Multilevel color form dropout: algorithms and media processor implementation

Abstract

Color dropout involves converting important information in digitized color forms to black and white documents without maintaining the form background. This process is typically achieved by automatically removing all of the form lines and labels, and keeping only the information that is entered when the form is filled out. This paper expands the scope of color dropout, so that partial information from the original form is maintained for the benefit of human viewers, in a manner that does not interfere with further processing. The proposed methods assume no prior knowledge of the color form to be processed. An existing bilevel color dropout method is extended and three different multilevel color dropout approaches are developed. Results of these novel methods for processing several standard forms are presented and discussed in terms of two visual metrics—character representation and form dropout. The computational complexity of the algorithms is less than that of other common dropout methods, which makes them suitable for implementation in parallel hardware environments. A media processor implementation is presented, which outperforms general processor implementations by a factor of 11.8 on average.