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Topics - vicviod

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General / Issues Processing Referenced Drone Data
« on: June 08, 2017, 04:38:36 PM »
I am working on a project using drone data. The drone data is referenced with lat, long, alt, yaw, roll, and pitch.

The issue is, when I try to align the photos, I get a strange tendency for the photos to "rotate". What I mean by that is that photoscan estimates that the camera is facing in the complete opposite direction from what the reference data indicates.

So, when I go into the reference data I get tremendous error margins next to some of this data, within the 100-300 degree range. This obviously messes up the picture a great deal. Do you know what is going on?

One issue might be a low refresh rate of the reference data--so sixteen consecutive images have the exact same GPS data. What I've done to remedy that is only use 1/16 frames, so there is no overlap between frames. This slightly improves the picture, but doesn't really fix the problem.

Do you have any ideas of what could be going on?

General / Tips for Speeding up Processing of UAV photos
« on: June 07, 2017, 07:33:52 AM »
Hello all,
I'm currently working on a project where speed of processing is a big priority. With that in mind, do you guys have any tips for speeding up processing of photos taken by a UAV? To be more specific,

  • Are there certain attributes of photos that make them quicker to process? For example, if pitch and roll are extremely close to zero, will this make an appreciable difference in processing speed? Are there any other tips I should keep in mind while taking data to help speed up processing?
  • Are there certain settings that will make the processing photos go faster (without sacrificing too much quality?
  • How much does the number of images affect processing time? For example, is processing time O(n) complexity (where n is the number of photos), or O(n^2), or something else? Should I make as much an effort as possible to trim out photos with too much overlap?
  • Is processing the data in multiple smaller chunks (for example, subdividing the region on the map) preferable to doing it all in one shot?
  • Does certain data in the reference make a big difference to have? Currently I have long, lat, altitude, yaw, pitch, and roll
  • Do you guys have any other tips?

This is my current process:

  • Trim photos
  • Align photos (using reference preselection)
  • Build the dense point cloud (on medium quality)
  • Generate mesh (arbitrary surface type)
  • Build UV (generic mapping mode)
  • Build Texture (with mosaic blending)
  • Build orthomosaic (using model data and mosaic blending)
  • Export orthomosaic in tif format

Knowing all this, is there anything I can do with regard to data collection, data trimming, settings modification, or anything else that will make a difference with processing time?

Thanks guys!

I am trying to automate the processing of a chunk (aligning photos,  building dense point cloud, generating mesh, adding texture, building orthomosaic, and exporting the orthomosaic)

However, when I try to build the orthomosaic, I get "error: empty frame path"

Here is my code:

Code: [Select]
import PhotoScan
import os
import sys

doc =
chunk = doc.chunk = PhotoScan.CoordinateSystem("EPSG::4326")

imagePath = sys.argv[1]

chunk.matchPhotos(accuracy=PhotoScan.HighAccuracy, preselection=PhotoScan.ReferencePreselection)
chunk.buildModel(surface=PhotoScan.Arbitrary, interpolation=PhotoScan.EnabledInterpolation)
chunk.buildTexture(blending=PhotoScan.MosaicBlending, size=4096), "test.psx"))

# Problem area
chunk.buildOrthomosaic(surface=PhotoScan.DataSource.ModelData, blending=PhotoScan.BlendingMode.MosaicBlending)
chunk.exportOrthomosaic(os.path.join(imagePath, "orthomosaic.tif"), format='tif')

It works until the saving of the file as a psx. Then I get the error when I try to build the orthomosaic.

I read somewhere that I should try to save the document before doing the processing steps, but when I tried that the outputs of the processing steps (tie points, dense point cloud, model, etc.) were not being added to the chunk, and when I tried to build the orthomosaic I got "Error: bad allocation"

I am using PhotoScan 1.2.0, and at the moment I am unable to change versions. How can I fix this?

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