| 摘要 |
<p>PURPOSE:To more reduce the distortion of a visually more important low-band component by giving a higher precision to a lower frequency component before multiplication at the time of fast cosine transform and multiplying a lower frequency component by a larger multiplier in the first multiplication at the time of inverse cosine transform. CONSTITUTION:In an 8th-order FDCT (fast cosine transform) device, Y0 to Y7 are transformed orthogonal components, and the subscript having a larger value indicates the component of a higher band. Ci (i=1 to 7) indicates a multiplier having a multiplier Ci, and intersections of arrows indicate adders, and wavy lines indicate inversion between positive and negative. Since the multiplier of the last multiplication for the orthogonal component Yi is indicated with 1/Ci [Ci=cos(ipi/16)], the orthogonal component of a higher band is multiplied by a larger multiplier. Therefore, the component in a lower band is handled with a larger value before the last multiplication, and the component of a lower band is handled with a higher precision. In an 8th-order IFDCT (inverse cosine transform) device, the component of a lower band is handled with a higher precision.</p> |
