Sharpening filter for images with automatic adaption to image type

Abstract

Abstract A method of filtering images with a filter that is dependent on image type. For binary images, a fixed Laplacian filter is used (202) for all pixels. For non-binary images, an automatic level-sensitive Laplacian filter is used (206, 208). For non-binary images, Laplacian filter coefficients and normalization divisors are made a function of intensity on a pixel by pixel basis. Pixels indicating a high intensity may be greatly changed by neighboring pixels. Pixels indicating a low intensity receive relatively little or no filtering. In a specific example embodiment, the intensity range is divided to bands, with a different filter for each band. The resulting images are visually sharpened (edge enhanced) with very little impact in darker areas of the image.

Inventors

• 👤 Patricia D. Lopez
• 👤 Jeffrey P. Lee
• 👤 Hal Hansen

Bibliographic Details