With recent advances in photography and sensor technology, high dynamic range images are becoming more and
more common. In order to view such images on low dynamic range displays, there is a need to reduce the dynamic
range of the images. An algorithm for high dynamic range reduction has been developed by Image Registration
and Fusion Systems that subdivides an image into subimages and maps shadings in each subimage to a lower
dynamic range while maximizing image entropy. The mapped subimages are then smoothly stitched together to
create the low dynamic range image. Image blending is used as the means to smoothly stitch the subimages
together. The main characteristic of this mapping is that it preserves chromas while reducing dynamic range in
shadings (luminances). An example of high dynamic range reduction by this algorithm is given below. Fig. 1 shows
the high dynamic range Stanford Memorial Church image when mapped to a lower dynamic range by this
algorithm. The original high dynamic range image may be obtained from www.debevec.org/Research/HDR/. The
software comes with an image viewer capable of viewing and saving a converted image in many formats including
jpg, tif, gif, png, rgb, and ppm.
more common. In order to view such images on low dynamic range displays, there is a need to reduce the dynamic
range of the images. An algorithm for high dynamic range reduction has been developed by Image Registration
and Fusion Systems that subdivides an image into subimages and maps shadings in each subimage to a lower
dynamic range while maximizing image entropy. The mapped subimages are then smoothly stitched together to
create the low dynamic range image. Image blending is used as the means to smoothly stitch the subimages
together. The main characteristic of this mapping is that it preserves chromas while reducing dynamic range in
shadings (luminances). An example of high dynamic range reduction by this algorithm is given below. Fig. 1 shows
the high dynamic range Stanford Memorial Church image when mapped to a lower dynamic range by this
algorithm. The original high dynamic range image may be obtained from www.debevec.org/Research/HDR/. The
software comes with an image viewer capable of viewing and saving a converted image in many formats including
jpg, tif, gif, png, rgb, and ppm.
Fig. 1. (a) Dynamic range reduction of the Stanford Memorial Church image. The original of image is courtesy of
Paul Debevec, debevec.org.
Paul Debevec, debevec.org.
With this software it is also possible to interactively change the image intensities while viewing the displayed
image. Intensity changes can be additive, multiplicative, exponential, or a combination of them. For instance,
brightening the image in Figs. 1 interactively the image shown in Figs. 2 is obtained.
image. Intensity changes can be additive, multiplicative, exponential, or a combination of them. For instance,
brightening the image in Figs. 1 interactively the image shown in Figs. 2 is obtained.
| Fig. 2. Brightening of the images in Fig. 1 by this image viewer. |
To obtain a license for this software, please follow the link=>
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| High Dynamic Range Viewer |
| Image Registration and Fusion Systems |