JPH04344906A - Camera position controlling system - Google Patents

Abstract

PURPOSE:To realize a camera position control system capable of stopping a camera precisely at a preset position at the time of moving the camera. CONSTITUTION:The camera control system 1 is constituted of a motor driven universal head 20 to mount the camera 10, a driving part 30 to move the motor driven universal head 20, and a detecting part 40 to measure the position of the television camera 10. Besides, it is provided with a time generator 50 to generate timing for detecting the position of the camera 10 and a position estimating part 60 to estimate the position of the camera 10 at the next timing from position data measured by the detecting part 40. Then it is constituted as follows. At every timing the time generator 50 generates, the position of the camera 10 at the next timing is estimated by the position estimating part 60, and when the preset position is located between the present position and the estimated position at the next timing, the camera is stopped at the present position.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for controlling the image capturing position of a camera. For example, in video conferencing systems and the like, preset control is widely used to move the camera by registering shooting positions in advance and specifying the registered positions as the meeting progresses.

[0002] Normally, in order to perform such control, a camera is mounted on an electric camera platform, moved by a motor, and the actual position of movement is detected from the output of a potentiometer.

[0003] Such a camera position control method is required to accurately stop the camera at a position as close to a preset position as possible.

0004

2. Description of the Related Art FIG. 3 shows a diagram illustrating a conventional example. In the figure, 10 is a camera, 20 is an electric pan head, 30 is a drive unit, 40
60A is a detection unit, 60A is a difference calculation unit, and 70 is a tripod.

FIG. 4 is a diagram illustrating a conventional stop position correction method. (A) is a diagram explaining the movement situation of the camera. In the figure, P is a preset position,
N is the current position, and α is a correction value (fixed value).

This figure shows a state in which the preset position is P, but when the camera 10 is actually moved, it has moved to the current position N with an error D. (B) is a flowchart illustrating a conventional stop position correction method. The correction operation will be explained according to the diagram.

■ The camera 10 is fixed on an electric camera platform 20, and is moved to a preset position P by a drive unit 30.
Move up to. (2) While the camera 10 is moving, the detection unit 40 measures the current position, that is, the current position N. This measurement data is input to the difference detection section 60A, the difference D from the preset position P is determined, and it is determined whether the difference D is larger than the correction value α.

If the difference D is larger than the correction value α, the amount of movement is insufficient, so the process returns to step (2) and the camera 10 is further moved. ■ In ■, if the difference D is smaller than the correction value α, the correct position has been reached, and the camera 10
stop moving.

[0009]

[Problems to be Solved by the Invention] In the conventional example described above, when stopping the camera 10 at a preset position, it takes a long time from the stop instruction until the actual operation stops due to physical inertia, response delay, etc. A misalignment occurs.

[0010]Furthermore, if the movement is stopped immediately after the start of movement, the deviation of the stop position becomes large. The present invention aims to realize a camera position control method that can accurately stop a camera at a preset position when moving the camera.

[0011]

Means for Solving the Problems FIG. 1 is a block diagram illustrating the principle of the present invention. 1 in the figure is a camera position control system, 10 is a camera, and 20 is a camera 10.
30 is a drive unit that moves the electric pan head 20, 40 is a detection unit that measures the position of the camera 10, and 70 is a tripod that fixes the electric pan head 20.

Further, 50 is a time generator provided in the camera position control system 1 and generates a timing for measuring the position of the camera 10, and 60 is a time generator that generates a timing for measuring the position of the camera 10, and 60 calculates the position at the next timing based on the position data measured by the detection unit 40. For each timing generated by the time generator 50, the position prediction unit 60 predicts the position of the television camera 10 at the next timing, and the preset position is a prediction of the current position and the next timing. If it is between the two positions, it is stopped at the current position.

[0013]

[Operation] The time generator 50 generates timing at regular intervals. The current position of the camera 10 is measured by the detection unit 40 at each fixed timing. camera 10
Due to physical inertia, there is a non-linear relationship between the passage of time and the amount of movement, so the position prediction unit 60 predicts the next amount of movement from the ratio of the previous amount of movement and the amount of current movement, and the preset position is determined. If it is between the current position and the predicted position for the next timing, it is stopped at the current position.

[0014] When the preset position is not between the current position and the predicted position at the next timing,
Since the amount of movement is insufficient, move to the next timing and predict the next position.

Furthermore, in order to perform position control with high precision,
When the camera 10 starts moving, the position prediction unit 60 predicts the position at the next timing at each timing generated by the time generator 50, and determines whether the preset position is closer to the current position or the predicted position at the next timing. is determined and stopped at the closest position.

[0016]

Embodiment FIG. 2 is a diagram illustrating an embodiment of the present invention. (A) is a diagram showing the movement status of the camera 10, in which timing is generated at fixed time intervals by a time generator 50,
The camera position at that timing is measured by the detection unit 40.

Even if the camera 10 is driven by the drive unit 30 that generates a constant driving force, the amount of movement will not be constant due to the physical inertia of the camera 10, response delay, etc. It is a general characteristic that the amount of movement increases with the passage of time.

(B) is a diagram illustrating prediction of the camera stop position according to the embodiment of the present invention. Since the amount of movement of the camera 10 is not constant over time, the next stop position is predicted from the previous and current movement amounts.

Pi (i=1 to n) shown in the figure indicates the stop position at the i-th timing, and Mi (i=1 to n) indicates the stop position at the i-th timing.
n) indicates the amount of movement between the (i-1)th timing and the i-th timing.

Here, the predicted value M of the next camera movement amount is
n is Mn = (Mn-1 /Mn-2) x Mn-1, and the next predicted stop position is Pn = Pn-1 +
It becomes Mn.

[0021] Here, if the preset position is before the predicted position, it is forcibly stopped there. If the preset position is not before the predicted position, the amount of movement is insufficient, so the movement is made to the next timing, and the position at the next timing is then predicted.

[0022] In order to control the camera position with even more precision, the preset position is set to PS, and the current position is set to Pn.
-1, the next predicted position is Pn, the distance Dn- between the preset position PS and the current position Pn-1
1. Preset position PS and next position Pn
Compare the distance Dn with the distance Dn and stop at the closest position.

The calculation in this case is as follows. Dn −Dn−1 =(Pn −PS)−(PS−Pn
-1 )=Pn +Pn-1 -2PS

[0024]

According to the present invention, when moving a camera to a preset position, the camera position is measured at fixed timings after the camera starts moving, the next stop position is predicted from the measured value, and the preset position is determined. By determining the camera stop position from the predicted stop position, it is possible to realize a camera position control method that can control the camera position with high accuracy.

[Brief explanation of drawings]

[Figure 1] Diagram explaining the principle of the present invention

[Fig. 2] Diagram explaining an embodiment of the present invention

[Figure 3] Diagram explaining a conventional example

[Figure 4] Diagram explaining the conventional stop position correction method

[Explanation of symbols]

1 Camera position control system 10 Camera 20 Electric pan head 30 Drive part 40 Detection part 50 time generator 60 Position prediction section 60A Difference detection part

Claims (2)

[Claims] 1. A position control system for moving a camera (10) for photographing images to a preset position, the system comprising: an electric pan head (20) on which the camera (10) is mounted; ), and a detection unit ( ) that measures the position of the television camera (10).
40), a time generator (50) that generates a timing for detecting the position of the camera (10), and the position data measured by the detection unit (40), the following: Said camera at timing (10
) is provided, and at each timing generated by the time generator (50), the position prediction unit (60) predicts the position of the camera (10) at the next timing. A camera position control method that predicts the position and stops the camera at the current position when the preset position is between the current position and the predicted position at the next timing. [Claim 2] A camera (10) and an electric camera platform (20)
In a camera position control system (1) comprising a drive unit (30), a detection unit (40), a time generator (50), and a position prediction unit (60), when the camera (10) starts moving, , the position prediction unit (60) calculates the position of the camera (
Claim 1 characterized in that the position at the next timing of 10) is predicted, it is determined whether the preset position is closer to the current position or the predicted position at the next timing, and the preset position is stopped at the closer position. Camera position control method described.