Problem with Hemisferic Photos

[JuanManuel Cellini]

Hello at every body

Im working with Hemisferic photos in forest canopy. My problem is that my camara is not a Full Frame camara and my photos arent a circle. And becouse of that I have to take 2 pictures to have the circle that I cant procesing with other soft.

When I try to merge the two photo with this tutorial,

http://hugin.sourceforge.net/tutorials/scans/en.shtml

Assistant - Load Images
Open 2 imagenes
Lens = Normal (r)
Focal L = 100 mm
Focal M = 1 x
Press boton Align

Preview TAB to see if everything is OK

Boton Move / Drag
I Move the image to the center
Press "Fit"
Press "Crop"
Auto crop
select all the image
Assistant -  3. Create panorama
JPEG 95% (o Preferencias - Stifching - JPEG 95%)

Everything was OK. But when I make the "Create Panorama" the software make a photo very different from the photo I saw in "Preview" Tab

How can I keep the "Preview" Photo??
I dont want to keep the HDR nor LDR photo.

Thanks!

[dkloi]

Why are you using the instructions for stitching together scanned documents? I assume you're using a fisheye lens to take upward shots of the forest canopy? You need to stitch them as you would a normal (partial) panorama using the right lens parameters like the lens type (fisheye) and focal length.

If you post some example photos and the information about your photo taking equipment and setup, we may be able to help.

[JuanManuel Cellini]

Thanks for your Reply Dklol.

I post 2 print screens of my problem, 2 original photos and 2 Stitch as result.
I managed to use the data I post (Lens = Normal (r) Focal L = 100 mm Focal M = 1 x) becouse I had better results stitching the pictures. But the problem itself is the product. As you can see, the best result I had is the preview in the print screen.

Why? Becouse I need to measure Forest Cover, and as you can see, only the preview picture without the PHOTOMETRICS is the best.

How can I save this preview picture?

Thank you very much.

Manuel.



I

[Bruno Postle]

The problem is that Hugin is trying to correct vignetting, but your photos overlap perfectly and this is giving bad vignetting parameters (Hugin expects partial overlap).
You need to use the 'advanced' Hugin option and use the 'reset exposure and vignetting' function before stitching.

The 'rectilinear' lens type is working for you because your photos have the same centre, but if they are even slightly misaligned you will get much better results with a 'fisheye' lens type.
Also if you use the right lens geometry Hugin can do other useful things you might want, like output an equal area projection.

I would recommend calibrating this lens by stitching a normal panorama and saving these parameters for future projects, this will save a lot of time and give consistent better results.

--
Bruno

On 29 March 2016 12:06:13 BST, JuanManuel Cellini wrote:
>
>Thanks for your Reply Dklol.
>
>I post 2 print screens of my problem, 2 original photos and 2 Stitch as
>
>result.
>I managed to use the data I post (Lens = Normal (r) Focal L = 100 mm
>Focal
>M = 1 x) becouse I had better results stitching the pictures. But the
>problem itself is the product. As you can see, the best result I had is
>the
>preview in the print screen.
>
>Why? Becouse I need to measure Forest Cover, and as you can see, only
>the
>preview picture without the PHOTOMETRICS is the best.
>
>How can I save this preview picture?

--
Bruno

[dkloi]

Here's an equi-solid-angle output projection of stitching the two source photos.

Are you using a panohead? I had some significant optimization errors, could be due to parallax. I had to guess at a focal length (8mm) and crop factor (1.5).

After creating your control points, just do alignment optimization, and skip the photometric optimization (what Bruno said). Then when you stitch, you should get what you're after. It's straightforward to do in Expert Interface mode. 

[JuanManuel Cellini]

Thank you very much Dklol & Bruno.
After 5 minutes I finaly find where the settings must apply.
I attach a photo of where is the "skip the photometric optimization"

Thanks!

PS: All this work I used to do in ArcView 3.2 with Image Analisis Add On. I simply georeferece the two images and export as mosaic... 30 minutes each image.

[dkloi]

Here's a step by step guide:

Open Hugin

Set the interface to be expert

Add images

Set the lens parameters when asked. What lens/camera combination are you using? I'm guessing 8mm and 1.5 crop. Choose circular fisheye.

Got to Masks tab. For each image, use the crop tab and drag the edges of the crop box and the crop circle to crop out the corners.

Go back to Photos tab.

Create control points (Hugin CP Find)

Optimise positions (incremental, starting from anchor)

Go to the stitcher tab

Change projection to what you need (I assume equisolid)

Change horizontal field of view to 180 degrees

Change canvas size to something like 3000x3000 (of whatever suits your input image size)

For panorama output options, only tick Exposure corrected, low dynamic range

Choose your output format

Press stitch.

It's about 2 mins worth all in all (depends on how fast your computer is to stitch). You can automate the whole process but someone else would have to explain the command line options and batch files required.

[JuanManuel Cellini]

Thanks Dklol,
Its less than 2 minutes per pair of images.

Problem solved.

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Juan Manuel Cellini
UNLP - JTP - Biometria Forestal
UNCa - Profesor Titular - Gestion de Recursos Naturales

Edificio de bosques Piso 1 Calle 130 # 469
La Plata B1904DPS Argentina

http://scholar.google.es/citations?user=LKrlm24AAAAJ