Method and device for compressing moving image

• US 8,705,628 B2
• Filed: 03/30/2011
• Issued: 04/22/2014
• Est. Priority Date: 10/29/2008
• Status: Active Grant

• Current Assignee: Panasonic Semiconductor Solutions Co., Ltd. (Winbond Electronics Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Tanaka, Yasuharu
• Primary Examiner(s): SENFI, BEHROOZ M
• Application Number:
  US13/076,085
• Publication Number:
  US 20110176027A1
• Time in Patent Office: 1,119 Days
• Field of Search: 348/441, 348/448, 348/452, 348/458, 348/459, 348/451, 348/699, 348/700, 348/701, 348/222.1, 348/416.1, 37524001-24026, 382/100, 382/199, 382/233, 382/286, 382/232
• US Class Current: 375/240.16
• 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 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/61 in combination with predictive coding

Abstract

A still block detector is provided at a stage before a moving image encoder. The still block detector divides a frame to be processed into a plurality of blocks, sorts the blocks in the frame in ascending order of movement amount, and sets the first one or more blocks the number of which is specified by a “corresponding block setting number” input from the outside of an encoding device, to “still blocks.” For the still blocks, the moving image encoder performs an inter-encoding process with respect to a moving image by forcibly setting motion vectors to zeros without performing a motion search or by forcibly setting DCT coefficients to zeros without performing DCT or quantization.

Claims

1. A method for encoding a moving image using motion vectors which are generated by dividing a frame to be processed into a plurality of blocks and performing a motion search with respect to each of the plurality of blocks using an input image and an already encoded reference image, the method comprising the steps of:

selecting S blocks from the plurality of blocks in the frame, where S is an integer of one or more and less than the number of all the blocks of the frame;

encoding the moving image by forcibly replacing the motion vectors with zeros without performing the motion search, with respect to the selected S blocks;

correcting the amount of data to be encoded by multiplying the amount of data to be encoded of a previous frame by the total number of blocks/S; and

performing a bit rate control based on the corrected amount of data to be encoded,

wherein the encoding the moving image by forcibly replacing the motion vectors with zeros is performed only r−

1 times with respect to r frames, where r is an integer of two or more.

2. A method for encoding a moving image using DCT coefficients which are generated by dividing a frame to be processed into a plurality of blocks and performing DCT and quantization with respect to each of the plurality of blocks, the method comprising the steps of:

selecting S blocks from the plurality of blocks in the frame, where S is an integer of one or more and less than the number of all the blocks of the frame;

encoding the moving image by forcibly replacing the DCT coefficients with zeros without performing the DCT and the quantization, with respect to the selected S blocks and performing the DCT and the quantization, except for the selected S blocks;

correcting the amount of data to be encoded by multiplying the amount of data to be encoded of a previous frame by the total number of blocks/S; and

performing a bit rate control based on the corrected amount of data to be encoded,

wherein the encoding the moving image by forcibly replacing the DCT coefficients with zeros is performed only r−

1 times with respect to r frames, where r is an integer of two or more.

3. A device for encoding a moving image using motion vectors which are generated by dividing a frame to be processed into a plurality of blocks and performing a motion search with respect to each of the plurality of blocks using an input image and an already encoded reference image, the device comprising:

an input image reducer configured to reduce the input image to be encoded, by a factor of n, where n is an integer of one or more, to generate a reduced input image;

a reference image reducer configured to reduce the already encoded reference image by a factor of n to generate a reduced reference image;

a movement amount detector configured to receive the reduced input image and the reduced reference image from the input image reducer and the reference image reducer, and detect a movement amount with respect to each of the plurality of blocks;

a movement amount storage configured to store the movement amounts detected by the movement amount detector;

a still block selector configured to compare the movement amounts stored in the movement amount storage and select S blocks in order of small movement amounts, where S is an integer of one or more and less than the number of all the blocks of the frame; and

a moving image encoder configured to encode the moving image by forcibly replacing the motion vectors with zeros without performing the motion search, with respect to the selected S blocks.

5. The device of claim 3, wherein the encoding the moving image by forcibly replacing the motion vectors with zeros is performed only r−

1 times with respect to r frames, where r is an integer of two or more.

6. The device of claim 5, further comprising:

a section configured to correct the amount of data to be encoded by multiplying the amount of data to be encoded of a previous frame by the total number of blocks/S, and perform a bit rate control based on the corrected amount of data to be encoded.

7. An imaging system comprising:

an image processing circuit including the device of claim 3;

a sensor configured to convert image light into an image signal;

an optical system configured to image incident image light onto the sensor; and

a converter configured to convert the image signal into digital data and output the digital data to the image processing circuit.

8. A signal processing system comprising:

an image processing circuit including the device of claim 3; and

a converter configured to convert an input image signal having an analog value into digital data and output the digital data to the image processing circuit.

4. A device for encoding a moving image using DCT coefficients which are generated by dividing a frame to be processed into a plurality of blocks and performing DCT and quantization with respect to each of the plurality of blocks, the device comprising:

an input image reducer configured to reduce the input image to be encoded, by a factor of n, where n is an integer of one or more, to generate a reduced input image;

a reference image reducer configured to reduce the already encoded reference image by a factor of n to generate a reduced reference image;

a movement amount detector configured to receive the reduced input image and the reduced reference image from the input image reducer and the reference image reducer, and detect a movement amount with respect to each of the plurality of blocks;

a movement amount storage configured to store the movement amounts detected by the movement amount detector;

a still block selector configured to compare the movement amounts stored in the movement amount storage to select S blocks having the smallest movement amounts, where S is an integer of one or more and less than the number of all the blocks of the frame; and

a moving image encoder configured to encode the moving image by forcibly replacing the DCT coefficients with zeros without performing the DCT and the quantization, with respect to the selected S blocks.

9. The device of claim 4, wherein the encoding the moving image by forcibly replacing the DCT coefficients with zeros is performed only r−

1 times with respect to r frames, where r is an integer of two or more.

10. The device of claim 9, further comprising:

a section configured to correct the amount of data to be encoded by multiplying the amount of data to be encoded of a previous frame by the total number of blocks/S, and perform a bit rate control based on the corrected amount of data to be encoded.

11. An imaging system comprising:

an image processing circuit including the device of claim 4;

a sensor configured to convert image light into an image signal;

an optical system configured to image incident image light onto the sensor; and

a converter configured to convert the image signal into digital data and output the digital data to the image processing circuit.

12. A signal processing system comprising:

an image processing circuit including the device of claim 4; and

a converter configured to convert an input image signal having an analog value into digital data and output the digital data to the image processing circuit.