Posted on 09/28/2008 8:19:34 AM PDT by dascallie
I have given it a lot of thought. Informed thought.
I have claimed that the VP-8 presents the data in a form where the reflected light intensity for each area scanned is plotted, converted if you will, proportionately to the Z axis on a three-dimensional grid where X and Y axes plot the location of that particular scan point. The VP-8 then adds a virtual light source and allows the three-dimensional grid to be rotated and viewed from an position. The DATA are not altered, merely transformed into a more convenient form to visualize. It makes a representation of the data in a two-dimensional plane which can be manipulated to see it better. As I stated you could also plot the data onto a two-dimensional grid in the form of numbers to represent the varying intensities of the reflected light from the image.
One could, and some researchers have, taken the data and plotted it in a REAL three-dimensional grid, taking the data converted from intensity to relative distance from zero on the Z axis, and carving those distances into a block of styrofoam. All the data manipulation is conversion from grey scale intensity percentage to distance from an arbitrary, fxed starting plane on the X, Y axes plane. It is a purely linear function.
I refer you again to the statement of the inventor and designer of the VP-8 Image Analyser:
The VP-8 Image Analyzer can vary the elevation scale (Z axis) relative to the X and Y axis scale. The VP-8 cannot change the linearity of the Z axis response, unless the unit is un-calibrated or the camera is improperly operated. A change of 10 percent in the incoming light level will produce an elevation change of 10 percent on the Z axis. It is a direct, linear function.
I would interpret from that, that a 10 unit change in image intensity from the base background image intensity is plotted as a 10 unit increase in the distance from zero on the Z-axis. That is the algorithm you are seeking.
Oops, I forgot to include the other participants in this discussion to my reply in 301.
Your description bothers me a bit. To fool the human eye into perceiving 3D in a flat image there must be an apparent light source. The light and dark areas of the original image are calculated to have a certain height above the plane of the image, then virtual shadows are applied. Virtual shadows will be applied to the existing image gradients, or the original gradients will be discarded in favor of virtual shadows. The resulting image is no longer the original.
The virtual incident light will have a direction and angle. I remain unconvinced that any angle and direction will produce equally undistorted results with the shroud image. Since none of the sources I have seen mention this possibility, I considered it an unexplored area.
It isn't. The VP-8's results are an extraction of certain data that is embedded in the picture. If the image were the original, then you could see that data in the original. It was not viewable until the those data were extracted from all the other data that makes up a Shroud image, or any image for that matter.
Color data is discarded, texture is discarded, suppleness of the cloth is discarded, only the intensity of the image is retained and its locations on the image. The VP-8 merely extracts reflected light variation data and displays that data in a form that graphically renders slight changes in intensity to changes in distance from the X, Y plane.
Looking at the resulting VP-8 images, I don't think the VP-8 adds a virtual light source; the Z-plot data is both plotted as a distance away from zero and is simultaneously given an equivalent brightness based on the distance from zero, with increases in distance from zero being brighter. This automatically provides the gradient that appears as simulated shadow and which the eye/mind connection interprets as three-dimensional form.
Then you didn't read fully the description Barrie Schwortz, the expert photographer of the Shroud, stated when describing the software that was developed from the VP-8 to allow people with PCs to manipulate the extracted data, that Diamond quoted above:
"And just like a real VP-8, you can turn up and down the gain, rotate the image, or tilt it up and down from flat to vertical."
I assure you, it has been thoroughly investigated, even looked at from inside the face. All angles. The Shroud is, according to many scholars, the most examined and researched single artifact of the last 110 years, with most of this research published in peer-reviewed scientific and scholarly journals, subject to critique and objections about methodology, and corrections.
You can manipulate the data to "distort" the results by changing scale... for example, you can increase the gain on the VP-8 to such an extent that the apparent 3D face is elongated, front to back, beyond human parameters. You can also decrease the gain until it is completely flat, as though you were looking at a resident of Flatland.
According to expert photographers, including Barrie Schwortz, they have found no artifacts created by light in the image. All expert analysis of the shroud image shows that its intensity is inversely proportional to the distance of the body part from the Shroud at the time of the image's formation... with the most intense being those actually in contact with the cloth. The image is, however, somehow collimated, as though the causal factor only operated in the vertical vector.
Un-enhanced, the apparent image fades to background noise after about 4 cm. With enhancement, researchers have been able to distinguish faint body images beyond that 4cm threshold of visibility. Barrie Schwortz told me that unpublished computer enhanced images have shown that the man on the Shroud is circumcized... something that is not visible in un-enhanced photographs. Expert Radiologists, examining the images of the Shroud have pointed out that they can seen the metecarpal bones in the hands, which is also apparent in un-enhanced photographs and is the reason some critics have claimed that the fingers of the Shroud image are too long. There are also faint shadows under the palm area that are apparently the thumbs. These radiologists, expert at reading shadow images, have also discerned the teeth under the lips and the orbits of the eye-sockets, also hidden under the skin.
Raising and lowering the VP-8 "Gain" Control
Cordially,
The only fearure of a flat surface that can cause the human eye to see three dimensions is light and shadow gradients that are consistent with a directional light source. An image in which higher objects are simply lighter will not appear three dimensional.
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