EP 2089812 A2 20090819 - EFFICIENT FIXED-POINT APPROXIMATIONS OF FORWARD AND INVERSE DISCRETE COSINE TRANSFORMS
Title (en)
EFFICIENT FIXED-POINT APPROXIMATIONS OF FORWARD AND INVERSE DISCRETE COSINE TRANSFORMS
Title (de)
EFFIZIENTE FESTPUNKTANNÄHERUNGEN AN DISKRETE VORWÄRTS- UND RÜCKWÄRTS-COSINUS-TRANSFORMATIONEN
Title (fr)
APPROXIMATIONS EN VIRGULE FIXE EFFICACES DE TRANSFORMÉES EN COSINUS DISCRÈTES INVERSES ET AVANT
Publication
Application
Priority
- US 2007072169 W 20070626
- US 81669706 P 20060626
- US 84136206 P 20060830
- US 84719406 P 20060925
- US 82966906 P 20061016
- US 86953006 P 20061211
- US 88393207 P 20070108
Abstract (en)
[origin: WO2008005757A2] Techniques are described to approximate computation of an inverse discrete cosine transform using fixed-point calculations. According to these techniques, matrixes of scaled coefficients are generated by multiplying coefficients in matrixes of encoded coefficients by scale factors. Next, matrixes of biased coefficients are generated by adding a midpoint bias value to a DC coefficient of the matrix of scaled coefficients. Fixed-point arithmetic is then used to apply a transform to the matrixes of biased coefficients. Values in the resulting matrixes are then right-shifted in order to derive matrixes of pixel component values. Matrixes of pixel component values are then combined to create matrixes of pixels. The matrixes of pixels generated by these techniques closely resemble matrixes of pixels decompressed using the ideal inverse discrete cosine transform ("IDCT").
IPC 8 full level
G06F 17/14 (2006.01); H04N 7/26 (2006.01)
CPC (source: BR EP KR)
G06F 17/147 (2013.01 - BR EP); H04N 19/42 (2014.11 - KR); H04N 19/45 (2014.11 - EP); H04N 19/61 (2014.11 - EP); H04N 19/625 (2014.11 - KR); H04N 19/45 (2014.11 - BR); H04N 19/61 (2014.11 - BR)
Citation (search report)
See references of WO 2008005757A2
Designated contracting state (EPC)
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC MT NL PL PT RO SE SI SK TR
DOCDB simple family (publication)
WO 2008005757 A2 20080110; WO 2008005757 A3 20110310; BR PI0713321 A2 20120313; BR PI0713321 B1 20181204; CA 2654116 A1 20080110; CA 2654116 C 20130402; CN 102037729 A 20110427; CN 102037729 B 20130227; EP 2089812 A2 20090819; JP 2010505287 A 20100218; JP 5129248 B2 20130130; KR 100963459 B1 20100617; KR 20090028736 A 20090319; TW 200823694 A 20080601; TW I336444 B 20110121
DOCDB simple family (application)
US 2007072169 W 20070626; BR PI0713321 A 20070626; CA 2654116 A 20070626; CN 200780023719 A 20070626; EP 07840291 A 20070626; JP 2009518523 A 20070626; KR 20087032218 A 20070626; TW 96123080 A 20070626