Adding a nadir cap (mirror ball)

Photoshop

I wrote a Photoshop action that produces these mirror spheres below out from an equirectangular panorama.
As you can see are three sizes available.




Small covers 5% ,Big 8% and XXL 12% of panorama height (equirectangular projection)
Below you can see the region that will be covered with the mirrorball.




Here the action set in Photoshop:



Download the Photoshop action here:
Media:cap.atn

A similar action with text:
Media:cap_text.atn

For a flexible nadir cap which can be streched to your needs:
Media:CapFlex.atn

Don't know how to install a Photoshop action?
Take a look at How to install actions in Photoshop


Worklflow
1.) Open equirectangular / psphere image in Photoshop
2.) Run desired action (small / big / xxl))
3.) Save as....
4.) Finished


Peter Nyfeler (Pitdavos)

ImageMagick

I wrote an ImageMagick Windows batch-file to add a mirror sphere to an equirectangular panorama:

set im_convert="C:\Program Files\ImageMagick-6.5.8-Q16\convert.exe"
set input_image=post_processed.tif
set output_image=nadir_balled.tif

rem Make the mirror ball.
rem	-crop		takes the part of the image without the nadir
rem	-resize		resizes the image to height of the nadir
rem	-flip		flips the image vertically
rem	-level		darkens the image, because reflection is never 100 percent
%im_convert% %input_image% -crop 12780x6130+0+0 -resize 12780x260! -flip -level 0,130%% temp_nadir_ball.tif

rem Make a gradient image from black to transparent. This is the ambient shadow that is casted by the mirror ball.
%im_convert% -size 12780x130 gradient:none-black temp_gradient.png

rem Place the shadow and the mirror ball on the image
%im_convert% post_processed.tif -page +0+6070 temp_gradient.png -flatten -page +0+6130 temp_nadir_ball.tif -flatten %output_image%

del temp_nadir_ball.tif
del temp_gradient.png

pause

Before using it, please adapt the following in the batch-file to your situation:

• the location of ImageMagick's convert.exe
• the input panorama image name
• the output panorama image name
• the size of the panorama without the nadir cap (12780x6130)
• the size of the nadir cap (12780x260)
• the size of the ambient shadow (12780x130)
• the position of the ambient shadow on the output panorama image (+0+6070)
• the position of the nadir cap on the output panorama image (+0+6130)

Here's an example of a mirror ball created in this way:



Bert Knops