3dmodv Stereo Dialog

This window provides control over two or three kinds of stereo displays, depending on whether the graphics hardware supports stereo. The combo box allows one to turn a particular kind of stereo on or off, the Angle slider allows one to adjust the angle of parallax between the two views, and the Vertical Offset slider allows one to adjust the offset between views in top/bottom stereo to bring the views into register when the monitor does two vertical scans per frame.

SIDE-BY-SIDE: This mode is the default when no internal or external hardware seems to available. Some people may find this useful if they can fuse the two images somehow.
TOP/BOTTOM: This mode is designed to be used when the monitor can be set to display the top and bottom of the display in two successive scans. When you activate this mode, the model view window will be stretched to the full height of the screen and the model will be shown in the top and bottom of this window. After you switch the monitor to display two scans, adjust the vertical offset slider until the two images coincide. Once you have determined this offset, you can define an environment variable IMOD_STEREO_TBOFFSET to have this value, and this offset will be applied automatically in the future.
HARDWARE: This mode is available if the display hardware supports left and right stereo buffers in OpenGL, such as with NVIDIA Quadro cards. When the mode is activated, the command defined in the environment variable IMOD_STEREO_COMMAND (if any) is executed. The two images are then drawn into the left and right buffers. When the mode is turned off, the command defined in the environment variable IMOD_STEREO_RESTORE (if any) is executed. These ancillary commands are unnecessary when activating stereo with an NVIDIA card.
On Macs, hardware stereo is often detected inappropriately and there can be bad consequences if it is entered inadvertently, or even if the capability is requested. Thus, by default stereo is disabled on a Mac. It can be enabled in the Behavior tab of the 3dmod - Preferences dialog. If you turn this on and the program crashes when opening Model View, turn it off again.

Hot Keys

Stereo is toggled with the S hot key. The first time this is used, the program will go into Top/Bottom mode if IMOD_STEREO_TBOFFSET is defined, otherwise into Hardware mode if stereo buffers are available (except on the Mac, as just indicated), otherwise into Side-by-side mode.

Stereo Image Display Controls

It is possible to display image pairs in stereo in the model view window using the controls at the bottom of this dialog. They are enabled when View Z image is selected in the Image View dialog. The image data can consist of a single tilt series, or of consecutive sets of tilted views of different areas. In the simplest case, the image stack would consist of consecutive stereo pairs. Before activating stereo, adjust the Tilted views per area spin box to the correct value. For a tilt series, set this to the number of images in the series.

Turn on Show images as stereo pairs to activate the image display mode. In this mode, the model and image will not be drawn at different angles in the left and right displays; rather, two different images will be drawn in the left and right buffers if possible. The current section will be drawn in the left buffer and a higher section in the right buffer, but only if the higher section is a view of the same area.

If you have more than 2 views of each area, adjust Sections between pairs to select a pair with a different stereo angle.

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