From Paul Cole
The law gets into a mess when a court does the right things for the wrong reasons.
By way of introduction, the present proceedings concern a method for the production of halftone images created at the University of Rochester.
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 Blue Noise Mask (BNM), a novel approach to providing high-quality halftones many times faster than the best algorithms available in the late 1980s. Dr. Parker, an expert in the field of medical imaging, 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 a fine mosaic of black and white dots. This fine mosaic pattern was mathematically constructed into a Blue Noise Mask. 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.
Researchers at the University of Rochester designed the mask with substantial computer power and several years of work. The BNM was introduced to graphics and other industries in 1991. At that time BNM was a leap forward in halftoning technology. BNM was the first method to combine high quality with virtually instantaneous halftoning.
“Blue noise” refers to an unstructured pattern with negligible low frequency noise components that produce a fine, visually appealing arrangements of dots. BNM is the best technology available for eliminating the wavy moire patterns that tend to occur using previous methods, particularly in color images. BNM is more isotropic (directionally uniform) than error diffusion, and produces less periodic (recurrent) patterns than ordered dither methods. Error diffusion techniques tend to show scanning and start-up artifacts, while BNM is free from these. The technology can be implemented either as a software filter in digital equipment, or as a plastic or glass screen in the optical processes widely used in photocopiers and newspaper publishing. BNM provides high-quality images at faster speeds using software that eliminates the computations previously required for digital halftoning in such devices as photocopiers, scanners, laser printers, and fax machines. No calculations are required because the BNM pattern is pre-built. Only a trivial comparison of the scanned pixels to the mask is required to generate a halftone. In a psychovisual test, BNM halftones were rated 2.7 times more pleasing than clustered-dot halftones, 1.6 times more pleasing than dispersed-dot-dither halftones, and about as pleasing as error-diffusion halftones which took 45 times longer to generate.
The asserted claim of US-A-5111310 reads as follows:
1. A method for utilising the halftoning of grey scale images by utilising a pixel-by-pixel comparison of the image against a blue noise mask in which the blue noise mask is comprised of a random non-deterministic, non-white noise single valued function which is designed to produce visually pleasing dot profiles when thresholded at any level of said grey scale images.
US-A-5341228 is a continuation-in part of the 310 patent and its asserted claim reads as follows:
11. A method for the halftoning of colour images comprising the steps of utilising, in turn, a pixel-by-pixel comparison of each of a plurality of colour planes of said colour image against a blue noise mask in which the blue noise mask is comprised of a random non-determininstic, non-white noise single valued function which is designed to provide visually pleasing dot profiles when thresholded at any level of said colour images, wherein a plurality of blue noise masks are separately utilised to perform said pixel-by-pixel comparison and in which at least one of said blue noise masks is independent and uncorrelated with the other blue noise masks
A European patent practitioner would have no difficulty with the proposition that a method of halftoning images qualifies as patentable subject matter. EPO Appeal Board decision T 204/84 VICOM rejected a claim to a method of digitally filtering data in the form of a two-dimensional data array using a small generating kernel operator matrix to achieve the effect of convolution with a larger operator matrix, but allowed a similarly worded claim when directed to a method of digitally processing images. The gist of the Appeal Board’s reasoning is apparent from the following extract from the decision:
“A basic difference between a mathematical method and a technical process can be seen, however, in the fact that a mathematical method or a mathematical algorithm is carried out on numbers (whatever these numbers may represent) and provides a result also in numerical form, the mathematical method or algorithm being only an abstract concept prescribing how to operate on the numbers. No direct technical result is produced by the method as such. In contrast thereto, if a mathematical method is used in a technical process, that process is carried out on a physical entity (which may be a material object but equally an image stored as an electric signal) by some technical means implementing the method and provides as its result a certain change in that entity. The technical means might include a computer comprising suitable hardware or an appropriately programmed general purpose computer.”
Further guidance is derived from the recent decision in G3/08 PRESIDENT’S REFERENCE/Programs for computers. The Enlarged Appeal Board held that a computer-readable data storage medium had the technical effects of being computer-readable and of being capable of storing data and was not excluded from patentability by article 54(2) and (3) EPC. On that basis it could not be excluded from patentability merely because it was “storing computer program X,” any more than a cup which was a technical article could be excluded from patentability merely because it was decorated with picture X. There was no case law to support the view that a claim to “a computer-readable storage medium with program X written on it” should lose its technical character merely because it was too generic or functionally defined. An EPO appeal board would hold on the present facts that a method of halftoning images was patentable subject matter, and that position should not be affected by any objections concerning lack of clarity or absence from the claim of essential technical features.
The Delphion database lists three granted European patents as equivalent to the 310 patent. The parent case whose claims are closest to 310 is EP-B-0560872. There was, as expected, no objection as to non-patentable subject matter. However, during prosecution the European examiner objected that the phrase “which is designed to produce visually pleasing dot profiles” was unclear since it merely represented a desired effect and that effect was itself unclear. Furthermore the “visually pleasing” feature did not distinguish over the prior art since one of the citations made many references to the pleasing effect of blue noise characteristics. In their reply the applicants argued that the expression was clear and explained that what was meant was that the mask did not produce a pattern of dots which clashed with the structure of an image by adding one of its own or degrade the image by being too noisy or uncorrelated. An interview followed attended by two members of the three-person examining division. The examiners maintained their objection that the claims lacked clarity and further objected that it lacked essential technical features defining the method of generating the blue noise mask. In consequence the examiners and the applicants’ representative drafted a new main claim in which the visually pleasing feature was removed and which reads as follows:
1. A method for the halftoning of grayscale images characterized in that the method utilizes a pixel-by-pixel comparison of the image or information derived from said image against a dither matrix c(i,j,) wherein the matrix is formed by
(a) establishing a blue noise dot profile at a certain gray level;
(b) building a plurality of blue noise dot profiles p(i,j) in which the dot profile for each gray level is dependent on the neighboring dot profiles for different gray levels and
(c) summing all of said dot profiles p(i,j).
In agreement with the EPO examiners, from a US standpoint, it is suggested that the term “visually pleasing” in claim 1 of the 310 patent is open to objection on the ground of indefiniteness having regard to the decision in Datamaze v Plumtree Software (Federal Circuit, 2005) that “aesthetically pleasing” in relation to a user interface screen lacked an objective anchor so that an application for summary judgment of invalidity succeeded.
Furthermore, the method, overall, is remarkably ill-defined in the US claims. The term “comparison” as a matter of English merely requires consideration of the similarities and differences between the image and the blue noise mask and fails to define any logical operation by which the required halftoning is brought about. The words “when thresholded” are used simply to define the characteristics of the mask, but do not explicitly call for a thresholding operation as part of the production of the halftoned image. Remarkably, the asserted claims are method claims without any explicitly defined steps. There would appear to be at least arguable objections that the claims in issue fail to set forth what the patentee regards as his invention and do not do so with the particularity and distinctness called for by 35 USC 112. Chief Judge Rader points out that:
“In Section 112 the Patent Act provides powerful tools to weed out claims that may present a vague or indefinite disclosure of the invention. Thus a patent that presents a process sufficient to pass the coarse eligibility filter may nonetheless be invalid as indefinite because the invention would “not provide sufficient particularity and clarity to inform skilled artisans of the bounds of the claim.”
These observations may serve to support the position of the CAFC if the case is appealed to the Supreme Court; they could equally be taken as a warning to the patentees that their success on the patentable subject matter issue should not be taken as an indication that their claims would survive section 112 scrutiny.
Judge Robert C. Jones may not have selected the best grounds for his conclusion that these are claims that should go no further. But it is to be hoped that these claims will not find their way to the Supreme Court; re-issuing the patent with clearer and more readily assertable claims could well be a better course.