Anamorphosis

Description

Anamorphosis is a distorted image projection or perspective, which appears in its true form when the viewer use special mirrors or occupy a specific vantage point to the anamorphosis. "Ana - morphosis" comes from the Greek words meaning "formed again."

Sometimes anamorphosis objects are integrated into an normal scene, as for example in Hans Holbein's well known painting "The Ambassadors" (Figure 1). Standing directly in front of the painting and looking on it, anyone would recognise all of the objects and people shown in it, except one distorted shape at the bottom of the image. However, viewing the painting from an acute angle transforms the distored shape into the simple form of a human scull.

In other cases the deformed object dominates (e.g. Schön's portraits of Charles the V, Ferdinand the I, Pope Paul the III and Francis the I included in the Vexier painting shown in Figure 2) or is surrounded by regular scene elements, as in the case of Schrot's portrait of Edward VI (Figure 3).

The Ambassadors Schön's Vexier painting Edward VI
Figure 1: Holbein's The Ambassadors Figure 2: Schön's Vexier painting Figure 3: Schrot's Edward VI

Figures 1 - 3 represent one of the two main types of anamorphosis images: the perspective (oblique) anamorphosis, that can be seen in the original form when viewed upon in a certain angle. The second type the catoptric anamorphosis uses a curved mirror, usually of cylindrical or conical shape, to restore the anamorphosis to the undistorted form, as shown in following figures.

Cylindrical anamorphosis Conical anamorphosis Jules Verne
Figure 4: Cylindrical anamorphosis Figure 5: Conical anamorphosis Figure 6: Cover to Mysterious Island from Jules Verne

In the past only artists who had the mathematical knowledge of creation such anamorphic images could construct and paint over and over again perspective or catoptric anamorphosis. Also the reconstruction manner was a well protected secret. Therefore, some artists used the distortion of original objects to fill the paintings with tenuous contents e.g. to criticise the government without being exposed. However, today anybody can create anamorphic pictures using mathematical description given by J. L. Hunt, B. G. Nickel and C. Gigault from the Department of Physics on the University of Guelph, Canada. By current computer technology also the resulting computational process is not a big task anymore. Thus, the algorithmic approach had been used by students of Friedrich-Alexander-University, in the seminar "Architectures of multi- and many-core-processorsystems" held in summer term 2010, to get the most out of the accessible computational performance of different multi-core systems. In four two-three people groups implementations of the Hunt-Nickel-Gigault algorithm for the IBM Cell BE, Intel's Core i7 and NVidia's general-purpose graphical processing units (GPGPU) were developed and optimized by adjusting to corresponding hardware elements. By transforming successive frames even a video can be transformed to a anamorphic representation, as shown in following animation.

By S. Hofmann and J. Harazny transformed music clip using NVidia's CUDA-capable GPGPUs.

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Contact

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E-Mail: max.schneider@informatik.uni-erlangen.de