3 research outputs found
Volumetric high dynamic range windowing for better data representation
Volume data is usually generated by measuring devices (eg. CT scanners, MRI
scanners), mathematical functions (eg., Marschner/Lobb function), or by
simulations. While all these sources typically generate 12bit integer or
floating point representations, commonly used displays are only capable of
handling 8bit gray or color levels. In a typical medical scenario, a 3D
scanner will generate a 12bit dataset, which will be downsampled to an 8bit
per-voxel accuracy. This downsampling is usually achieved by a linear
windowing operation, which maps the active full accuracy data range of 0 up to
4095 into the interval between 0 and 255.
In this paper, we propose a novel windowing operation that is based on methods
from high dynamic range image mapping. With this method, the contrast of
mapped 8bit volume datasets is significantly enhanced, in particular if the
imaging modality allows for a high tissue differentiation (eg.,
MRI). Henceforth, it also allows better and easier segmentation and
classification. We demonstrate the improved contrast with different error
metrics and a perception-driven image difference to indicate differences
between three different high dynamic range operators
Abstract Volumetric High Dynamic Range Windowing for Better Data Representation
Volume data is usually generated by measuring devices (eg. CT scanners, MRI scanners), mathematical functions (eg., Marschner/Lobb function), or by simulations. While all these sources typically generate 12 bit integer or floating point representations, commonly used displays are only capable of handling 8 bit gray or color levels. In a typical medical scenario, a 3D scanner will generate a 12 bit dataset, from which a subrange of the active full accuracy data range of 0 up to 4096 voxel values will be downsampled to an 8 bit per-voxel accuracy. This downsampling is usually achieved by a linear mapping operation and by clipping of value ranges left and right of the chosen subrange. In this paper, we propose a novel windowing operation that is based on methods from high dynamic range image mapping. With this method, the contrast of mapped 8 bit volume datasets is significantly enhanced, in particular if the imaging modality allows for a high tissue differentiation (eg., MRI). Thus, it also allows better and easier segmentation and classification. We demonstrate the improved contrast with different error metrics and a perceptiondriven image difference to indicate differences between three different high dynamic range operators