JPS59123371A - Angle of view detector of television camera - Google Patents

Abstract

PURPOSE:To detect automatically a picture angle by calculating the picture angle of a television camera based on position information corresponding to an infinite point in a picture signal obtained from the television camera and a vertical picture angle of a lens of the camera and an effective scanning line number. CONSTITUTION:A video signal from the television camera 1 is transmitted to a binary-coding circuit 20 and a synchronism separating circuit 50 respectively. The bright and dark of the signal is binary-coded at the binary-coding circuit 20 and a coordinate corresponding to the position of an illumination lamp is detected by a white point detecting circuit 30. The synchronous separating circuit 50 extracts a synchronizing signal, which is formed into an original signal to a timing clock and an address transmitted to the white point detecting circuit 30 and a coordinate storage section 40 via a timing generating circuit 60. A microcomputer 70 obtains an infinite point based on a data in the coordinate storage section 40. The main scanning line number (position information) belonging to the Y coordinate is obtained therefrom for the infinite point and the microcomputer 70 obtains the picture angle of the television camera 1 based on the effective scanning line number, the vertical picture angle of the lens and the number of scanning lines.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention relates to the D of a television camera such as a surveillance T camera.
The present invention relates to a j'j angle detection device.

[Technical background of the invention]

In general, in a measurement system that measures the size of each part of an object shown on both sides using the screen obtained by a television camera, the distance γ from the television camera to the object; The television camera is used as a dedicated measurement sensor. Therefore, the parameters necessary for measurement and related to the television camera should be set in advance and used in a fixed manner. others\
The i-angle of television cameras is no exception; the angle of view was only understood as a fixed parameter.

[Problems with background technology]

However, a surveillance system that requires changing the angle of view of a television camera in a timely manner-f! For example, in a monitoring system for expressway tunnels, an operator has to input view angle data every time the view angle is changed, which requires a great deal of effort. Furthermore, since input is done manually, input errors are likely to occur, and input takes a lot of time.

In the above-mentioned surveillance system, the above-mentioned problems were a major drawback in the system, as it was equipped with a television camera.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned drawbacks, and its purpose is to provide a device for determining the angle of view of a television camera from an image signal obtained from the television camera, and to provide a device for determining the angle of view of a television camera from an image signal obtained from the television camera. It is possible to automate the calculation of dimensions.

[Summary of the invention]

Therefore, in the present invention, there is provided a television camera installed so as to capture a point approximately at infinity, a position detecting means for detecting position information corresponding to the point at infinity in an image signal obtained from the television camera, and a position detecting means for detecting position information corresponding to the point at infinity in an image signal obtained from the television camera. Based on the number of effective scanning lines based on the image signal output from the television camera and the vertical angle of view of the lens of the television camera given in advance, the angle of view of the television camera is determined by jγ. The angle of view detection device of a television camera was configured to imitate the calculation means.

[Embodiments of the invention]

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

FIG. 1 is a block diagram of an embodiment of the invention.

In the figure, 1 indicates a television camera. This television camera 1 is placed, for example, in a tunnel, and photoelectrically converts a subject as shown in FIG. 2 into a video signal. The video signal obtained from this television camera 1 is transmitted to a binarization circuit 20.
and the synchronous separation circuit 50, respectively. Binarization circuit 2
0 indicates dark areas in a given video signal (e.g. -1,
This circuit converts the parts of the tunnel (other than the lighting lights) to black, and the bright parts (for example, the lighting parts of the tunnel) to white. A synchronization signal (both horizontal and vertical) is extracted by the synchronization separation circuit 50 from the video signal input to the synchronization separation circuit 50.

The extracted synchronization signal is sent to the timing generation circuit 60, and the timing generation circuit 60 outputs the white spot detection circuit 30.
, be the original signal between the timing clock sent to the coordinate storage unit 40 and the address.

On the other hand, the binarized signal is sent to the white spot detection circuit 30, and coordinate values corresponding to the position of the illumination light are detected. Specifically, the white point detection circuit 30 detects the white point LH+L12°''·, Lln, in FIG. 3 corresponding to the illumination light in FIG.
It is assumed that both signals including L21 HLzz, . . . HLzn are serially sent from the binarization circuit 20 for each scanning line. Therefore, the white point detection circuit 30 searches for a white point every scanning line. Finally, the Y-direction address in Figure 3 is incremented with a clock synchronized with one main scan, and the X-direction address in Figure 3 is incremented with a clock synchronized with 1 bit for each main scanning line to create a white dot. to touch. When a white point is detected, the control unit in the white point detection circuit 30 outputs the Y7F less value and the X7) value of the white point as coordinates 1. is output to section 40. To the coordinate storage unit 40,
An address is given from the timing generation circuit 60, and the X and Y addresses of the detected white point are stored in the coordinate storage unit 40.
is stored at a predetermined address within.

In this way, all white points L+t, Ltz in FIG.

-, Lln, L21. L22. ---, the (x, y,) address corresponding to Lxn is stored in the coordinate storage section 40.

Therefore, the microcomputer 70 uses the coordinate storage unit 40
Find the point at infinity based on the data within.

Specifically, for example, do as follows. Among the white points, find the two points with the farthest X addresses. This 4 corresponds to Ll l and L21 in FIG. Next, find the white point (corresponding to Ll2) with the closest distance 1"ifL from Lll,
Find the white point closest to L21 (corresponding to L22).

Then, a straight line is found from the coordinates of Ln and Ll2, and another straight line is found from the coordinates of Ll and L22. Let the intersection of these straight lines be the point at infinity. In addition, as a method for finding the point at infinity other than the above, after finding Lll and Llz, find the white point 4th to 5th hundredth farthest from each, and process it in the same way as above, and each of Lu and L21. After finding the closest white points L12 and L22 from and finding two straight lines, L+
Find the two white points closest to each of 21L22, find the two straight lines, repeat this a predetermined number of times, and draw the two straight lines based on the average slope of each of the 11 series J and zt series. Find these intersection points without l! i',! Possible methods include setting the point to ＞. It should be noted that in tunnel-type objects, the middle may be curved, and except in cases such as those shown in Figure 2, LII and L2I are different from each other.
5: It cannot be used in the case of 〈There is not necessarily a white point +: Find the IT far point.''

When the point at infinity is found in this way, the Y of this point at infinity is
From the coordinates, nothing! I,! Find the number of I-I lines to which the consecutive points belong (place 1" L Xi77 = ':1.'). For example, as shown in Figure 3, there are 2'40 I-J effect lines. , If you return the Y address from 0 to 239-,!, then
Since the Y7) pulse of the infinite iA point is from X''''C, this is the number of main scanning lines that is 1 for the 11 points at infinity.

By the way, as shown in Figure 4, the television camera 1
If it is installed so that the optical axis of lens 2 is aligned with the straight line +B4<x parallel to
The angle of view θX of the television camera 1 corresponds to the number of scanning lines X up to infinity, and the following equation holds true.

θv/240-θ, x/x-(1) Therefore, the angle of view θX of the television camera is determined by θX-θv-X,/240'' (2).

Therefore, the microcomputer 70 determines the preset number of effective scanning lines 240 and the vertical angle of view θV of the lens 2.
The angle of view θX of the television camera 1 is determined by the number of scanning lines X obtained.
seek.

Next, the TV camera 10 angle of view θX obtained as follows
We will explain the case of calculating distance using .

In FIG. 5, the angle of view θV of the lens 2 is a straight line IJx that reaches infinity and a straight line l· that reaches a point A' on the road 3.

When the robot is in a box, an image like the one shown in Figure 6 is displayed on the screen of the TV monitor. , (indicates that point B' is on straight line B and point A' is on straight line A).

Therefore, point A' in Fig. 5 and point 0 directly below the television camera 1.
', and the distance between point B' and point 0', if the height between TV camera 1 and road 3 is h, then 0'A == h / tan 0v O'B' = h/ l, an (θv/2).

In such a case, the angle of view θX of the television camera l does not have to be a problem, since θ■2θX.

However, suppose that the angle of view θX of the television camera 1 is changed as shown in FIG. Then, an image like the one shown in Figure 8 is displayed on the screen of the TV monitor (the small fish is on straight line B,
(The point on the line indicates that the point lies above the straight line). Therefore, when finding the distance between the points in Fig. 7 and point 0' and the distance between point w' and point 0', 0'A = b / tan (θv
/2) 0'13"==h/tan (θv/4)
Be asked for it.

In other words, by finding the angle of view θX (=θV/2) of the television camera 1, it can be seen that the distance can be found from the above equation. Therefore, the actual distance corresponding to the position on the screen is determined. In the example, the lighting inside the tunnel was used as the element for determining the point at infinity, but for example, the line segment created by both ends of the road, the center line, the wall, the guardrail, etc.
The invention can also be practiced using elements that focus at infinity, such as illumination poles.

〔Effect of the invention〕

As explained above, according to the present invention, even if the angle of view of the television camera changes, it can be automatically calculated. Therefore, even when the present invention is used in a monitoring system,
It is possible to always obtain an accurate angle of view of the television camera, and for example, it is possible to accurately calculate distances and speeds. In addition, since there is no need for manual input, there is no need for input time, and there is no need for input errors. Furthermore, even if the angle of view of a plurality of television cameras is switched at a timely manner as in a surveillance system, the angle of view can be automatically calculated, which is extremely convenient.

[Brief explanation of drawings]

Figure 1 is a block diagram of an embodiment of the present invention, Figure 2 is a diagram showing a subject captured by a television camera, Figure 3 is a diagram of the subject in Figure 2 binarized, and Figure 4. 1 is a diagram showing the relationship between the angle of view of a television camera and the point at infinity, and FIGS. 5 to 8 are explanatory diagrams for calculating distance according to the present invention. 1... TV camera, 20... Binarization circuit 30...
- White point detection circuit, 40... Coordinate storage section 50... Synchronization separation circuit, 60... Timing generation circuit 70... Microcomputer θV... Lens vertical viewing angle θX... Television camera Angle of View Agent Patent Attorney Book 1) Takashi Figure 1 Figure 2 (Figure 3 Figure 4 Figure 5 Figure 1 Figure 6 Figure 7) Figure 8 A

Claims (2)

[Claims] (1) A television camera installed so as to capture a point approximately at infinity, and a position detection means for detecting position information corresponding to the point at infinity within both A-11 obtained from the television camera;
Position 1: □゛ Based on the information, the effective scanning rA number based on the image signal outputted from the television camera, and the vertical angle of view of the lens of the television camera given in advance, calculate both corners of the television camera. Side: The calculation means to be output and the ingredients (!i
A device for detecting both angles of a television camera that uses +i as a /R) sign. (2) The position detection means is a TV camera. ↑The image signal is binarized, the scanning line cut corresponding to the point at infinity is set as the position information 1λ, and the means for outputting ↓ is the corresponding position 1i'l: l
- The +'i signal corresponds to both corners of the television camera, the number of effective scanning lines based on both signals corresponds to the vertical angle of view of the lens of the television camera, and the angle of view and the number of scanning lines are in a proportional relationship. The angle of view detection device for a television camera according to claim 1, wherein the angle of view of the television camera is determined by proportional calculation based on .