JPH06167332A - Device for automatically tracking subject - Google Patents

Abstract

PURPOSE:To provide a device where a camera can constantly capture a subject at the center of a screen however it may move. CONSTITUTION:A television camera 10 is mounted to a device main body 1 consisting of spinning drive part and a power supply part which consist of two sensors 5a and 5b whose optical axes are parallel to each other and which captures a subject 20 and sensor amplifiers 21a and 21b, a servo motor 17 spinning a tracking device mounting part 2 basing on the instruction from a differential amplification part 21c, a reduction gear 18 etc., thus tracking the move of the subject 20 and constantly capturing the subject 20 at the center of a camera finder.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for automatically tracking the movement of a dancer when a video camera shoots a dance or the like, even if the photographer is not present.

[0002]

2. Description of the Related Art When a person holds a video camera to track the movement of a subject, there is no problem and the copy can always be captured in the center of the screen.

However, since the video camera cannot be moved when there is no person to photograph, the photographer has no choice but to photograph from a long distance so that the entire range of movement of the subject enters the screen.

For example, in the case of dance, it is difficult to understand from a long distance such as fine classification, so it is inevitable to shoot close. In other words, there was no way to take a picture of my dance from a close distance without a photographer, which was extremely inconvenient.

[0005]

When the video camera is set on a tripod and the subject is aimed at, the subject moves only in the horizontal plane. Therefore, the camera can follow the subject by turning left and right only in the horizontal plane. . Therefore, it is necessary to recognize the position of the subject with respect to the optical axis of the camera, and to orient the camera in that direction. That is, the problems are the recognition of the position and direction of the subject, the turning motion of the camera in that direction, and the recognition that the subject has entered the center of the screen of the camera.

It is an object of the present invention to provide a device in which the camera can always capture the subject at the center of the screen no matter how the subject moves.

[0007]

According to the present invention, two sensors for capturing an object, a sensor amplifier, a differential amplifier for detecting a difference between the object and the optical axis of a camera, and a command from the differential amplifier are provided. Based on the configuration, the video camera is fixed to the main body of the apparatus, which includes the turning drive section for turning the tracking apparatus mounting section and the power supply section. An infrared sensor that detects infrared rays emitted from the human body is used as a sensor for detecting a subject, but there is also a method in which a transmitter is attached to the subject to transmit a signal and follow the transmission source. Further, radio waves, sound waves, lines of magnetic force, light, or the like can be used as the transmission signal.

[0008]

Now, if the optical axes of the two sensors are set parallel to each other and set at a certain interval, and the subject is placed exactly in the middle,
The outputs of both sensors are the same, and the servo motor drive unit does not operate. However, if the subject approaches either one of the sensors, the output of the sensor on the other side will be on the plus side and the sensor on the other side will be on the minus side, so the servo motor drive circuit will operate with the output of the differential amplifier. , The device body is rotated so that the outputs are the same, and the subject is always in the middle of both sensors.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1A is a side view of an embodiment of the automatic tracking device of the present invention, FIG. 1B is an explanatory view of the operating principle of this device, and FIG. 2 is a front view of the same device of the present invention. In this embodiment, a human body is used as a subject and a thermoelectric stack for detecting infrared rays emitted from the human body is used as a sensor.

In the figure, since the tripod 9 is normally provided with the platform 8, it can be set at the elevation angle of the optical axis of the video camera 10. The tracking device mounting portion 2 mounted on the automatic tracking device body 1 is fixed by the mounting screw of the platform 8, and the video camera mounting screws 4a and 4b mounted on the device body 1 are further fixed.
Fix the camera 10 with. That is, screw 4b to camera 10
It is screwed into the screw hole and locked with the screw 4a. At this time,
The lens surface of the video camera 10 and the left and right sensor lenses 5a and 5b attached to the automatic tracking device body 1 are set on the same side. Power is supplied from the connector 3 and turned on and off by the power switch 7.

FIG. 3 is a plan view showing the inside of the main body 1 of the automatic tracking device. 6a is a radiator, 6b is a cooling element utilizing the Peltier effect, and 6c is a heat conducting plate fixed to the thermoelectric stack sensor 11 for cooling these sensors. Although the part can be omitted when explaining the principle of the present invention, in practice, holding the thermoelectric stack sensor 11 at a constant temperature of about 10 ° C., which is slightly lower than the ambient temperature, stabilizes the operation and improves the performance.

Since the output of the thermoelectric stack sensor 11 is extremely weak, it is amplified by the sensor amplifier printed circuit board 12 and sent to the servo motor drive printed circuit board 13. Electric power is supplied from the constant voltage power supply 16 to the sensor amplifier and the servo motor driver.

FIG. 4 is a front view of the automatic tracking device main body 1, and FIG.
FIG. 3 is a side view showing the inside of the automatic tracking device main body 1, in which the automatic tracking device main body 1 pivots with respect to the tracking device mounting portion 2 by the servomotor 17 and the reduction gear device 18. As shown in FIG. 3, the cam 15 is fixed to the shaft of the tracking device mounting portion 2. Therefore, when the automatic tracking device body 1 turns to a certain angle, either of the limit switches 14a and 14b is turned off.
It becomes FF and shuts off the motor circuit.

Next, the operating principle of the device of the present invention will be described with reference to FIG. 1B.

Lenses 5a and 5b are mounted on the thermoelectric stack sensors 11a and 11b, respectively, at the focal length positions. The lens is drawn like a convex lens for explanation, but the subject 2
0, for example, infrared rays radiated from the human body do not pass through glass, so a Fresnel lens made of polyethylene is often used.

The directional characteristics of the sensors 11a and 11b with the lens attached are as shown in 19a and 19b, and the maximum sensitivity on the optical axis, and the angle at which the sensitivity becomes 1/2 is called the half-value angle depending on the lens focal length. change. Now two sensors 11
If the optical axes of a and 11b are set in parallel with each other at a certain distance and the subject (human body) 20 is located near the sensor 11a, the output of the sensor 11a becomes larger than the output of the sensor 11b. On the contrary, if the human body 20 is near the sensor 11b, the output of the sensor 11b becomes large. If the human body 20 is in the middle, the outputs of both sensors will be the same. That is, the output of the sensor 11a is the right sensor amplifier 21a.
In addition, the output of the sensor 11b is applied to the left sensor amplifier 21b, and each amplified output is applied to the differential amplifier 21c. The output of the differential amplifier 21c is positive when the human body 20 is near the sensor 11a and negative when the human body 20 is near the sensor 11b.
By this, the servomotor 17 operates clockwise or counterclockwise.

Since the servomotor 17 turns the automatic tracking device main body 1 by means of the reduction gear 18, if the human body 20 is near the sensor 11a, the human body 20 will always be turned if the servomotor 17 is rotated clockwise. Both sensors 1
This is because the automatic tracking device main body 1 turns so as to have the same output between 1a and 11b, that is, the output is the same, and as a result, the automatic tracking device body 1 is tracked no matter how the human body 20 moves. When the movement of the servo motor 17 is slow, it may not be possible to follow the fast movement of the human body 20, so the responsiveness of the servo motor 17 is important.

In this embodiment, the infrared ray radiated from the human body is tracked by the thermoelectric sensor, but when the subject is not the human body and does not radiate the infrared ray, the source of ultrasonic waves or magnetic field lines is used as the subject. It can also be attached to and tracked. Since the principle is exactly the same and each method has advantages and disadvantages, it is necessary to select it according to the application and environment.

[0019]

As described above, in the subject automatic tracking apparatus of the present invention, no matter how the subject moves, the video camera reliably tracks the subject and always captures the subject in the center of the screen. You can know the details of your actions without yourself. Especially in the case of dance, you can study the details of fine dance. In addition, if a directional microphone is mounted instead of a camera, an application is possible in which the speaker moving around on the stage can be tracked to capture the voice of the speaker and the microphone can always be used in an optimal state.

[Brief description of drawings]

FIG. 1A is a side view showing an embodiment of the device of the present invention.

FIG. 1B is an explanatory diagram showing the operating principle of the device of the present invention.

FIG. 2 is a front view showing an embodiment of the device of the present invention.

FIG. 3 is a plan view showing the inside of the device body of the present invention.

FIG. 4 is a front view of the device body of the present invention.

FIG. 5 is a side view showing the inside of the device body of the present invention.

[Explanation of symbols]

 1 Auto Tracking Device Main Body 2 Tracking Device Mounting Part 3 Power Connector 5a Right Sensor Lens 5b Left Sensor Lens 7 Power Switch 10 Video Camera 11a Right Thermoelectric Stack Sensor 11b Left Thermoelectric Stack Sensor 12 Sensor Amplification Printed Circuit Board 13 Servo Motor Drive Printed Circuit Board 14a Right turn cutoff limit switch 14b Left turn cutoff limit switch 15 Cam 16 Constant voltage power supply 17 Servo motor 20 Subject 21a Right sensor amplifier 21b Left sensor amplifier 21c Differential amplifier 22 Servo motor drive circuit

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display area H04N 5/232 C

Claims (1)

[Claims] 1. A two sensor for capturing a subject, a sensor amplifier, a differential amplifier for detecting a difference between the subject and an optical axis of a camera, and a tracking device mounting portion based on a command from the differential amplifier. An automatic subject tracking device characterized in that a video camera is fixed to a device main body composed of a turning drive unit and a power supply unit for turning, and the movement of the subject is tracked so that the subject is always captured in the center of the camera finder.