Storage and retrieval of large digital images

A method for compressing a large digital image for storage in a computer memory, the method comprising the steps of:

• storing a complete set of image data array I(x,y) representing said image in a first memory location of said computer;
• defining a plurality of discrete tile image data T.sub.ij (x,y) subsets of said I(x,y), where said I(x,y) is formed by superposition of said T.sub.ij (x,y);
• performing on a computer one or more discrete wavelet transformation (DWT)-based compression processes over each said tile image data T.sub.ij (x,y) in a selected sequence to output each said T.sub.ij (x,y) as a succession of DWT coefficients in a succession of subband sets, where one subband of each set is a low-resolution representation of said T.sub.ij (x,y) to form a sequence of low-resolution representations of said I(x,y) to selected resolutions;
• and
• maintaining updated sums of said DWT coefficients from said discrete tile image T.sub.ij (x,y) to form a seamless DWT of said I(x,y) and storing said sums in a second memory location of said computer.

A method for selectively viewing areas of an image at multiple resolutions in a computer having a primary memory for data processing and a secondary memory for data storage, the method comprising the steps of:

• storing a complete set of image data array I(x,y) representing said image in a first secondary memory of said computer;
• defining a plurality of discrete tile image data T.sub.ij (x,y) subsets, where said complete set of image data I(x,y) is formed by superposition of said discrete tile image data T.sub.ij (x,y);
• performing one or more discrete wavelet transformation (DWT)-based compression processes on each said tile image data T.sub.ij (x,y) in a selected sequence to output each said discrete tile image data T.sub.ij (x,y) as a succession of DWT coefficients in a succession of subband sets, where one subband of each set is a low-resolution representation of said discrete tile image data T.sub.ij (x,y) to form a sequence of low-resolution representations of said image data array I(x,y) to selected resolutions;
• selecting a viewing set of said image data array I(x,y) to be viewed at a desired resolution:
• determining a viewing subset of said DWT wavelet coefficients that support said viewing set of said image data at said desired resolution;
• and
• forming from said subset of said DWT wavelet coefficients a computer display of said viewing set of said image data at said desired resolution.