JPS5920134B2 - Television image area signal forming circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a region signal forming circuit for forming a region signal representative of a designated region of a television image.

When erasing a displayed figure (or character) on a CRT display, a light pen is placed on the figure to detect the light from the figure, and this is sent to the computer to erase the figure. I try to do it.

In this case, although the figure itself can be erased, it is not possible to erase the entire area on the screen. Another problem is dividing the television screen into multiple areas and inserting separate images into each area. The shapes of such divided regions generally include vertical and horizontal divisions by vertical and horizontal lines, divisions into circles, diamond shapes, etc., but the screen can also be divided by arbitrary curves or a combination of straight lines and curves. I couldn't. The present invention has been made in view of the above-mentioned problems.The present invention obtains an area signal indicating an area of an image divided by an arbitrary curve, and erases, rewrites, or displays information on an arbitrary area of the screen. The purpose is to enable things such as inserting images.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a television screen showing the operation of the light pen of the image area signal forming device according to the present invention, FIG. 2 is a block circuit diagram of the gate signal forming device, and FIG. 3 is the waveform of each part of FIG. 2. FIG. As shown in FIG. 1, an arbitrary curve A is drawn on a television screen 1 with a light pen 2. As shown in FIG. This light pen 2 is a well-known type consisting of an optical pen and a photocell. The light pen 2 detects the light from the CRT beam,
It is supplied to the memory 3 in FIG. 2 as a pulse signal. This memory 3 may be, for example, a frame memory made of a semiconductor memory, and input signals are recorded based on horizontal addresses and line addresses supplied from an address counter 4. Next, the contents of the memory 3 are read out based on the address supplied from the address counter 4.

The output signal of the memory 3 is, for example, a pulse obtained at two locations on the left side and the right side of the curve A, as shown in FIG. 3A, for the scanning line Ln. Regarding the scan Ln at the lower end (or upper end) of the curve A, only one relatively wide pulse is obtained as shown in FIG. 3C. Even in this case, reading of the memory 3 is performed twice for the same scanning line, and as shown by the arrow in FIG. For example, if the first reading is performed from the left to the right of the screen, the second reading is performed in the opposite direction from the right to the left of the screen.
The output signal of memory 3 is supplied to T flip-flop 5.

Therefore, for scanning line Ln, T flip-flop 5
As shown in FIG. 3B, is set at the rising edge of the first pulse of the output signal of the memory 3 (FIG. 3A), and is reset at the rising edge of the next pulse. In this case, scanning line Ln
Almost the same signal (FIG. 3B) is obtained from the T flip-flop 5 during the first readout and the second readout. The output of the T flip-flop 5 is supplied to line memories 6 and 7 via a switch circuit 10. The switch circuit 10 performs a switching operation so that the output of the T flip-flop 5 is supplied to the line memory 6 during the first reading, and the output is supplied to the line memory 7 during the second reading.

Note that the line memory is a memory that can store the signal of one scanning line. The line memory 6 is supplied with the same address signal as the first read address signal of the memory 3 as a write address signal J, and the line memory 7 is supplied with the second read address of the same scanning line of the memory 3. The same address signal as the write address signal is provided as the write address signal. That is, the line memory 6 stores data from the left to the right of the scanning line, and the line memory 4 stores data from the right to the left. memory 3
When the first and second reading of the same scanning line is completed, the memory 3 is used for a period of 1H (H: horizontal scanning period) until the next scanning line is read in order to process the stored information in the line memories 6 and 7. reading is stopped.

During this stop period, a read address signal is supplied to the line memories 6 and 7, and the contents of these memories are simultaneously read out and supplied to the gate circuit 8. Note that the reading directions of the line memories 6 and 7 are both the same direction, that is, from the left to the right of the screen with respect to the scanning line. This gate circuit 8 may be an AND gate, for example a third
Regarding the scanning line Ln in the figure, since the outputs of the line memories 6 and 7 are substantially the same pulse as shown in FIG. 3B, the output of the gate circuit 8 is substantially the same as this pulse. The output of this gate circuit 8 is supplied to a memory 9. Note that memory 9 is a frame memory, and line memory 6
, 7 is supplied as a write address signal. Also, the scanning line L in FIG.
Regarding m (end of curve A), during the first reading of the memory 3, the T flip-flop 5 is set at the rising edge a of the readout output (FIG. 3C), and this set state is at the end point of the scanning line Lm. is retained until The output of the T flip-flop 5 is then stored in the line memory 6 via the switch circuit 10. Furthermore, when reading the memory 3 for the second time, the rising position of the readout output is at CO)b in FIG.
is set as shown in FIG. 3E, and this set state is maintained until the starting point of the scanning line Lm. In the second readout, the output of the T flip-flop 5 is switched to the switch circuit 10.
The data is stored in the line memory 7 via. Then, as described above, the reading operation of the memory 3 is stopped, and the line memories 6 and 7 are simultaneously read.

In this case, the signal shown in FIG. 3D is read out from the line memory 6, and the signal shown in FIG. 3E is read out from the line memory 7. These signals are supplied to the gate circuit 8, so that the pulses shown in FIG. 3F are formed from the output of the gate circuit 8. This pulse is almost the same as the stored content of the memory 3 shown in FIG. 3C, and the scanning line Lm
It represents the section of line A that is in contact with . The output of gate circuit 8 is stored in memory 9. The memory 9 is read based on the read address signal Ad, and its output is supplied to the outside as an image area signal indicating the area inside the curve A as shown in FIGS. 3B and 3F.

The area signal of this image is used, for example, as an erasing signal for erasing the area inside the curve A of the television screen, or as a punching signal for inserting another image into the area of the curve A. Although the curve A is a closed curve in the above embodiment, if a line segment extending from the top to the bottom of the TV screen is stored in the memory 3 and retrieved via the flip-flop 5, the screen can be changed to the above line segment. A region signal of the image for right and left division can be formed.

Further, in the above embodiment, two line memories 6,
7, the memory 3 is first read out in the left direction of the scanning line, and then supplied to the line memory via the flip-flop 5, and then read out in the right direction with respect to the scanning line of the memory 3, The configuration may be such that the contents are read out in the right direction and the read outputs are compared by the gate circuit 8. As described above, the first aspect of the present invention is to draw an arbitrary curve on the television screen using a light pen, store the output of the light pen in a memory means, and take out the output of the memory means via a flip-flop. Since a region signal of an image delimited by a curved line is formed, a region signal of a television image whose boundary line is an arbitrary curve can be formed.

A second aspect of the present invention is to read the contents of the memory means in the first aspect to the right and left of each scanning line, and supply the respective readout outputs to a flip-flop. and a second output signal, and compare these first and second output signals to form an image area signal, so that the same effect as the first invention is achieved, and the curve A stable image area signal can be formed even at the upper and lower ends of the image.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a television screen showing the operation of the light pen of the image area signal forming device according to the present invention, FIG. 2 is a block circuit diagram of the image area signal forming device, and FIG. 3 is each part of FIG. 2. FIG. In addition, in the symbols used in the drawings, 1...
・Television screen, 2...Light pen, 3.
...Memory, 5...T flip T-flop, 6...Line memory, 7...
Line memory, 8... Gate circuit, 9...
...It's memory.

Claims (1)

[Scope of Claims] 1. A light pen and a memory means capable of storing one frame of image are respectively provided, and the light pen is used to draw an arbitrary curve on a television screen, and the output of the light pen is drawn on the above curve. a television image, wherein contour pulses along the curve are stored in the memory means, and the output of the memory means is taken out via a flip-flop to obtain an area signal indicating the area of the image delimited by the curve. area signal forming circuit. 2. A light pen and a memory means capable of storing one frame of image are each provided, the light pen draws an arbitrary curve on the television screen, and the output of the light pen outputs a contour pulse along the curve. The stored contents of the memory means are read out for each scanning line in the rightward and leftward directions of the scanning line, and the respective readout outputs are supplied to flip-flops to generate first and second output signals. of a television image, the first and second output signals being supplied to comparing means to obtain from the output of the comparing means an area signal indicative of the area of the image delimited by said curve. Area signal forming circuit.