JPH0287781A - Contour emphasis circuit - Google Patents

Abstract

PURPOSE:To mount the circuit to a VTR circuit for a camera incorporating type VTR enhance the circuit utilizing efficiency by utilizing part of a Y comb- line circuit so as to constitute a contour emphasis circuit for a luminance signal. CONSTITUTION:A luminance signal 200 inputted to a contour emphasis circuit 1 is inputted to an adder 12 directly and via a 1H delay circuit 11. A noncorrelation signal and a crosstalk signal are outputted from the adder 12 to a limiter circuit 13, which outputs only the crosstalk signal to an adder 14. The adder 14 adds the crosstalk signal to the luminance signal 200 in an opposite phase to eliminate the crosstalk signal. On the other hand, a slice circuit 15 outputs a noncorrelation signal to a variable resistor 17 via a switch circuit 16. The adder 14 forms a luminance signal whose contour is emphasized and outputs the result. The switch 8 is opened at recording. The comb-line characteristic and the contour emphasis characteristic are provided by the delay circuit 11 only in this way to enhance the circuit utilizing efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an edge enhancement circuit for a video signal processed by a video tape recorder (VTR) or the like.

(Prior Art) Conventionally, when the camera circuit side and the VTR circuit side are divided in a camera-integrated VTR, the above-mentioned contour enhancement circuit belongs to the camera circuit side, and its circuit configuration is as shown in FIG. be. That is, the one-day (one horizontal period) delay circuit 10 shown in FIG.
When a luminance signal 100 as shown in A> is input, this luminance signal 100 is delayed for one day and becomes a delayed signal 200 as shown in FIG. . Since the luminance signal 100 is also directly input to this subtracter 20, this subtracter obtains a difference signal 300 between the two signals as shown in FIG.
It is input to 0. This slice circuit 30 creates a signal by removing signals close to DC and signals with little difference from the input signal, and outputs this to an adder 40.

Since the brightness signal 100 is also directly input to this adder 40, the signal from the slice circuit 30 is added to this brightness signal 100, and the brightness signal 400 which is this added signal is output. By the way, since the slicing circuit 30 removes signals close to DC and signals with little difference from the input signal as described above, the signal output from the slicing circuit 30 becomes a signal of the outline portion of the image. Therefore, the tightening device 40
The luminance signal outputted from the is a signal with emphasized contours. However, the VTR circuit side is also provided with a Y-comb circuit, which is a circuit similar to the above-mentioned contour emphasizing circuit. Therefore, in the conventional camera-integrated VTR, substantially the same circuit is installed on both the camera circuit side and the VTR circuit side, which has the drawback of poor circuit utilization efficiency. Furthermore, when contour enhancement is conventionally performed on the camera circuit side, there is a drawback that contour enhancement can only be performed during recording.

(Problems to be Solved by the Invention) Conventional camera-integrated VTRs have an edge enhancement circuit on the camera circuit side and a similar Y<L-shaped circuit on the VTR circuit side, which improves circuit utilization efficiency. The problem was that it had poor performance and a large number of parts. Another drawback was that contour enhancement could only be performed during recording. Therefore, the present invention aims to eliminate the above-mentioned drawbacks by constructing a brightness signal contour enhancement circuit using a part of the Y-comb circuit, and installing this circuit in the VTR side circuit of a camera-integrated VTR. It is an object of the present invention to provide an edge enhancement circuit that can significantly improve circuit utilization efficiency.

[Structure of the Invention] (Means for Solving the Problems) The ring DIS emphasizing circuit of the present invention includes a signal delaying means for delaying a manually input luminance signal for a predetermined period, and an output signal from the signal delaying means and the luminance signal. a first addition means for producing a difference signal by adding the first addition means; an amplitude limiting means for removing a correlation signal from the difference signal outputted from the first addition means to extract a noise component; signal slicing means for extracting a correlation signal by removing noise components from the difference signal output from the means; and signal slicing means for removing noise components output from the amplitude limiting means only when the luminance signal is a reproduction signal of a video tape recorder The luminance signal is configured to include a switch means for passing the luminance signal, and a second addition means for adding the correlation signal outputted from the signal slicing means and the output signal of the switch means to the luminance signal.

(Function) In the edge enhancement circuit of the present invention, the signal delay means delays the input luminance signal by a predetermined period, and transfers this delayed signal to the first
output to the adding means. The first adding means adds the output signal from the signal delaying means and the luminance signal to create a difference signal, and outputs this to the amplitude limiting means and the signal slicing means. The amplitude limiting means removes the correlation signal from the difference signal output from the first adding means, extracts a noise component, and outputs it to the switch means. The signal slicing means removes noise components from the difference signal output from the first addition means, extracts a correlation signal, and outputs this to the second addition means. The second adding means adds the correlation signal outputted from the signal slicing means or the correlation signal and the noise component outputted from the amplitude limiting means to the luminance signal. The switch means inputs the noise component output from the width limiting means to the second adding means only when the luminance signal is a reproduction signal of a video tape recorder.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the contour emphasizing circuit during reproduction according to the present invention. 1 is an edge enhancement circuit having comb-shaped characteristics. 2 is a detection circuit that detects the reproduced FM signal; 3
is a low-pass filter that extracts only the baseband luminance signal. 4 is a de-emphasis circuit, which has characteristics opposite to those of the de-emphasis circuit during recording. 11 is a one-day delay circuit that delays the input signal for 1H period, 12゜14
is an adder, 13 is a limiter circuit that limits the amplitude of the input signal, 15 is a slice circuit that slices the input signal, 16
1 is a switch circuit, and 17 is a variable resistor.

Next, the operation of this embodiment will be explained. Playback FM signal 1
After the signal 00 is detected by the detection circuit 2, it is input to the low-pass filter 3 and becomes a baseband N-group 1 detour signal. This luminance signal is converted into a signal having a 1:1 characteristic equivalent to the luminance signal at the time of recording by the de-emphasis circuit 4, and is inputted to the contour emphasizing circuit 1. The brightness signal 200 input to the edge enhancement circuit 1 is input to the adder 12, and is also input to the adder 12 after being delayed by one day in the one-day delay circuit 11. From there, a non-correlation signal and a crosstalk signal are output to the limiter circuit 13. After removing the uncorrelated signal from the input signal, the limiter circuit 13 converts only the cross 1 - 1 signal to the Jall circuit 14 . Since n types of luminance signals 200 are inputted to this adder 1/I, the hnn vaporizer 14 inversely adds the crosstalk signal outputted from the +Tr limiter circuit 13 to this luminance signal 200 to obtain the luminance signal 200. Remove the cross 1-1 signal from.

On the other hand, the uncorrelated signal and crosstalk signal output from the tightener 12 are input to the slice circuit 15, where:
Only the uncorrelated signal is extracted, and this uncorrelated signal is output to the variable resistor 17 via the switch circuit 16. Since the uncorrelated signal whose level has been adjusted by the variable resistor 17 is input to the adder 14, the adder 14 adds the uncorrelated signal to the luminance signal from which the crosstalk component has been removed.
This creates a brightness signal with enhanced contours and outputs it. In addition, during equivalent pulse vertical synchronization, the luminance signal is 200
Since a non-correlated signal is generated in
If it is added to the luminance signal in the equivalent pulse vertical synchronization lj, an abnormality will occur during the equivalent pulse vertical synchronization. is controlled so that it is opened at the time of equivalent pulse vertical synchronization.

According to this embodiment, as described in ``D'', the contour emphasizing circuit of this example uses only one IN delay circuit 11 to provide the comb characteristic and the contour emphasizing characteristic. V
The contour emphasizing circuit of this embodiment can be mounted on the comb filter portion of the TR side circuit, thereby reducing the number of parts and significantly improving circuit usage efficiency. Also, when recording (
(described later), it is also possible to enhance the outline of a camera-integrated VTR during playback.

FIG. 2 is a block diagram showing an embodiment of an edge enhancement circuit during recording according to the present invention. The contour emphasizing circuit 1 of this example has a circuit in which a switch 18 is inserted between the limiter circuit 13 and the adder 14, and the variable resistor 17 in the previous embodiment is omitted, and other circuits are used. The configuration is the same as the previous embodiment.

However, a Y/C separation circuit 5 and a low-pass filter 6 for separating a luminance signal and a color signal are provided before the edge enhancement circuit 1. The composite video signal 300 is input to the Y/C separation circuit 5, where it is separated into a luminance signal and a color signal component, and only the luminance signal is input to the low-pass filter 6.

The luminance signal input to the low-pass filter 6 is input to the contour enhancement circuit 1 after high-frequency components are removed here. The adder 12 of the edge enhancement circuit 1 extracts the non-correlated signal and the cross signal of the input luminance signal 200, and inputs them to the limiter circuit 13 and the slice circuit 15, as in the previous embodiment.

The limiter circuit 13 removes the uncorrelated signal from the luminance signal 200, leaving only the crosstalk signal, and transfers this signal to the switch 18.
It is output to the adder 14 via. However, the switch 18 is set to the recording time path so that the cross 1 to - - signals output from the limiter circuit 13 are not input to the adder 14 during recording. On the other hand, the uncorrelated signal and crosstalk signal No. 5 inputted to the slice circuit 15 now become only uncorrelated signals, and are inputted to the adder 14 via the switch circuit 16. Therefore, the adder 14 adds only the non-correlated signal to the luminance signal 200 output from the low-pass filter 6 to create a luminance signal with enhanced contours, which is then output. Therefore, during recording, only the edge enhancement function works, and the comb filter function does not work.

According to this embodiment, the contour of the luminance signal during recording is set to ■1°R.
It can be emphasized on the side and the circuit efficiency can be improved. It should be noted that the switch circuit 16 is circuited between the equivalent pulse duplex and direct synchronization and light periods as in the previous embodiment.

FIG. 3 is a block diagram showing another embodiment of the edge enhancement circuit during recording according to the present invention. In this example, the one-day delay circuit 11
Since it has a circuit configuration in which the late Tooms delay/low circuit 19 is inserted between the crimping device 12 and the crimping device 12, the delay period of the delay signal input to the crimping device 12 can be made longer (or shorter) than 11-1. The adder 14 can also perform horizontal edge enhancement. Other effects are similar to those of the previous embodiment.

[Effects of the Invention] As described above, according to the contour enhancement circuit of the present invention, Y<
A part of the L-shaped circuit is used to configure a brightness signal contour enhancement circuit, and this circuit is installed in the VTR side circuit of a camera-integrated VTR, thereby significantly increasing circuit usage efficiency.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the contour emphasizing circuit during reproduction according to the present invention, FIG. 2 is a block diagram showing an embodiment of the contour emphasizing circuit during recording according to the present invention, and FIG. A block diagram showing another embodiment of the edge enhancement circuit during recording of the present invention,
FIG. 4 is a block diagram showing an example of a conventional edge enhancement circuit, and FIG. 5 is a waveform diagram showing the operation timing of each signal in the circuit shown in FIG. 1... Contour enhancement circuit 11... 1 day delay circuit 12, 14... Adder 13... Limiter circuit 15... Slice circuit 19... Delay circuit Agent Patent attorney Noriyuki Chika Yudo Hiroshi Uji

Claims (1)

[Claims] a signal delay means for delaying an input luminance signal for a predetermined period; a first addition means for adding the output signal from the signal delay means and the luminance signal to produce a difference signal;
amplitude limiting means for removing a correlation signal from the difference signal output from the addition means to extract a noise component; and extracting a correlation signal by removing the noise component from the difference signal output from the first addition means. a signal slicing means for
A switch means for passing a noise component output from the amplitude limiting means, and a second addition means for adding a correlation signal output from the signal slice means and an output signal of the switch means to the luminance signal. A contour enhancement circuit characterized by: