Patent ID: 7228009

Claim:
An apparatus that scales a digital image signal comprising: a memory unit, which receives originally formatted input pixel data, updates and stores the pixel data on a plurality of lines passing through an interpolation location, and outputs the updated pixel data in response to a control signal; a scaling interpolator, which determines a direction of interpolation of the interpolation location from LPF-filtered data of the updated pixel data in response to the control signal, calculates pixel data values at points where an extended line that passes through the interpolation location and extending in the direction of interpolation intersects horizontal or vertical lines of the display using Lagrangian or polyphase filtering wherein the points are not included in the originally formatted input pixel data, applies Lagrangian filtering to the calculated pixel data on the extended line, and obtains and outputs interpolation data of the interpolation location to provide an interpolated pixel value to a display to provide a scaled-up image thereon compared to the originally formatted input pixel data; and a controller which generates the control signal, which controls the LPF-filtering, and the Lagrangian filtering or polyphase filtering, wherein the scaling interpolator comprises: a direction determination unit, which LPF-filters the updated pixel data in response to the control signal, determines the direction value which corresponds to the direction of interpolation of the interpolation location from the LPF-filtered data, and outputs the direction value; and a directional interpolator, which calculates the pixel data values of the intersections of the horizontal (or vertical) lines and the extended line using Lagrangian in response to the control signal, applies Lagrangian filtering to the calculated pixel data, and obtains and outputs the interpolation data of the interpolation location, wherein the LPF filtering is performed by an LPF with the property: x ′ ⁡ ( i , j ) = x ⁡ ( i - 1 , j ) + 6 × x ⁡ ( i , j ) + x ⁡ ( i + 1 , j ) 8 , wherein x′(i, j) is the filtered data and x(i, j) is pixel data at the i-th row and j-th column.