixel positions corresponding to the first and second positions in the image, respectively; calculating a first distance between the first pixel position and a center point of the image sensor, and a second distance between the second pixel position and the center point of the image sen

Assignees

• Lite On Technology Corp

Inventors

• Lo Yi-Chung
• Li Zong-Sian

Classifications

• H04N13/0271

  Electricity · mapped topic

• G06T2207/10028

  Range image; Depth image; 3D point clouds · CPC title

• G06T7/0051

  Physics · mapped topic

• G06T7/004 Primary

  Physics · mapped topic

• G06T2207/30244

  Camera pose · CPC title