Is it possible to do the measurement from the calibrated parameter ?

[lyhour]

Excuse me everyone. To do the measurement in Agisoft, the marker or scale bar must be conducted and present in the Image. My object measurement is aggregate height on pavement surface. Therefore, I have to move measurement point many locations on the pavement. The installing of GCP is take much time. I am not measure in Agisoft, I use Agisoft only generated the dense point cloud. Then I do the computation in Matlab. I am notice that the pre-calibrated parameter in Camera alignment step is effect to the model generation point cloud. Therefore, I come up with idea that If I create the image acquisition with the fix distance and illumination, I get the pre-calibrated camera parameter by conducting the marker only one time. Then, I use the calibrated camera parameter for my image acquisition to generate the dense point cloud. Thus, is it possible that I can generate the point cloud and measure my object using the pre-calibrated parameter that I calibrate ? Well, I have been done the trail test methodology that I describe already, But, it gives me the different result from the same batch of image. Therefore, anybody give me some suggestion regarding to my issue. I am sorry for my English. Thank very much

[Kiesel]

Hello Iyhour,

even I don't fully understand what you want to do, an answer from my side. Generally a model by photogrammetry needs to be scaled and oriented. This can be done by:

1. known camera coordinates (where was the camera when the photo was taken), eventually/even better with known orientation data (where was the camera pointing to)
2. scale bars in all 3 space directions x, y, z
3. a calibrated stereo (or multi) camera rig with known stereo base (offsets) and eventually orientation, like for example the calibrated stereo camera Leica BLK3D.
4. known coordinates of points (GCPs) you can use to set scale (and georeference, if they have geographic coordinates).

Once a point cloud or a model is scaled you can measure in it or export it and take your measurments in another application, no scale bars or GCPs needs to be visible in the area where you want to measure.

In the hope that this helps you a little bit,

regards,

Kiesel