Blue Noise Mask
Printing devices have long used the technique of halftoning to render the appearance of shades of gray using dot patterns. But high-quality halftones required an exasperating amount of time for printout. Drs. Kevin Parker and Theophano Mitsa developed a novel approach they named Blue Noise Mask to provide high-quality halftones up to 45 times faster than conventional methods. Dr. Parker, an expert in the field of cancer treatment using ultrasound waves, had noticed that printouts from his team's diagnostic equipment were slow and plagued by distracting "noise" patterns called image artifacts. The researchers were unable to tell whether a spot on a picture represented an incipient tumor or an artifact added to the image during printing.
For a faster, more accurate way to render the pictures, they conceptualized pictures as being composed of mountains (black dots) and valleys (white areas). To build mountain ranges of certain sizes, they mathematically dug holes and piled up the excavated volume. After a computer calculates the optimum mask for a printing device, the pre-built mask is stored in the printer's software to produce halftones almost instantly. For color printers, the mask also halves the number of bits needed to produce a high-quality image, permitting major savings in printing speeds and computer memory.
RCT has developed a formidable portfolio of patents covering this technology, including:
U.S. Patents (pdf format)
- 5,726,772 (2.8MB) certificate of correction (62KB)
- 5,708,518 (2.6MB) certificate of correction (22KB)
- 5,543,941 (1.9MB) certificate of correction (284KB)
- 5,477,305 (2.3MB) certificate of correction (338KB)
- 5,341,228 (1.7MB) certificate of correction (167KB)
- 5,111,310 (845KB) certificate of correction (25KB)
Foreign patents
A third European patent application is allowed and will issue soon. Multiple patent applications are pending in Canada and Ireland.
Inventors
Drs. Kevin Parker and Theophano Mitsa at the University of Rochester
Blue Noise Mask Overview
Download PDF (401KB)
Licensing
RCT achieved wide industry acceptance for Blue Noise Mask and has licensed it to a variety of companies that use the software in a broad range of products.