This is an extended question to my previous question: Leading customers to use cheaper solution invented for another domain instead of expensive patented solution. Infringement?

As far as I know, if one component is different from the registered patent, it is not an infringement.

For example, in claim 1 of the following patent, authors are claiming a patent on a markerless system with stereo vision, which I understood that if I use a marker or 3 cameras instead of stereo vision, it is not infringing their patent whereas others say just changing one or few parts of the patent could be still patent infringement.


I understand that the interpretation of infringement could be different under different situations but I was wondering what you guys think.

I am taking it to a patent attorney next week after studying the patent law myself a little bit. I will share the result here too.

  • 2
    I seem to recall that it depends on how the patent is written and if your change is unexpected. I can't find my copy of the paten law at the moment. Aug 15, 2023 at 5:55
  • @RohitGupta. “Unexpected” has more to do with patentability not infringement. But you are correct in “how the patent is written”; it’s everything. Aug 19, 2023 at 1:10

1 Answer 1


Reading and interpreting claims is a very technical task and it differs by jurisdiction.

I would point out some issues - first, yes, especially in jurisdictions with “peripheral claiming” like the US, all positively claimed elements must be present to infringe. Leaving one out should avoid direct infringement. Or substituting an element that has a similar contribution to the function but done in a different way.

In the US and possibly other jurisdictions there is a doctrine of equivalents (DOE) such that one element might be substituted for a claimed element but if it works the same way for the same purpose you could still be deemed to infringe. DOE has been out of favor with US courts lately.

One thing to be careful of - a system with three cameras does have two cameras. A four legged table does have three legs. Adding elements does not prevent infringement, leaving out elements does. Or a different configuration or interconnection of the same elements that, therefore works differently might escape infringement.

At least in the US there is an important distinction between “comprising two cameras” and “consisting of two cameras”. Comprising is open ended. It would mean “at least two cameras”. “Consisting of” would mean exactly two cameras. With other wording it might be less clear which sense is meant.

Also, very importantly, there are other patents in the world besides this one. You might need a “freedom to operate” search that covers the core aspects of your proposed product or service in the jurisdiction you plan to operate within.

  • 1
    This is interesting - so (ages ago) I could have patented a 15 camera 3D vision system, and prevented anyone else from not only replicating it, but even improving upon it by reducing the number of cameras?
    – Tim
    Aug 16, 2023 at 17:33
  • You have it backwards. A 4 camera system does not have 15 cameras. I can count 4 cameras in a fifteen camera system. I’ll clarify the answer. Aug 18, 2023 at 19:14
  • Leaving things out and you don’t infringe, adding things you probably do infringe. Aug 18, 2023 at 19:21

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