JPS59173705A - Image pickup range finding system - Google Patents

Abstract

PURPOSE:To make a large-scale transmitting and receiving device, etc. unnecessary by providing a zoom lens on a television camera, and operating the zoom lens so that a video of an object whose dimensions are known is brought to an image pickup to set dimensions on a monitor television picture. CONSTITUTION:A target A placed at a point of a front distance D of a television camera 1 is brought to an image pickup through a zoom lens 2 by the television camera 1, and its video is reflected on a picture of a monitor television 3. Therefore, the zoom lens 2 of the television camera 1 is driven and operated so that the video dimensions of the monitor television 3 becomes set dimensions, for instance, basing on a scale drawn on the picture. According to such a system, a conventional large-scale transmitting and receiving device, etc. are not required, and an extremely simple device is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a distance measuring method using a television camera.

A number of devices that use light waves, electromagnetic waves, ultrasonic waves, etc. have been proposed as devices for measuring the distance between objects in real time in a completely non-contact manner. The drawback is that it requires large-scale transmitting and receiving equipment, is not simple, and is expensive; for example, it is not possible to use all such rangefinding equipment in civil engineering surveys that are carried out while moving outdoors. Ta.

The present invention has been made in view of the above-mentioned drawbacks of conventional distance measuring devices, and its entire purpose is to provide a simple and low-cost distance measuring device.

To this end, in the present invention, a television camera with a zoom lens is used to image the entire object of known size, and the image of the object projected on the monitor television screen is of constant size. The zoom lens of the television camera is fully operated, and the distance between the object and the television camera is calculated from the amount of zoom operation.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a block diagram showing a distance measuring device according to an embodiment of the present invention, and FIG. 2 is an analysis diagram for explaining the operation of the embodiment of the present invention.

In Fig. 1, 1 is a TV camera, 2 is a zoom lens of the TV camera L, 3 is a monitor TV that monitors the image, 4 is a distance measurement calculation unit that calculates the total distance from the amount of movement of the zoom lens 2, and A is a dimension. This is an object for which r is known and is to be imaged by the television camera 1 (hereinafter referred to as a target). In addition, R is the full field of view of the TV camera 1, θ is the full field of view of the zoom lens 2, and D is the distance between the target A and the TV camera 1.
This indicates the distance to be measured by the distance measuring device.

By the way, between the total field of view R at the point where the target A is placed in front of the television camera 1, that is, the distance point, and the total field of view angle θ, as is clear from Fig. 1, the following equation is established. A relationship is established.

From this equation (1), the distance is as follows.

If the ratio id of the dimension r of the target A placed at the above distance and the total field of view R is d=-...(3) From the relationship between equations (2) and (3) above, the distance is as follows. become that way.

From this equation (4), if the zoom lens is operated so that the ratio d is constant, the total viewing angle θ of the zoom lens 2 can be detected since the dimension r of A is known.
That is, by measuring the operation Nk of the zoom lens 2, the distance can be known.

The operation to keep the ratio d constant will be explained with reference to FIG.

The fact that the above ratio d is constant means that the ratio between the dimension r' of the video A' of target A captured at the imaging position of the television camera 1 and the effective screen size R' at the imaging position is constant. That is, since R' is constant, making the ratio d constant means operating so that the dimension r' of the image A' of the target A is constant.

It is at a distance from the imaging position of TV camera 1.

Suppose that target (target) A at the position of target (target) A approaches the television camera 1 to a position of distance D2.The same is true even if we consider that the position of target (target) A is fixed and the television camera 1 approaches the target target (target) A). , To keep the above ratio d constant (keep the dimension r'r of the image A' constant), fc, as is clear from FIG. That is, the focal length of the lens of the 7-Level camera 1 may be changed from k F 1 to F2. Moreover, since the position of target (Target) A is usually arbitrary depending on the difference between the points to be measured, the change in the above-mentioned total viewing angle must be continuous. As is well known, this change is achieved by the function of a zoom lens, and therefore, the television camera 1 only needs to be equipped with a zoom lens 2.

In addition, when calculating the above formula (4), the distance should be ``
D - F" (F is the variable focal length of the zoom lens 2), but normally °'D:>F", so D - F
: Analyzed as D.

Next, referring to FIG. 1, the entire operation of the distance measuring device according to the embodiment of the present invention will be explained.

Tarke 9 placed at a distance in front of TV camera 1
The shot A is imaged by a television camera 1 through a zoom lens 2, and the image is displayed on the screen of a monitor television 3. Therefore, the zoom lens 2 of the television camera 1 is operated so that the image size on the screen of the monitor television 3 becomes a set size based on, for example, a scale drawn on the screen.

A sensor is attached to the zoom lens 2 to detect the entire amount of movement of the zoom lens 2. A signal proportional to the amount of movement of the zoom lens 2 is sent from this sensor to the distance measurement calculation section 4. The distance is calculated by calculating the above-mentioned equation (4) based on the signal, and the distance is displayed on the screen of the monitor television 3. Note that the distance may be displayed not on the screen of the monitor television 3 but on a separate display.

As explained in detail above, the present invention provides a completely new distance measuring method using imaging, and does not require large-scale transmitting/receiving equipment as in the past, and is an extremely simple distance measuring device. can be obtained. Therefore, for example,
Recently, even in cases such as civil engineering surveying where it is necessary to measure distances at multiple points while moving outdoors, the measuring device of the method according to the present invention can be used. The captured image of the target is always of a constant size, and the secondary effect is that it is easy to monitor.

Although the distance measuring device according to the present invention uses a method in which the operator visually observes the size of the target on a monitor television screen, if high accuracy is required for measurement, an image captured by a television camera may be used. For example, when the ratio d is analyzed by an image analyzer and the ratio d of the target on the screen matches the set ratio by operating the zoom lens, a matching signal is displayed on the monitor TV screen. By displaying , highly accurate measurement becomes possible.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is an analytical diagram for explaining the operation of the embodiment of the present invention. 1...TV camera, 2...Zoom lens, 3
...Monitor TV, 4...Distance measurement calculation section.

Claims (1)

[Claims] 1. A zoom lens is provided in all television cameras, and the zoom lens is operated so that an image of an object with a known size is captured on a monitor television screen with a set size, and the zoom lens is adjusted at that time. An imaging and ranging method that determines the distance between the television camera and the object from the amount of operation. 2. The imaging distance measuring method according to claim 1, wherein the measured distance is displayed on a monitor television screen.