Abstract: A method and apparatus for resizing digital or stored images initially retrieves a one-dimensional sample of the image, such as a line of pixels. A final image size D is determined so that the absolute value of the original sample size M-2.sup.N *D is a minimum, and where N is an integer greater than or equal to 0. The discrete series of pixels in the line are then converted to a continuous function under a cubic convolution interpolation technique. From the continuous function, intermediate pixel values are determined. Pyramid filtering is employed to filter the intermediate pixel values to a final series of pixel values D. The routine is performed along the opposite dimension so as to alter the size of a two-dimensional stored image.

Abstract: A method and apparatus for resizing or processing images initially retrieves a one-dimensional sample of the image, such as a line of pixels. The image can be of a machine-readable symbol, or other data. A moving window having, for example, five pixels, includes a center "hard core" and four surrounding pixels. Two or more structural sets or multisets are applied to the window to produce a set of pixels greater than the set of pixels in the original image. For example, the center pixel is repeated three times, while immediately adjacent left and right pixels are repeated twice. Thus, a series of nine pixels results. The resulting nine pixels are then sorted based on descending gray scale levels. The n-th largest pixels is selected, such as the third largest. The image is updated, the window moved, and the method repeats again. Pyramid filtering, cubic convolution interpolation, or other techniques can be used to reduce the size of an image, and more complex windows and structural sets can be employed.

Abstract: A method and apparatus locates edges of patterns in a stored image, such as edges of bars or finder patterns of machine-readable symbols. The present invention first selects an edge point or pixel within a stored image. A dominant direction is determined therefrom by examining a region surrounding the selected point. A smaller window is then examined around the edge point to derive a hexadecimal code based on binary values of pixels which surround the edge point. The hexadecimal code is compared to a table of codes, where each code maps to a similar window and identifies a next edge point. The process continues in the dominant direction until the entire edge is located. Circuitry for rapidly performing the its location of patterns in a stored image, such as ages of bars of finder patterns of machine-readable symbols.