JPS6361829B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image contour detection device used for recording and displaying only the contour of an image from an analog signal such as a television video signal on a television receiver or thermal recording paper.

FIG. 1 shows a block diagram of a case in which a hard copy is obtained by recording an analog signal such as a television video signal on heat-sensitive recording paper having binary shading, and FIG. 2 shows its waveform diagram. A video signal as shown in Figure 2a is input to the input terminal 1 in Figure 1, and the slice circuit 2 slices it at the level A in Figure 2a to generate a binary signal (digital signal) Figure 2b get. When the sliced signal is stored in the memory circuit 4 under the control of the memory control circuit 3 and further recorded on a printer 5 such as a thermosensitive recording device, the display will be as shown in FIG. The part marked "b" will be white and will not be recorded.

If the video signal is simply sliced and stored in a storage circuit to obtain a hard copy, there is a drawback that changes in the image cannot be determined. Also, fluctuations in slice level when converting video signals to binary,
Alternatively, it is necessary to constantly adjust the slice level due to fluctuations in the level of the video signal. Further, when using thermal recording, there is a drawback that the life of the head is shortened due to heat as the number of recording sections increases.

The present invention aims to eliminate the above-mentioned drawbacks, and one embodiment of the present invention will be described below with reference to the drawings.

In FIG. 3, 10 is a video signal input terminal, 11
12 is a differential circuit, 12 is a waveform shaping circuit, 13 is a waveform conversion circuit, 14 is a synchronization signal input terminal, 15 is a clock generation circuit, 16 is an input processing circuit, 17 is a storage circuit, 18 is an output signal processing circuit, and 19 is a contour a correction circuit; 20 a control circuit; 21 a thermosensitive recording device;
E, A, and B are the outputs of each block.

Next, the operation of each block will be explained with reference to the waveform diagrams of FIGS. 4 to 6. Video signal input terminal 10
The video signal shown in FIG. 4a is input to the , and the video signal is differentiated by the differentiating circuit 11, and as shown in FIG. Generating pulses. The synchronizing signal portion of the negative direction and positive direction pulses is removed by a waveform shaping circuit 12 using a synchronizing signal inputted from a terminal 14, and a polarity inverting circuit inverts the polarity of the pulse, and a pulse with inverted polarity and a pulse without inverted polarity are generated. It is converted into a positive-direction-only digital signal by a known polarity matching circuit composed of an OR circuit and the like. This signal is applied to the waveform conversion circuit 13, which is triggered by the rising edge of the pulse shown in FIG. 4c to create a positive pulse as shown in FIG.
As shown in FIG. 5A, the value is set to a constant value greater than one cycle of the recording circuit control clock signal (FIG. 5B). The reason why the pulse width of the signal of the contour part is widened in this way is that the signal of this contour part is
This is to ensure that when recording in the memory circuit 17 using the clock signal shown in FIG. Since the pulse width of the differentiated signal is narrow, even if you try to record it directly using the clock signal, it will often not match the latch timing of the clock signal, and there will be many cases where it will not be possible to record. By widening the pulse width to one cycle or more, it is possible to reliably latch and record accurately. FIG. 5a is an enlarged view of the time axis of a part of an arbitrary data period in FIG. 4d. The clock generation circuit 15 generates the clock signal shown in FIG. 5b synchronized with the horizontal synchronization signal of the television, and the input processing circuit 16 latches the data shown in FIG. 5a with the clock signal shown in FIG. 5b. The clock signal is synchronized with the clock signal as shown in FIG. 5c. The control circuit 20 is a clock generation circuit 15.
Based on the recording control clock signal generated in the memory recording clock signal D shown in FIG. 5d, and the memory reproducing clock signal H shown in FIG. A strobe signal B and a strobe signal A obtained by dividing the frequency of the clock signal shown in FIG. 6a by one-eighth are respectively generated and output. Note that Figure 5 a, b, and c are written on the same time axis,
Figures 5d and 5e are compressed time axes of Figures 5a, b, and c. Further, a in FIG. 6 depicts the portion e in FIG. 5 d.

Now, the storage circuit 17 stores the data from the input processing circuit 16 at the timing of the recording timing portion d in FIG. 5, which is the output of the control circuit 20. After a certain number of bits have been stored, the stored contents in the storage circuit 17 are read out at the timing of part E in FIG. 5d, and the read signal is serial-parallel converted in the output signal processing circuit 18. . In that case, the load pulse shown in FIG. 6b, the parallel output is the falling edge of the clock in FIG. 6b,
The signal shown in FIG. 5e is output only when it is at a high level and is applied to the contour correction circuit 19. The contour correction circuit 19 correlates two adjacent bits of the 8 bits of parallel input, and if both of these two bits are low level or both high level, the signal is set to low level and is not output to the print screen. ing. This is because if two adjacent bits are both 1 signals that should be displayed, the displayed line width will widen when displayed on a screen or recorded on thermal recording paper, etc., making it impossible to display clear outlines. This is because the light disappears, and in such cases there is often a continuous change in brightness and darkness.
This is because better display can be achieved if the outline is not displayed. The thermosensitive recording device 21 is controlled by the data signal and the control signal from the control circuit 20 to obtain a hard copy.

As described above, according to the present invention, it is possible to represent the state of change in an image, and there is no need to adjust the slice level. Furthermore, the present invention provides an apparatus that differentiates and detects the outline of a television image represented by an analog video signal, temporarily stores this in a memory circuit, reads it out, and displays it on a television screen or records it on thermal recording paper or the like. In this method, the pulse obtained by differentiating the analog video signal is shaped into a pulse with a width equal to or larger than one period of the clock signal for the storage circuit, and then supplied to the input processing circuit of the recording circuit. Even if the pulse width of the contour signal obtained by differentiating the video signal is narrow and it cannot be sampled when latched by the clock signal of the recording circuit, resulting in many recording errors, the pulse width of the contour signal obtained by differentiating the video signal is narrow enough to exceed one period of the clock signal. By shaping and widening the contour signal in advance to a width of 100 mm, this inconvenience can be solved and the contour signal can be reliably sampled and recorded using the clock signal.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a conventional image contour detection device, FIG. 2 a and b are waveform diagrams for explaining the same device, and FIG. 3 is a block diagram of an image contour detection device in an embodiment of the present invention Figure 4 a, b, c,
d, Fig. 5 a, b, c, d, e, and Fig. 6 a, b are waveform diagrams for explaining the device. 10... Video signal input terminal, 11... Differential circuit, 12... Waveform shaping circuit, 13... Waveform conversion circuit, 14... Synchronization signal input terminal, 15... Clock generation circuit, 16... Input processing circuit, 17... Memory circuit, 18... Output signal processing circuit, 19... Outline correction circuit, 20... Control circuit, 21... Thermal recording device.

Claims (1)

[Claims] 1. Converting an analog video signal representing an image such as a television video signal into a digital signal, storing it in a storage circuit, reading it out, and displaying it on a television screen or recording it on thermal recording paper with binary gradation. The device includes a differentiating circuit that differentiates the analog video signal to obtain positive direction pulses and negative direction pulses, and a differential circuit that shapes and converts the waveforms of these pulses in one direction only and one period of the clock signal for controlling the storage circuit. Waveform shaping to unify pulses with a pulse width of minutes or more,
A waveform conversion circuit, a memory circuit that stores the output pulses thereof, and reads and outputs an image contour signal from the memory circuit in synchronization with a basic clock signal for displaying on the television screen or the thermal recording paper, etc. An image contour detection device characterized by comprising a circuit. 2 The readout circuit converts the serial pulses read from the storage circuit into serial-to-parallel format using a basic clock signal for display on a television screen or the thermal recording paper, etc., and converts each bit of the parallel signal between each bit. The image contour according to claim 1, wherein an output pulse is not generated when two consecutive bits of the same pulse are successively read out from the memory circuit. Detection device.