Patented method of traffic detection not infringedMarch 2, 2010

In an opinion released in July last year, the Court of Appeals for the Federal Circuit issued a ruling in the case of Wavetronix v. EIS Electronic Integrated Systems. This case involved a traffic monitoring system that had been patented by Wavetronix, and EIS had received summary judgment for noninfringement of the Wavetronix patent at the district court. Wavetronix appealed the noninfringement summary judgment and EIS cross appealed on various matters. On appeal, the CAFC affirmed the decision of the lower court on all matters raised on appeal.

During the trial at the District Court for the District of Utah, the judge found, as a matter of law, that EIS had not infringed the patent asserted by Wavetronix. Interestingly, the district court was able to make this determination without determining the meaning of the disputed claim under claim construction. The CAFC, after construing the claim, found that the District Court's decision of noninfringement was proper.

The patent at issue is directed towards a method of accurately counting vehicular traffic, information important for city planning and traffic control. Specifically, the patent describes a method of initializing a radar vehicle detection device to recognize the location of the lanes in a highway by analyzing the location of passing vehicles. The Wavetronix patent describes a system of gathering data about passing cars, providing this information in a histogram, determining the peaks and valleys of the histogram, and associating the peaks with the centers of the lanes and the valleys with the spaces between the lanes. The radar vehicle detection device would then use this lane data to know how many cars passed the device and in which lanes.

In contrast, the EIS product includes a number of preset fields, each set at three meters (approximately the width of a traffic lane). In its automated initialization process, it analyzes each of the preset fields and counts the number of "hits" it receives in each field, where each vehicle may deliver a number of hits. The device then communicates with a laptop which determines, according to a mathematical formula, whether each field constitutes a lane. Once this determination has been made, the software in the device will only count vehicles which pass in a field which has been specified to be a lane. Other verification steps are also included in the process.

As previously discussed, the district court did not construe the claim in this case. During the decision on appeal, both sides asked the court to construe the claim, rather than remand the case to the district court to construe the claim. The court agreed to do so for three reasons.

First, although the district court did not specifically construe the claim term, its opinion references the question of claim construction, and it is apparent that the district court's views on the matter have been exhausted… Second, both parties have agreed that we should construe the claim limitation. Third, we agree that the record, which includes considerable evidence and expert testimony, has been sufficiently developed to enable us to construe the claim term without prejudicing either party.

Slip op. at 14, internal citations removed.

The court then engaged in a lengthy discussion of the various elements of the claim and the definition of the terms used within the claim, according to the standard methodology. Both parties agreed that only one term was under dispute, and that this issue was determinative as to whether infringement had occurred. Armed with this definition, the court then moved on to consider the facts and whether summary judgment had been properly granted for either literal infringement or infringement under the doctrine of equivalents, ultimately concluding that summary judgment had been proper.

One issue of note is that the court dismisses one of Wavetronixs' arguments for doctrine of equivalents because "[n]either claim 1 nor the specification foresees the use of a multiplicity of [Probability Density Function Estimates] to define lanes. The claim language describes defining lanes from "said" PDFE, and every embodiment in the specification teaches the use of a method that can be described by a single PDFE." Id. at 26.

The case of Wavetronix v. EIS Electronic Integrated Systems is available here.