JPH0710102B2 - Field interpolation signal generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention performs non-interlaced scanning to obtain high image quality.
About IDTV (Implayed Definition Television).

<Summary of the Invention> The present invention relates to a field interpolation signal generation device used for IDTV, in which a certain point in an image is divided into a plurality of points located in the vicinity of the point in the scanning lines vertically adjacent to the point and the point. By determining the interpolation signal using the signal one field before at the same position, it is possible to create a natural image without blur even during a moving image.

<Prior Art> An IDTV is a standard television signal as shown in FIG. 4 (a) (having 262.5 horizontal scanning lines per field).
Based on the above, as shown in FIG. 4 (b), an appropriate interpolated horizontal scanning signal is formed between the actually sent one horizontal scanning signal (current signal) and the adjacent current one horizontal scanning signal. This results in twice the density of standard TV signals (525 per field).
Book has horizontal scan lines. There is an IDTV that scans horizontally.

Conventionally, as shown in FIG. 5, an arithmetic mean (m + n) / 2 of the vertically adjacent current horizontal scanning signals or only one of the current signals is used as an interpolation signal regardless of whether the image is a still image or a moving image. It was

<Problems to be Solved by the Invention> In this conventional example, there is no particular problem in the case of a still image, but in the case of a moving image, image quality deterioration such as blurring of vertical contours and jagged diagonal lines occurs.

<Means for Solving Problems> In the present invention, for a certain point in an image, several points located in the vicinity of the point in the scanning lines vertically adjacent to the point and one field at the same position as the point The previous signal is used to determine the interpolated signal.

<Operation> With this, it is possible to create an appropriate interpolation signal without blur even in a moving image.

<Example> An example applied to a luminance component having a high frequency characteristic will be described below.

FIG. 1 is an overall block circuit diagram of the apparatus. In this figure, the composite video signal input from input terminal 1 is the A / D
It is converted into a digital signal by the (analog / digital) converter 2 and Y is converted by the Y / C (luminance signal / color signal) separator 3.
The (luminance) component signal a is extracted. This signal a is directly applied to the double speed converter 9, the signal selection switch 8 and the pattern detector.
Entered in 12. The signal a is 263H ([1 field +
1 / 2H] 1H is output as a signal p through the delay unit 4 having a delay period of 1 horizontal scanning period). Furthermore, the signal a
And the signal c obtained by delaying the same signal a by 1H by the 1H delay unit 5 by the adder 6 and halving it by the divider 7 from the divider 7 to the phase of two adjacent horizontal scanning lines. The averaged signal d is taken out.

The signal selection switch 8 selects three types of signals a, c and d.
, And only one signal is selected as an interpolation signal by the control of the pattern detector 12 which recognizes the pattern around the position of the interpolation signal.

Using the interpolated signal thus obtained and the current signal output from the Y / C separator 3, the double speed converter 9 doubles the horizontal scanning speed and inserts the interpolated signal between the current signals.
When converted to an analog signal by the (digital / analog) converter 10, a Y signal having a scanning line density doubled is taken out.

In FIG. 1, 13 is a clock signal generator that creates a clock used in the system.

Next, pattern detection and signal selection will be described in detail with reference to FIGS. 2 and 3. FIG. 2 shows the internal structure of the pattern detector 12 of FIG. First, the input signal c
From the signal c ₁ and 1S (1 sample period when A / D conversion is performed), the signal c ₂ and the signal c ₂ delayed by 1S by the delay device 14 are further added.
The signal c ₃ delayed by a total of 2S is generated via the 1S delay device 15, and these signals c ₁ , c ₂ , c ₃ are input to the control signal generator 19. Similarly to the signal c, the input signal a also uses the two 1S delay units 16 and 17 to generate the original signal a ₁ , the 1S delayed signal a ₂ and the 2S delayed signal a ₃ and control these signals. Input to the signal generator 19. The input signal b is 1S delayed by the 1S delay unit 18 to generate a signal b ₂ which is input to the control signal generator 19.

Then, a pattern is detected by using the signals c ₁ , c ₂ , c ₃ , a ₁ , a ₂ , a ₃ and the signal b ₂ to generate a control signal e.

This operation will be described using the scanning line model of FIG. FIG. 3B shows the scanning line of the current field, and FIG. 3A shows the scanning line of the immediately preceding field. Points c ₁ and c ₂ in FIG. 3B
c ₃ , a ₁ , a ₂ , and a ₃ correspond to the respective signals in FIG. ₂ , and the “•” mark in FIG. 3 (a) indicates the position of the interpolation signal.

From these seven signals, the pattern is determined as follows.

_First , if any of a ₂ and c ₁ , c ₂ , c ₃ has the same data, a ₂ is appropriate as the interpolation signal because the images are connected.

If there is no identical data in a ₂ and c ₁ , c ₂ , c ₃ , then c ₂ and a ₁ , a ₂ ,
If there is no identical data in a ₃ , then it is judged whether or not there is identical data in c ₂ and a ₁ , a ₂ , a ₃ , and if there is identical data, c ₂ is used as an interpolation signal.

If a ₂ and c ₂ cannot both be used as interpolation signals, c ₁ , c ₂ and c
_{The three} data matches of 3 and the match of three data of a ₁ and a ₂ a ₃ are detected, and if there is a match of both data, the signal has a strong horizontal correlation and no vertical correlation. c ₂ ,, a ₂ and b
The data of ₂ are compared and the one closer to b ₂ is used as the interpolation signal. If there is no match, the signal d output from the divider 7 in FIG. 1 which is the arithmetic mean of a ₂ and c ₂ is used. Table 1 shows the above pattern detecting operation.

In this table, the detection data are points a ₁ , a ₂ , a ₃ , b ₂ ,
Corresponding to c ₁ , c ₂ and c ₃ , the selection signal as the interpolation signal corresponds to the signals a, c and d in FIG.

<Effects of the Invention> As described above, if the interpolation signal for a moving image is created based on the peripheral pattern recognition result, it is possible to configure an IDTV that displays a natural image without blur even during a moving image. It is effective for future digital television receivers expected to be used.

[Brief description of drawings]

1 to 3 show an embodiment of the present invention. FIG. 1 is an overall block circuit diagram of the apparatus, FIG. 2 is a block circuit diagram of the pattern detector 12 in FIG. 1, and FIG. a) and (b)
Is a scanning line diagram of the previous field and the present field, FIGS. 4 (a) and 4 (b) are scanning line diagrams of a standard television signal and an IDTV signal, and FIG. 5 shows a conventional method of creating an interpolation signal. It is a scanning line diagram. 1: Input terminal, 2: A / D converter, 3: Y / C separator, 4: 263H delay device, 5: 1H delay device, 6: Adder, 7: Divider, 8: Signal selection switch, 9 : Double speed converter, 10: D / A converter, 11: Output terminal, 12:
Pattern detector, 13: Clock generator, 14, ..., 18: 1S delay device, 19: Control signal generator.

Claims (1)

[Claims] 1. A Y / C separator for separating an input video signal into a luminance signal and a color signal, and a luminance signal obtained by delaying the luminance signal (a) Y / C separated by the Y / C separator by one field. A field memory for outputting (b), a line memory for outputting a brightness signal (c) obtained by delaying the brightness signal (a) for one horizontal scanning period, and a brightness for outputting the brightness signal (a) and the line memory An adder for adding the signal (c), a divider for outputting a luminance signal (d) whose output level is halved, and the luminance signal (c) delayed by one sample period. Two 1-sample period delay devices connected in series to obtain a luminance signal (c1, c2, c3) and a luminance signal (a1, a2, a3) obtained by delaying the luminance signal (a) by one sample period Two one-sample period delays connected in series for obtaining the luminance signal 1 sample period delay device for obtaining the luminance signal (b2) obtained by delaying b) by 1 sample period, and the pattern of correlation of these 7 signals a1, a2, a3, c1, c2, c3, b2 is determined. Then, a control signal generator that outputs a selection signal (e) according to the condition, the brightness signal (a), the brightness signal (c), and the brightness signal (d) are input, and the selection signal ( and a signal selection switch for selecting and outputting the three types of luminance signals based on e), and the control signal generator firstly comprises the luminance signal (a2) and the luminance signals (c1, c2). , c3) and comparing the luminance signal (a
2) and the luminance signal (c1, c2, c3) are equal to each other, the selection signal (e) for selecting the luminance signal (a) is output, and when the first condition is not satisfied, the second signal is output. And comparing the luminance signal (c2) and the luminance signal (a1, a2, a3), and when the luminance signal (c2) and the luminance signal (a1, a2, a3) are equal, the luminance signal ( The selection signal (e) for selecting c) is output, and when the second condition is not satisfied, the luminance signals (a1, a2, a3) are mutually and the luminance signals (c1, c2, c3) are , Respectively, and when they are equal, successively compare the luminance signal (b2) and the luminance signal (a2, c2) to the luminance signal (b2) which is closer to the luminance signal (a,
It outputs a selection signal (e) for selecting any of c), and finally outputs a selection signal (e) for selecting the arithmetic mean signal (d) when none of the above conditions is satisfied. A field interpolation signal generation device characterized by: