Interpolation method and apparatus for fast image magnification

DETAILED DESCRIPTION According to the present invention, methods and apparatus for generating pixel values in a magnified destination image of an object in a destination image space are provided.
The pixel values in the destination image are generated from a source image of the object in a source image space.
The destination image and the source image each comprise a two-dimensional array of pixels.
Each of the pixels has a value representative of the object.
Pixel locations of the destination image in the destination image space are determined from a magnification factor and the size and location of the source image.
A first pixel in the destination image is transformed to a first resampled point in the source image space.
Neighbor pixels of the first resampled point in the source image space are determined.
Intermediate pixel values are determined by interpolation between vertically-aligned neighbor pixels in the source image space.
A value of the first resampled point in the destination image is determined by a single horizontal interpolation between the intermediate pixel values.
The above process is used to determine the value of the first pixel in a pixel row of the destination image.
Then, the values of the remaining pixels in the current pixel row of the destination image are determined sequentially, each pixel value being determined as follows.
A current pixel in the destination image is transformed to a current resampled point in the source image space.
The current pixel is adjacent to the previous pixel in the current row of the destination image.
Next, a determination is made if the current resampled point in the source image space has the same neighbor pixels as the previous point.
When the current resampled point has the same neighbor pixels as the previous point, a value of the current resampled point in the destination image may be determined by a single horizontal interpolation between the intermediate pixels calculated for the previous point.
When the current resampled point does not have the same neighbor pixels as the previous point, a single current intermediate pixel value may be determined by interpolation between a current set of vertically-aligned neighbor pixels of the current resampled point, and the value of the current resampled point in the destination image may be determined by a single horizontal interpolation between the current intermediate pixel value and at least one of the intermediate pixel values corresponding to the previous point