ContectCapture QR codes Creator ~ explanation of various QR constraints available and how to use them in practice

Hi,

We are exploring the use of ContectCapture to create reality meshes from photographs taken by drone, DSLR and mobile phone of existing buildings. We would like to create digital twins of both the interior and exterior of the existing buildings. We have experimented with the QR codes Creator and would like some more information to assist us with:

~ explanation of various QR constraints (Control Point, User Tie Point, Origin, Axis, Plane and Scale) available, and

~ how to use them in practice, typical case studies would be very helpfull

  • Thanks Oto, that's a really useful tool. I can see why the QR codes aren't going to be of much use in some applications, but in some limited circumstances it might be: I'm an archaeologist and when we use drones for capturing excavation data we are often operating less than 20 m above our surface and the tool suggests that the required pixel size is within a practical range. However, for the most part I'd say that standard targets are going to be the more practical option

  • QR codes are very bad choice for such purpose as it contains many pixels so are hard to read in low resolutions. For pixel size on ground see this calculator - https://www.propelleraero.com/gsd-calculator/

    So for 100m altitude you need at least 3cm/pixel for QR code so the physical size for even empty(null) QR code will need to be at least 1m x 1m. If it contains more data then it will need to be even larger.

    Other option would be to get closer on each QR code but it is not possible in automatic flight.

  • A little related to Phillip's question, I'm interested to know if someone has run any experiments in regards to QR code target size and effective recognition distance using different platforms? i.e., if I have a 25 x 25 cm target and a Phantom 4 CC will detect the QR code if the camera is within X metres of the target, but if I have a 50 x 50 cm target I can be within X+ metres of the target.

  • QR codes work(or doesn't work) the same as the corresponding constraints just you don't need to provide the points manually that is all. Meant to be use when the same site needs to be inspected regularly.

    In practice the QR codes are of limited use as QR codes contain too much information embedded in small space so it requires very good resolution to be recognizable by software.