JPS6248433B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a television image processing device, and more particularly to a moving object trajectory display device that displays the trajectory of a desired moving object, such as a baseball, together with a stationary background.

Conventionally, an image of a moving object is detected by comparing a video signal for one frame at a certain point in time with a video signal for one frame m (m is an integer) frames before. There is known a device that displays the trajectory of a moving object by sequentially storing frames in an image memory in a superimposed manner (Japanese Patent Publication No. 51-12369).

However, in this case, when comparing full-screen images, all moving objects on the screen will be detected.For example, even if you try to display the trajectory of a baseball ball, the movements of the pitcher and assistant players will also be detected. , there is an inconvenience that the screen becomes unsightly. Therefore,
It is conceivable to generate a window signal that defines a desired area (window) on the television screen and perform comparison only within this window to detect only the desired moving object image. Since the image moves frame by frame, the window must also move with it.For example, when an operator is looking at a television screen and wants to display the trajectory of a ball thrown by a pitcher in baseball, the window must be moved accordingly. When playing a ball, it is necessary to input the position of the window each time using a light pen or the like, which is extremely tedious.

There is also a need to simplify the circuit configuration for storing video signals of detected moving objects in a sequentially superimposed manner.

This invention allows only the trajectory of a desired moving object to be clearly displayed by automatically moving the position of the window as the moving object moves.
Normally, the image of a moving object is something like a baseball or golf white ball, and the image signal of the moving object has a signal level different from that of the background image signal. An object of the present invention is to provide a device for displaying a trajectory of a moving object in a television image, which simplifies a circuit for storing data in a superimposed manner.

An embodiment of the present invention will be described below. Note that in the following explanation, for convenience, the video signal is handled in units of frames, but of course it can also be handled in units of fields. In FIG. 1, a video signal is sent from a continuous television video signal source 10, such as a television camera, through a NAM circuit 22 to a television one-screen video memory 20, such as a frame synchronizer. As is generally known, the NAM circuit 22 is a video signal processing circuit that compares two video signals and outputs the one with a higher signal level.
The basic configuration consists of two NPN type transistors 61 and 62 connected to one common emitter resistor 63, as shown in FIG.
Each base of 62 is used as two input terminals a and b, and the emitter is used as an output terminal c. Since only one of the video signals is input here, the video signal is sent as is to the video memory 20, and in this way, the video signal for one frame at a certain point in time is stored.

The video signal stored in the video memory 20 is sent to a subtraction (comparison) circuit 30 (which actually also has a video signal processing function) and is compared with the video signal m frames later. When the current video signal is subtracted from the video signal m frames before, the positive pulse resulting from the subtraction becomes a signal indicating the position of the moving object m frames before, and the negative pulse from the subtraction result becomes a signal indicating the position of the moving object m frames before. The pulse becomes a signal indicating the current position of the mobile object. The obtained current moving object position signal is input to the AND gate 31 together with the window signal from the window signal generation circuit 40. As a result, subtraction is performed only within the window, and if there are no other moving objects within the window, the position of the desired moving object can be reliably detected. The output of this AND gate 31 is sent to a window signal generation circuit 40 via an OR gate 33. The OR gate 33 is also configured to receive a signal from a light pen or the like indicating the initial position of the desired moving object.

The window signal generation circuit 40 generates a window signal that defines, for example, a window (area) having a desired width in the vertical and horizontal directions of the television screen centered on the input position signal, for example, in accordance with the input position signal.
Therefore, for example, the ring counter 41 counts the horizontal synchronizing signal and makes one cycle in the vertical scanning period, and the ring counter 41 counts the clock signal which is phase-locked to the horizontal synchronizing signal and has k times the frequency of the horizontal synchronizing signal and makes one cycle in the horizontal scanning period. A ring counter 42 is provided, and both counters 41 and 42 are reset by the position signal. Each counter 41, 42
After being reset by a position signal, the ring count is performed with the time point at which the position signal is input as "0" (reset state) until the next position signal is input. "i" and "j" before and after "0" of the counter 41 and "p" and "q" before and after "0" of the counter 42 are decoded, and flip-flops 43 and 44 are set with these decoded outputs.
If the outputs of both flip-flops 43 and 44 are input to the AND gate 45, the AND gate output will be
j, the window signal has a width of p to q in the horizontal direction, and the current position signal is located at the center thereof.

This window signal is input to the window memory 50 via the OR gate 51. This window memory 50 consists of a one-bit ("0", "1") area memory on the amplitude side. The output of this window memory 50 is
The signal is inputted again to the window memory 50 via the OR gate 51, and the window signal is stored in a superimposed manner. The output of the window memory 50 is sent to the AND gate 21. The video signal of m frames before is input to this AND game 21,
As a result, only the portion of the video signal within the window (defined by the output of the window memory 50) is sent to the NAM circuit 22 m frames before. Therefore, the NAM circuit 22 essentially operates within the window, and the current video signal is sent to the video memory 20 as it is outside the window.

Inside the window, it works as follows. For example, if the moving object is white like a baseball and the signal level is higher than the background signal level, both video signals are transmitted to both input terminals a and b (see Figure 4) as positive polarity video signals as shown in Figure 5. ). Assuming that the background is stationary, the signal level of the background video signal Y is the same for both input video signals, so the video signal appearing at the output terminal c (see Figure 4) is the same background video signal Y. , the video signal X ₁ of the moving object m frames before and the video signal X ₂ of the current moving object are superimposed. In this way, m frames after the first storage, only the image of the moving object among the first stored video signals is superimposed on the current video signal and stored in the video memory 20. .

After the next m frames (2m frames from the beginning)
, a video signal on which the moving object image of the first frame is superimposed is sent to the subtraction circuit 30. thus
The position signal of the moving object after 2m frames is
It is sent to AND gate 31. The window signal input to the AND gate 31 has predetermined sizes i to j and p to q so that the moving object will enter the window after m frames have elapsed. Therefore, by inputting this new position signal, a window signal whose position has been moved by the same magnitude (moved so that the new position signal is located at the center of the window) is obtained.

To explain this situation with reference to Figure 3A, the moving object is at position A in the first frame, at position A' after m frames, at position A'' after 2m frames, and at position A after 3m frames. , and after 4 m frames, it moves to A〓.In the first frame, position A is input using a light pen, etc., and a window signal (shown by a dotted line) is created so that position A is the center.A' As long as the position of is within this window, the wind signal moves with the same magnitude so that A' becomes the center. After 2 m frames, the wind signal continues to move in the same way so that the center is at the new moving object position. moves.

As a result, the moved windows are stored in the window memory 50 in a superimposed manner one after another, as shown in FIG. 3C. This window memory 50
The output of is sent to AND gate 21. For example, after 2m frames, the video signal output from the video memory 20 includes the moving object image at the time of the first frame and the moving object image at the time m frames later, and both moving object images are displayed on the window. Since the signal is gated by the AND gate 21 and input to the NAM circuit 22, the video signal output from the NAM circuit 22 includes the first frame, m frames later, and 2m
Images of the moving object at three points in time after the frame will be included. In this way, after 4m frames, the five moving object images that have moved in the order of A→A′→A″→A→A〓 will all be superimposed on the background image after 4m frames, as shown in Figure 3B. When the video signal on which the past image of the moving object is superimposed is taken out as an output signal by the NAM circuit 22 or the video memory 20 and displayed on the television picture tube, the image of the moving object as shown in FIG. It is displayed as a trajectory.

Above, we have described an example in which the signal level of a moving object such as a white ball is high, but if the signal level of the moving object is lower than the signal level of the background, such as when the color of the moving object is black, the video signal is set to positive polarity. For this purpose, an inverse NAM circuit as shown in FIG. 6 may be used, or the aforementioned NAM circuit (FIG. 4) may be used with the video signal of negative polarity. To explain the inverse NAM circuit,
Basically, as shown in Fig. 6, two NPN type transistors 71 and 72 and one common emitter resistor 73 are used.
The bases of both transistors 71 and 72 are used as input terminals a and b, and the commonly connected emitters are used as an output terminal c. m frames before,
When the two current video signals are applied to input terminals a and b as shown in Figure 7, the lower signal resulting from the comparison of both input video signals appears at output terminal c, so the common background signal A video signal is obtained in which the video signal Y is superimposed with the video signal X ₁ of the moving object m frames before and the video signal X ₂ of the current moving object. In addition,
This inverse NAM circuit can also be used as a negative polarity video signal when the moving object is white.

As described above in the embodiments, the moving object trajectory display device for television images according to the present invention includes an image memory for storing video signals for one screen of the television image, and a vertical direction within one screen of the television image. and a window signal generation circuit that generates a window signal defining a window having a predetermined area in the horizontal direction;
a comparison circuit for detecting an image of a moving object within the window by comparing the video signal for the screen with the video signal for the previous one screen at a predetermined time stored in the image memory; The window signal generation circuit includes a circuit that changes the vertical timing and horizontal timing of the window signal in accordance with the moving object image signal output from the comparison circuit, and further sequentially changes the shifted window signal. The video signal for one screen at a certain point in time is compared with the video signal for one screen stored in the image memory only in an area defined by the window memory stored in a superimposed manner and the storage contents of the window memory. Since it is configured with a video signal processing circuit that outputs only one of the higher or lower signal level and writes it into the image memory, it detects only the trajectory of the moving object within the window and also detects the trajectory of the moving object within the window. It is possible to automatically follow the movement of a desired moving object, clearly display only the trajectory of a desired moving object, and to simplify the circuit that stores the video signals of the detected moving object so as to be sequentially superimposed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention;
FIG. 2 is a waveform diagram for explaining the operation of FIG. 1,
Figures 3A, 3B, and 3C are diagrams showing signals displayed on the television screen, Figure 3B shows the relationship between the window and the position of a moving object, and Figure 3B shows past images of a moving object. The superimposed video signal is shown, Fig. 3C shows the output signal of the window memory, and Fig. 4 shows the NAM
A circuit diagram showing the circuit, Fig. 5 is a waveform diagram to explain the circuit in Fig. 4, Fig. 6 is a circuit diagram showing the inverse NAM circuit, and Fig. 7 is a waveform diagram to explain the circuit in Fig. 6. It is a diagram. 10...Television video signal generation source, 20...
...Video memory, 22...NAM circuit, 30...Subtraction circuit, 40...Window signal generation circuit, 41,
42...Counter, 50...Wind memory.

Claims (1)

[Claims] 1. An image memory that stores video signals for one screen of television images, and a window signal generation circuit that generates a window signal that defines a window having a predetermined area in the vertical and horizontal directions within one screen of television images. and 1 at a certain point in time
a comparison circuit that detects an image of a moving object within the window by comparing the video signal for one screen with the video signal for one screen stored in the image memory and stored in the image memory for one screen, and The window signal generation circuit includes a circuit that changes the vertical timing and horizontal timing of the window signal in accordance with the moving object image signal output from the comparison circuit, and further superimposes the shifted window signal in sequence. The video signal for one screen at a certain point in time is compared with the video signal for one screen stored in the image memory only in an area defined by the window memory and the storage contents of the window memory. 1. A moving object trajectory display device for television images, comprising a video signal processing circuit that outputs only one of a higher level or a lower level and writes it into the image memory.