Abstract: An apparatus for compressing holographic data includes an image capture device for capturing an image of an interference pattern reconstructed by irradiating a reference beam and converting the image into m bits. In such an apparatus, a splitter removes least significant j bits from the m-bit data and divides m?j bits of the m-bit data into most significant k bits and remaining m?j?k bits. Thereafter, a compressor converts the most significant k bits into l bits, which is combined with the m?j?k bits to output n bits, wherein l<k and n=l+m?j?k. In this way, by compressing a certain number of most significant bits of the m-bit data and thus relatively increasing the number of the remaining least significant bits of the m-bit data, the BER of final reconstructed image data can be improved.

Abstract: A block coding algorithm uses an original block group having n+1 original blocks of m-bit message, which a first original block of m-bit message is encoded as a reference block of n-bit codeword and n original blocks of m-bit message placed after the first original block of m-bit message are encoded as n weighted blocks of n-bit codeword, based on a bit sequence of the reference block. A block decoding algorithm decodes n weighted blocks to generate corresponding original blocks of m-bit message and reconstructs the first original block of m-bit message from a sequence of reference bits, wherein each reference bit implies whether each of n weighted blocks is an A type weighted block or a B type weighted block.

Abstract: The present invention relates to an error correction encoding method using a three-dimensional Reed-Solomon code. In the error correction encoding method, pieces of input information are arranged in a three-dimensional data block. Three-dimensional error correction encoding is performed with respect to the three-dimensional data block, thereby adding horizontal, vertical and z-axial error correction parity symbols to the three-dimensional data block in horizontal, vertical and z-axial directions, respectively.

Abstract: A method and apparatus for modifying rectangular page data to be recorded in a holographic digital storage system may be used to reduce information loss due to image distortion. After each rectangular page data is divided into a central region and a peripheral region, only the peripheral region is rearranged to generate a rearranged peripheral region. The central region is merged with the rearranged peripheral region to generate modified page data which has a shape of circle or n-polygon, n being an integer equal to or larger than 5.

Abstract: An apparatus for compressing holographic data includes an image capture device for capturing an image of an interference pattern reconstructed by irradiating a reference beam and converting the image into m bits. In such an apparatus, a splitter removes least significant j bits from the m-bit data and divides m−j bits of the m-bit data into most significant k bits and remaining m−j−k bits. Thereafter, a compressor converts the most significant k bits into l bits, which is combined with the m−j−k bits to output n bits, wherein l<k and n=l+m−j−k. In this way, by compressing a certain number of most significant bits of the m-bit data and thus relatively increasing the number of the remaining least significant bits of the m-bit data, the BER of final reconstructed image data can be improved.

Abstract: A coding scheme encodes a series of M-bit message words into a series of N-bit codewords having a bounded unbalance. A part of the M-bit message words are used to index bits and others source words. The message words are grouped to a plurality of subsets using the index bits thereof. The unbalanced codewords are classified to a plurality of sets based on a state transition in a trellis. Each of the classified unbalanced codewords is stored at a codebook for each codeword set, respectively. The codebook has the source words, a codeword ID for each of the source words and the classified unbalanced codewords. The message words are encoded into the respective codeword in the codebook, respectively, by using the index bits of the message words and the state transition in the trellis having states and levels. The codewords are selected by transition for each state at each level stage of the trellis based on correlations.

Abstract: A block coding algorithm uses an original block group having n+1 original blocks of m-bit message, which a first original block of m-bit message is encoded as a reference block of n-bit codeword and n original blocks of m-bit message placed after the first original block of m-bit message are encoded as n weighted blocks of n-bit codeword, based on a bit sequence of the reference block. A block decoding algorithm decodes n weighted blocks to generate corresponding original blocks of m-bit message and reconstructs the first original block of m-bit message from a sequence of reference bits, wherein each reference bit implies whether each of n weighted blocks is an A type weighted block or a B type weighted block.

Abstract: A method and apparatus for modifying rectangular page data to be recorded in a holographic digital storage system may be used to reduce information loss due to image distortion. After each rectangular page data is divided into a central region and a peripheral region, only the peripheral region is rearranged to generate a rearranged peripheral region. The central region is merged with the rearranged peripheral region to generate modified page data which has a shape of circle or n-polygon, n being an integer equal to or larger than 5.

Abstract: A coding scheme encodes a series of M-bit message words into a series of N-bit codewords having a bounded unbalance. A part of the M-bit message words are used to index bits and others source words. The message words are grouped to a plurality of subsets using the index bits thereof. The unbalanced codewords are classified to a plurality of sets based on a state transition in a trellis. Each of the classified unbalanced codewords is stored at a codebook for each codeword set, respectively. The codebook has the source words, a codeword ID for each of the source words and the classified unbalanced codewords. The message words are encoded into the respective codeword in the codebook, respectively, by using the index bits of the message words and the state transition in the trellis having states and levels. The codewords are selected by transition for each state at each level stage of the trellis based on correlations.

Abstract: A method for mapping 2N message N-tuples into 2N+1 codeword (N+1)-tuples is developed. The 2N+1 codeword (N+1)-tuples are categorized into M subsets of codeword (N+1)-tuples, wherein M is an integer larger than 1, each subset G has NG codeword (N+1)-tuples and the total number of codeword (N+1)-tuples in the M subsets is 2N. Each subset G has a predetermined number KG of lower bits and a predetermined number (N+1−KG) of higher bits, and the number of lower bits in every codeword (N+1)-tuple in any subset is not equivalent to that of lower bits in every codeword (N+1)-tuple in any other subset. The 2N message N-tuples are matched with the 2N codeword (N+1)-tuples in the M subsets, respectively, in one-to-one correspondence to generate a lookup table.