Patent ID: 6636641
Filing Date: 2003-10-21
Classification: H04N

Abstract:
An encoding apparatus comprising:a picture element memory for receiving and storing a picture element having a value within a predetermined range as an encoding picture element, and for outputting a value of an encoded picture element adjacent to the encoding picture element as the value of a reference picture element; a mode determinator for selecting one of a specific encoding mode and an encoding mode other than the specific encoding mode from a plurality of predefined encoding modes for the encoding picture element based on the value of the reference picture element; a first encoding section for predicting the value of the encoding picture element, determining whether the prediction is correct, encoding the value of the encoding picture element based on a result of the determination, and for outputting a codeword for the encoding picture element; a second encoding section for predicting the value of the encoding picture element, encoding the value of the encoding picture element, and for outputting a codeword for the encoding picture element; and an encoding controller for selectively operating said first encoding section and said second encoding section based on a selected result of said mode determinator, wherein said first encoding section comprises: a first predictor for calculating a prediction value of the encoding picture element based on the value of the reference picture element; a first prediction error calculator for calculating an error between the value of the encoding picture element and the prediction value calculated by said first predictor as a prediction error; a determinator for determining whether the prediction error calculated by said first prediction error calculator is a specific value, and for outputting a result of the determination; a first encoder for receiving and encoding the result of the determination output from said determinator, and for outputting the codeword for the encoding picture element to be encoded in the selected specific encoding mode; and a second encoder for encoding the prediction error calculated by said first prediction error calculator when the prediction error is other than the specific value for the encoding picture element to be encoded in the selected specific encoding mode, and for outputting the codeword for the encoding picture element to be encoded in the selected specific encoding mode; wherein the mode determinator receives the value of the reference picture element output from said picture element memory and the result of the determination output from said determinator, and selects the encoding mode based on the value of the reference picture element and the results of the determination.