Granted Patent B2

US 9,766,067 · App. 13/919,116 · Granted Sep 19, 2017

Abstract

Claims (45)

1. A method of acquiring a horizontal distance between a camera including an optical system and a photoelectric conversion device and a target, which is a horizontal distance between a central point of the optical system of the camera and a ground landing point of the target, the method comprising:

acquiring a relative target angle, which is an angle between a ground and a camera-target connection line which connects the central point of the optical system of the camera and the ground landing point of the target;

acquiring a height of the camera which is a height of the central point of the optical system of the camera on a basis of a vertical position of the ground landing point of the target; and

setting a quotient of the height of the camera divided by a tangent value of the relative target angle as the horizontal distance between the camera and the target,

wherein the camera-target connection line is different from the optical axis, and

wherein the acquiring the relative target angle comprises:

calculating a ground-camera angle which is an angle between the ground and the optical axis of the camera, based on a focal distance of the optical system and a sensor tilting distance that is a vertical distance between a sensor central point and a sensor horizontal point, the sensor central point being a point where the optical axis reaches the photoelectric conversion device of the camera and the sensor horizontal point being a point where an extended line from a straight line parallel to the ground reaches the photoelectric conversion device;

calculating a camera-target angle which is an angle between the camera-target connection line and the optical axis of the camera, based on the focal distance of the optical system and an image vertical distance that is a vertical distance between a sensor central point and a target-image landing point, the target-image landing point being a point where the camera-target connection line reaches the photoelectric conversion device; and

calculating the relative target angle based on the ground-camera angle and the camera-target angle.

2. The method of claim 1 , wherein a tilting angle acquired in a tilting control of the camera is set as the ground-camera angle.

3. The method of claim 1 , wherein, when the optical axis of the camera is parallel to the ground, the camera-target angle is set as the relative target angle.

4. The method of claim 1 , wherein, if the ground-camera angle includes the camera-target angle, the relative target angle is equal to the ground-camera angle minus the camera-target angle.

5. The method of claim 1 , wherein, if the camera-target angle includes the ground-camera angle, the relative target angle is equal to the camera-target angle minus the ground-camera angle.

6. The method of claim 1 , wherein, if the ground-camera angle does not include the camera-target angle, and the camera-target angle does not include the ground-camera angle, the relative target angle is equal to the ground-camera angle minus the camera-target angle.

7. The method of claim 1 ,

wherein the acquiring the ground-camera angle comprises:

acquiring a vertical coordinate of sensor central point;

acquiring a vertical coordinate of the sensor horizontal point;

acquiring the sensor tilting distance; and

acquiring a quotient of the sensor tilting distance divided by the focal distance of the optical system, and setting an arctangent value of the quotient as the ground-camera angle.

8. The method of claim 1 ,

wherein the acquiring the camera-target angle comprises:

acquiring a vertical coordinate of the sensor central point;

acquiring a vertical coordinate of the target-image landing point;

acquiring the image vertical distance; and

acquiring a quotient of the image vertical distance divided by the focal distance of the optical system, and setting an arctangent value of the quotient as the camera-target angle.

9. A camera for acquiring a horizontal distance between the camera and a target, which is a horizontal distance between a central point of an optical system of the camera and a ground landing point,

wherein the camera includes an optical system and a photoelectric conversion device,

wherein the camera is configured to acquire a relative target angle, which is an angle between ground and a camera-target connection line which connects the central point of the optical system of the camera and the ground landing point of the target,

acquire a height of the camera which is a height of the central point of the optical system of the camera on a basis of a vertical position of the ground landing point of the target, and

set a quotient of the height of the camera divided by a tangent value of the relative target angle as a horizontal distance between the camera and the target,

wherein the camera-target connection line is different from the optical axis, and

wherein the camera is further configured to acquire the relative target angle by

calculating a ground-camera angle which is an angle between the ground and the optical axis of the camera, based on a focal distance of the optical system and a sensor tilting distance that is a vertical distance between a sensor central point and a sensor horizontal point, the sensor central point being a point where the optical axis reaches the photoelectric conversion device of the camera and the sensor horizontal point being a point where an extended line from a straight line parallel to the ground reaches the photoelectric conversion device;

calculating a camera-target angle which is an angle between the camera-target connection line and the optical axis of the camera, based on the focal distance of the optical system and an image vertical distance that is a vertical distance between a sensor central point and a target-image landing point, the target-image landing point being a point where the camera-target connection line reaches the photoelectric conversion device; and

calculating the relative target angle based on the ground-camera angle and the camera-target angle.

10. A surveillance system comprising:

a camera including an optical system and a photoelectric conversion device; and

a host device connected to camera, the host device acquiring a horizontal distance between the camera and a target which is a horizontal distance between a central point of an optical system of the camera and a ground landing point of the target,

wherein the host device is configured to acquire a relative target angle, which is an angle between ground and a camera-target connection line which connects the central point of the optical system of the camera and the ground landing point of the target, acquire a height of the camera which is a height of the central point of the optical system of the camera on a basis of a vertical position of the ground landing point of the target, and set a quotient of the height of the camera divided by a tangent value of the relative target angle as the horizontal distance between the camera and the target,

wherein the camera-target connection line is different from the optical axis, and

wherein the host device is further configured to acquire the relative target angle by

calculating a ground-camera angle which is an angle between the ground and the optical axis of the camera, based on a focal distance of the optical system and a sensor tilting distance that is a vertical distance between a sensor central point and a sensor horizontal point, the sensor central point being a point where the optical axis reaches the photoelectric conversion device of the camera and the sensor horizontal point being a point where an extended line from a straight line parallel to the ground reaches the photoelectric conversion device;

calculating a camera-target angle which is an angle between the camera-target connection line and the optical axis of the camera, based on the focal distance of the optical system and an image vertical distance that is a vertical distance between a sensor central point and a target-image landing point, the target-image landing point being a point where the camera-target connection line reaches the photoelectric conversion device; and

calculating the relative target angle based on the ground-camera angle and the camera-target angle.

Assignments (9)