yaw, pitch, roll using a tripod.

[Diego ROn]

Hi everybody,

since photoscan uses it, here in the lab, we were trying to figure out how to record yaw, pitch and roll in close range photogrammetry using a tripod. Does any of you ever tried to do something like that?

Since we are on very early stage of this any suggestion would be precious. We are thinking to use a 3axis gps, an accelerometer and a data logger, but it's just something we discussed yesterday having a beer....

thanks,

Diego.

[frank.stremke]

as far as i understand from the tutorial vidio it is not yet used information

[RalfH]

Diego ROn,

why would you want go through all the trouble recording yaw, pitch and roll for close-range photogrammetry? It's quite difficult to measure these parameters with sufficient accurracy and precision. And why usye a GPS for close-range photogrammetry? It is so much simpler to build the model and do the scaling and orienting with a few well-measured control points.

[Diego ROn]

We generally work using a total station to mesure control points and the accurancy seems to be fine enough. We tought that recording yaw pitch and roll we could speed up the allignment process, this seems to be true for airborn photos so we tought to try a ground solution.
Tanks,
Diego.

[Alexey Pasumansky]

Hello Diego,

Currently sourse values for yaw, pitch and roll are not utilized in any PhotoScan processing steps. Only corresponding error values are colculated using this type of data.

[RalfH]

Interesting idea, but I think that you'd have to put quite a bit of money and effort into such a solution would be quite high. You'd need a differential GPS to even get centimetre resolution while a total station usually provides millimetre resolution. Using a three-axis accelerometer and magnetometer to get yaw, pitch and roll with respect to compass directions together with a data logger is quite simple in principle. The low-cost devices you can get these days have error margins between one and a few degrees, and in particular the magnetometers are quite susceptible to calibration issues (so while precision may look relatively good, accuracy may not be). Of course you can get almost any precision if you're willing and able to pay for it, but there's a big price jump between the low-precision (and low-cost) chips (that are mass-produced for the smart phone and tablet market) and high-precision devices.

If you were working somewhere where you can't put control points it may be worthwhile looking at yaw/pitch/roll solutions because your camera parameters are all that you have. But especially when working with close-range projects, setting up a few control points is just too easy and cheap.

[Diego ROn]

mmmmmm we've got an old trimble 5700 we could use for that, but since recording yaw pitch and roll does not seem to effect the photo alignment I'm going to give up on this idea thanks to everybody!