JPH05130577A - Image signal band divider - Google Patents

Abstract

PURPOSE:To completely decode even a part at an end of an image when an image signal is processed by band division by using a filter. CONSTITUTION:A horizontal line converting circuit 103 adds signals on mutually opposite sides to both ends of one line in a line memory 102. A horizontal band dividing circuit 104 performs the band division. A band-divided signal in a frame memory 105 is read out by one horizontal scanning line and a vertical line converting circuit 106 adds the signals on the mutually opposite sides to both the ends of the line. A vertical band dividing circuit 107 performs the band division.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image signal band divider for dividing an image signal into a plurality of frequency bands by a frequency band dividing filter.

[0002]

2. Description of the Related Art In audio coding, sub-band coding is often used in which an audio signal is band-divided and the divided band is coded. When applying this encoding to an image signal, the problem is the processing of the edge portion corresponding to the periphery of the screen. Conventionally, as a technique of such end processing, a method has been devised in which an image signal is folded back in a mirror shape at the end, an image signal is newly added to the end, and then the band is divided by a frequency band division filter.

FIG. 3 is a block diagram showing a conventional image signal band divider. In FIG. 3, 301 is a signal input terminal, 302 is a first mirror circuit, 303 is a first buffer,
304 is a horizontal counter, 305 is a horizontal band division circuit, 306 is a frame memory, 307 is a second mirror circuit, 308 is a second buffer, 309 is a vertical counter, 310 is a vertical band division circuit, 311
Is a signal output terminal. The operation of the image signal band divider configured as described above will be described below (FIG. 3).

Assuming that the image signal input from the signal input terminal 301 has M signals in the scanning line direction, the horizontal counter 30
4 counts up each time an image signal is input and counts from 1 to M. First mirror circuit 302
When the number of taps of the frequency band division filter in the horizontal band division circuit 305 is 8, when three image signals are input, the signals are output in the order reverse to the input order.
The first buffer 303 delays the image signal by three signals and outputs it. The horizontal band division circuit 305 has a horizontal counter 304.
If the count value of 1 is 1, the signal from the first buffer 303 is added to the signal from the first mirror circuit 302 on the left side.
The first buffer for the signal from
A signal obtained by adding the signal from the first mirror circuit 302 to the right side of the signal from 303 is band-divided using a frequency band division filter. Then, the horizontal frequency band division signal subjected to the band division is output to the frame memory 306.

When the horizontal frequency band division signal is stored in the frame memory 306, one line of the horizontal frequency band division signal in the vertical direction of the scanning line is output as a vertical line. Now, assuming that there are N signals on the vertical line, the vertical counter 309 counts up each time a horizontal frequency band division signal is input, and counts from 1 to N.
When the number of taps of the frequency band division filter in the vertical band division circuit 310 is 8, the second mirror circuit 307 outputs the horizontal frequency band division signal in the reverse order of the input order when only three signals are input. The second buffer 308 is
The signal output from the frame memory 306 is delayed by 3 signals and output. When the count value of the vertical counter 309 is 1, the vertical band division circuit 310 uses the second buffer 308.
To the signal obtained by adding the signal from the second mirror circuit 307 to the signal on the upper side, the signal from the second buffer 308 in the case of 2 or more and less than M, and the second signal in the case of N.
A signal obtained by adding the signal from the second mirror circuit 307 to the right side of the signal from the buffer 308 is band-divided using a frequency band division filter. Then, the band-divided signal is output to the signal output terminal 311 (for example, "Su
bband Coding of Color Images Using Finite State Ve
ctor Qu-antization ”Proc IEEE Int Conf Acoust Spee
ch Signal Process 1988 [Vol.2]).

[0006]

However, in the above-mentioned configuration, when the image signal is subjected to band division using the frequency band division filter, the degree of decoding at the edge portion of the image is increased. It had a problem that it cannot be completely decrypted.

[0007]

In order to solve the above problems, an image signal band divider of the present invention is an image signal band divider that divides an image signal into a plurality of frequency bands, which is input from a signal input terminal. Stores one line of image signal,
When a line memory output as a horizontal line and the horizontal line output from the line memory are input, a predetermined number K1 (K1 is a natural number) of the image signal at the right end of the horizontal line is added to the left end of the horizontal line, A horizontal line conversion circuit that outputs a signal obtained by adding the image signal at the left end of the horizontal line to the right end of the horizontal line as an additional horizontal line, and the additional horizontal line output from the horizontal line conversion circuit. A horizontal band division circuit for performing frequency band division by a frequency band division filter is provided.

[0008]

According to the present invention, with the above-mentioned structure, the end portions of the image can be completely decoded by connecting the end portions of the image with each other.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An image signal band divider according to 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 an image signal band divider according to the present invention. In FIG. 1, 101 is a signal input terminal, 102 is a line memory, 103 is a horizontal line conversion circuit, 104 is a horizontal band division circuit, 105 is a frame memory, 106 is a vertical line conversion circuit, 107 is a vertical band division circuit, 108 is a signal output terminal. The operation of the image signal band divider configured as described above will be described below (FIG. 1).

The image signal input from the signal input terminal 101 is stored in the line memory 102 for one scanning line. The line memory 102 outputs the stored one line to the horizontal line conversion circuit 103 as a horizontal line. Now, suppose that there are M signals on the horizontal line, and they are 0, 1, 2, ..., M-1 from the left. When the horizontal line is input, the horizontal line conversion circuit 103 adds the image signal at the right end of the horizontal line to the left end of the horizontal line by 3 signals if the number of taps of the frequency band division filter in the horizontal band division circuit 104 is 8. Then, by adding only 3 signals to the right end of the horizontal line and the image signal at the left end of the horizontal line, new M-3, M-2, M-1,0,1,., M-2, M-1, It is output to the horizontal band dividing circuit 104 as an additional horizontal line set to 0, 1, 2. The horizontal band division circuit 104 sequentially performs band division on the additional horizontal line from the left using a frequency band division filter. Then, the horizontal frequency band division signal subjected to the band division is output to the frame memory 105.

When the horizontal frequency band division signal is stored in the frame memory 105, one line in the vertical direction of the scanning line is read out as a vertical line. Now, it is assumed that there are N signals in the vertical line, and 0, 1, 2, ..., N-1 from the top. When a vertical line is input, the vertical line conversion circuit 106 adds three signals to the upper end of the vertical line if the number of taps of the frequency band division filter in the vertical band division circuit 107 is eight. , Add the image signal of the upper end of the vertical line to the lower end of the vertical line by 3 signals,
It outputs to the vertical band division circuit 107 as additional vertical lines N-3, N-2, N-1,0,1,., N-2, N-1,0,1,2. The vertical band division circuit 107 sequentially divides the additional vertical line from the top using a frequency band division filter and outputs the result to the signal output terminal 108.

FIG. 2 is a block diagram showing another embodiment of the image signal band divider according to the present invention. In FIG. 2, 201 is a signal input terminal, 202 is a first memory, 203 is a horizontal line conversion circuit, 204 is a horizontal band division circuit, 205 is a second memory, 206 is a vertical line conversion circuit, and 207 is a vertical band division circuit. A circuit, 208 is a signal output terminal. The operation of the image signal band divider configured as above will be described below (FIG. 2).

The image signal input from the signal input terminal 201 has one line of the image signal in the scanning line direction as a horizontal line, and N (N is a natural number) horizontal lines are stored in the first memory 202. The first memory 202 outputs one horizontal line to the horizontal line conversion circuit 103. Now, assuming that there are M signals in the horizontal line, the image signals of the horizontal line first read from the first memory 202 are S [1,1], S [1,2], ... ,
S [1, M], and the image signal of the second horizontal line read below is S [2,1], S [2,2], ..., S [2, M] from the left, The image signal of the Nth horizontal line read is the same as S [N, 1], S
Let [N, 2], ..., S [N, M].

First, when the first horizontal line is read from the first memory 202, the horizontal line conversion circuit 203 causes the right end three signals S [N, M-2], S of the Nth horizontal line to be read from the first memory 202.
[N, M-1], S [N, M] and the leftmost three signals S [2,
Read 1], S [2,2], S [2,3]. Then, the read signals are S [N, M-2], S [N, M-1], S [N, M], S [1,1], S [1,2], ... , S
[1, M], S [2,1], S [2,2], S [2,3] are rearranged and output as an additional horizontal line. For the second horizontal line and beyond,
When the Kth horizontal line is read out, the right end three signals S [K-1, M-2], S [K from the first memory 202 are read from the (K-1) th horizontal line.
-1, M-1], S [K-1, M] and the leftmost three signals S [K + 1,1], S [K + 1,2], S [K + of the (K + 1) th horizontal line Read 1,3]. Then, the read signals are converted into S [K-1, M-2], S [K-1, M-1], S [K-1, M], S
[K, 1], S [K, 2], ..., S [K, M], S [K + 1,1], S [K + 1,2], S [K + 1,3]
And rearrange and output as an additional horizontal line. The additional horizontal lines for the Nth horizontal line read last are S [N-1, M-2], S [N-1, M-1], S [N-1, M], S [N, 1], S [N,
2], ..., S [N, M], S [1,1], S [1,2], S [1,3]. The horizontal band division circuit 204 divides the additional horizontal line output from the horizontal line conversion circuit 203 into bands using a frequency band division filter sequentially from the left. Then, the horizontal frequency band division signal subjected to the band division is output to the second memory 205. When the horizontal frequency band division signal is stored in the second memory 205, one vertical line of the scanning line is read as a vertical line. Now, assume that the subscript of the band-divided signal is changed from S to T.

First, when the first vertical line is read from the second memory 205, the vertical line conversion circuit 206 causes the lower end three signals T [N-2, M], T [of the Mth vertical line from the second memory 205 to be read. N
-1, M], T [N, M] and the upper 3 signals T [1,2], T of the second vertical line
Read [2,2], T [3,2]. Then, the read signal is
T [N-2, M], T [N-1, M], T [N, M], T [1,1], T [2,1], ..., T [N, 1],
T [1,2], T [2,2], T [3,2] are rearranged and output as additional vertical lines. For the second and subsequent vertical lines, when the L-th vertical line is read, the first memory 202 stores the (L-th vertical line).
-1) T [N-2, L-1], T [N-1, L- for the bottom three signals of the vertical line
1], T [N, L-1] and the upper 3 signals T of the (L + 1) th vertical line
Read [1, L + 1], T [2, L + 1], T [3, L + 1]. Then, the read signals are T [N-2, L-1], T [N-1, L-1], T [N, L-1], T [1,
L], T [2, L], ..., T [N, L], T [1, L + 1], T [2, L + 1], T [3, L + 1] Correct and output as an additional vertical line. The additional vertical lines for the Mth vertical line that is finally read are T [N-2, M-1], T [N-1, M-1], T [N, M-1], T [1, M], T [2,
Let M], ..., T [N, M], T [1,1], T [2,1], T [3,1]. The vertical band division circuit 207 sequentially divides the additional vertical lines output from the vertical line conversion circuit 206 from the top by using a frequency band division filter.

In this embodiment, the number of taps of the frequency band division filter is set to 8, and the number to be added to the horizontal line is one half of the number of taps of the frequency band division filter to 1.
However, the present invention is not limited to this, and various changes can be made.

[0018]

As described above, according to the present invention, it is possible to interpolate the ends of a line by connecting both ends of the line even if band division is performed using a filter. Therefore, it can be completely decoded by the inverse filter.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an image signal band divider according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of an image signal band divider according to another embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a conventional image signal band divider.

[Explanation of symbols]

 102 line memory 103 horizontal line conversion circuit 104 horizontal band division circuit 105 frame memory 106 vertical line conversion circuit 107 vertical band division circuit 202 first memory 203 horizontal line conversion circuit 204 horizontal band division circuit 205 second memory 206 vertical line conversion circuit 207 Vertical band division circuit

Claims (7)

[Claims] 1. An image signal band divider for dividing an image signal into a plurality of frequency bands, a line memory for storing one line of an image signal input from a signal input terminal and outputting it as a horizontal line, and the line memory. When the horizontal line output from the horizontal line is input, a predetermined number K1 (K1 is a natural number) of the image signal at the right end of the horizontal line is added to the left end of the horizontal line, and only the K1 horizontal lines are added to the right end of the horizontal line. A horizontal line conversion circuit that outputs a signal to which the leftmost image signal is added as an additional horizontal line, and a horizontal band that performs frequency band division on the additional horizontal line output from the horizontal line conversion circuit by a frequency band division filter. An image signal band divider comprising a dividing circuit. 2. The image signal band divider according to claim 1, wherein the predetermined number K1 to be added to the horizontal line is a number obtained by subtracting 1 from half the number of taps of the frequency band division filter. 3. A horizontal frequency band division signal, which is subjected to frequency band division in the scanning line direction by a horizontal band division circuit, is stored, and one line of the horizontal frequency band division signal in the vertical direction to the scanning line direction is stored. Is a vertical line, and when a frame memory that outputs the vertical line and a vertical line that is output from the frame memory are input, a predetermined number K2 (horizontal frequency band split signal of the lower end of the vertical line is added to the upper end of the vertical line. (K2 is a natural number), and a vertical line conversion circuit that outputs a signal obtained by adding the horizontal frequency band division signal at the upper end of the vertical line to the lower end of the vertical line as an additional vertical line, and the vertical line conversion circuit. And a vertical band division circuit for performing frequency band division by a frequency band division filter on the additional vertical line output from The image signal band divider according to claim 1, further comprising: 4. An image signal band divider for dividing an image signal into a plurality of frequency bands, wherein the image signal input from a signal input terminal is a horizontal line for one line of the image signal in the scanning line direction, and N (N Is a natural number) When a first memory that stores horizontal lines and a horizontal line that is sequentially output from the first memory are input, an image signal at the right end of the immediately preceding horizontal line is set to the left end of the current horizontal line. Number K3
(K3 is a natural number), and a horizontal line conversion circuit for outputting a signal obtained by adding the image signal of the left end of the next horizontal line by K3 to the right end of the current horizontal line as an additional horizontal line, and the horizontal line conversion. And a horizontal band dividing circuit for dividing the additional horizontal line output from the circuit by a frequency band dividing filter. 5. The horizontal line conversion circuit adds a predetermined number K3 of image signals at the right end of the horizontal line to be output last from the first memory to the left end of the horizontal line first output from the first memory. Outputting, to the right end of the last horizontal line output from the first memory, the image signal of the left end of the first horizontal line to be first output from the first memory by K3 as an additional horizontal line. The image signal band divider according to claim 4, wherein: 6. The image signal band division according to claim 4 or 5, wherein the predetermined number K3 added to the horizontal line is a number obtained by subtracting 1 from half of the number of taps of the frequency band division filter. vessel. 7. A horizontal frequency band division signal, which is subjected to frequency band division in the scanning line direction by a horizontal band division circuit, is stored, and one line of the horizontal frequency band division signal in the vertical direction to the scanning line direction is stored. Is a vertical line, and a second memory that outputs the vertical line and a vertical line that is sequentially output from the second memory are input, the horizontal frequency of the lower end of the vertical line that was output immediately before is added to the upper end of the current vertical line. A predetermined number K4 (K4 is a natural number) of band-split signals are added, and a horizontal frequency band-split signal of the upper end of the next vertical line by K3 is added to the lower end of the current vertical line and output as an additional vertical line. A vertical line conversion circuit, and a vertical band division filter that performs frequency band division on the additional vertical line output from the vertical line conversion circuit. An image signal band divider according to claim 4, further comprising a band dividing circuit.