Viewers can cross their eyes behind the image plane, thereby inverting their depth perception but still resulting in a 3D image. But in an SIS, because the separation between the strips is smaller than the distance between our eyes, there is an alternative, more comfortable way to view the image. With stereo photography and classic RDS images, viewers must always cross their eyes in front of the image plane. Actually, an RDS pair works just like an SIS with two strips. These differences allow the perception of depth.įigure 41-5 Viewing a Stereogram with Four Stripsįor an RDS, the eye crossing point must be farther in front of the image plane (that is, closer to the viewer) than in an SIS, so that the displacement of the images seen is the size of the image itself. Our eyes are separated from each other by about 65 mm, and this disparity causes slightly different images to be presented to the brain. The idea behind stereo photography is to take two similar photographs, but from different positions displaced horizontally (like our eyes). Stereo photography is very old, dating back to 1838, but some of the old stereo cameras and stereo photograph viewers, such as the one shown in Figure 41-1a, can still be found at antique shops. Stereograms evolved from stereo photography, in which two photographs are taken from slightly different camera positions (representing the displacement between our eyes). It all started back in the 1960s, when Bela Julesz, who worked at (AT&T) Bell Labs researching human vision-particularly depth perception and pattern recognition-created the random-dot stereogram (RDS). 41.1 What Is a Stereogram?Ī stereogram is a 2D image that encodes stereo information so that, when viewed correctly, it reveals a hidden 3D scene. The CD content, including demos and content, is available on the web and for download. You can purchase a beautifully printed version of this book, and others in the series, at a 30% discount courtesy of InformIT and Addison-Wesley. One of the most common ways to create a stereogram is to hold both of your index fingers in front of you with the tips touching and cross your eyes to create the illusion that you have an extra finger.GPU Gems GPU Gems is now available, right here, online. Salvador Dalí created some impressive stereograms in his exploration in a variety of optical illusions. Magic Eye books refer to autostereograms as stereograms, leading most people to believe that the word stereogram is synonymous to autostereogram.
5d stereogram series#
The Magic Eye series is a popular example of this. Stereograms were re-popularized by the creation of autostereogram on computers, where a 3D image is hidden in a single 2D image, until the viewer focuses the eyes correctly. These stereoscopes were immensely popular for decades. invented an improved form of stereoscope in 1861, which had no mirrors and was inexpensive to produce. He found an explanation of binocular vision which led him to construct a stereoscope based on a combination of prisms and mirrors to allow a person to see 3D images from two 2D pictures. Stereogram was discovered by Charles Wheatstone in 1838. One of the most common ways to create a stereogram is to hold both of your index fingers in front of you with the tips touching and cross your eyes to create the illusion that you have an extra finger. Other types of stereograms include anaglyphs and autostereograms. Originally, stereogram referred to a pair of stereo images which could be viewed using stereoscope. A stereogram is an optical illusion of depth created from flat, two-dimensional image or images.
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