The aim of Windowing is to take image or volume data with a high number of brightness values and to reduce these to just 256 brightness values, so that they may be displayed on computer screens or printed. We present an algorithm which is based on the well known Reinhard method and extend it to work on a large variety of data. In our focus are normal images, medical volumetric datasets and curvilinear grids. We compare our algorithm with other existing methods from Ashikhmin and Durand to demonstrate its quality and artefact freeness.

The algorithm works in both two and three dimensions. Because the speed of gaussian filtering (the central part of the algorithm) is especially crucial with large medical volumes, we tested different approaches to maximise its speed. For 3D volumes a separable convolution in the spatial domain proved to be superior to a frequency domain convolution with fast fourier transformations. Our implemented algorithm works in linear time (not cubic) for any width of the 3D filter kernel.





  Hdrw (Win32)     Hdrw 1.01 for all versions of Microsoft Windows. 3.24 MB
  Hdrw (Unix)     Hdrw 1.01 compiled under Suse Linux 9.1 (Intel IA-32 platform). 5.17 MB



Full featured description of the program and the algorithms in the PDF format. Optimized for double-sided printing. Update 2004/12/05. (German)

<40 MB
  LowRes Report     Same as above but the images have reduced size and quality, for low bandwidth connections. <10 MB
  Report Images     All Images, which are shown in the report, as PNG files. <200 MB
  Medical Volume     1 medical volume, Sample of the following archive. 14.9 MB
  Medical Volumes     5 three-dimensional medical volumes. (Source: Dirk Bartz) 190 MB
  Color Image     1 color image, Sample of the following archive. 1.71 MB
  Color Images     17 two-dimensional color images. After loading press Alt+C to view the images in color. Then we recommend to set Gamma to 2,2 or 2,5 and to activate Color Gamma Correction. (Source: Erik Reinhard) 114 MB
  Curvilinear Grids     15 scientific volumes with curvilinear grids. (Source: NASA) 5,28 MB
  Source Code     Source Code of the program. For Details see ReadMe.txt within the archive. 4,89 MB


  Creators in randomized order

Many thanks to our supervisor Dirk Bartz, who had the idea for Hdrw.

Ludwig Gauckler (Ashikhmin and Durand methods)
Benjamin Schnaidt (Overall base program)
Jirko Cernik (Curvilinear grid support)



E-Mail Benjamin
E-Mail Jirko
E-Mail Ludwig


Hdrw Copyright 2004-2005 Benjamin Schnaidt (, Jirko Cernik (, Ludwig Gauckler

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