Messages

1

General / Re: Close-range photogrammetry terminology

« on: August 11, 2021, 06:46:26 AM »

I'm no expert and I don't know the context of your work but I would agree that CRP is a dated term from when photogrammetry was strongly associated with aerial survey. It's become ubiquitous enough in other applications that just photogrammetry is a sufficient description. The context of the discussion in your manuscript should be sufficient to separate it from aerial photogrammetry

2

Python and Java API / Re: Gradual Selection Python Script

« on: April 19, 2020, 11:02:17 PM »

That runs perfectly. Thank you, much appreciated UAV_project

3

Python and Java API / Re: Gradual Selection Python Script

« on: April 10, 2020, 10:09:12 PM »

Alexey,

I've run the two scripts you referenced. The gradual selection script runs smoothly and I'm looking to modify it to my needs. The selection by percentage script, cut and pasted from the post, produces the error below. What am I missing ?

2020-04-10 13:49:14 Analyzing point cloud...
2020-04-10 13:49:15 Finished processing in 0.25 sec (exit code 1)
2020-04-10 13:49:15 Traceback (most recent call last):
2020-04-10 13:49:15   File "F:/Documents/Photogammetry/Python Scripts/selectfixedpercentageofpoints.py", line 21, in <module>
2020-04-10 13:49:15     for i in range(list_values):
2020-04-10 13:49:15 TypeError: 'list' object cannot be interpreted as an integer
2020-04-10 13:49:15 Error: 'list' object cannot be interpreted as an integer

Also,
What is the correct syntax for including the camera optimization after, or in, the "for chunk in Metashape" statements. I've tried several different placements and only generate errors. Sucks being a noob

Thanks for your help
>>>

4

Python and Java API / Re: Gradual Selection Python Script

« on: April 03, 2020, 12:47:14 AM »

Thank you Alexey,

The gradual selection procedure I’ve found, that has been successful for my work is:
1.   Reconstruction Uncertainty – 50% of points or as near as possible to 10
2.   Optimize Cameras
3.   Projection Accuracy – 50% of points or as near as possible to 2.5
4.   Optimize Cameras
5.   Reprojection Error – 10% of points or as near as possible to .3
6.   Optimize Cameras with all lens parameters checked
7.   Repeat Reprojection Error/Optimize Camera until all above .3 pixels on reference error removed

The examples you provided I think contain all the elements needed for this. The target values and percentages can be constants. Some error checking on the iterative procedures would be probably be necessary. I may be able to put something together with this. It looks pretty straight forward. Any help would be greatly appreciated.

5

Python and Java API / Gradual Selection Python Script

« on: April 01, 2020, 08:12:44 PM »

Hi All,
I really need a python script to go through the gradual selection process in between camera alignment and dense cloud. There’s nothing in the list of programs on the wiki or github and although I’ve seen some discussions in the forum it’s fragmented and not a complete procedure. While many years ago I use to program in Pascal and Basic, I do not know python well enough to do this on my own. Thanks for any help I can get.

6

Python and Java API / Split into Chunks Dense Cloud w High Quality Setting w Aggressive Filtering

« on: July 28, 2019, 08:24:26 PM »

I've looked over the Split_into_chunks code and I'm not sure where and what I have to change to generate a high quality dense cloud w aggressive filtering.

Under the section - "if buildDense :" there are several if- then statements and I don't program in python...yet.
Isn't there somewhere at the top we could declare the constants and leave it at that?

Thanks for your help

Edit:ok, there's an unmarked button to define the quality...I missed that. Sry

7

Python and Java API / Orientation in Split into Chunks

« on: December 31, 2018, 10:35:22 PM »

I have a model that is too big for my computer so I am going to use the Split_into_Chunks python script to process it. As currently oriented, I want to break the model into three chunks along the z axis (1X3). From reading over the code I get the impression that the program generates chunks along the X and Y axis. Reorienting the model is not a big deal but I thought I would confirm this before making any changes. If it is x and y, is there any easy way to mod the code to generate along the z axis?

Also wanted to check if, after updating to MetaShape if I need to change the references to Photoscan in the code to Metashape ex. "import Photoscan" to "import Metashape". I imagine so.

8

General / Accuracy and precision in Photoscan

« on: August 16, 2016, 05:08:44 PM »

I’m trying to determine a metric for the accuracy and reliability of measurements taken off of a photogrammetric model created in Photoscan.

If I take a picture using a 24mp camera and a 60mm lens from 1 meter away the best resolution I will have is approximately 0.2mm. That’s the size (0.2mm^2) of a pixel normal to the camera and I assume the smallest piece of information I can obtain.

When I take 500 of these pictures and compile them into a photogrammetric model using photoscan, I get a point cloud with point spacings of less than 0.05mm. There is clearly a fair amount of interpolation and extrapolation going on.

The pixel size times the rms reprojection error I think would fairly represent the most accuracy one could expect but I have seen details in the models that should not have been resolved if this were the case.

I assume, the initial point cloud in photo alignment effectively establishes benchmark locations over the model then the dense cloud creation carries that process further based on the imagery information but at what point does extrapolation and interpolation take over from accurate determination of xyz coordinates based on the photo comparisons and how accurate are those point determinations.

Any thoughts on this would be appreciated. I get the feeling at times that the precision of the models far exceed the accuracy of the base information. Like using a tape measure and recording the results to the 4th decimal place.

9

General / Re: Adding independent graphics card for performance boost

« on: July 05, 2016, 01:09:38 AM »

Thanks to you both for the info. I'll try it and see what happens

10

General / Adding independent graphics card for performance boost

« on: July 02, 2016, 06:38:09 PM »

I'm currently running an AMD R9 290 graphics card in my PS computer. I have an older graphics card AMD 6950(?) doing nothing. If I add that into the PS computer as an independent graphics card (obviously not crossfired) will I get a performance boost or will I just screw things up? I have both the power and cooling capacity to support it.

11

General / Re: Exported tiled model problems

« on: June 22, 2016, 05:31:52 PM »

I had this same problem and its because the background of the texture map is white. There are several ways to handle this. In 3ds max, go into the material editor for the object, there is a color selector to the right of the map file name. Change it to black. An alternate that may work that I haven't tried, assuming you're importing an obj file, in the import window, under materials is a button that says "force black ambient" I think that does the same. Worst case scenario you can photoshop the map file and fill the background with a color similar to your object.. I think

Hope this helps

12

General / Re: Upgrading for speed

« on: June 20, 2016, 06:00:15 PM »

Thanks Alexey,
Right now I'm limited by an LGA 1150 socket and I don't see any chips greater than 4-core for that socket. With a new motherboard (LGA 2011-3) I can get an I-7 6950X which has 10 cores and evidently overclocks quite well. Would PS take advantage of 10 cores over 6?

13

General / Re: Measurements

« on: June 19, 2016, 07:42:06 AM »

Not an answer to your problem, but if your markers are on your model just scale it in 3ds Max

14

General / Re: Manual Photo Alignment and adding photos

« on: June 19, 2016, 07:37:09 AM »

Good idea. I tried just adding the detail shots in a new chunk but they didn't align well. Adding shots from the original chunk should do the trick...Thanks.

15

General / Upgrading for speed

« on: June 17, 2016, 06:45:53 PM »

It’s clear from my growing experience that I need to upgrade my system to get processing results in a reasonable amount of time. I’m currently using a windows system with an i5-4690k @ 3.5ghz with 16gb of memory and an AMD R9 290 graphics card. Increasing memory to 32gb is a must, but which would give me a better performance boost, adding another graphics card or replacing the CPU with say an i7-4790 4ghz.