Producing anaglyphs from synthetic images

Distance learning and virtual laboratory applications have motivated the use of inexpensive visual stereo solutions for computer displays. The anaglyph method is such a solution. Several techniques have been proposed for the production of anaglyphs. We discuss three approaches: the Photoshop algorithm and its variants, the least squares algorithm proposed by Eric Dubois that optimizes in the CIE color space, and the midpoint algorithm that minimizes the sum of the distances between the anagylph color and the left and right eye colors in CIEL*a*b*. Our results show that each method has its advantages and disadvantages in faithful color representation and in stereo quality as it relates to region merging and ghosting. 1. ANAGLYPHS Recent interest in virtual laboratories for distance learning applications have revived research in anaglyphs because the stereo image can be transmitted efficiently, inexpensive viewing devices can be used and several people can view the image simultaneously. Anaglyphs require the user to view the image with glasses having different color filters for each eye. The anaglyph color at a pixel is computed from the left eye color and the right eye color at the pixel. Most filters for electronic displays are designed so that the left eye filter blocks combinations of blue and green and the right eye filter blocks red. Blocking means that the color is seen as black or dark gray through the filter. In the discussion that follows, we use the red/cyan glasses No. 7003 from REEL3D (www.reel3d.com). We assume no depth information in the scene is available. We consider some of the anomalies that may occur in creating anaglyphs from stereo pairs. We ignore the important issue of retinal rivalry2 which can create the appearance of ghosting. We will restrict our attention to CRTs, but the analysis is similar for other color displays that use the RGB color system.