Automatic calibration of PTZ camera system

Patent metadata

Field	Value
Publication number	US-10630971-B2
Application number	US-201715800824-A
Country	US
Kind code	B2
Filing date	Nov 1, 2017
Priority date	Aug 8, 2008
Publication date	Apr 21, 2020
Grant date	Apr 21, 2020

Abstract

A method to determine a base focal length of a pan-tilt-zoom (PTZ) camera system. The method includes generating a spherical mosaic with a feature track by the camera system and determining, by the camera system, a base focal length by analyzing a conic trajectory created by the feature track on an image plane.

First claim

What is claimed is:

1. A method of determining an actuation delay of a pan-tilt-zoom (PTZ) camera in a camera system, the method comprising:
issuing a velocity command to the PTZ camera by the camera system;
capturing successive frames from the PTZ camera by the camera system;
detecting PTZ camera motion by comparing successive captured frames by the camera system;
determining an actuation delay of the PTZ camera by the camera system, wherein the actuation delay is the amount of time between issuing the velocity command to the PTZ camera and observing PTZ camera motion;
sending a query command to the PTZ camera;
receiving a response to the query command from the PTZ camera; and
determining the query delay of the PTZ camera, wherein the query delay is the amount of time between sending the query command and receiving the response to the query command.

2. The method as claimed in 1 , wherein the camera system includes a PTZ controller that outputs the velocity and query commands.

3. A method of determining an actuation delay of a pan-tilt-zoom (PTZ) camera in a camera system, the method comprising:
issuing a velocity command to the PTZ camera by the camera system;
capturing successive frames from the PTZ camera by the camera system;
detecting PTZ camera motion by comparing successive captured frames by the camera system; and
determining an actuation delay of the PTZ camera by the camera system, wherein the actuation delay is the amount of time between issuing the velocity command to the PTZ camera and observing PTZ camera motion, the method further comprising:
(a) sending a first query command to the PTZ camera;
(b) sending a second query command to the PTZ camera after the expiration of a wait interval;
(c) receiving a response to the second query command;
(d) determining whether the received response comprises a valid response to the second query command and setting the minimum query interval equal to the wait interval when the minimum query interval comprises the valid response to the second query command; and
(e) increasing the wait interval and repeating steps (a) through (d) when a non-valid response to the second query command is received.

4. The method as claimed in 3 , wherein the camera system includes a PTZ controller that outputs the velocity, first query and second query commands.

5. One or more tangible non-transitory computer-readable storage media for storing computer-executable instructions executable by a computer system, the media storing one or more instructions for:
issuing a velocity command to the PTZ camera;
capturing successive frames from the PTZ camera;
detecting PTZ camera motion by comparing successive captured frames; and
determining an actuation delay of the PTZ camera, wherein the actuation delay is the amount of time between issuing the velocity command to the PTZ camera and observing PTZ camera motion;
sending a query command to the PTZ camera;
receiving a response to the query command from the PTZ camera; and
determining the query delay of the PTZ camera, wherein the query delay is the amount of time between sending the query command and receiving the response to the query command.

6. One or more tangible non-transitory computer-readable storage media for storing computer-executable instructions executable by a computer system, the media storing one or more instructions for:
i) issuing a velocity command to the PTZ camera;
ii) capturing successive frames from the PTZ camera;
iii) detecting PTZ camera motion by comparing successive captured frames;
iv) determining an actuation delay of the PTZ camera, wherein the actuation delay is the amount of time between issuing the velocity command to the PTZ camera and observing PTZ camera motion;
v) (a) sending a first query command to the PTZ camera;
v) (b) sending a second query command to the PTZ camera after the expiration of a wait interval;
v) (c) receiving a response to the second query command;
v) (d) determining whether the received response comprises a valid response to the second query command and setting the minimum query interval equal to the wait interval when the minimum query interval comprises the valid response to the second query command; and
v) (e) increasing the wait interval and repeating steps v (a) through v (d) when a non-valid response to the second query command is received.

7. A pan-tilt-zoom (PTZ) camera calibration system comprising:
a PTZ camera;
an actuation delay engine to:
issue a velocity command to the PTZ camera,
capture successive frames from the PTZ camera,
detect PTZ camera motion by comparing successive captured frames, and
determine an actuation delay of the PTZ camera, wherein the actuation delay is the amount of time between issuing the velocity command to the PTZ camera and observing PTZ camera motion; and

a query delay engine to:
send a query command to the PTZ camera,
receive a response to the query command from the PTZ camera, and
determine the query delay of the PTZ camera, wherein the query delay is the amount of time between sending the query command and receiving the response to the query command.

8. The PTZ camera calibration system as claimed in claim 7 , wherein each of the actuation delay engine and the query delay engine comprise respective software code embodied on a computer readable medium.

9. The PTZ camera calibration system as claimed in claim 7 , wherein the actuation delay engine and the query delay engine together form part of a PTZ calibration module.

10. The PTZ camera calibration system as claimed in claim 9 , further comprising a PTZ controller configured to receive information from the PTZ calibration module.

11. The PTZ camera calibration system as claimed in claim 10 , wherein the PTZ controller is further configured to output commands to PTZ camera based on the received information.

12. A pan-tilt-zoom (PTZ) camera calibration system comprising:
a PTZ camera;
an actuation delay engine to:
issue a velocity command to the PTZ camera,
capture successive frames from the PTZ camera,
detect PTZ camera motion by comparing successive captured frames, and
determine an actuation delay of the PTZ camera, wherein the actuation delay is the amount of time between issuing the velocity command to the PTZ camera and observing PTZ camera motion; and

a minimum query interval engine to:
(a) send a first query command to the PTZ camera;
(b) send a second query command to the PTZ camera after the expiration of a wait interval; (c) receive a response to the second query command;
(d) determine whether the received response comprises a valid response to the second query command and setting the minimum query interval equal to the wait interval when the minimum query interval comprises the valid response to the second query command; and
(e) increase the wait interval and repeating steps through (d) when a non-valid response to the second query command is received.

13. The PTZ camera calibration system as claimed in claim 12 , wherein each of the actuation delay engine and the minimum query interval engine comprise respective software code embodied on a computer readable medium.

14. The PTZ camera calibration system as claimed in claim 12 , wherein the actuation delay engine and the minimum query interval engine together form part of a PTZ calibration module.

15. The PTZ camera calibration system as claimed in claim 14 , further comprising a PTZ controller configured to receive information from the PTZ calibration module.

16. The PTZ camera calibration system as claimed in claim 15 , wherein the PTZ

Assignees

• Avigilon Fortress Corp

Inventors

• Gupta Himaanshu
• Chosak Andrew J
• Taylor Geoffrey R
• Brewer Paul C
• Haering Niels
• Lipton Alan J

Classifications

• H04N17/002 Primary

  for television cameras · CPC title

• G08B13/1963

  Arrangements allowing camera rotation to change view, e.g. pivoting camera, pan-tilt and zoom [PTZ] · CPC title