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Messages - AndyC

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Feature Requests / Re: Request: Dense Cloud Filtering
« on: January 28, 2016, 08:38:49 PM »

General / Understanding Image Residuals
« on: January 28, 2016, 08:22:15 PM »
Please can anyone clarify exactly what the image residuals presented in the camera calibration section of the processing report indicate?

I believe it is (1) the amount of distortion (error) corrected by the lens model. However, I was also wondering whether it might instead be (2) the amount of distortion (error) that remains uncorrected after the lens model was applied?

(Apologies if this has already been answered elsewhere, I wasn't able to find this explained)

Python and Java API / Re: Match Photos preselection
« on: July 25, 2015, 12:30:40 AM »
Please could someone explain what criteria are used to decide whether photos are likely to be overlapping (and therefore will be compared) or not when using the reference preselection mode?

If the criteria are relatively open, the alignment process will be slightly longer, and slightly less efficient.

However, if these criteria are too stringent, isn't there a risk that photos will not be aligned, because they are not compared to the correct 'neighbouring' images? (For example, for UAVs, photos taken from higher altitudes may overlap with several neighbouring images in any direction, and therefore would need to be compared with several neighbours in each direction to optimise alignment. Another case could be for lower altitude flights, where errors in location (due to GNSS (GPS) signal problems) or differences in camera orientation could mean that photos which appear to be neighbouring, could actually be of subjects some distance from each other; this would reduce matching if images are only compared against images from a small neighbourhood).

Pap1956, probably not the cause of the error, but is your script trying to query the projected coordinates of point 0,0 twice?

I've a few questions for the latest script (for V1.1.0) (apologies in advance if they're rather basic, I'm rather new to Python).

(1) Is the user input 'camera index' the total number of ‘cameras’ (images) for which footprints should be exported??

(2) When specifying the path for the output file, is is necessary to specify the format? If so which formats are permissible?

(3) Should the 'step' parameter be adjusted for the coordinate system? (e.g., is using a coordinate system in m, with camera footprints of ~30 m, would it be best to reduce the step from 100 down to perhaps 1?)

(4) Will each camera footprint be exported as an individual unit (e.g., multiple polygons in a single shapefile), or will they be amalgamated?

Thanks, Andy

Feature Requests / Adding detail to processing reports
« on: April 23, 2015, 06:58:42 PM »
The Processing Reports generated by PhotoScan are useful, but I often find I need additional detailed information which I have to extract manually from Chunk Info.

Would it be possible to enhance the Generate Report process to allow user specified options as to what outputs are desired? I expect many users would find this functionality increasingly useful as the sophistication and processing options of PS continues to develop.


Python and Java API / Re: Setting mapping region
« on: November 27, 2014, 01:23:38 PM »
I'm also trying to use the API to prescribe a reconstruction region.

Can anyone explain how to determine the parameter values needed for the MapRegionVec array as described by jmsuomal? (My chunk is in the geographic coordinate system ESPG::4326).

Thanks, Andy

General / Defining precise bounding box (before dense reconstruction)
« on: November 14, 2014, 02:09:34 PM »
Is there any way to use XY coordinates to define the reconstruction volume bounding box precisely, rather than visually?

I guess one roundabout approach is adding additional markers with the desired coordinates at each corner and zooming in to set the bounding box visually, but I was wondering if there might be a neater approach?

Thanks, Andy

Feature Requests / Reporting information on reconstruction processing
« on: November 14, 2014, 01:05:26 PM »
When generating reconstruction processing reports, I think it might be helpful to include the project file name in the report (facilitating version tracking when working with multiple projects), and add an option to also include the 'chunk info' (parameters used for each processing step and maybe processing times) in the default report?

Feature Requests / Re: Aerial Footprints
« on: November 14, 2014, 12:55:29 PM »

General / Re: Depth Filtering Mode for UAV Imagery (lots of trees)
« on: October 09, 2014, 01:16:47 AM »
Hi Fernandoker,

The best setting for this parameter will depend on what you want to use the resulting point cloud for?
For example, deriving a digital surface model (DSM) or a digital terrain model (DTM).

You'll need to be more specific about what you're trying to achieve,

Good luck,

General / Re: New version instructions
« on: October 08, 2014, 02:50:14 AM »
The current user manual doesn't explain how to select whether to reuse depth maps or not (when building dense point clouds); or why it might be useful to keep depth maps when setting up the PhotoScan environment.

It reusing computationally more efficient, but less accurate and more prone to errors if the remains of previous unsuccessful depth maps are present from previous processing?

General / Selecting Data Layout when Importing Photos?
« on: October 08, 2014, 01:46:46 AM »

When adding photos to a project, if I select the 'Add Folder' option PhotoScan presents a choice of Data Layout, allowing the imagery to be loaded either as (i) individual 'cameras', or (ii) one multiframe camera.

What is the difference between these options? (I would guess that it determines whether the camera intrinsic parameters are allowed to vary between each image or whether the same derived parameters are applied to the entire data set; but I don't know whether this is correct?)

When is each option is best; is the 'multiframe camera option intended for when using a high quality camera with a prime lens? (I'm processing imagery obtained using a nonmetric consumer camera, so it's conceivable some of the lens elements may have shifted very slightly over the course of several hundred frames).

Thanks, Andy

General / Re: The size of coded markers for UAV acquisition
« on: October 08, 2014, 01:28:19 AM »
I'm looking forward to the increased functionality for the coded targets; is it possible to get a rough idea when the next PhotoScan version might be released?

General / Re: Align point limit
« on: October 08, 2014, 01:09:08 AM »
I've been wondering the same thing; it would be really useful to have some more clarification on this parameter in the User manual

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