Reprojecting equirectangular images for a printed presentation – Scripts

During our talk about “Reprojecting equirectangular images for a printed presentation” in Palmela and Vienna we presented two scripts you can use to reproject images using a so called Droste – effect. See some examples in these posts.

Here is a short overview over the software we used, you can consider this as the required runtime environment for the scripts:

Software Version Platform
The Gimp 2.6.11 Windows; Linux; Mac
Mathmap Plugin for The Gimp 1.5.3 Windows; Linux; Mac
Adobe Pixel Bender Toolkit 2.5.449694 Windows; Mac

One of these is a script for the Gimp’s Mathmap Plugin. The other one is a script for the Pixel Bender Toolkit. The problem with the original two scripts is, that the parameters they use have different names and they are implemented differently! E.g. sizes are pixel sizes in one script and percentages of the image size in the other script. I wanted to be able to use the same parameters in both environments. So I started to bring the scripts back together.

The main motivation for this was to be able to work on large files. The Pixel Bender stand alone version has a size limitation depending on your graphics card. This may be a maximum of 2048×2048 pixels or like in my case 4096×4096 pixels. When you want to process larger images you have to switch to The Gimp. These size limitations do not apply there! The Mathmap rendering on the other hand is really slow compared to the Pixel Bender. This is because Mathmap renders the final image and the preview on a single core of your CPU. The Pixel Bender toolkit renders both on the GPU!

This table shows links to the original scripts (Mathmap V10 and Pixel Bender V1.1) and the modified versions with exchangable parameters (Mathmap V11 and Pixel Bender V2).

Script (Download link) Version Link
Droste for Mathmap (Original) V10
Droste for Mathmap (PixelBender compatible Version) V11 This article
Droste for PixelBender (Original) V1.1 Homepage
Droste for PixelBender (Mathmap compatible version) V2 This article

See two screenshots of some sample settings using Mathmap and Pixel Bender and the original and transformed image:

For an example workflow on how to generate a Droste spiral effect from a 360° panoramic (or equirectangular) image image read this post.

Acknowledegements go to the following persons, who started the first versions of the scripts: Mathmap: breic, Josh Sommers; Pixel Bender: Tom Beddard
You find further information about the Math behind the Droste effect here and here.

Sesimbra Castle Church

This panorama shows the interior of the church of Sesimbra castle. All the walls are covered with beautifully glazed tiles.


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Pousada de Setúbal; Hotel São Filipe

Pousada de Setúbal; Hotel São Filipe; Morning Mist


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Printed Royal Wedding Gigapixel Panorama

This panorma shows a panoramic photographer taking a panorama of Henry Stuart’s printed version of his Royal Wedding Gigapixel Panorama.


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The meeting venue of the Interational Panoramic Photography Festival in Palmela

This panorama shows the meeting venu of the Interational Panoramic Photography Festival in Palmela. It was taken with a pole in the center of the Cine-Teatro São João.

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Reprojecting equirectangular images for a printed presentation

We held a talk at the Palmela International Panoramic Photography Festival: Reprojecting equirectangular images for a printed presentation and also at the PanoTools Meeting 2011 in Vienna.

You can find the video recording of the talk in Palmela here.

The talk showcased the benefits of reprojecting equirectangular panoramas for static presentations. We have presented “simple” reprojections and also two–step reprojections using a series of transformations. An overview was given about the different available tools to reproject panoramas. Numerous “real life” examples were shown, including the original equirectangular image and possible reprojections.

The presented reprojections were based on scripts working with two different tools PixelBender (stand alone or plugin for PhotoShop) and the MathMap plugin for The Gimp.

Download the Droste reprojecting script for PixelBender here: PixelBender Droste Reprojection Script

Download the Droste reprojecting script for Mathmap here: Mathmap Droste Reprojection Script

Gala dinner at the Interational Panoramic Photography Festival in Palmela

This panorama shows one of the tables at the gala dinner of the Interational Panoramic Photography Festival in Palmela. The location is the Castle of Palmela. The image was taken with a little tripod on the table. It should be an easy task to spot both of the Panotwins 😉


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