JPH02122769A - Contour compensating device for sequential scanning television signal - Google Patents

Abstract

PURPOSE:To reduce contour compensation processing speed to half, and to improve compensating accuracy by using the title device for the generation of an interpolating field by means of a motion application control, and executing the vertical contour compensation before the time compression of the sequential scanning for respective original field. CONSTITUTION:A contour compensating device 1 is set between a motion applicable type interpolating field generating part 2a on the front stage and a time base compressing circuit 2b on a rear stage of a sequential scanning converter, and an adder 32 of the generating part 2a averages picture element signals on an adjoining line during an output to a delay memory 31a, and generates an interpolating line with the use of a correlation. Further, an adder 33 averages the picture element signal on the previous line of a delay memory 31c and the picture element signal on the same line immediately after the field of the memory 31a, and generates the interpolating line with the use of the correlation. The both interpolating line signals are synthesized by coefficient multipliers 34 and 35 altered according to motion magnitude in the picture and an adder 36 by the control of a detection/coefficient generating part 38, inputted to an input terminal 12 of the device 1, and the signal in the original field is inputted to an input terminal 11.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a contour compensation device for progressive scan television signals used in high-definition television receivers and the like.

(Prior art) High-definition (IDTV, EDTV) television receivers currently under development first convert received television video signals of existing standard formats such as NTSC into digital video signals.
After performing various image quality improvement processes such as /C separation, noise reduction, conversion to progressive scanning, and contour compensation, the signal is converted back to an analog video signal and supplied to the display section.

As shown in FIG. 8, the scan conversion device that performs the conversion to the sequential scan described above includes delay memories 61a and 61 connected in cascade.
b, 61c, adder/subtractor 62, 63°66.67, coefficient unit 64.65, motion detection/coefficient generation circuit 68, and time axis compression circuit 69, and interlace scanning supplied to input terminal IN. The NTSC television signal is converted into a progressive scanning television signal with twice the line density and output to the output terminal 01JT.

Focusing on the pixel signal α appearing at the output terminal of the 262-line delay memory 61a, and assuming that it exists on the 2nth line of the current field (assumed to be an even field) as shown in FIG. Stage 1 line delay memory 61
The pixel signal β appearing at the output terminal b exists on the (2n-2)th line one line before in the current field of the interlaced scanning method. In addition, 262 line delay memory 61
The pixel signal T appearing at the output terminal of C and the pixel signal δ appearing at the 262-line delay memo IJ 61 a input terminal are:
As shown in FIG. 8, they appear one field before and after the current field containing pixel signals α and β (2
This is a pixel signal on the (n-1)th line, which appears between the 2nth line and the (2n-2)th line of the current field. In other words, if the current field containing pixel signals α and β is an even field in interlaced scanning, the field containing pixel signal T is an odd field one field before, and the field containing pixel signal δ is an odd field one field after. It is an odd field.

The adder 62 outputs an interpolated line signal (α+β) generated as the average value of pixel signals on each line in the current field based on the correlation between adjacent lines, and the adder 63 outputs an interpolated line signal (α+β) based on the correlation between adjacent frames. Based on this, an interpolated line signal (T+δ) generated as the average value of pixel signals on the same line in fields before and after one field is output. Each interpolation line signal is processed by a synthesis ratio aO and bl which can be changed in a synthesis circuit consisting of an adder 66 and a coefficient multiplier 64.65.
(-1/2-ao), and the following interpolated line signal ε is generated.

=a O(α+β) +bl(γ+δ)・・
・ ・ ・ (1) The motion detection circuit 68 detects motion in the display screen based on the inter-frame difference signal output from the subtracter 67, and adjusts the coefficient values of the coefficient units 64 and 65 according to the detected motion. By controlling the ratios aO and bl, the synthesis ratios aO and bl are dynamically controlled. If there is no movement at all, aO in equation (1) becomes 0 b
l is set to 1/2, and the interpolated line signal ε is composed only of components (γ+δ)/2 generated based on the correlation between adjacent frames. If there is a large movement, aO in equation (1) is set to 1/2 and bl is set to O, and the interpolated line signal ε is a component (
It consists only of α+β)/2.

As shown in FIG. 10, the device that performs vertical contour compensation on the progressively scan-converted television signal includes cascade-connected L-line delay memories 71 and 72, and adders and subtracters 73 and 74 (!: However, since the time axis has been compressed in half by progressive scan conversion, the delay time for one line due to l line delay ° memories 71 and 72 is equal to the delay time for half a line in the interlaced scanning method. Applicable.

Therefore, if the pixel signal appearing at the input terminal of the 1-line delay memory 71 is the target pixel signal α in FIGS. 8 and 9, the pixel signal appearing at the input terminal and the output terminal of the 1-line delay memory 72 The signals are pixel signals ε in FIGS. 8 and 9, respectively.
and β. By subtracting half (α+β)/2 of the output of the adder 73 from the pixel signal ε in the subtracter 74, a contour compensation signal for the pixel signal ε, Δε=[ε−(α+β)/2]... (2) is generated and output to the output terminal OUT.

(Problems to be Solved by the Invention) When vertical contour compensation is performed using a contour compensation device having the configuration shown in FIG. There is a problem that the contour compensation function is impaired.

That is, in the pixel signal of the interpolated line, the component generated from the adjacent line in the field increases as the movement in the display screen increases. In particular, when there is rapid movement, the pixel signal ε of the interpolated line has only a component (α+β)/2 based on the correlation between adjacent lines within the field. In this case, the vertical contour compensation signal Δε output from the subtracter 74 in FIG. 10 becomes completely zero, as is clear from equation (2), and the contour compensation function is completely impaired.

In addition, in conventional contour compensation devices, contour compensation is applied to signals after sequential scan conversion using time axis compression.
There is a problem that processing at twice the speed is required compared to the case of the interlaced scanning method, and the compensation accuracy decreases.

(Means for Solving the Problems) A contour compensation device for a progressive scan television signal according to the present invention includes an interpolation field generated by motion adaptive control;
By applying vertical contour compensation to each of the original fields used to generate this interpolated field prior to time axis compression for sequential scanning, the processing speed for contour compensation can be reduced by half, and the compensation accuracy can be improved. It is designed to improve the performance.

Furthermore, the contour compensating device of the present invention is capable of detecting each line in one of the interpolation field and the original field, and two adjacent lines in the other field separated by one line before and after the interpolation field.
An inter-line contour compensation signal generation unit that creates a contour compensation signal for each line from the pixel signal of the line, and pixel signals of each line in one field and two adjacent lines in this field separated by one line before and after it. a 2-line contour compensation signal generation section that creates a contour compensation signal from the 1-line contour compensation signal generation section; a synthesis section that synthesizes the outputs of the 1-line contour compensation signal generation section and the 2-line contour compensation signal generation section at a changeable synthesis ratio; The synthesis ratio side that controls the synthesis ratio in this synthesis section in a direction that increases the synthesis ratio of the output of the two-line contour compensation generation section as the movement in the display screen increases? By applying motion adaptive control to contour compensation, the contour compensation function can be maintained even when there is large movement.

Hereinafter, the operation of the present invention will be explained in detail together with examples.

(Embodiment) FIG. 1 is a block diagram showing the configuration of a contour compensating device for a progressive scan television signal according to an embodiment of the present invention, in which 1o is a contour compensation unit for an original field, and 20 is a contour compensation unit for an interpolated field. In the compensator, I1 is an input terminal for an original field signal to be subjected to contour compensation, and Ol is an output terminal for an original field signal subjected to contour compensation processing. Further, I2 is an input terminal for an interpolated field signal to be subjected to contour compensation, and o2 is an output terminal for an original field signal subjected to contour compensation processing.

The contour compensation unit 1o for the original field includes cascade-connected one-line delay memories lla and llb, and an adder 12a.
, 12b, subtracters 13a, 13b, and coefficient unit 14,
Nonlinear processing circuits 15a and 15b, synthesis section 16, adder 17, horizontal bypass filter 18, and adder 1
9. Similarly, the contour compensator 20 for the interpolation field also includes a 1-line delay memory 2 connected in series.
1a, 21b, adders 22a, 22b, and adder 23
a, 23b, a coefficient unit 24, a nonlinear processing circuit 25a,
25b, a combining section 26, an adder 27, a horizontal bypass filter 28, and an adder 29.

FIG. 2 is a block diagram showing the mutual relationship between the contour compensation device of FIG. 1 and a motion adaptive progressive scan conversion device;
The contour compensator 1 shown in FIG. 1 is installed between a motion-adaptive interpolation field generating section 2a that constitutes the front stage of the motion-adaptive progressive scan conversion device and a time axis compression circuit 2b that constitutes the rear stage. It shows that there is.

The adder 32 of the interpolation field generation section 2a in FIG.
By averaging pixel signals on adjacent lines appearing at the input/output terminals of the line delay memory 31b, an interpolated line is generated using the correlation between adjacent lines within the field.

The adder 33 also outputs pixel signals on the line of the immediately previous field appearing at the output terminal of the 262-line delay memory 31C, and pixel signals on the same line of the field immediately after appearing at the input terminal of the 262-line delay memory 31a. By averaging pixel signals, interpolation lines are generated using the correlation between adjacent frames. These line signals between both sleeves are combined by a coefficient unit 34, 35 whose coefficients are changed according to the magnitude of movement in the screen under the control of a motion detection/coefficient generation unit 38, and an adder 36. This becomes a motion-adaptive interpolation field and is supplied to the input terminal (2) of the contour compensation device 1. on the other hand,
The signal of the original field used to generate this interpolated field is supplied to the input terminal 11 of the contour compensator 1.

1-line delay memories lla and llb in FIG.

The interval of one line in H.213.21b corresponds to the interval of one line in the original field before progressive scan conversion. corresponds to the spacing of two lines in the field.

That is, as shown in FIG. 3, the original field appearing at the input terminal 1 is an arbitrary even field, and the pixel signal α arranged at the center on the 2nth line LZn in this even field is 1. Suppose that the line delay memory is appearing between lla and llb. At this time, the pixel signal β on the immediately preceding line L2°-2 in this even field appears at the output terminal of the 1-line delay memory llb, and the pixel signal β on the immediately preceding line L2°-2 in this even field appears at the input terminal of the 1-line delay memory lla. Pixel signal γ on immediately following line L2.8□
appears.

On the other hand, pixel signals in the odd field generated from the even original field in the interpolation field generating section 2a at the previous stage and interpolated thereto appear at the input terminal I2. That is, as shown in FIG. 3, between the l-line delay memories 21a and 21b, there is a line L2n-1 in the odd field to be interpolated between the pixel signals α and β in the even original field. Pixel signals δ arranged in the upper center appear. At this time, the output terminal of the line delay memory 21b is connected to the immediately preceding line L2. ．． −
3, the pixel signal ε above appears, and the immediately following line L2 . ．． . 1 The upper pixel signal ζ appears.

In the contour compensation unit 10 for the original field shown in FIG. A line-to-line contour compensation signal generation system is constructed. This two-line contour compensation signal generation system consists of one-line delay memories lla and ll.
On the line appearing between b and 2. ．． The upper pixel signal α and
Before and after that, lines L 2n-2+ L Zn are separated by two lines at the time interval within the field after sequential scanning conversion.
A compensation signal for the pixel signal α, Δ2α=2α−(β+T) (3), is generated from the pixel signals β and T on +□.

Further, the 1-line delay memory 21a, the adder 22a, the coefficient unit 14, the subtracter 13b, and the nonlinear processing circuit 15b constitute an 1-line contour compensation signal generation system for the original field. This line-to-line contour compensation signal generation system uses pixel signal α and two adjacent lines L2A1 in the interpolation field.
The pixel signal δ on +LZ11°1 is therefore the contour compensation signal for the pixel signal α, Δ1α−2α−(δ+ζ)
... (4) is generated. Two adjacent lines L2n-11LZl in the interpolation field where pixel signals δ and ζ appear
The lines l+1 are arranged one line apart before and after the line l-2h where the pixel signal α appears in the field after progressive scanning conversion. Therefore, the part that generates the contour compensation signal for the pixel signal in the original field from the pixel signals on two adjacent lines in the interpolation field is referred to as the line-to-line contour compensation signal generation system. On the other hand, two adjacent lines arranged before and after an arbitrary line in the original field are arranged with an interval of two lines before and after the field after progressive scanning conversion. Therefore, the part that generates the contour compensation signal for the pixel signal in the original field from the pixel signals on two adjacent lines in the original field is called a two-line contour compensation signal generation system.

Both contour compensation signals Δ2α and Δ1α are subjected to nonlinear processing in nonlinear processing circuits 15a and 15b, respectively, and then synthesized in a motion adaptive synthesis circuit 16 at a synthesis ratio according to the magnitude of the motion. , a vertical contour compensation signal Δ α −(1−kr)Δ, α+krΔ2α (5) for the pixel signal of the original field, and is added to the pixel signal α to be compensated in the adder 17. The pixel signal for which this vertical contour compensation process has been completed is added to the horizontal contour compensation signal generated by the horizontal high-pass filter circuit 18 in an adder 19, and is sent to an output terminal connected to a time axis compression circuit. Supplied to O3.

Similarly, the contour compensator 2 for the interpolation field in FIG.
0, cascaded one line delay memory 21
A, 21b, adder 22b, coefficient unit 24, subtracter 23a, and nonlinear processing circuit 25a constitute a two-line contour compensation signal generation system for the interpolation field.

This two-line contour compensation A8 generation system generates an interpolated line L2n appearing between the one-line delay memories 21a and 21b.
Since the pixel signal δ on -1 and the pixel signal ε on the interpolation line L Kn-3+ L Zn+ + separated by two lines before and after it (at the time interval within the field after progressive scanning conversion), the interpolated pixel signal δ is Contour compensation signal for Δ
2δ=26−(ε+ζ)...(6) is generated.

In addition, a line delay memory llb, an adder 12a, a coefficient unit 24, a subtracter 23b, and a nonlinear processing circuit 25b constitute a line-to-line contour compensation signal generation system for the interpolation field, and generate a pixel signal δ and an original field before and after it. within 1
Contour compensation signal for interpolated pixel signal δ from pixel signals β and α on interpolation line L2n-2+LZn separated by line, Δ1 δ=26-(α + β)...
(7) is generated.

Both contour compensation signals Δ2δ and Δ1 for the interpolated pixel signal δ
After being subjected to nonlinear processing in each of the nonlinear processing circuits 25a and 25b, δ is processed by the motion adaptive synthesis circuit 26.
vertical contour compensation signal Δ δ = (1-ki) Δ1 δ+ki Δ2 δ... (
8) and is compensated in the adder 27 and added to the target pixel signal δ. The pixel signal for which this vertical contour compensation process has been completed is added to the horizontal contour compensation signal generated by the horizontal high-pass filter circuit 28 in an adder 29, and is sent to an output terminal connected to a time axis compression circuit. 02.

Based on the interframe difference signal ΔF output from the subtracter 37, the motion coefficient/coefficient generation circuit 38 in the interpolation field generation unit 2a shown in FIG. Coefficient kr, 1-k for contour compensation
It also generates r, ki, 1-ki.

As shown in the block diagram of FIG. 4, the motion detection/coefficient generation circuit 38 includes an absolute value circuit 41 and three comparison circuits 42.
a, 42 b, 42 c, and a decoder 43,
It is composed of coefficient generation circuits 44a, 44b, and 44c, a 1-line delay memory 45, and a maximum value selection circuit 46.

The inter-frame difference signal ΔF supplied to the input terminal I becomes a non-polar inter-frame difference signal in the absolute value circuit 41 and is supplied to one input terminal of each of the three comparison circuits 42a, 42b, and 42c. Reference values A, B, and C that increase in order are supplied to the other input terminals of the comparison circuits 422 to 42C, and the comparison results x, y, and z are sent to the decoder 43.
supplied to As shown in FIG. 5, the absolute value of ΔF is less than the base αζ value A, less than the base Y$ value 8 to upper B, greater than or equal to the reference value B and less than C, or the absolute value of ΔF is less than the base αζ value A; There are four types of combinations of comparison results (x y
z) is supplied to the decoder 43, which receives it and outputs a 2-bit binary signal.

The coefficient generation circuit 44a receiving this binary signal generates coefficients aO, bl for interpolation field generation as illustrated in FIG.
generate. Further, the coefficient generation circuits 44b and 44c provide coefficients ki and 1-ki to be supplied to each coefficient unit of the contour compensation device 1.
, kr, 1-kr.

As shown in FIG. 5, the coefficients ki and kr are set to O in the range where the movement in the display screen is minimal. In this case, contour compensation in the vertical direction is performed only by the outputs Δ, α and Δ, δ of the line-to-line contour compensation signal generator shown in FIG. On the other hand, the coefficients ki and kr are set to l in the range where the movement in the display screen is maximum. In this case, the contour compensation in the vertical direction is the output Δ2 of the contour compensation signal generator between two lines in FIG.
This is done only by α and Δ2δ. In the range where the movement on the display screen is intermediate, the coefficients ki and kr are 0.375 or 0.375.
625, and contour compensation in the vertical direction is performed by a composite value of the output of the 1-line compensation signal generation section and the output of the 2-line contour compensation signal generation section.

Nonlinear circuits 15a, 15b, 25a in FIG.

25b, as shown in the block diagram of FIG. 6, is composed of a sign discrimination circuit 51, an absolute value circuit 52, a coring circuit 53, a slope setting circuit 54, a limiter circuit 55, and an encoding circuit 56. Concerning the contour compensation signal supplied to the input terminal I, coring processing is performed to remove noise as shown in the input/output characteristic diagram in Fig. 7, and slope setting and amplitude limiting processing are performed to adjust the degree of contour enhancement. Non-linear processing including this is performed, and the output is supplied from the output terminal O to the synthesis unit 16 or 26.

The vertical contour compensation signal outputted from the combining section 16.26 is converted into pixel signals α,
is added to δ, resulting in a pixel signal that has been subjected to contour compensation in the vertical direction. For this pixel signal, the horizontal bypass filter 18.
The horizontal contour compensation signal generated in step 28 is sent to adder 19.
．． 29, and output terminals 05.29 as progressively scan-converted television signals subjected to contour compensation in the vertical and horizontal directions. Supplied in Oz.

As described above, when there is a large movement in the display screen, the vertical contour compensation signal Δα for the pixel signal α in the original field is the contour compensation signal component output from the two-line compensation signal generation section. The main component is Δ2α. As is clear from equation (3) and FIG. 3, this contour compensation signal component Δ2α is generated only from lines within the original field, so that double image interference due to movement is effectively prevented, and The contour compensation function is maintained even in a large range of motion.

Similarly, when there is a large movement in the display screen, the vertical contour compensation signal Δδ for the pixel signal δ in the interpolation field is calculated using the contour compensation signal component Δ2δ output from the two-line compensation signal generator. It becomes the subject.

As is clear from equation (6) and FIG. 3, this contour compensation signal component Δ2δ is generated only from lines within the interpolation field. In the case of large motion, the interpolation field is generated from only the lines in the original field using the correlation between lines in the motion adaptive interpolation field generation section 2a at the previous stage, so double image interference is effectively prevented. The contour compensation function is maintained even in a large range of motion.

In the above, a configuration has been exemplified in which the motion detection/generation circuit 38 in the interpolation field generation section 2a disposed at the previous stage is used as a coefficient generation section for motion adaptive control.

However, if necessary, a dedicated coefficient generation section may be installed.

(Effects of the Invention) As explained above in detail, the contour compensation device for progressive scanning telephony signals according to the present invention has a contour compensation device for a progressively scanned telephony signal according to the present invention. On the other hand, since vertical contour compensation is performed prior to time axis compression for sequential scanning, the processing speed for contour compensation is reduced by half, and compensation accuracy can be improved accordingly.

In addition, the contour compensation device of the present invention includes: (1) an inter-line contour compensation signal generation section, an inter-line contour compensation signal raw bottom section, and a synthesis section that synthesizes the outputs of each of these contour compensation signal generation sections at a changeable synthesis ratio; and a composition ratio control section that adaptively controls the composition ratio in this composition section, and increases the composition ratio of the two-line contour compensation signal as the motion increases. Compared to a configuration in which signals are used in a fixed manner, the contour compensation function can be maintained while effectively avoiding double image interference even when there is large movement, and image quality can be improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a contour compensation device for a progressive scan conversion television signal according to an embodiment of the present invention, and FIG. 2 is a mutual relationship between the contour compensation device of FIG. 1 and the progressive scan conversion device. 3 is a conceptual diagram showing the positional relationship on the display screen between the pixel signals appearing in each part of FIG. 1, and FIG. 4 is a configuration of the motion detection/coefficient generation circuit 38 of FIG. 2. A block diagram showing an example, FIG. 5 is a conceptual diagram for explaining an example of the operation in FIG. 4, and FIG. 6 shows an example of the configuration of the nonlinear processing circuits 15a, 15b, 25a, and 25b in FIG. 7 is a conceptual diagram showing an example of the input/output characteristics of the nonlinear processing circuit shown in FIG. 6, FIG. 8 is a block diagram showing the configuration of a conventional progressive scan conversion device, and FIG. A conceptual diagram for explaining the operation of progressive scan conversion, FIG. 10 is a block diagram showing the configuration of a conventional contour compensation apparatus for progressive scan conversion television signals. ■ Contour compensation device, 2a... Interpolation field generation unit of the progressive scan conversion device, 2b... Time axis compression circuit of the progressive scan conversion device, I, ... Original field signal to be subjected to contour compensation processing. Input terminal, ■2... Input terminal for interpolation field signal to be subjected to contour compensation processing, 10... Contour compensation section for original field signal, 20... Contour compensation section for interpolation field signal, lla, llb, 21a
, 21b...1 line delay memory, 15a, 15b. 25a, 25b... nonlinear processing circuit, 16, 26...
- Motion adaptive synthesis unit for contour compensation signal, 18°28...Horizontal bypass filter, 38...Motion detection/coefficient generation circuit, 01...Output terminal for original field signal subjected to contour compensation processing, o2... Output terminal of interpolated field signal subjected to contour compensation processing, Δα... Contour compensation signal in vertical direction for pixel signal α of ring field, Δδ... Contour compensation signal in vertical direction for pixel signal δ of interpolation field, Δ1 α, Δ1 δ...1-line contour compensation signal,
Δ2α, Δ2δ...contour compensation signal between two lines. Patent applicant: NEC Home Electronics Co., Ltd.

Claims (1)

[Claims] A combination ratio of an interpolated line signal based on the average value of pixel signals on adjacent lines in a field and an interpolated line signal based on the average value of pixel signals on the same line in the previous and previous fields in accordance with the movement in the display screen. A sequential scanning method in which contour compensation is applied to an interpolated field consisting of a group of interpolated lines generated by compositing a group of interpolated lines, and to the original field used to generate this interpolated field, prior to time axis compression for sequential scanning. A contour compensation device for a television signal, in which a contour compensation signal for each line is created from pixel signals of each line in one field and two adjacent lines in the other field separated by one line before and after the line. a two-line contour compensation signal generation section that generates a contour compensation signal from pixel signals of each line in one field and two adjacent lines in this field separated by one line before and after the line; , a motion-adaptive synthesis section that synthesizes the outputs of the one-line contour compensation signal generation section and the two-line contour compensation signal generation section while increasing the ratio of the latter as the movement in the display screen increases. 1. A contour compensation device for a progressive scan television signal, characterized in that: