Measurement method and apparatus

Patent metadata

Field	Value
Publication number	US-11017552-B2
Application number	US-201716323472-A
Country	US
Kind code	B2
Filing date	May 31, 2017
Priority date	Aug 15, 2016
Publication date	May 25, 2021
Grant date	May 25, 2021

Abstract

A measurement method and apparatus are provided. The measurement method is applicable to an image acquisition device, and includes: acquiring image data to generate an image data file (S101); capturing an object to be measured in an image corresponding to the image data file (S102); obtaining a first distance between a horizontal line going through a lowest point of the object to be measured in the image and a horizontal line going through a center point of the image (S103); and calculating a second distance between the object to be measured and the image acquisition device based on the first distance, an installation height of the image acquisition device and a pitch angle of the image acquisition device (S104). Compared with the relevant art, the image acquisition device can measure the distance to an object to be measured while achieving relatively low production cost and easy installation. As a result, actual demands can be better satisfied.

First claim

What is claimed is:

1. A measurement method, applicable to an image acquisition device, comprising:
acquiring image data to generate an image data file;
capturing an object to be measured in an image corresponding to the image data file;
obtaining a first distance between a horizontal line going through a lowest point of the object to be measured in the image and a horizontal line going through a center point of the image; and
calculating a second distance between the object to be measured and the image acquisition device based on the first distance, an installation height of the image acquisition device and a pitch angle of the image acquisition device,
wherein, obtaining the first distance between the horizontal line going through the lowest point of the object to be measured in the image and the horizontal line going through the center point of the image comprises:
enclosing the object to be measured with a target rectangle, the target rectangle having a pair of sides parallel to the horizontal line going through the center point of the image and being a rectangle with a minimum area among rectangles that can enclose the object to be measured; and
taking a distance between a side of the pair of sides that is closer to the ground and the horizontal line going through the center point of the image as the first distance.

2. The method according to claim 1 , wherein, calculating a second distance between the object to be measured and the image acquisition device based on the first distance, an installation height of the image acquisition device and a pitch angle of the image acquisition device comprises:
calculating a third distance between a first target point and a center point of an imaging plane according to the first distance, wherein the first target point is on the imaging plane of an optical lens of the image acquisition device and corresponds to the lowest point;
calculating an angle between a first line and the ground according to the third distance and the pitch angle of the image acquisition device, wherein the first line goes through a physical position of the lowest point and an optical center of the optical lens; and
calculating the second distance between the object to be measured and the image acquisition device according to the angle between the first line and the ground, and the installation height of the image acquisition device.

3. The method according to claim 1 , wherein, after capturing an object to be measured in an image corresponding to the image data file, the method further comprises:
obtaining a fourth distance between a horizontal line going through a highest point of the object to be measured in the image and the horizontal line going through the center point of the image; and
after calculating the second distance between the object to be measured and the image acquisition device, the method further comprises:
calculating a height of the object to be measured based on the second distance, the fourth distance, the installation height of the image acquisition device, and the pitch angle of the image acquisition device.

4. The method according to claim 3 , wherein, calculating a height of the object to be measured based on the second distance, the fourth distance, the installation height of the image acquisition device, and the pitch angle of the image acquisition device comprises:
calculating a fifth distance between a second target point and a center point of an imaging plane according to the fourth distance, wherein the second target point is on the imaging plane of an optical lens of the image acquisition device and corresponds to the highest point;
calculating an angle between a third line and the ground according to the fifth distance and the pitch angle of the image acquisition device, wherein the third line goes through a physical position of the highest point and an optical center of the optical lens; and
calculating the height of the object to be measured according to the angle between the third line and the ground, the installation height of the image acquisition device, and the second distance.

5. The method according to claim 3 , wherein, obtaining a fourth distance between a horizontal line going through a highest point of the object to be measured in the image and the horizontal line going through the center point of the image comprises:
enclosing the object to be measured with a target rectangle, the target rectangle having a pair of sides parallel to the horizontal line going through the center point of the image, and being a rectangle with a minimum area among rectangles that can enclose the object to be measured; and
taking a distance between a side of the pair of sides that is farther from the ground and the horizontal line going through the center point of the image as the fourth distance.

6. The method according to claim 5 , wherein, before capturing an object to be measured in an image corresponding to the image data file, the method further comprises:
processing the image data file to change a bit width of the image data file to a set bit width.

7. The method according to claim 3 , wherein, calculating a height of the object to be measured based on the second distance, the fourth distance, the installation height of the image acquisition device, and the pitch angle of the image acquisition device comprises:
detecting whether the pitch angle of the image acquisition device changes;
if the pitch angle of the image acquisition device changes, correcting the pitch angle of the image acquisition device; and
calculating the height of the object to be measured based on the second distance, the fourth distance, the installation height of the image acquisition device, and the corrected pitch angle of the image acquisition device.

8. The method according to claim 1 , wherein, calculating a second distance between the object to be measured and the image acquisition device based on the first distance, an installation height of the image acquisition device and a pitch angle of the image acquisition device comprises:
detecting whether the pitch angle of the image acquisition device changes;
if the pitch angle of the image acquisition device changes, correcting the pitch angle of the image acquisition device; and
calculating the second distance between the object to be measured and the image acquisition device based on the first distance, the installation height of the image acquisition device, and the corrected pitch angle of the image acquisition device.

9. A non-transitory storage medium for storing an executable program code, which, when executed, performs the measurement method according to claim 1 .

10. An image acquisition device, comprising:
a processor, a memory, a communication interface and a bus, wherein
the processor, the memory and the communication interface connect and communicate with each other via the bus;
the memory is configured for storing an executable program code;
the processor is configured for executing a program corresponding to the executable program code by reading the executable program code stored in the memory, so as to perform the operations comprising:
acquiring image data to generate an image data file;
capturing an object to be measured in an image corresponding to the image data file;
obtaining a first distance between a horizontal line going through a lowest point of the object to be measured in the image and a horizontal line going through a center point of the image; and
calculating a second distance between the object to be measured and the image acquisition device based on the first distance, an installation height of the image acquisition device and a pitch angle of the image acquisition device,
wh

Assignees

• Hangzhou Hikvision Digital Tec

Inventors

• Cai Xiaowang
• Xiao Fei
• Yu Hai
• Fan Meng

Classifications

• G01C3/12 Primary

  with monocular observation at a single point, e.g. coincidence type (G01C3/20 takes precedence) · CPC title

• G06T7/50

  Depth or shape recovery · CPC title

• G06T7/70 Primary

  Determining position or orientation of objects or cameras (camera calibration G06T7/80) · CPC title

• G01C3/00 Primary

  Measuring distances in line of sight; Optical rangefinders (tapes, chains or wheels for measuring length G01B3/00; active triangulation systems, i.e. using the transmission and reflection of electromagnetic waves other than radio waves, G01S17/48) · CPC title

• G01C11/30

  by triangulation · CPC title