JPS63229983A - Field still reproducing device for component television signal - Google Patents

Abstract

PURPOSE:To suppress the deterioration of oblique edge by executing interpolation with respect to a period corresponding to the oblique edges included in picture signals with an interpolation method different from that in the period excepting the oblique edges. CONSTITUTION:Video signals read from a field memory 1 are inputted to isolated detectors 3 and 4 through a 1H delay unit 2. The detector 4 detects a bit of isolated information in an l-th line and the detector 3 detects the isolated information in (l+1)-th line. A multiplexer controller 6 judges whether respective isolated edges are oblique edges or not, and the inclination (left slant or right slant) if they are oblique edges. It is decided whether the upper line (l) or the lower line (l+1) is selected from the timely relation between the judged result, isolated edges and respective sample points, whereby a multiplexer 5 is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a field still playback device for component digital VTRs and the like.

In a conventional digital VTR, by having a memory on the playback side, high-quality still playback images can be easily obtained. In order to reproduce one complete still image, one frame of memory is required. However, in a frame still image of a moving image that moves quickly compared to the field period, pre-motion occurs. Therefore, field still is essential for digital VTRs. In field still, the playback side only has memory for one field, so in order to play a complete image of one frame, the field stored in memory must be interlaced with the other fields. I need to interpolate the signal. A conventional example of this interpolation is shown in FIG.

In the method shown in FIG. 2, the signal one line above or one line below is replaced as is, and b is interpolated using the average value of the upper and lower lines. In Figure 2,
The lines shown in solid lines are the lines read from the field memory, and the lines shown in dotted lines are interpolation lines. Still, 2 represents the number of the line and q(n) is the second
represents the signal value of the th line.

Problems to be Solved by the Invention In a field still image, the number of effective lines is % compared to a frame still image, so the vertical resolution is H. When the vertical resolution is reduced to %, it is the diagonal edges that are most visually degraded. That is, if the signal on the lower line is replaced as is, the amount of zigzag in the diagonal edge portion will double as shown in FIG.

This situation is exactly the same when the above line signal is replaced as is. Furthermore, when interpolation is performed using the average value of the upper and lower line signals, diagonal edge portions become blurred.

The present invention has been made to solve the above problems, and provides a component television signal that can achieve the same clarity as frame stills without blurring diagonal edges even in field stills. The present invention provides a field still playback device.

Means for Solving the Problems In order to solve the above problems, the present invention has means for detecting diagonal edge portions included in an image signal, and detects one of the periods corresponding to the detected diagonal edges. Interpolation is performed for all or part of the period using an interpolation method different from the interpolation method for periods other than diagonal edges.

As a result, even though it is a field still, the smoothness of diagonal edges can be as good as that of a frame still, and a large visual improvement in image quality can be obtained.

Embodiment A first embodiment of the present invention is shown in FIG. In FIG. 1, 1 is a field memory, 2 is a 1H (H: 1 horizontal scanning period) delay device, and 3 and 4 are isolated edge detectors (1), (n
), 6 is a multiplexer, 6 is a multiplexer controller, 7 is a changeover switch, and 8 is an output terminal. As described above, the present invention focuses on the fact that when a field still image is used, the deterioration of the diagonal edge portion is visually most noticeable. Therefore, the key point is to first detect the diagonal edges in the television screen and how to interpolate to these edges.

The operating principle of this embodiment will be explained in detail below with reference to FIGS. 4 to 7. First, the isolated edge detector (1),
(n) The operations of 3 and 4 will be explained using FIGS. 4 and 6. FIG. 4 is a flowchart showing the operation, and FIG. 5 is a waveform diagram for each signal in the flowchart. First, f(
i) is a signal waveform when focusing on a certain line. 6th
Figure a shows sample points when sampling at frequency f8, and Pl.

The portions corresponding to P2 and P3 correspond to edge portions. In the flowchart of FIG.

Step 9: First, find the absolute value 1((1)-f(i-1)I) of the difference between the sample value i(i) at time l and the sample value f(i-1) at time (i-1), This value is compared with a threshold level T that has escaped in advance, and an edge signal E(1) is generated.

Step 1o: Next, edge signal E(i
) and the edge signal E(i-1) at time (i-1).

Step 11: Then, the time l of the sample point at which the value of D(1) becomes "1" is stored in the register R(k) as the rising point of the second edge, and the value of ■j) becomes "-1". The time j of the sample point corresponding to , is stored in the register F(k) as the falling point of the th edge.

Step 12: Next, find the average value of R(k) and F(k) above, and use this value as the center point of the edge in register C(
k).

Here, [x] is a Gaussian signal representing the largest integer that does not exceed the value of X.

Through the above operations, all the center points of edges having slopes greater than a certain value within one lie are found. However, the edge information obtained in this manner includes a lot of extra information in addition to the diagonal edge portions that originally require interpolation. That is, patterns that vary minutely in the horizontal direction are also detected, but in the case of such patterns, even with conventional interpolation, the deterioration is not visually noticeable. If the interpolation of the present invention is performed on such a pattern, the image quality may deteriorate due to interpolation errors. Therefore, in order to eliminate this inconvenience, it is necessary to find isolated edges within a certain range. In other words, step 13: Whether the edge is an isolated edge or not is determined by a certain distance (10 samples in this example) from the (k-1)th edge and the (k+1)th edge.
You can check whether it is further away.

If the conditional expression in step 13 is satisfied, it is determined to be an isolated edge (14), otherwise it is determined to be a non-isolated edge (15)
.

Based on the isolated edge information of the Cth line and the isolated edge information of the (1-z)th line obtained as described above, the multiplexer controller 6 selects the upper line 2 as the interpolation signal, or selects the lower line ( n+1) to be selected and controls the multiplexer 5. The operating principle of this multiplexer controller will be explained using FIGS. 6 and 7.

FIG. 6 is a brooch yard showing the operation of the multiplexer controller.

Step 16: First, use the method described above to find the second isolated edge C(J!) on the second line and the (ff+1)th line.
, k), C(n+1.k) is detected.

Step 17: Next, in order to determine whether this isolated edge is a diagonal edge, C(fi, k) and C(fl,
+1. The absolute value of the difference in k) is compared with a certain constant value (10 in this example).

As a result, if the absolute value of the difference is less than a certain value, the two isolated edges are located close to each other, and these edges are determined to be diagonal edges.

If it is not a diagonal edge, return to the beginning again.
Search for isolated edges. If it is determined to be a diagonal edge, the process proceeds to step 18: The direction of inclination of the diagonal edge is determined.

Step 19: If the value of C(necessary, k) is C(J2+1
．． k), this is determined to be a left diagonal edge, and interpolation as shown in FIG. 7a is performed.

Sunawachi, [尼υ5K) + C堡Go1 sacrifice] ≦i≦F (translation,
For sample points that exist in the range of
Replace directly with (Q+1). Here, the symbol [ ] is the Gauss symbol mentioned above.

Step 2o: Contrary to the above, the value of C(Q, k) is changed to C(
fl, +1. If the edge is thicker than the value of k), this is determined to be a right diagonal edge, and interpolation as shown in FIG. 7 is performed.

In other words, for sample points existing in the range, the upper line q (
fi) as is, and for the rest, use the line q(fl
, +l). Finally, selector switch 7
, the field still image is output to the output terminal 7 by alternately switching between the field memory output and the multiplexer output for each field.

Second and third embodiments of the present invention are shown in FIGS. 8 and 9. First, in Fig. 8, the parts Pl and P3 are on the upper line q(n
) and replace the P2 part with the line q(fi+1) below.

In Fig. 9, the upper and lower parts of the Pl and P4 parts are the upper line q(fi), and the lower part of the P3 part is the lower line q(n+
, 1) respectively.

As described in detail, according to the present invention, it is possible to suppress the deterioration of diagonal edges during field still playback of component television signals, and it is possible to obtain visually high image quality approximately equivalent to that of frame stills. Can be done. This makes it possible to reproduce high-quality still images without blurring even for moving images that move quickly compared to the field period, and can be applied to digital VTRs with great effects.

[Brief explanation of drawings]

FIG. 1 is a block diagram corresponding to a first embodiment of the present invention;
FIG. 2 is an explanatory diagram showing the conventional interpolation method, FIG. 3 is an explanatory diagram showing how the image quality deteriorates in the conventional example, FIG. 4 is a flowchart explaining the operation of the isolated edge detector, and FIG. FIG. 6 is a flowchart explaining the operation of the multiplexer controller, FIG. 7 is an explanatory diagram showing the interpolation method of the first embodiment, and FIG. 8 is a diagram of the second embodiment. FIG. 9 is an explanatory diagram showing an example interpolation method. FIG. 9 is an explanatory diagram showing an interpolation method according to a third embodiment. 1...Field memory, 2...1H delay device, 3.4...Isolated edge detector, 6...
...Multiplexer, 6...Multiplexer controller, 7...Selector switch, 8...
...Output terminal. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
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b) Figure 4 Figure 5 Figure 6 Figure 7j ST diagram (/l) Figure 8 Figure 9

Claims (3)

[Claims] (1) In a device that constructs one frame image by interpolating and synthesizing a second field signal that is in an interlaced relationship with the first field signal, diagonal edges are interpolation for a part or all of the period corresponding to the detected diagonal edge using a different interpolation method from the interpolation method for the period other than the detected diagonal edge; 1. A field still playback device for component television signals, characterized in that the field still playback device includes means for reproducing component television signals. (2) The interpolation means replaces the first half or the second half of the period corresponding to the diagonal edge with a signal one line above or one line below, and replaces the other periods with a signal one line below or one line above. Claim 1 characterized in that
A field still playback device for component television signals as described in Section 1. (3) The interpolation means replaces the first half of the period corresponding to the diagonal edge with a signal one line above or one line below, replaces the second half with a signal one line below or one line above, and replaces the other periods. 2. The field still reproducing apparatus for component television signals according to claim 1, wherein the field still reproducing apparatus for component television signals is replaced with an average value of signals one line above and one line below.