US 6,311,328 B1Granted

Apparatus and method for enlarging/reducing a video picture size

AssigneeSony Corporation

InventorsShinichiro Miyazaki, Akira Shirahama, Takeshi Ono, Nobou Ueki

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Abstract

A picture processing apparatus for picture-in-picture applications where the number of pixels n in the horizontal direction of an original picture, the number of pixels m in the vertical direction thereof, the number of pixels N in the horizontal direction of the converted picture, and the number of pixels M in the vertical direction thereof are supplied to a dividing device. Thus, ratios A=N/n and B=M/m are obtained. The inverse number 1/A of the value A is cumulated by circuits. An address generating circuit generates addresses at four points for calculating a density value a of a converted pixel corresponding to the integer part of a cumulated value Σ(1/A). These addresses are supplied to memories. The pixel data at the four points that are read from the memories are supplied to respective multiplying devices. The decimal part of the value Σ(1/A) is supplied as an interpolating coefficient p to a multiplying device. A coefficient (1−q) is supplied to a multiplying device. Likewise, in the vertical direction, coefficients q and (1−q) are supplied to respective multiplying devices. These multiplying devices and adding devices perform operations. Thus, the density value a of the converted pixel is obtained and supplied from a terminal.

Claims10

Dependent claims

A picture processing apparatus for enlarging/reducing a picture formed of pixels of digital data by any selected ratio, comprising:

a display monitor for displaying an original picture;
user input means for enabling a user to select a selected picture size for an enlarging/reducing process by manipulating the user input means to vary a size and a position of the selected picture size while the selected picture size is displayed on the display monitor by displaying frame lines to give the user visual feedback of the selection before performing the enlarging/reducing process;
means for obtaining a converting ratio by using a number of pixels of the original picture to be reduced/enlarged as a denominator and a number of pixels of a converted picture as a numerator in response to the selected picture size;
cumulating means for cumulating an inverse of the converting ratio for each pixel of the original picture and producing a result;
position information generating means for generating position information for original pixel data to be interpolated using a value of an integer part of the result produced by the cumulating means;
interpolating means for interpolating the original pixel data so as to obtain a value for a converted pixel;
and
interpolation coefficient generating means for generating an interpolation coefficient corresponding to a decimal part of the result produced by the cumulating means, the interpolation coefficient being used by the interpolating means for interpolating the original pixel data thus generating the converted picture, wherein the interpolation coefficient generating means includes
a counter for counting pulses of a sampling clock and producing a count value based on the pulses counted, and
a comparator for comparing the count value with an output value from the cumulating means and producing a pulse when the count value is equal to or greater than the output value from the cumulating means;
and
means for displaying the converted picture on the original picture on the display monitor.

9 more elements

A picture processing method for enlarging/reducing a picture formed of pixels of digital data by any selected ratio, comprising the steps of:

displaying an original picture on a display monitor;
inputting a user-selected picture size for an enlarging/reducing process by enabling a user to vary a size and a position of the user-selected picture size while the user-selected picture size is displayed on the display monitor by displaying frame lines to give the user visual feedback of the selection before performing the enlarging/reducing process;
obtaining a converting ratio by using a number of pixels of the original picture to be reduced/enlarged as a denominator and a number of pixels of a converted picture as a numerator in response to the user-selected picture size;
cumulating an inverse of the converting ratio for each pixel of the original picture and producing a result;
generating position information for original pixel data to be interpolated using a value of an integer part of the result produced in the cumulating step;
generating an interpolation coefficient corresponding to a decimal part of the result produced in the cumulating step;
interpolating the original pixel data, thus generating the converted picture, using the interpolation coefficient so as to obtain a value for a converted pixel;
counting pulses of a sampling clock and producing a count value based on the pulses counted;
comparing the count value with an output value from the cumulating step and producing a pulse when the count value is equal to or greater than the output value from the cumulating step;
and
displaying the converted picture on the original picture on the display monitor.

8 more elements

Dependencies are inferred from the claim text.