JPH05252531A - Contour emphasizing circuit - Google Patents

Abstract

PURPOSE:To provide a contour emphasizing circuit by which not only the contour part of a picture prepared by the change of a reproduction luminance signal, but also the contour part of the picture prepared only by the change of a reproduction chrominance signal can be emphasized. CONSTITUTION:A differentiating circuit 1 differentiates an input luminance signal (a), and outputs it through a slicer 3 and an amplifier 4 to a limiter 5. The limiter 5 generates a square ware-shaped control signal (d) from the inputted differentiation signal, and outputs it through a delay circuit 6 to the control terminal of an amplifier 9. A differentiating circuit 8 differentiates a chrominance signal 100 inputted from a detecting circuit 7, and outputs it to the amplifier 9. The amplifier 9 generates a contour emphasizing signal (f) by changing the polarity of the differentiation signal (e) of the inputted chrominance signal based on the control signal (d), and outputs it to an adding circuit 10. The adding circuit 2 generates a contour emphasizing luminance signal (g) by adding the contour emphasizing signal (f) to the luminance signal inputted from a delay circuit 2, and outputs it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contour emphasizing circuit for emphasizing a contour portion of a reproduced luminance signal reproduced by a video tape recorder (VTR) or the like, and more particularly to a color contour portion.

[0002]

2. Description of the Related Art Conventionally, a contour emphasizing circuit is used in order to give a reproduced image reproduced by a VTR or the like. This kind of contour emphasizing circuit has a structure in which the contour portion of the reproduction luminance signal is detected by some means and the contour portion of the reproduction luminance signal is emphasized based on the detection result. Therefore, in such a conventional contour enhancement circuit, since the contour portion of the reproduced luminance signal is extracted and the contour is enhanced, the contour of the image formed by changing only the color signal without changing the luminance signal. Since there is no means for detecting this portion for the portion, there is a drawback that it is not emphasized even though it is the outline of the image.

[0003]

As described above, the conventional contour emphasizing circuit detects the contour portion of the reproduced luminance signal and enhances the contour portion of the image by emphasizing this portion. However, there is a drawback that the contour portion of the image formed by changing only the color signal cannot be detected, and such contour portion cannot be emphasized.

Therefore, according to the present invention, the above-mentioned drawbacks can be eliminated, and the contour portion of the image formed by the change of the reproduction luminance signal as well as the contour portion of the image formed by only the change of the reproduction color signal can be emphasized. The purpose is to provide a contour enhancement circuit.

[0005]

The contour emphasizing circuit of the present invention includes a differentiating circuit for differentiating an input luminance signal and a pulse-like control signal synchronized with the generation position and polarity of the differential signal obtained from the differentiating circuit. A signal creation circuit to create, an edge emphasis signal creation circuit to create an edge emphasis signal by differentiating after detecting an input color signal, and a polarity of the edge emphasis signal created by this edge emphasis signal creation circuit to the signal creation A polarity variable circuit that performs inversion or non-inversion control based on the control signal output from the circuit, and a contour enhancement signal output from this polarity variation circuit is added to the input luminance signal to obtain a contour enhanced luminance signal. And an adder circuit for outputting.

[0006]

In the contour emphasizing circuit of the present invention, the differentiating circuit differentiates the input luminance signal. The signal creating circuit creates a pulsed control signal synchronized with the generation position and polarity of the differential signal obtained from the differentiating circuit. The contour emphasizing signal generation circuit detects the input color signal and then differentiates it to generate a contour emphasizing signal. The polarity variable circuit performs control to invert or non-invert the polarity of the contour emphasis signal generated by the contour emphasis signal generation circuit based on the control signal output from the signal generation circuit. The adder circuit adds the contour enhancement signal output from the polarity variable circuit to the input luminance signal and outputs a contour enhanced luminance signal.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the contour emphasizing circuit of the present invention. 1 is a differentiating circuit for differentiating the input luminance signal a, 2 is a delay circuit for delaying the input luminance signal a,
3 is a slicer for removing the noise portion of the differential signal, 4 is an amplifier for amplifying the differential signal c, 5 is a limiter for limiting the level of the differential signal to produce a square wave control signal, and 6 is a time delay for the control signal. A delay circuit, a detection circuit 7 for detecting the input color signal 100, a differentiation circuit 8 for differentiating the detected color signal b, and a control 9 for inputting the polarity of the differentiation signal of the input color signal from the delay circuit 6. An amplifier 10 that changes based on the signal d is an adder circuit that adds the input luminance signal and the contour emphasis signal f output from the amplifier 9.

Next, the operation of this embodiment will be described. V
Input luminance signal a of video signal reproduced by TR or the like
Has a waveform as shown in FIG. 2A and is input to the differentiating circuit 1 and the delay circuit 2. The delay circuit 2 delays the input input luminance signal a by the output delay time of the contour emphasis signal f, and then outputs it to the adding circuit 10. On the other hand, the differentiating circuit 1 differentiates the inputted input luminance signal a and then outputs it to the slicer 3. As a result, the slicer 3 removes the noise component from the input differential signal, creates a differential signal c as shown in FIG. 2C, and outputs this to the amplifier 4. The amplifier 4 amplifies the differential signal of the input luminance signal a and then outputs it to the limiter 5. The limiter 5 limits the amplitude level of the input differential signal to form a square wave control signal, and outputs this to the delay circuit 6. The delay circuit 6 differentiates the input control signal from the differentiation circuit 8
After being delayed by the output delay time of the differential signal e of the color signal output from the control signal d as shown in FIG. 2D, this is output to the control terminal of the amplifier 9.

In parallel with the above processing, the detection circuit 7 inputs the input color signal 100 of the video signal reproduced by the VTR.
Is input and a detection signal b as shown in FIG. 2B obtained by detecting this is output to the differentiating circuit 8. The differentiating circuit 8 differentiates the input detection signal b to create a differential signal e of the color signal as shown in FIG. 2 (E), and outputs it to the amplifier 9. Here, the amplifier 9 sets its gain to 1 when the control signal d shown in FIG. 2D is a positive pulse, and sets its gain to -1 when it is a negative pulse. Therefore, the amplifier 9 receives the input color signal 1 as shown in FIG.
If the control signal d has a positive polarity,
Output the phase as it is, and in the case of negative polarity, set the phase to 1
Invert 80 degrees and output. As a result, the amplifier 9 is shown in FIG.
The contour emphasis signal f as shown in (F) is output to the adding circuit 10. Therefore, the adder circuit 10 adds the contour emphasizing signal f inputted from the amplifier 9 to the luminance signal inputted from the delay circuit 2 and outputs the contour emphasizing luminance signal g as shown in FIG. To do.

According to this embodiment, when the contour enhancement signal is created by capturing the changing portion of the color signal, the polarity of the contour enhancing signal is determined based on the changing direction of the luminance signal a in the changing portion of the luminance signal. 2A is created because a final contour enhancement signal f is created by adding to the input luminance signal a to obtain the contour enhancement luminance signal g. As shown in FIG. 2B, if there is a portion B where the color signal 100 changes as shown in FIG. 2B even in the portion where the luminance signal does not change, the luminance signal is outlined at the portion B as shown in FIG. 2G. Can be emphasized. As a result, in this example, the contour enhancement can be performed even in the portion where only the color signal changes to form the contour of the image. The contour enhancement circuit of this example can be applied to a video signal or the like which is received and reproduced by a television receiver or the like to obtain the same effect.

[0011]

As described above, according to the contour emphasizing circuit of the present invention, the contour portion of the image formed by the change of the reproduction luminance signal as well as the contour portion of the image formed by only the change of the reproduction color signal are displayed. Can be emphasized.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a contour emphasizing circuit of the present invention.

FIG. 2 is a time chart explaining an outline emphasis operation of the circuit shown in FIG.

[Explanation of symbols]

 1, 8 ... Differentiation circuit 2, 6 ... Delay circuit 3 ... Slicer 4, 9 ... Amplifier 5 ... Limiter 7 ... Detection circuit 10 ... Addition circuit

Claims (1)

[Claims] 1. A differentiating circuit for differentiating an input luminance signal, a signal creating circuit for creating a pulsed control signal synchronized with the generation position and polarity of the differential signal obtained from the differentiating circuit, and an input color signal being detected. After that, the contour enhancement signal creating circuit that differentiates to create the contour enhancement signal, and the polarity of the contour enhancement signal created by the contour enhancement signal creating circuit is inverted or inverted based on the control signal output from the signal creating circuit. A polarity variable circuit that performs non-inversion control; and an adder circuit that adds a contour enhancement signal output from the polarity variable circuit to the input luminance signal and outputs a contour enhanced luminance signal. A characteristic edge enhancement circuit.