</COMMENT> </CENTER> <CENTER> This applet requires a Java 1.1 browser to function. If you are seeing this message, you are either not using a Java 1.1 enabled browser, you have Java turned off, or the applet is broken ,or you are using a browser that is suppose to work but does not&nbsp; Or you are using Opera and it is working just fine cept you still see this </CENTER> <CENTER>You may consider looking at screen shots if they exist.

After the applet has  (finally) read in the data you will see three images  which are cross sections of a human head.  Each image is surrounded by a  rectangle colored red, green, & blue. These correspond to the front, top and  side views of  planes through the center of the 3D solid.  When the mouse is dragged on these images the colored cross hairs (which appear whenever the mouse is in the applet) will move to follow the mouse.  The other  two images will update so that they contain the planes indicated by the cross hairs on in the image that the mouse is in. These three images will collectively be referred to as the orthogonal images.

You will also see two buttons marked "Reset" and "Refresh" as well as two check boxes marked "Depth Cue" and "Arbitrary Image". The check boxes are to accommodate various levels of hardware and patience. (I am not offering the thread bomb version.) By default,  neither check boxes are selected. You may want to first play around a bit with just the orthogonal images , then the Depth  Cue  then the Arb Image and finally both.

If you check the  "Arb Image" box a fourth "arbitrary image" will appear surrounded by a yellow rectangle,  underlined  by a cyan line and  flanked on the right by a magenta line. The cross hairs in the orthogonal images will switch to three lines (cyan, magenta,  and yellow) emanating from your current location within the model (called a "axis cross hair"). The behavior of the orthogonal images is just as it was except the arbitrary plane also moves to contain the common point of the orthogonal planes at the center of the arbitrary image. You can also drag the mouse on the arbitrary image which does not cause any change in the orthogonal images but does cause the arbitrary plane and hence the cross hairs to rotate about the common point.  Dragging the mouse on the arbitrary image causes rotation of the arbitrary plane about the point at the center of the arbitrary image.

If you check the "Depth Cue" box, all three or four images of the model are subject to being updated with information from "deeper" within the model.  The behavior of dragging on the orthogonal and arbitrary images is still as it was, except that when the mouse button is released images may again be updated as follows. If a pixel in the image falls beneath a certain threshold of  "brightness" the applet starts looking for a brighter voxel in the direction (within the model) you were heading.  The applet also keeps track of how far it has looked and if it finds a brighter voxel it darkens it proportionately to how far it had to look before replacing the dark pixel of the original image with the color of the found and darkened voxel.
note: deeper for arbitrary image the is the direction from your current location  along the yellow axis.
Applet coding by Tom Conlin