Method and apparatus for recording/reproducing mesh pattern data

Claim 2

A data reproduction method comprising the steps of: reading an encoded image as image data from a recording medium on which image elements including a mesh pattern having a rectangular shape as a whole and including dark and light image elements which are arranged at two-dimensional distributed positions, whose arrangement is determined based on a changed two-dimensional matrix obtained by changing an original two-dimensional matrix constituting target data in accordance with predetermined pseudo random numbers, respective randomized target data b n being obtained by executing an exclusive OR operation for target data b n with pseudo random numbers rnd(n); detecting image elements from the read image data, and obtaining the elements of the randomized data to form the changed two-dimensional matrix; and changing the elements on the formed two-dimensional matrix according to the predetermined pseudo random numbers to form the original two-dimensional matrix, thereby reproducing the target data, said target data b n being obtained by executing an exclusive OR operation for the randomized target data b n with the same pseudo random numbers rnd(n).

Claim 3

A data reproduction apparatus comprising: image sensor means for reading an encoded image as image data from a recording medium on which image elements including a mesh pattern having a rectangular shape as a whole and including dark and light image elements which are arranged at two-dimensional distributed positions, and whose arrangement is determined based on a changed two-dimensional matrix obtained by changing an original two-dimensional matrix constituting target data in accordance with predetermined pseudo random numbers, respective randomized target data b n being obtained by executing an exclusive OR operation for target data b n with pseudo random numbers rnd(n); image element decoding means for detecting image elements from the read image data, and obtaining the elements from the read image data, and obtaining the elements of the randomized data to form the changed two-dimensional matrix; and derandomizing means for changing the elements on the formed two-dimensional matrix according to the predetermined pseudo random numbers to form the original two-dimensional matrix, thereby reproducing the target data, said target data b n being obtained by executing an exclusive OR operation for the randomized target data b n with the same pseudo random numbers rnd (n).

Claim 4

A data reproduction apparatus comprising: image sensor means for reading an encoded image as image data from a recording medium on which image elements including a mesh pattern having a rectangular shape as a whole and including dark and light image elements which are arranged at two-dimensional distributed positions, and whose arrangement is determined based on a changed two-dimensional matrix obtained by changing an original two-dimensional matrix constituting target data in accordance with predetermined pseudo random numbers, respective randomized target data b n being obtained by executing an exclusive OR operation for target data b n with pseudo random numbers rnd(n); image element decoding means for detecting image elements from the read image data, and obtaining the elements from the read image data, and obtaining the elements of the randomized data to form the changed two-dimensional matrix; and derandomizing means for changing the elements on the formed two-dimensional matrix according to the predetermined pseudo random numbers to form the original two-dimensional matrix, thereby reproducing the target data, said target data b n being obtained by executing an exclusive OR operation for the randomized target data b n with the same pseudo random numbers rnd (n).