JPH0315282B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic spotlight tracking device for automatically tracking a spot of a spotlight on a moving target.

Conventionally, as shown in FIG. 1, the direction of a target 2 having a transmitter 1 is detected by a transmitting direction detector 3,
An automatic spotlight tracking device has been proposed in which the motor 4 is automatically controlled by the output of a control section 6 that is operated in response to the detection output, so that the spotlight 5 is always directed toward the target 2. However, in such a conventional example, in order to perform a tracking operation with high precision, it is necessary to narrow the detection angle range of the transmitting direction detector 3. However, if the detection angle range is narrowed too much, if the target 2 moves quickly. If the signal from the transmitter 1 is interrupted by an object or an obstacle, the target 2 may be lost, making automatic tracking impossible.

The present invention was made in order to solve these problems of the conventional example, and provides automatic tracking of a spot light that is less likely to lose sight of the target and can perform highly accurate tracking operation. The purpose is to provide a device.

The configuration of the present invention will be described below with reference to illustrated embodiments. 2 to 5 show an embodiment of the present invention, and as shown in FIG. 2, a zoom lens 7 is provided inside the transmission direction detector 3. The servo motor 8 allows the field of view to be widened or narrowed. The spotlight 5 is a lamp 9 that serves as a light source.
It has an iris 10 that determines the spot diameter, and a focusing lens 11, so that a spot of an appropriate size can be irradiated onto the target 2 position. Reference numeral 4 denotes a motor that rotates the spotlight 5 and the transmission direction detector 3 in conjunction with each other. Among the lenses constituting the zoom lens 7, the front lens 7a, the erecting lens 7b, and the relay lens 7c are fixed, and the changing lenses 7d, 7e and the correction lens 7f are moved back and forth by the servo motor 8 together with the lens barrel 7g. It is now possible to move in any direction. This transmitting direction detector 3 is designed to receive modulated light transmitted from a transmitter 1 possessed by the target 2, and this modulated light is transmitted to a light receiving section provided on the bottom surface of the transmitting direction detector 3. 12, the signal is converted into an electrical signal. FIG. 3 shows a block diagram of the control system of this embodiment. X ₁ and X ₂ are a pair of optical sensors,
They are arranged side by side in the light receiving section 12 in the horizontal direction (that is, in the direction perpendicular to the paper surface of FIG. 2). The _output of _each optical sensor
₁ and 13 ₂ and only the modulated light component is amplified. The outputs of each tuning amplifier 13 ₁ and 13 ₂ are input to averaging circuits 14 ₁ and 14 ₂ where they are rectified and smoothed, and then input to a differential amplifier 15 and an adder 16, respectively. The differential amplifier 15 detects the output difference between the averaging circuits 14 ₁ and 14 ₂ to obtain a signal corresponding to the angular error between the detection axis direction of the transmission direction detector 3 and the signal transmission direction from the transmitter 1. 4 and 5 show the principle of operation. First, as shown by the solid line in FIG. 4, when an image is formed approximately in the middle of a _pair of photosensors X _{1 and}
The difference in output from X ₂ is almost zero. In addition, as shown by the dotted line in the same figure, if the direction in which the light arrives from the transmitter 1, which is the light source, and the detection axis direction C of the transmitting direction detector 3 are misaligned, the amount of light that hits _one optical sensor Since the amount of light hitting the other photosensor _X1 is greater, the output of photosensor _X2 is larger than the output of photosensor _X1 . On the other hand, if the direction in which the light arrives is deviated from the direction indicated by the dotted line in Fig. 4 with respect to the optical axis direction C, the output of optical sensor X ₁ is higher than the output of optical sensor X ₂ . also becomes larger. For this reason, the direction of light arrival and direction of light emission is detected by the detector 3.
Let θ be the angular deviation from the detection _axis C _of It is something to do. In FIG. 5, curve A shows the characteristics when the field of view of the zoom lens 7 is narrowed, and curve B shows the characteristics when the field of view of the zoom lens 7 is narrowed.
This shows the characteristics when the field of view is widened. However, the output of the differential amplifier 15 is inputted to the motor drive section 17, where the power is amplified, and the motor 4 is driven to rotate. As the motor 4, a motor such as a DC motor that has a large starting torque and whose rotational direction is reversed depending on the polarity of the drive voltage is used, and the direction in which the output of the differential amplifier 15 becomes zero is used. The spotlight 5 and the transmission direction detector 3 are rotationally driven.

Next, the output of this differential amplifier 15 is the absolute value circuit 1
8 and is converted into an absolute value signal, which is compared with a reference voltage Vo in a comparator 19. When the absolute value of the output of the differential amplifier 15 exceeds this reference voltage Vo, the output of the comparator 19 becomes H level and the transistor 21 is turned on via the OR circuit 20. As a result, the charge on the capacitor C _T is instantly discharged, and the inverter 2
When the output of the zoom lens 2 becomes H level, the servo motor 8 is driven, and the field of view of the zoom lens 7 is widened. Therefore, even if the target 2 moves quickly and the direction of the detection axis of the transmission direction detector 3 and the direction of arrival of the light from the transmitter 1 are largely deviated, the field of view of the zoom lens 7 is widened. Never lose sight of Target 2. When the transmitter 1 is captured within the field of view of the wide-angle zoom lens 7, the output of the absolute value circuit 18 decreases, the output of the OR circuit 20 becomes L level, and the transistor 21 is turned off. This allows the capacitor to
C _T is charged through resistor R _T and its terminal voltage gradually increases. When the terminal voltage of the capacitor C _T exceeds the threshold voltage of the inverter 22, the output of the inverter 22 becomes L level, and the field of view of the zoom lens 7 is narrowed again by the servo motor 8. Then, before the delay time determined by the time constant of the capacitor C _T and the resistor R _T elapses, the direction of the spotlight 5 and the transmitting direction detector 3 is changed so that the transmitter 1 is approximately at the center of the field of view of the zoom lens 7. It is controlled by a motor 4. Then, as the delay time elapses and the field of view of the zoom lens 7 is narrowed, the position of the spotlight 5 can be adjusted with even greater precision.

On the other hand, in FIG. 3, the adder 16 is the averaging circuit 1.
4 ₁ and 14 ₂ are added, and the intensity of the modulated light from the transmitter 1 received by the optical sensors X ₁ and X ₂ is calculated. Adder 16
The output from the transmitter 1 is compared with a predetermined reference level by a comparator 21, and if the signal from the transmitter 1 is interrupted by an obstacle, the adder 1
6 output decreases and the output of the comparator 21 becomes H level, the servo motor 8 operates via the OR circuit 20, the transistor 21 and the inverter 22, and the field of view of the zoom lens 7 becomes wide for a certain period of time. ing. Therefore, even if the signal from the transmitter 1 is temporarily interrupted by an obstacle or the like, the transmitting direction detector 3 will not lose sight of the target 2.

Next, FIG. 6 shows a circuit diagram of a main part of another embodiment of the present invention, in which the field of view of the zoom lens 7 is continuously changed using a relatively slow-speed servo motor 8a. It is. 20 in Figure 6
is an OR circuit which outputs the logical sum of the outputs of the comparators 19 and 21. However, if the transmitter 1 is far out of the field of view of the zoom lens 7, or if the signal from the transmitter 1 is interrupted by an obstacle, the output of the OR circuit 20 becomes H level, and the transistor ₂₃₁ becomes Turns on. Further, since the output of the inverter 24 becomes L level, the transistor 23 ₂ is turned off. therefore resistance
R ₂ to limit switch 26 ₁ , die auto 25
₁ , servo motor 8a, and transistor 23 ₁
A current flows through the path, and the servo motor 8a rotates in a direction that widens the field of view of the zoom lens 7. The resistance value of the resistor _R2 is set to be relatively small, so that the field of view of the zoom lens 7 is widened at a relatively high speed.
Next, when the transmitter 1 is captured in the field of view of the wide-angle zoom lens 7 and the output of the OR circuit 20 becomes L level, the transistor 23 ₁ is turned off and the transistor 23 ₂ is turned on. Therefore, current flows from the resistor _R1 through the servo motor 8a, the diode ₂₅₂ , the limit switch ₂₆₂ , and the transistor ₂₃₂ , and the servo motor 8a rotates in a direction that narrows the field of view of the zoom lens 7. be. The resistance value of the resistor _R1 is set to be relatively large, so that the field of view of the zoom lens 7 is narrowed at a relatively low speed. By setting the speed at which the field of view becomes narrower to be lower than the maximum tracking speed possible by the motor 4, it is possible to prevent the servo motor 8a from repeating forward and reverse rotations little by little. limit switch 26
₁ and 26 ₂ are for automatically stopping the servo motor 8a when the widening and narrowing of the field of view reaches its limit.

In the description of the embodiments of the present invention, a transmitter 1 that emits modulated light is shown, but it is also possible to use a transmitter 1 that emits infrared rays, ultrasonic waves, microwaves, etc. be.

The present invention is configured as described above, and includes a detection angle range control means for widening the detection angle range of the transmission direction detector when the angle error detected by the transmission direction detector is larger than a predetermined reference value. Therefore, if the target moves quickly and the signal transmission direction from the transmitter deviates greatly from the detection axis direction, the detection angle range of the transmission direction detector is widened, so it is difficult to detect the direction of the target. It has the advantage that there is less risk of losing sight of the target, and when the movement of the target is small and the angular error between the signal transmission direction from the transmitter and the detection axis direction is small, the detection angle range of the transmission direction detector is narrowed. , it has the advantage of being able to perform tracking operations with good accuracy. Another advantage is that even if the direction of the spotlight deviates significantly from the target when starting automatic tracking, the detection angle range of the transmitting direction detector is widened, so tracking can be started smoothly. .

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a conventional example, Fig. 2 is a partially cutaway side view of an embodiment of the present invention, Fig. 3 is a block circuit diagram of the same control system, and Figs. 4 and 5 are the same as the above. The operation explanatory diagram, FIG. 6, is a main part circuit diagram of another embodiment of the present invention. 1 is a transmitter, 2 is a target, 3 is a transmission direction detector,
4 is a motor, 5 is a spotlight, 7 is a zoom lens, 8 is a servo motor, 15 is a differential amplifier, 1
9 is a comparator.

Claims (1)

[Claims] 1 The transmitter held by the target illuminated by the spotlight and the direction of the detection axis are approximately parallel to the light irradiation direction of the spotlight, and the angular error between the direction of the signal transmitted from the transmitter and the direction of the detection axis is detected. A transmitting direction detector, a driving means for controlling the direction of the spotlight and the transmitting direction detector in conjunction with each other, and a means for feedback controlling the driving means so that an angular error detected by the transmitting direction detector is minimized. The automatic tracking device comprising a detection angle range control means for widening the detection angle range of the transmission direction detector when the angle error detected by the transmission direction detector is larger than a predetermined reference value. An automatic tracking device for spot lights, which is characterized by: