JPS61140281A - Rotation controlling system of industrial television camera - Google Patents

Abstract

PURPOSE:To select the movement of a video image on an ITV monitor to attain ease of convenient use by controlling so that the camera rotating speed is inversely proportional to the focus in changing the focus of the ITV camera by zooming. CONSTITUTION:When a signal 29 proportional to a focus (f) is outputted from a focus detection section 23, the camera is rotated to the left/right in a pan angular velocity Wpan inversely proportional to the focus by a pan motor control circuit 30. That is, when the focus (f) is larger by zooming up, the pan angular velocity Wpan is smaller in inverse proportion to the increase, and when the focus (f) gets smaller by zooming down conversely, the pan angular velocity Wpan is larger. Thus, even when an optical lens system 22 is zoomed up, it is easy to match the center axis of the camera with the detail of a picture image.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a rotation control system for an industrial television (hereinafter simply referred to as ITV) camera, and particularly to a rotation control method for a VTS (Vesse TV) camera.
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The present invention relates to an ITV camera rotation control system suitable for controlling the vertical and horizontal rotation speed of a V camera.

[Prior art]

In VTS, ITV equipment is used to observe various targets scattered over a wide area, and these targets are monitored using ITV cameras. In the up/down (T I LT) and left/right (PAN) operations of the tTV camera used in conventional VTS, even if the focal length changes due to zooming, the rotation speed of the ITV camera in the up/down/left/right direction remains constant.

FIG. 2 is a conceptual diagram of the ITV camera lens system. In the figure, 1 is Il! 2 is a lens, and 3 is a photosensitive surface of an image sensor. In the case of a tube image sensor, the shape of the photosensitive surface 3 is circular, so the diameter of the photosensitive surface 3 is shown in FIG. 1, and f is the focal length of the lens system.

The image formed at a point P at a distance X from the center of the photosensitive surface 3 is the lens 2
This is light incident from a direction relative to the central axis A through the center axis A. When considering the rotation speed of the ITV camera, both the angle θ and the distance
When differentiated by , the following equation (2) is obtained.

Diameter of photosensitive surface and focal length f of ITV camera for VTS
From the relationship, it can be considered that (x/f) times 1 in the usage range, so dθ/dt in the above equation (2) becomes approximately the following equation (3).

When the camera is rotated by ITV with the rotational speed dθ/dt constant, the movement of a specific point P on the photosensitive surface of the TTV camera is f−dθ/dt, and the larger the focal length f, the more the movement of the specific point P is It gets faster.

[Problem that the invention seeks to solve]

However, compared to the conventional zooming method described above, the method of controlling the vertical and horizontal rotational speed of the ITV camera at a constant speed even if the focal length f changes, as described above, the larger the focal length f, the more the image on the photosensitive surface 3 changes. This has the disadvantage that the movement speed becomes faster, making it less user-friendly for the operator. That is,
When the angular velocity of the ITV camera in the vertical and horizontal directions is constant, there is a problem in that as the zoom is increased, it becomes difficult to align the central axis of the camera with the details of the image.

The present invention has been made in view of the above points.

When monitoring targets that are scattered over a wide area near or far from the ITV camera, it is possible to perform lens zooming and camera pan/tilt adjustments while coordinating with human operations, and to adjust the focal length of the lens. According to IT
ITV that controls the vertical and horizontal movement speed of the V camera
The object of the present invention is to provide a camera rotation control method.

[Means for solving problems]

In order to solve the above problems, the present invention provides a rotation control device for an ITV camera, which includes a focal length detection means for detecting the focal length of the optical system of the camera, a tilt motor control circuit, and a panning motor control circuit. The detection signal from the detection means is guided to a tilt motor control circuit and a pan motor control circuit to rotate the camera vertically and horizontally at a rotation speed inversely proportional to the focal length.

[Effect]

With the above configuration, even if the focal length increases, that is, even if the zoom is increased, the vertical and horizontal rotational speed of the camera will slow down in inverse proportion to it, so the central axis of the camera can be aligned with the details of one image. This makes it easier.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an ITV camera rotation control device to which an ITV camera rotation control method according to the present invention is applied. In the figure, 21 is a sensor (image pickup tube body) of the ITV camera system, 22 is an optical lens system for forming an optical image on the photocathode of the sensor, and 23 is a focal length for detecting the focal length f of the optical lens system. Detector (for example, a calibrated potentiometer), 24 is an ITV camera operation unit that operates the ITV camera system, 25 is a maximum panning speed setting value signal (voltage signal, contact signal, resistance value signal, etc.), and 26 is a tilt Maximum speed setpoint signal (voltage signal,
27 is a signal that commands panning operation (voltage signal or contact signal), 28 is a signal that commands tilting operation (voltage signal value or contact signal)
, 29 is a focal length signal (voltage signal or resistance value signal) from the focal length detector 23, 30 is a panning motor control circuit, 31 is a panning lens drive motor, and 32 is a dynamic motor for driving the panning lens. 33 is a tilt motor control circuit, 34 is a tilt lens drive motor, and 35 is a mechanical signal for driving the tilt lens.

Panning and tilting operations are the same except for whether they are horizontal or vertical movements, so the panning operation will be explained. Set the maximum panning speed setting signal 2.5 to an appropriate angular velocity (for example, 3 degrees/sec). When a signal instructing a panning operation is given from the ITV camera operation unit 24 to the panning motor control circuit 32.

The panning motor control circuit 30 controls the panning motor so as to rotate the camera left and right at a panning angular velocity W p a n given by equation (4) below.

Here, Kp is the focal length fmin at which the focal length f is the minimum
The panning angular velocity when , is given to the system by setting the maximum panning velocity. Also, Ap is the focal length f
This is a constant that determines how the pan angular velocity ypan changes relative to the focal length f, and is a systemically settable constant determined by giving the pan angular velocity when the focal length f is the maximum focal length fmax.

As explained above, according to the above embodiment, when the focal length detection section 23 outputs the signal 29 proportional to the focal length f, the panning motor control circuit 30 operates according to the above equation (4).
Pan angular velocity W p a that is inversely proportional to focal length f
Rotate the camera left and right with n.

That is, when the focal length f increases due to zooming up, the pan angular velocity Wpan decreases in inverse proportion to it, and conversely, when the focal length f decreases due to zooming down, the pan angular velocity Wpan increases. Therefore,
Even when the optical lens system 22 is zoomed up, it becomes easier to match the central axis of the camera with the details of the image.

〔Effect of the invention〕

As explained above, according to the present invention, when the focal length of the ITV camera is changed by a zooming operation, the rotation speed of the camera is controlled to be inversely proportional to the focal length, so that the image on the ITV monitor is An extremely excellent effect can be obtained in that movements can be selected in a manner that is easy to use.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an ITV camera rotation control device to which the ITV camera rotation control method according to the present invention is applied, and FIG. 2 is a conceptual diagram of an ITV camera lens system. In the figure, 21... Camera system sensor, 22... Optical lens system, 23... Focal length detector, 24... ITV
Camera operation unit, 30...Pan motor control circuit, 31
...Pan motor, 33...Tilt motor control circuit. 3, 4... Tilt motor.

Claims (1)

[Claims] Focal length detection means for detecting the focal length of an optical lens system of the camera, in a rotation control device for an industrial television camera that controls the rotation of the camera vertically and horizontally by controlling a tilt motor and a pan motor using signals from an operation unit. , a tilt motor control circuit and a pan motor control circuit are provided.
A detection signal from the focal length detection means is sent to a tilt motor control circuit and a pan motor control circuit, and the tilt motor control circuit and pan motor control circuit rotate the camera vertically and horizontally at a rotation speed inversely proportional to the focal length. A rotation control system for an industrial television camera, which is characterized by the following: