Patent ID: 8811716

Claim:
A method to determine a fiducial point for holographic data storage, comprising steps: receiving a gray-level image; using a first reference gray-level frame to sequentially retrieve from said gray-level image regional images each having a same size as said first reference gray-level frame to function as first retrieved images, comparing said first reference gray-level frame with each said first retrieved image to obtain a plurality of first values, and using said first values to construct a first 2D proto-matrix; transforming said first 2D proto-matrix into a first 2D matrix via letting said first values which are smaller than 0 be 0 and keeping unchanged said first values equal to or greater than 0; using said first 2D matrix and a retrieving matrix, which has a dimensionality equal to or smaller than that of said first reference gray-level frame, to obtain a first anchor matrix, and finding a greatest said first value in a central region of said first 2D matrix to function as a first anchor value according to said first anchor matrix; and using said first anchor value to find a first position corresponding to said first anchor value in said gray-level image, and using said first position as a position of a first fiducial point, wherein said gray-level image has a grayscale depth of N bits, and wherein said first value is denoted by V1 and obtained according to an equation: V ⁢ ⁢ 1 = ( 2 ⁢ μ x ⁢ μ yI + C 1 ⁢ I ) ⁢ ( 2 ⁢ σ xyI + C 2 ⁢ I ) ( μ x 2 + μ yI 2 + C 1 ⁢ I ) ⁢ ( σ x 2 + σ yI 2 + C 2 ⁢ I ) wherein x is said gray-level image and yI is said first retrieved image, wherein 0<C 1I <0.1 and 0<C 2I <0.1, wherein μ x and μ yI are respectively image strengths of said gray-level image and said first retrieved image, wherein σ x and σ yI are respectively image standard deviations of said gray-level image and said first retrieved image, wherein σ xyI is a covariable of said gray-level image and said first retrieved image, wherein μ x = 1 N ⁢ ∑ i = 1 N ⁢ x i , μ yI = 1 N ⁢ ∑ i = 1 N ⁢ y ⁢ ⁢ I i , σ x = [ 1 N - 1 ⁢ ∑ i = 1 N ⁢ ( x i - μ x ) 2 ] 1 / 2 , σ yI = [ 1 N - 1 ⁢ ∑ i = 1 N ⁢ ( y ⁢ ⁢ I i - μ y ⁢ ⁢ I ) 2 ] 1 / 2 , σ xy ⁢ ⁢ I = 1 N - 1 ⁢ ∑ i = 1 N ⁢ ( x i - μ x ) ⁢ ( y ⁢ ⁢ I i - μ y ⁢ ⁢ I ) , and wherein said gray-level image has a plurality of blocks, and wherein each said block contains n×n pieces of pixels, and wherein n is a natural number, and wherein retrieving said first retrieved images starts from a first row and a first column of said blocks and advances toward a last row and a last column sequentially pixel by pixel.