Encoding and decoding apparatuses and image processing apparatus using the same

A method of encoding/decoding N units of image each having a predetermined size independently and sequentially, comprising the steps of:

• preparing a first learning memory for storing a first group of reference data to be used for encoding/decoding n-th (1≦n≦N) unit of image, initializing said first learning memory before a use of encoding/decoding the n-th unit of image, and updating the first group of reference data in response to a result of encoding/decoding the n-th unit of image;
• and
• preparing a second learning memory for storing a second group of reference data to be used for encoding/decoding (n+1)-th unit of image, initializing said second learning memory before a use of encoding/decoding the (n+1)-th unit of image, and updating the second group of reference data in response to a result of encoding/decoding the (n+1)-th unit of image,
• wherein the first and second groups of reference data have same contents on being initialized.

An encoding/decoding apparatus for encoding/decoding a plurality of units of image independently and sequentially, comprising:

• a learning memory for storing a group of reference data to be referred for encoding/decoding each unit of image and .updated in response to a result of encoding/decoding each unit of image;
• and
• an update timing storing memory for storing data indicating whether or not each reference data in said learning memory has been updated during a process of encoding/decoding a given unit of image,
• wherein, when data read out of said update timing storing memory indicates that reference data read out of said learning memory has not been so updated, said reference data read out of said learning memory is replaced with predetermined initial reference data.

A method of encoding/decoding a plurality of units of image independently and sequentially, comprising the steps of:

• preparing a learning memory for storing a group of reference data to be referred for encoding/decoding each unit of image and updated in response to a result of encoding/decoding each unit of image;
• preparing an update timing storing memory for storing data indicating whether or not each reference data in the learning memory has been updated during a process of encoding/decoding a given unit of image;
• and
• when data read out of the update timing storing memory indicates that reference data read out of the learning memory has not been so updated, replacing the reference data read out of the learning memory with predetermined initial reference data.