Patent ID: 8805107
Filing Date: 2014-08-12
Classification: H04N

Abstract:
1. An image data coding apparatus comprising: a subband partitioning device for obtaining subband coefficients by partitioning image data into a plurality of subbands of different frequency components; a code block partitioning device for partitioning the subband coefficients, which have been obtained by said subband partitioning device, into a plurality of code blocks; a coding device for obtaining coded data by generating coding passes per bit plane with respect to subband coefficients included in the code blocks resulting from partitioning by said code block partitioning device, and binary coding the subband coefficients within the coding passes; a deciding device for deciding, in coding-pass units, coded data, from among the coded data obtained by said coding device, for which a distortion ratio at a time of decoding into an image will fall within prescribed limits; a layer generating device for repeating the coding by said coding device as well as the deciding of the coded data by said deciding device with regard to the plurality of code blocks resulting from partitioning by said code block partitioning device, thereby generating a layer that is to undergo adjustment of amount of coded data, the layer being a collection of coded data for which the distortion ratio at the time of decoding into an image will fall within prescribed limits; and a coded data amount adjusting device for adding, in coding-pass units, coded data having little influence upon image quality to a layer to undergo adjustment of amount of coded data, or deleting, in coding-pass units, coded data having little influence upon an image quality from a layer to undergo adjustment of amount of coded data, in such a manner that the amount of coded data included in a layer generated by said layer generating device will take on a target amount of data, wherein the coded data added on or deleted comprises coded data, from among the coded data obtained by said coding device, which is included in a layer to undergo adjustment of amount of coded data, wherein the coded data amount adjusting device adds, in coding-pass units, coded data having little influence upon image quality to a layer to undergo adjustment of amount of coded data in such a manner that the amount of coded data included in a layer generated by the layer generating device will take on a target amount of data, and wherein the coded data added on comprises coded data, from among the coded data obtained by the coding device, which is included in a layer to undergo adjustment of amount of coded data.