05 November 2010

Computer Program Claim not Excluded from Patentability under the EPC

In decision  T 979/06 of 21 September 2010, Technical Board of Appeal 3.5.04 of the EPO had to decide on sufficient disclosure (Art. 123 EPC), clarity (Art. 84 EPC) and inventive step (Art. 56 EPC) of an invention relating to reducing luminance flicker in a video image sequence by means of a computer-implemented method. Claims 1 and 11 of the main request read:
1. A method of reducing luminance flicker in a video image sequence comprising a plurality of video images produced by a camera, comprising:
  • digitally filtering on a per pixel basis, using a  finite impulse response filter of maximum length N+1, temporally successive video images of the video image sequence; said digitally filtering comprising:
  • adjusting a filter length, measured in terms of a number of pixel values, corresponding to a current image pixel value of the finite impulse response filter to increase the filter length 
    • if an absolute difference between the current image pixel value and a correspondingly spatially disposed previous pixel value of respective current and previous temporally spaced successive images of the video image sequence is less than a threshold value up to the maximum filter length of N+1, and 
  • otherwise setting the filter length to one, measured in terms of a number of pixel values.
    11.  A computer program comprising computer program code means adapted to perform all the steps of claims 1 to 4 when the program is run on a computer.
    Oral proceedings were held on 5 March 2009 in the absence of the appellant. At the end of the oral proceedings, the chairman announced that the proceedings would be continued in writing.

    The Board informed the appellant in a Communication dated 26 March 2010 that it had formed the opinion that the subject-matter of claims 1 to 10 of the main request was patentable and that the Board intended to stay the appeal proceedings until the opinion of the Enlarged Board of Appeal in case G 3/08 was available, since requested claims 11 and 12 were directed to a computer program.

    The G 3/08 opinion: The referral G 3/08 of former EPO President Alison Brimelow comprised four questions, among which question 1 related to claim categories and thus to the instant case:
    Can a computer program only be excluded as a computer program as such if it is explicitly claimed as a computer program?
    The referral claimed a divergence between decisions T 1173/97 (Computer program product/IBM), placing the emphasis on the function of the computer program rather than the manner in which it is claimed (e.g. as computer program, computer program product, or computer-implemented method), and T 424/03 (Clipboard formats I/MICROSOFT), which placed emphasis on the manner in which the computer program was claimed. Following the reasoning of the latter decision, only a claim of the form "computer program for method 'X'" could possibly be excluded from patentability as a computer program as such, whereas claims of the form "computer implemented method 'X'" or "computer program product storing executable code for method 'X'" would not be excluded, irrespective of the nature of the method 'X'.

    The opinion of the Enlarged Board of Appeal in case G 3/08 was issued on 12 May 2010. Regarding the above question and the two decisions cited in the grounds of the referral, the Enlarged Borad explained that
    • the assessment whether or not a claim directed to a computer program is excluded from patentability should be determined independent of prior art;
    • T 1173/97 had deliberately abandoned the former "contribution approach", according to which the further technical effect required from a computer program to avoid exclusion had to be new, and that this choice stands as the established case law and cannot be overturned; 
    • T 1173/97 and T 424/03, in fact, took different views on the exclusion of claims to a program on a computer-readable medium but this, however, represents legitimate development rather than a conflict in case law;  
    • the present position of case law is that a claim relating to a computer program can avoid exclusion under Art. 52 (2), (3) EPC by explicitly mentioning the use of a computer or a computer-readable storage medium; and
    • a claim which specifies no more than e.g."Program 'X' on a computer-readable storage medium" will overcome the exclusion of Art. 52 (2), (3) EPC but will lack an inventive step pursuant Art. 56 EPC.
    The instant decision: The present Board thus concluded that the Enlarged Board of Appeal found, inter alia, that there was no (real) conflict between T 1173/97 and T 424/03 and that the definition of the "further technical effect" given in decision T 1173/97 stood as the established case law.

    Regarding instant claims 11 and 12, the board then examined whether the subject-matter of claims 11 and 12 has a technical character because the claimed program, when run on a computer, causes a "further technical effect", as required by T 1173/97. It was observed that computer programs of claims 11 and 12 have the effect that, when run on a computer, luminance flicker in a video image sequence comprising a plurality of video images produced by a camera (and input into the computer) is reduced. The board thus concluded that this effect is a "further technical effect" as required by established case law, such that the computer programs of claims 11 and 12 are not objectionable under Art. 52 (2), (3) EPC.

    (The above illustration shows a program in the Piet programming language, printing "Hello, World!", for explanation please see here; (C) 2006 by Thomas Schoch via Wikimedia under the terms of a CC license)