I believe that fast optimization like in fastPTOptimizer will also be 
available in Hugin in the next official release.

I see fastPTOptimizer and Hugin++ as a possibility to publish my ideas as 
sources and also binaries a bit earlier - for encouraging discussions and 
also because I like using these features for my own panoramas.

Maybe there are some features in Hugin++ that shall not be integrated into 
Hugin for some reasons, e.g. there was a discussion whether weights for 
control points make sense.
Anyway I try to avoid unnecessary changes to the source code in order to 
facilitate a possible integration of my new features into Hugin.

Florian

Tobias schrieb am Montag, 28. Juni 2021 um 17:19:18 UTC+2:

> Hello,
>
> what is the reason, that fastPTOptimizer is not part of the official hugin.
>
> Regards,
> Tobias
>
> Florian Königstein schrieb am Montag, 28. Juni 2021 um 09:31:08 UTC+2:
>
>> Hugin++ is a fork of Hugin that is linked to fastPTOptimizer, a fork of 
>> the libpano13 library.
>>
>> When you have only a small or medium number of images and control points, 
>> the original optimizer does the optimization in a fairly short time. 
>> However if you have a large number of images (several hundrets or even more 
>> than thousand) and many control points, the original optimizer typically 
>> needs much time for the optimization of the parameters.
>>
>> With Hugin++ the time for the geometrical optimization is much shorter 
>> for large panoramas. Speedup factors of 100 or more are possible.
>>
>> Update 28.06.2021:
>>
>> I have added support for weights for control points. The default weight 
>> for each control points is 1. Assigning a weight higher than 1, say 'w', to 
>> a control point is equivalent to have 'w' control points with weight 1 at 
>> the same position. This causes the control point's error to contribute 'w' 
>> times more to the (weighted) sum of squares that the optimizer tries to 
>> minimize.
>>
>> A control point with a high weight tends to have a small error after 
>> optimization - if this is
>> possible. But high weights should be used with care: In the extreme case 
>> that all control points have a weight of e.g. 1000 the optimizer finds 
>> exactly the same parameters as if the control points had the weight 1. What 
>> counts is the relation of the weights for the different control points.
>>
>> What makes sense is assigning higher weights to control points that are 
>> likely placed precisely and lower weights to points that are less precise, 
>> e.g. if the object where they are placed may have moved in the meantime 
>> between shooting the two images.
>> You may also assign high weights to control points on objects where 
>> larger errors would be visually striking - if you are sure that these 
>> objects have not moved much.
>>
>> For example, I have shot photos for a panorama where are trees, a stream 
>> and a bridge over the stream. After optimization without weights for 
>> control points (or all CPs having equal weight) there were visually 
>> striking errors on the bridge. On the other hand I know that the bridge has 
>> not moved noticeably.
>> So I could assign higher weights to CPs on the bridge. Other CPs, e.g. on 
>> the trees, might have moved - especially if they are on leafs of smaller 
>> branches of trees. Of course I tried not to place CPs on leafs but instead 
>> on trunks or bigger branches of the trees. But this in not always possible 
>> - especially if you use a high focal length (low angle of view).
>>
>> Generally, assigning higher weight to a control point can lead to smaller 
>> errors of the CPs - if this it possible. But this is on the cost of getting 
>> larger errors on other control points.
>> If the CP with a higher weight is placed precisely, the increase of 
>> errors on other control points will probably be tolerable. A counterexample 
>> is the following: If a "bad" control point, e.g. an outlier (placed on 
>> different objects) or on a moving object, is assigned a higher weight, the 
>> error for this CP might decrease, but all other errors might increase in a 
>> non-tolerable way.
>>
>> The "weights for control points" feature is currently available in a 
>> development version of Hugin++:
>> https://sourceforge.net/projects/huginplusplus/files/development/
>>
>> Currently the only way to assign weights other than 1 to control points 
>> is changing the weight manually in the "control points" tab of Hugin++.  
>> Control points that are generated automatically, e.g. by CPfind, will 
>> currently have weight 1.
>> A nice task for the future would be to change CPfind so that the control 
>> points get a weight other than 1 automatically. Some algorithm - including 
>> machine learning algorithms - might predict whether the control points 
>> might be on a moving object and how large a possible movement might be. 
>> With this information the CP detector could assign reasonable weights to 
>> the control point.
>>
>

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