SIGNAL PROCESSING DEVICE AND MOVING IMAGE CAPTURING DEVICE

• US 20120328008A1
• Filed: 09/05/2012
• Published: 12/27/2012
• Est. Priority Date: 03/09/2010
• Status: Active Grant

• Current Assignee: Panasonic Semiconductor Solutions Co., Ltd. (Winbond Electronics Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: HOJO, Masahiro, UCHIDA, Tomokazu
• Granted Patent: US 9,854,167 B2
• Time in Patent Office: Days
• US Class Current: 375/240.03
• CPC Class Codes: H04N 19/103 Selection of coding mode or of prediction mode
• 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 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 23/6811 based on the image signal
• CPC Class Codes: H04N 23/6812 based on additional sensors, e.g. acceleration sensors

Abstract

A frame skipping process suited to a scene is achieved by providing an encoder which encodes input image data, an encoding determination unit which compares image movement information with a threshold to determine whether or not encoding is to be performed, a frame skipping controller which performs a frame skipping control if encoding is not to be performed, and a threshold correction unit which corrects the encoding determination threshold based on the result of the encoding process. The image movement information used in the encoding determination unit is any one or a combination of pixel movement information obtained by a representative point matching scheme performed by a pixel movement calculation unit, angular velocity sensor information obtained from a lens controller, and frequency information obtained from an image processor.

Claims

1. A signal processing device for compressing image data of a plurality of frames to generate a stream, comprising:

an encoder configured to encode input image data;

an image processor configured to obtain frequency information of the image data;

an encoding determination unit configured to compare image movement information indicating the amount of a movement of the same image between two frames, with an encoding determination threshold, thereby determining whether or not encoding is to be performed;

a frame skipping controller configured to perform a frame skipping control if the encoding determination unit determines that encoding is not to be performed;

a threshold correction unit configured to correct the encoding determination threshold of the encoding determination unit based on the number of bits allocated for encoding and a quantization parameter value in a frame, or a motion vector value in a frame, or the number of intra-macroblocks,

wherein

the encoding determination unit determines whether or not encoding is to be performed, after temporarily changing the encoding determination threshold if the frequency information indicates a high frequency, or without changing the encoding determination threshold if the frequency information indicates a low frequency.

2. The signal processing device of claim 1, further comprising:

a pixel movement calculation unit,

wherein

the image movement information used in the encoding determination unit is pixel movement information obtained by a representative point matching scheme performed by the pixel movement calculation unit.

3. The signal processing device of claim 1, further comprising:

a lens controller,

wherein

the image movement information used in the encoding determination unit is angular velocity sensor information obtained from the lens controller.

4. The signal processing device of claim 1, further comprising:

at least one of a pixel movement calculation unit and a lens controller,

wherein

the image movement information is a combination of at least one of pixel movement information obtained by a representative point matching scheme performed by the pixel movement calculation unit and angular velocity sensor information obtained from the lens controller, and the frequency information obtained from the image processor.

5. The signal processing device of claim 1, wherein

the encoding determination unit has a still image threshold as the encoding determination threshold, and determines that encoding is not to be performed on a frame which is lower than the still image threshold.

6. The signal processing device of claim 1, wherein

the encoding determination unit has a moving image threshold as the encoding determination threshold, and determines that encoding is not to be performed on a frame which is higher than the moving image threshold.

7. The signal processing device of claim 1, wherein

the encoding determination unit has a still image threshold and a moving image threshold as the encoding determination threshold, and determines that encoding is not to be performed on a frame which is lower than the still image threshold and a frame which is higher than the moving image threshold.

8. The signal processing device of claim 1, wherein

if the encoding determination unit determines that encoding is not to be performed, the encoder does not perform encoding, and the frame skipping controller inserts a dummy frame including only skipped macroblocks.

9. The signal processing device of claim 1, wherein

the encoding determination unit selects a picture type which is to be skipped based on the picture configuration of the stream, for a frame for which the encoding determination unit determines whether or not encoding is to be performed.

10. The signal processing device of claim 1, wherein

the encoding determination threshold used in the encoding determination unit is changed based on a bit rate, a frame rate, or an image resolution of the stream to be generated.

11. The signal processing device of claim 1, wherein

if the encoding determination unit determines that a motion is small or that a motion is large, frame skipping is performed at predetermined intervals for a first frame for which the determination is performed and a plurality of frames succeeding the first frame.

12. The signal processing device of claim 1, wherein

the encoding determination unit has a plurality of encoding determination thresholds so that the number of frames which are to be continuously skipped is changed.

13. The signal processing device of claim 1, wherein

the encoding determination unit determines whether or not encoding is to be performed, by using, instead of the image movement information, any of the number of intra-macroblocks in a frame obtained from the encoder, the motion vector value in a frame obtained from the encoder, and the number of bits allocated for encoding and a quantization parameter value obtained from the encoder.