Method of and apparatus for enlarging/reducing two-dimensional images

An apparatus for converting a first two-dimensional image on first column direction and row direction scales to a second two-dimensional image on second column direction and row direction scales, said first and second two-dimensional images being of image elements arranged in first and second matrices, respectively, the ratios between said first and second scales being predetermined column direction and row direction scales factors, respectively, comprising:

• means for preparing at least one data sequence of fundamental cycle representing differences between those column order numbers in said first matrix which are particularly related to coordinates of image elements in said second matrix and those column order numbers in said first matrix which are particularly related to coordinates of image elements adjacent to the first-mentioned image elements in aid second matrix;
• means for selecting at least one row of image elements in said first matrix;
• means for selecting sequentially at least one of the image elements in said first matrix within said selected row by the use of said prepared data sequence;
• and
• means for determining sequentially a data value for each of the image elements on one row in said second matrix on the basis of the value for said selected at least one image element.

A method of converting a first two-dimensional image on first column direction and row direction scales to a second two-dimensional image on second column direction and row direction scales, said first and second two-dimensional images being of image elements arranged in first and second matrices, respectively, the ratios between said first and second scales being predetermined column direction and row direction scale factors, respectively, comprising the steps of:

• determining, on the basis of the ratio between said first and second row direction scales, at least one data sequence for a first fundamental cycle for row direction periodic sequences of data, which first fundamental cycle of data defines the positional relation between the position on said first image corresponding to nay one of said second image elements and four first elements lying on the intersections between two adjacent rows and two adjacent columns in said first image elements matrix surrounding the position of said one second image element on said first image, said four first image elements constituting a reference frame for said one second image element;
• selecting two of the row in said first matrix;
• determining a reference frame for each of said second image elements from the image elements on said selected two rows in the first matrix and on the basis of said data sequences for said first fundamental cycles;
• producing at least one of the vertical and horizontal coordinates for each of said second image elements within its associated reference frame on the basis of said ratios between said first scales and second scales;
• and
• determining a data value for each of said second image elements the basis of the data value for at least one of the four first image elements of its associated reference frame and at least one of said vertical and horizontal coordinates of the position on said first image corresponding to the said second image element.

An apparatus for converting a first two-dimensional image on first column direction and row direction scales and row direction scales, each of said first and second two-dimensional image being of image elements arranged in matrix, in which the position on said first image corresponding to each of said second image elements is associated with a reference frame constituted by four first image elements lying on the intersections of two adjacent rows and two adjacent columns in the first image element matrix surrounding said second image elements, the apparatus comprising:

• means for producing at least one data sequence for a first fundamental cycle for row direction periodic sequences of data as determined on the basis of the ratio between said first and second row direction scales, which first fundamental cycle of data defines the positional relation between said second image elements and their associated reference frames in said first image element matrix;
• means for selecting two rows of image elements data in said first matrix;
• means for storing said selected two rows of image element data;
• means coupled with said data sequence producing means for determining a reference frame for each of said second image elements from said stored image element data;
• means for producing the vertical and horizontal coordinates for each of said second image elements within its associated reference frame, said coordinates having a predetermined relationship with said ratio between said first and second scales;
• and
• means coupled with said reference frame determining means and with said coordinates producing means for determining a data value for each of said second image elements.

An image scale converting apparatus for converting a first two-dimensional image to a second two-dimensional image, said first and second two-dimensional images being of image elements arranged in first and second matrices respectively, comprising:

• a buffer memory for storing a plurality of lines of image element data of said first two-dimensional image a first controller for controlling inputs to said buffer memory;
• a second controller for controlling shifting operation of said buffer memory;
• interpolation calculator means connected to receive data from said buffer memory for providing data values representative of the saturation level if image elements of said second two-dimensional image subjected to image scale conversion;
• and a plurality of circulating registers for storing interpolating address information to be supplied to said first and second controllers and said interpolation calculator means, one of said circulating registers storing at least one data sequence of fundamental cycle which represents a difference between those column order numbers in said first matrix which are particularly related to coordinates of image elements in said second matrix and those column order numbers in said first matrix which are particularly related to coordinates of image elements adjacent to the first-mentioned image elements in said second matrix, and said second controller including means for controlling said shifting operation of said buffer memory on the basis of the output of said circulating register.

A method of enlarging or reducing a first two-dimensional image of image elements arranged in matrix with predetermined column direction and row direction scale factors to form a second two-dimensional image of image elements arranged in matrix, where an image element at the intersection between i-th row and j-th column in the matrix for said first image is represented by P.sub.ij, an image element at the intersection between m-th row and n-th column in the matrix for said second image and surrounded by four first image elements P.sub.X.sbsb.m.sub.Y.sbsb.n, P.sub.X.sbsb.m.sub.+1Y.sbsb.n, P.sub.X.sbsb.m.sub.Y.sbsb.n.sub.+1 and P.sub.X.sbsb.m.sub.+1Y.sbsb.n.sub.+1 is represented by Qmn, and the vertical and horizontal coordinates of said second image element within the rectangular region defined by said four first image elements are represented by u.sub.m and v.sub.n, respectively, the method comprising:

• preparing data sequences for fundamental cycles for periodic sequences of data u.sub.m, v.sub.n and .DELTA.Y.sub.n =Y.sub.n+1 -Y.sub.n determined on the basis of stored scale factors;
• selecting at least a pair of m-th and (m+1)-th rows of image elements in the first image matrix;
• selecting four first image elements within said selected rows by referring to said data sequences for said fundamental cycle of data .DELTA.Y.sub.n ;
• determining said coordinates u.sub.m and v.sub.n of each of said second image elements by referring to said data sequences for said fundamental cycles;
• and
• determining a data value for each of said second image elements by use of the values of said selected four first image elements and said determined coordinates U.sub.m and V.sub.n.

An apparatus for enlarging or reducing a first two-dimensional image of image elements arranged in matrix with predetermined column direction and row direction scale factors to form a second two-dimensional image of image elements arranged in matrix, where an image element at the intersection between i-th row and j-th column in the matrix for said first image is represented by P.sub.ij, an image element at the intersection between m-th row and n-th column in the matrix for said second image and surrounded by four first image elements P.sub.X.sbsb.m.sub.Y.sbsb.n, P.sub.X.sbsb.m.sub.+1Y.sbsb.n, P.sub.X.sbsb.m.sub.Y.sbsb.n.sub.+1 and P.sub.X.sbsb.m.sub.+1Y.sbsb.n.sub.+1 is represented by Q.sub.mn, and the vertical and horizontal coordinates of said second image element within the rectangular region defined by said four first image elements are represented by u.sub.m and v.sub.n, respectively, the apparatus comprising:

• means for storing data sequences for fundamental cycles for periodic sequences of data u.sub.m, v.sub.n and .DELTA.Y.sub.n =Y.sub.n+1 -Y.sub.n determined on the basis of said scale factors;
• means for selecting at least a pair of m-th and (m+1)-th rows of image elements in said first image matrix;
• means for selecting four first image elements within said selected rows by referring to said data sequences for said fundamental cycles of data .DELTA.Y.sub.n ;
• means for determining said coordinates u.sub.m and v.sub.n of each of said second image elements by referring to said data sequences for said fundamental cycles;
• and
• means for determining a data value for each of said second image elements by use of the values of said selected four first image elements and said determined coordinates u.sub.m and v.sub.m.

An apparatus for enlarging or reducing a first two-dimension image of image elements arranged in a matrix with predetermined column direction and row direction scale factors to form a second two-dimensional image of image elements arranged in a matrix, where an image element at the intersection between the i-th row and j-th column in the matrix for said first image is represented by P.sub.ij, an image element at the interseciton between the m-th row and the n-th column in the matrix for said second image and surrounded by four first image elements P.sub.X.sbsb.m.sub.Y.sbsb.n, P.sub.X.sbsb.m.sub.+1Y.sbsb.n, P.sub.X.sbsb.m.sub.Y.sbsb.n.sub.+1 and P.sub.X.sbsb.m.sub.+1Y.sbsb.n.sub.+1) by Q.sub.mn, and the vertical and horizontal coordinates of said second image element within the rectangular region defined by aid four first image elements are represented by u.sub.m and v.sub.n, respectively, the apparatus comprising:

• first means for storing image element data of said first image;
• second means for previously storing at least one data sequence for a fundamental cycle for periodic sequences of data .DELTA.Y.sub.n =Y.sub.n+1 -Y.sub.n ;
• third means for coupled to said first means for reading out at least one row of image element data;
• fourth means for selecting image element data, identified by addresses updated by said data sequence for said fundamental cycle of data .DELTA.Y.sub.n, within said read out image element data and for temporarily storing selected data;
• fifth means for previously storing data sequences for fundamental cycles for periodic sequences of data of said vertical and/or horizontal coordinates u.sub.m and v.sub.n ;
• and
• sixth means coupled to said fourth and fifth means for determining data values for said second image elements on the basis of said data sequences for said fundamental cycles for said vertical and horizontal coordinates data u.sub.m and v.sub.n successively read out from said fifth means and said element data successively selected within said read out image element data.

A method of converting a first two-dimensional image on first column direction and row direction scales to a second two-dimensional image on second column direction and row direction scales, said first and second two-dimensional images being of image elements arranged in first and second matrices, respectively, the ratios between said first and second scales being predetermined column direction and row direction scale factors, respectively, comprising:

• first step of preparing in memory means a data sequence representing differences between those column order numbers in said first image matrix which are placed in particular relation with mutually adjacent second image elements through mapping of a plurality of second image elements contained in one row in said second image matrix onto said first image matrix according to said row direction scale factor;
• second step of selecting at least one row in said first image matrix;
• third step of selecting at least one image element within of image elements contained in said selected at least one row by the use of said data sequence prepared in said memory means;
• and
• fourth step of determining a data value for one second image element on the basis of the value of said selected at least one image element in said first image matrix;
• said third and fourth steps being repeated to determine the values for the second image elements on one row in said second matrix related to said selected one row in said first matrix.

An apparatus for converting a first two-dimensional image on first column direction and row direction scales to a second two-dimensional image on second column direction and row direction scales, said first and second two-dimensional images being of image elements arranged in first and second matrices, respectively, the ratios between said first and second scales being predetermined column direction and row direction scale factors, respectively, comprising:

• means for preparing in memory means a data sequence representing differences between those column order numbers in said first image matrix which are placed in a particular relation with mutually adjacent second image elements through mapping of a plurality of second image elements contained in one said in said second image matrix onto said first image matrix according to said row direction scale factor;
• means for selecting at least one row in said first image matrix;
• means for selecting sequentially at least one image element within a plurality of image elements contained in said selected at least one row by the use of said data sequence prepared in said memory means;
• and
• means for determining sequentially a data value for each of the second image elements on one row in said second matrix on the basis of the value of said selected at least one image element in said first image matrix.