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| Choose the option "Autostereogram" entry in the menu bar and a dialog appears which enables you to create real Autostereograms.
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| All pictures generated with CyberMotion are, in fact, created on a three-dimensional basis but become just two-dimensional illustrations.
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| To really see a three-dimensional picture, two separate pictures must exist - one for the left eye and one for the right. Conventional methods are primarily two separate pictures in stereoscopic, virtual reality helmets with two built-in screens, or the calculation of red-green pictures, with which filter glasses for the left and right eye individually filter out the red and green portion, so that two separate pictures are formed again and the 3D impression is obtained.
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| However, there is also a method with which you can obtain a real three dimensional impression from a two-dimensional picture-presentation - so-called Autostereograms. In an Autostereogram the pixels required for the "stereo-views" for both eyes are combined within one picture.
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| Rendering of an Autostereogram proceeds as follows: Instead of only rendering a "picture-point", the depth-information of the scene is also used, and two horizontally-separated picture-points are rendered for every screen depth-value. These two points are given the same color-value. The three-dimensional effect for the point originates provided that the left eye observes the left picture-point and the right eye the right.
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| There are two possibilities you can consider enabling you to see the points truly separately with both eyes:
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| · | By deliberately unfocusing the eyes (looking through the picture into the distance) the scene resolves and both eyes see specific points.
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| · | The same can also be obtained by squinting. However, the depth information is inverted by this method.
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| Both viewing methods are not accessed without practice. Some tips that should enable access to the "concealed" picture-information follow at the end of the chapter.
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| The raytracing algorithm is used to determine the depth values of the picture. It specifies this time, however, only the depth-value of each picture screen-pixel for the scene. The depth value is computed first for both eye-points. To get the three-dimensional impression these must both be set to the same color. Here the eye-points for the left and right eyes lie on the left or right respectively of the relevant screen depth-point and, on rendering, the pixel colors do not refer to material-colors or to any effects like reflections, shadows etc. They serve no purpose, because the resultant picture is split on rendering anyway. Instead, you can choose if a random color or a texture is used here.
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| Despite raytracing, a very much higher speed is reached here on rendering by relinquishing all effects.
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| The "depth-resolution" of the picture is very dependent on the screen or printer resolution in dpi.
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| dpi = dots per inch (points per inch), 1 inch = 2.54cm.
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| This resolution indicates how many points per 2.54 cm your printer can show and is used in the picture rendering. It is important to know the resolution the printer regarding the pixel spacing in order to calculate both rendered eye-points. Fixing eye and projection-plane spacing enables the pixel spacing for left and right eye pixel to be determined exactly.
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| It follows from this that you must have previously specified the resolution at which you will render the picture. For example, if the picture is rendered to be viewed on the screen with 70 dpi, you could not print it out later with 300 dpi, because then the eye-spacing set for the points will no longer be correct. On the other hand you would not be able to recognize the depth information of a picture on the screen if it had been calculated for a denser resolution of 300 dpi - because the screen resolution simple could not represent it.
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| Autostereograms are expensive on storage space. As already mentioned above, the depth-resolution is dependent on the print resolution of the printer. Monitor resolutions of about 70 dpi have only very low depth-resolution and it is noticeable that the scene appears as a sort of layered model - a sphere, for example, appears to be formed from a number of thick disks. If higher resolutions are used (for example 300 dpi) the depth resolution is good. However, there are again the consequences normally associated with high resolutions. A resolution of around 3500* 2500 picture-points is required to render a DIN A4 picture at 300 dpi, for example. Autostereograms are rendered as True Color-pictures, which signifies a storage area of around 25 MB (uncompressed TIF) at this resolution.
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| When composing the scene, you should also consider that only limited depth-resolution is represented. If, for example, you set up objects arranged over a great range of depths, the spacing of the depth-steps can be so high that details of objects can no longer be recognized. The objects to be represented, therefore, should be quite compact and not far from each other.
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Resolution
| You can determine the resolution for distribution, at which the picture is to be rendered in dpi, using the "Resolution" parameter.
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| The value for a normal 14" screen at 640 x 400 picture-points should amount to approximately 65-70 dpi. You can determine the precise value by the following: Visible screen-width in cm. divided by 2.54 gives the result in inches. Divide the screen-resolution in pixels (only horizontal resolution is important) by the value calculated.
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| Example:
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| 2.54 cm x 640 pixel horizontal resolution = ca. 68 dpi
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| 24 cm screen width
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| The object-depth of the scene is automatically adapted and scaled to the depth-resolution. You can, however, obtain more precise variation of the depth-resolution with the Depth parameter. The greater the value, the deeper the picture appears to be. Values between 0.30 and 0.40 seem to produce the best pictures. At greater values it is no longer easy to get a completely sharp picture. Instead, you have to attempt to dive downwards into the depths with individual objects and continually have to adjust your eyes for each depth.
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| With the "patterns" selection box you can decide to use random colors or a texture for coloring of the individual picture pixels.
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| Random Colors: If you use the random-color algorithm to color the individual picture pixels, an incoherent picture is rendered with no recognizable pattern. The picture appears on first glance to be entirely blank, as neither texture nor any other structures give a hint that it hides a complete three-dimensional picture. The absence of recognizable structures has, however, one further advantage - the eyes are not distracted by the structure of the texture, therefore when viewing an Autostereogram it makes it much easier for "beginners" to unfocus their eyes. When beginning for the first time, therefore, on each occasion generate an Autostereogram using random colors.
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| Instead of random colors you can produce an Autostereogram using random gray-scale or monochrome. For those that do not display their pictures and also do not have a high-quality color-printer, the monochrome mode is certainly relevant, because the depth-information of the picture still remains clearly recognizable in the monochrome-mode with only black and white points. The picture-file, however, is always saved as 24 bit TRUE COLOR data.
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| Textures: Textures can also be used for the color-determination of pixel-pairs. Simply choose the <Texture> entry in the "Patterns" popup dialog.
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| Peculiarity of textures: Depth perception is based on pixel-pairs of the same color. If, however, you now get two pixel-pairs of the same color value lying side by side, then the picture loses its information value. From this it follows that the texture should be very detailed and variable in the horizontal direction. This is required only for the horizontal resolution, however (in the vertical direction there are no such limitations). Taking it to the extreme, you could even use a texture that was composed of nothing but colored vertical lines.
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| The application of textures makes a further special circumstance available. A constant value (E/2) for the depth-value calculated for the pixel spacing for pixel-pairs of steps "completely at the back". When the texture is scaled at this value the completed picture appears to be regularly tiled. (At least for the areas that lie entirely at the back). CyberMotion, however, again offers you the possibility of trying out any combination:
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| Tiles: The textures for scaled tiles are based on the above-mentioned spacing. You can, however, also eliminate the tiling and use entire pictures as textures. However, a breakup of the picture then occurs through the effect of the pixel-pairs and their calculated eye spacing intervals. Nevertheless it can result in interesting effects. A project you can try out sometimes, is to first render a completely normal raytraced picture of your scene (i.e. wealth of detail output) and then use this picture in a second operation as the texture from which to render an Autostereogram If you have switched on tiles, then you can still choose from under following scaling-types in the "tile-width" selection box:
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| · | 1: 1: The tile-texture is used in its original state.
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| · | X = E/ 2: The tile-texture is scaled horizontally in the method described above, so that it results in a regular tiling of the whole picture in horizontal direction.
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| · | X, Y = E/ 2: The standard: The texture is scaled horizontally and vertically, in the above mentioned method.
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| Bitmapfile
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| In order to use a bitmapfile as a texture-pattern, proceed in exactly the same way as when selecting bitmapfiles for object-textures. Here again, the bitmap files used must be available in one of the 4 pre-defined paths. You need only choose the "Bitmapfile" field and select the file from the file selection box that appears.
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| Picture or animation rendering is started directly from the dialog. Once you have set things up you can operate the "Render" <Picture> or <Animation> button and insert the picture or video file format and path in the file selection box that appears. Everything else then operates exactly as when rendering a normal raytracing. In the Render Options dialog the settings for the picture resolution in pixels and the "Control Picture" <Off> button are relevant - all other settings are ignored when rendering the Autostereogram
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| Example: A little bycicle is hidden here
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| Some eye-gymnastics can be necessary to see Autostereograms. Try the following exercise: Holds your forefinger at reading distance and fix your eyes on it. The forefinger represents the Autostereogram. It appears sharp because your eyes are focused on it. However, you cannot see the forms on the Autostereogram. Now look past your finger at a far distant object. If you focus on this object, your finger becomes blurred and is seen in double. Depending on the distance of the object you are looking at, your eyes look further or less apart. The same is true for the blurred views of your finger. It is precisely through this eye-movement that you can focus your eyes on the pixel-pair of an Autostereogram and recognize the latent depth-information.
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| The speed with which you learn this process depends entirely on the individual. Many find the hidden picture at once, others need several minutes for the first time until they have the knack, and a very small percentage of people cannot develop it at all. In each case you loose everything if you try too hard, because if you try to look for the objects and force the picture to appear, inevitable you will not relax the eye muscles (which is required for separating the eyes).
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| An interesting effect is the transition, as the picture appears slowly and blurred and then suddenly becomes sharp. The outlines of the picture are first recognized then the eye is automatically drawn into the picture - as it views a normal picture.
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| · | At first it is easier to view pictures with incoherent random colors, as the eyes are not distracted by textures, which you normally instinctive and automatically focus on.
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| · | First hold the picture right at the tip of your nose and look "through" the picture. Then try to maintain this eye spacing while you slowly and steadily move the picture further away.
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| · | Sometimes light-reflections appear in your picture or presentation screen so try to focus on them - this will also enable you to obtain the effect.
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| · | Many people find it is easier to squint than to relax their eyes to achieve the spacing. The depth-information can also be found by squinting, however the depth-information is reversed by it (from a consensus it is hollow). Furthermore, consciously remaining cockeyed is quite tiring and can rapidly lead to headaches.
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