© Steffen Weber, February 1999
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This applet was inspired by Dr.Conradin Beeli, who used this method on transparencies as a Moirée-analogon to holography.
Usage:
Select an example image from the choice box or click "new drawing" for drawing your own image. Then click "encode image". The right window will then show the the encoded image (object wave=line grid modulated by the image) and overlay a linegrid (which serves as coherent reference wave). Thus the original image can be reconstructed when the overlayed grid has a suitable translation (phase shift). You may use the sliders to modify translation and rotation of the overlayed line grid.
This applet uses a phase shift of 120deg=2Pi/3=1pixel for the encoding. The line spacing of the grids is therefore 3 pixel.
Note that this is just a simple demonstration of the principle. The visual effect is limited by the screen resolution and pixel size. If you do the same on transparencies (using PostScript language for example) it will look much nicer and it is not so easy to make out the contours of the encoded image as it is here.