Abstract: An apparatus for and method of truncating images during data compression. The present invention truncates an image when the memory requirements for the compressed image exceeds a predetermined threshold. However, unlike prior art systems, the present invention contemplates replacing all of the pixels that are eliminated by the truncation process with a series of "0's" thereby "white filling" the truncated portion of the image. The present invention avoids the disadvantages in the prior art by ensuring that the truncated image contains the same number of pixels as a non-truncated image. Further, the data extent of the truncated image may be the same as a non-truncated image. Finally, the resulting images, either non-truncated images or, if necessary, truncated images, may be stored in a preselected memory size.

Abstract: An image scaler which enlarges gray scale images, comprised of any number of gray scales, by any rational factor expressible as a ratio of integers between 1:1 and 2:1. The scaling method is "data conservative" in that it always keeps all of the original gray scale pixel values of the input image, generating additional pixel values as needed to produce an enlarged output image. The scaler generates an insertion number sequence for determining where to insert vacant pixel storage locations and calculates gray scale values for those newly created vacant locations by interpolating between values of neighboring pixels.