Re: Clouds in hi resolution pano (Celeste 2.0?)

Yuv escreveu:
> hi all,
>   
    Hi! See point 2 below, please.
> I'm currently dealing with a lot of clouds (when traveling quickly
> through many locations I have no other choice than take the meteo
> conditions as they are). Since the introduction of Celeste (that works
> great, thanks Tim!) this is no longer an issue for the proper
> alignment and stitching of everything but the clouds. However in multi-
> rows high resolution shots the clouds end up being an issue at the
> blending stage. The rows become visible.
>
> The lazy way to deal with this is to mask out the sky and replace it
> with whatever photo editor is at hand, but the result inevitably looks
> artificial (shade zones on the mountains and so).
>
> When Tim was coding Celeste, we sparred about what kind of mask should
> Celeste generate around the clouds, if any.
>
> Now, having such a mask could be useful for the following idea,
> assuming the clouds movement is constant throughout the photoshooting:
> 1. generate control points for the static parts in the image. Use them
> to position the images in relationship to one another and create the
> master panoramas, using Celeste to prune CPs from the clouds and mask
> the coulded areas.
> 2. generate control points in the clouds (area masked by Celeste) and
> calculate the translation related to the positioning in 1 (which is
> the translation vector multiplied by the time differential between the
> reference image and the current image)
>   

    Ok, but, if I don´t misunderstood: in the perhaps usual case of wind
in mainly the same direction and speed, if someone take shots for a 360
deg panorama, the algorithm has to deal with many cases: clouds
approaching the camera, then (say, rotating camera clockwise) coming
from left, then going farther, then coming from right, and at 360=0
again towards the photographer. I think that any solution to this
problem - cloud movement at 360 degrees apnos -  would "distort" the
sky  somewhere in the result.
    But, in other cases, when clouds are always going in the same
direction/speed, this solution is great!
> 3. use the translated cloud images to generate an additional panorama
> of the sky
> 4. mask the sky out from the static panorama and add the sky panorama
> as a layer
>
> there will be some areas of the sky that will be "empty" (e.g. when a
> cloud moves behind an object or out from it), but those will be much
> smaller areas to deal with in an image editor than generating the sky
> artificially or dealing with the shift across all images.
>
> to do this we need:
> - an additional category of CPs to compose the sky panorama (sky-CPs)
> - a measurement of the displacement of those CPs related to the
> position of the image in the static pano
> - some math to average / optimize the displacement measures
> - some glue/script to generate the second panorama
> - a tool to mask the sky from the rest of the panorama (I don't think
> that Celeste's mask are fine enough for that).
> - some glue/script to add the mask and the sky to the resulting
> panorama.
>
> does this sound logic? or have I missed something? should I record
> this as a feature request? maybe a future GSoC project?
>
> Yuv
> -
>   

    Thanks for your attention,

    Luís Henrique

--
Luis Henrique Camargo Quiroz, M.Sc. - Internal Combustion Engines Group
IPT - Sao Paulo State Technological Researches Institute
phone: 55-11-37674391  fax: 55-11-37674010  www.ipt.br  BRAZIL
http://luishcq.tripod.com - http://www.christusrex.org/www2/cantgreg



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