Motion-adaptive image signal processing system

• US 5,565,921 A
• Filed: 03/15/1994
• Issued: 10/15/1996
• Est. Priority Date: 03/16/1993
• Status: Expired due to Term

• Current Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Original Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Inventors: Fukuda, Hiroyuki, Sasaki, Hiroshi, Hatakenaka, Akira
• Primary Examiner(s): Chin, Tommy P.
• Assistant Examiner(s): Au, A.
• Application Number:
  US08/213,973
• Time in Patent Office: 945 Days
• Field of Search: 348/401, 348/407, 348/409, 348/415, 348/412, 348/419
• US Class Current: 375/240.13
• CPC Class Codes: H04N 19/117 Filters, e.g. for pre-processing or post-processing sub-band filter banks H04N19/635
• 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 19/14 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 19/159 Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
• 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 19/18 the unit being a set of transform coefficients
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/82 involving filtering within a prediction loop

Abstract

An inter-frame predicted error signal generation unit generates an inter-frame predicted error signal for selectively performing prediction between an input image signal of the current frame and a decoded image signal of the previous frame, and between the input image signal of the current frame and the image signal of the previous frame. A coding unit selectively codes the inter-frame predicted error signal generated by the inter-frame predicted error signal generation unit and the input image signal with high-efficiency compression. A statistical amount calculation unit calculates a statistical amount of the inter-frame predicted error signal generated by the inter-frame predicted error signal generation unit. Based on the statistical amount of the inter-frame predicted error signal calculated by the statistical amount calculation unit, a discrimination unit discriminates whether or not coding by the coding unit is to be performed. A transmission unit transmits a discrimination signal indicating that coding is not to be performed when the discrimination unit discriminates that coding by the coding unit is not performed.

Claims

1. A motion image signal compression apparatus for selectively performing intra-frame coding and inter-frame coding by selectively using an image signal of a current frame, an image signal of a previous frame, and a decoded image signal of the previous frame with respect to an inputted image signal which is continuously inputted in units of frames, comprising:

inter-frame predicted error signal generation means for selectively performing a comparison between one of a) the image signal of the current frame and the decoded image signal of the previous frame and b) the image signal of the current frame and the image signal of the previous frame, and for generating an inter-frame predicted error signal representing a result of the comparison performed;

statistical amount calculation means for calculating a statistical amount of the inter-frame predicted error signal;

discrimination means for determining that the current frame of the inputted image signal is an ineffective frame when the statistical amount of the inter-frame predicted error signal is greater than a predetermined value, and for determining that the current frame of the inputted image signal is an effective frame when the statistical amount of inter-frame predicted error signal is not greater than the predetermined value; and

coding means for selectively coding by high-efficiency compression one of a) the inter-frame predicted error signal so as to perform inter-frame coding when the current frame is determined by said discrimination means to be an effective frame and the current frame follows an effective previous frame and b) the image signal of the current frame so as to perform intra-frame coding when the current frame is determined by said discrimination means to be an effective frame and the current frame follows an ineffective previous frame by a predetermined interval, said coding means being set in an off state when the current frame is determined by said discrimination means to be an ineffective frame; and

wherein said inter-frame predicted error signal generation means includes means for comparing the image signal of the current frame and the decoded image signal of the previous frame when the previous frame was determined by said discrimination means to have been an effective frame, and means for comparing the image signal of the current frame and the image signal of the previous frame when the previous frame was determined by said discrimination means to have been an ineffective frame.

2. The motion image signal compression apparatus according to claim 1, further comprising:

transmission buffer means for transmitting a coded output of said coding means; and

wherein said discrimination means includes means for determining that the current frame is an ineffective frame when an occupation amount of said transmission buffer for storing one-frame coded data is greater than a predetermined value.