Image signal coding system

• US 20010000072A1
• Filed: 12/04/2000
• Published: 03/29/2001
• Est. Priority Date: 10/22/1991
• Status: Active Grant

• Current Assignee: Hirofumi Nishikawa, Kohtaro Asai, Tokumichi Murakami, Yoshihisa Yamada
• Original Assignee: Hirofumi Nishikawa, Kohtaro Asai, Tokumichi Murakami, Yoshihisa Yamada
• Inventors: Yamada, Yoshihisa, Nishikawa, Hirofumi, Asai, Kohtaro, Murakami, Tokumichi
• Granted Patent: US 6,307,973 B2
• Time in Patent Office: Days
• US Class Current: 382/238
• CPC Class Codes: H04N 19/105 Selection of the reference unit for prediction within a chosen coding or prediction mode, e.g. adaptive choice of position and number of pixels used for prediction
• CPC Class Codes: H04N 19/112 according to a given display mode, e.g. for interlaced or progressive display mode
• CPC Class Codes: H04N 19/119 Adaptive subdivision aspects, e.g. subdivision of a picture into rectangular or non-rectangular coding blocks
• CPC Class Codes: H04N 19/124 Quantisation
• CPC Class Codes: H04N 19/132 Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking
• CPC Class Codes: H04N 19/137 Motion inside a coding unit, e.g. average field, frame or block difference
• CPC Class Codes: H04N 19/14 Coding unit complexity, e.g. amount of activity or edge presence estimation H04N19/146 takes precedence
• CPC Class Codes: H04N 19/152 by measuring the fullness of the transmission buffer
• CPC Class Codes: H04N 19/16 for a given display mode, e.g. for interlaced or progressive display mode
• CPC Class Codes: H04N 19/172 the region being a picture, frame or field
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/577 Motion compensation with bidirectional frame interpolation, i.e. using B-pictures
• CPC Class Codes: H04N 19/61 in combination with predictive coding

Abstract

An adaptive blocking coding system selects an effective blocking of an input image signal to be encoded in accordance with the correlation between fields, even if motion is detected between the fields. The blocking patterns include an individual field blocking, a non-interlace blocking, a split blocking and an inverted split blocking. Further, the coding system searches for motion from both odd and even fields of a frame for producing a motion compensated prediction signal in order to provide high-efficient coding.

Claims

1. An adaptive blocking image coding system for encoding an input image signal obtained by interlaced scanning in units of the block of M pixels×

N lines, comprising;

blocking means for selectively forming a first type block including only the pixels of M pixels×

N lines belonging to the odd field of the input image signal or the pixels of M pixels×

N lines belonging to the even field thereof, a second type block wherein the pixels of the M pixels×

N/2 lines belonging to the odd field and the pixels of the N/2 lines belonging to the even field are arranged alternately in every other line corresponding to scanning positions on a display screen, a third type block wherein the pixels of M pixels×

N/2 lines belonging to the odd field are arranged in the upper or lower half of the block and the pixels of M pixels×

N/2 lines belonging to the even field are arranged in the remaining half of the block, and a fourth type block wherein the pixels of M pixels×

N/2 lines belonging to the odd field are arranged in the upper or lower half of the block, the pixels of M pixels×

N/2 lines belonging to the even field are arranged in the remaining half of the block and the pixels of either field are inverted upside down in the vertical direction with respect to the display screen;

blocking determining means for determining the type of blocking by said blocking means;

transform means for orthogonally transforming the block formed by said blocking means;

quantizing means for quantizing the transform coefficient obtained by said transform means; and

coding means for encoding the quantized index obtained by said quantizing means.

2. An adaptive blocking image coding system according to

claim 1

wherein said quantizing means for quantizing the transform coefficient variably controls the quantization accuracy in accordance with the type of arrangement provided by said blocking means.

3. An adaptive blocking image coding system according to

claim 2

wherein said coding means for encoding the quantized index obtained by quantizing said transform coefficient determines the scanning sequence of quantizing the transform coefficient in accordance with the type of arrangement to be blocked by said blocking means.

4. An adaptive blocking image coding system according to

claim 2

further comprising blocking determining means for determining the type of arrangement to be blocked in said blocking means in accordance with the value obtained by multiplying a predetermined weighting coefficient with the pixels of each line included in the block and then totaling the multiplied values.

5. An adaptive blocking image coding system according to

claim 2

further comprising blocking determining means for determining the type of arrangement having the minimum coefficient power of a predetermined high-frequency component among the transform coefficients obtained by the discrete cosine transform of the block.

6. A coding system comprising:

(a) input means for inputting an input signal to be encoded;

(b) a field memory for storing the input signal by dividing said signal into a plurality of fields such as the odd field and even field;

(c) predictive signal output means for outputting a plurality of predictive signals predicting the change of input signal corresponded to each signal stored in said field memory;

(d) a selector for selecting a predictive signal from the predictive signals provided by said predictive signal output means; and

(e) coding means for encoding the input signal using the relationship between said predictive signal selected by said selector and the input signal from said input means.

7. A coding system according to

claim 6

further comprising an interpolation means for outputting an interpolated predictive signal in response to predictive signals of a plurality of types from said predictive signal output means.

10. A coding system according to

claim 7

wherein said interpolation means produces the interpolated signal by computing the arithmetic mean of the plurality of predictive signals.

11. A coding system according to

claim 7

wherein said interpolation means produces the interpolated signal by computing the arithmetic mean of the plurality of predictive signals weighted by predetermined weighting factors.

8. A coding system comprising:

(a) an input means for inputting an input signal to be encoded by division into a plurality of fields, such as an odd field and even field;

(b) a blocking selection section for selecting, at the time of blocking and encoding the signal from said input means, a block suitable for the encoding from the block consisting of the signal of only one kind of field and the block consisting of the signal combining signals of a plurality of fields;

(c) a block forming section for forming a block selected by said blocking selection section; and

(d) coding means for encoding a block formed by said block forming section.

9. A coding system according to

claim 8

wherein said blocking selection means comprises at least one of the following selecting means:

(a) selecting means for selecting, from a plurality kinds of blocks, the block with the least amount of encoding information generated;

(b) selecting means for selecting, from a plurality kinds of blocks, the block with the least amount of encoding errors; and

(c) selecting means for selecting, from a plurality kinds of blocks, the block with the least amount of high-frequency components contained in the signal to be encoded.