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Topics - janoz

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General / PRJ File
« on: November 29, 2015, 04:03:35 AM »
I am trying to create a new .prj file. I downloaded the desired coordinate . prj from the web When I want to import .prj into agi, it cannt open it. Where am I wrong in my procedure ?

General / Tie points once again
« on: March 05, 2015, 01:12:34 AM »
Having used Tie points config option in v.1.1 for some while I am stil having some problems with understanding this feature. In many cases leaving the default setting at 1000 causes too sparse "sparse point cloud" leading in next step to some inaccuracies in generating dense point cloud espacially in too thin parts of the sparse point cloud. These problems are  mostly solvable by disabling tie point limit feature (setting limit at 0). Is there any additional benefit by the implementation of tie point limit beside speeding up the process (I think in one of the posts it is stated that tie point config automatically filters out "badly" projected points but is  this objective not achievable in better or more controlled way by the application of traditional reprojection error decreasment?) . Is there any other desirable tie point limit setting beside 1000 that would turn out as a good presupposition for dense point cloud generation.
And what is exactly the relation of tie points to key points. If sparse point cloud is determined solely by tie point config why to bother any more about key point config?
I am probably missing some  substantial knowledge on this topic but explanation in user manual especially on tie point is too theoretical for me :(

General / Noisy data
« on: January 14, 2015, 06:01:56 PM »
Recently i have serious problem when documenting flat surfaces - like flat facades covered by fine plaster. Regardless of number of photos and photo setting (i always use ISO lower than 200 and  never higher) i always get big noise on flat areas. On parts of roofs , for instance, there is no problem with the same photo data. This occures only on flat walls with plaster. If a wall  is in "raw" rock material there is no problem. Problem is visible already on sparse pointcloud, where on flat areas only the border lines of particular plaster color borders are visible whereas on roof the density of points is sufficient. It seems to me that the SW cannot determine neccessary amount of tie and image specific points on flat one colour areas. But on the other hand i have seen posts where the guys were able to generate very smooth dense clouds on car models so there must be some solution..... By the way the alignment is always OK

General / Dense point cloud - processing time
« on: January 07, 2015, 08:13:19 PM »
I have an experience :  after optimalization procedure according to GCPs when i start to process dense point cloud once again - the procsseing time is usually 3 or 4 times higher in comparison to the first dense pointcloud generation. Quality parametres remain the same. The situation is accompanied by the log message. "skipping pair: unable to estimate disparity range" which i wasnt aware of before. The situation is the same as tracted in the post:,  but without any further explanation or answers.

I have to stress that i am currently still using  1.0.0 vesrion bacause i am in the middle of the project and dont wanna jump to higher version until i finish it.

General / Reconstruction uncertainty
« on: December 08, 2014, 01:04:09 AM »
Is there by gradual selection using "reconstruction uncertainty" feature all valid desdirable limitation (value) just like by reprojection error (under 1.0) ?

General / Aligning points - point limit
« on: December 08, 2014, 01:01:00 AM »
I would like to ask why is the point limit by the detection of image specific points predefined to 40 000 and if changing this value has an impact upon the results of the alignment step.

General / Sparse and dense point cloud
« on: July 05, 2014, 02:49:59 AM »
I would like to ask if editing of the sparse point cloud does have influence on dense point cloud generation. From purely logical point of view I d think that deleted parts of sparse point cloud are not taken into account during dense point cloud generation. But roughly from "macroscopic" observetaion it seems to me as if deleted parts of sparse point cloud  in some way "reappear" in dense point cloud. Am I right?
What is the relationship between sparse and dense point cloud in the sense of their subsequent dependancy. I have a feeling that a basic source for dense point clouds are source photos rather than sparse point cloud.

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