Fraunhofer STAN User manual

STAN - The Stereoscopic Analyzer
Manual: version 2.10-0-1-Z

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STAN Manual STAN version 2.10-0-1-Z
Overview
Introduction................................................................................................................................ 2
First Steps ................................................................................................................................... 3
Select Input Device ................................................................................................................. 3
Select Input Raster.................................................................................................................. 4
Adjust Vertical and Horizontal Flip ......................................................................................... 5
Calibrating your Stereo Rig......................................................................................................... 8
Mechanical Alignment............................................................................................................ 8
Roll Error Adjustment ........................................................................................................... 12
Vertical Offset Adjustment ................................................................................................... 12
Keystone Error Adjustment .................................................................................................. 12
Tilt Keystone Error Adjustment ............................................................................................ 13
Y-Offset Adjustment ............................................................................................................. 13
Zoom-Level Adjustment ....................................................................................................... 13
Calibration Options............................................................................................................... 14
Depth Volume adjustment....................................................................................................... 16
Measuring the Depth volume............................................................................................... 16
Adjusting the Interaxial Distance / Stereo Baseline ............................................................. 17
Adjusting the Convergence / Angulation ............................................................................. 19
Horizontal Image Translation (HIT) / Sensor Shift................................................................ 22
Visualization of the Depth Structure .................................................................................... 22
Color Adjustment Assistance ................................................................................................... 24
Color Temperature assistance.............................................................................................. 24
Brightness Assistance ........................................................................................................... 25
Electronic Image Alignment ..................................................................................................... 27
STAN –Specifications ........................................................................................................... 28
HD-SDI Input Formats ........................................................................................................... 28
Working Directory ................................................................................................................ 29

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Config File settings................................................................................................................ 29
Width and Height of the GUI: ............................................................................................... 30
Enable HDMI-Output ............................................................................................................ 30
Width and Height of the HDMI-Output Window: ................................................................ 30
HDMI-Output mode:............................................................................................................. 30
Width and Height of the HDMI-Output Window: ................................................................ 31
Side-by-Side HD-SDI Input: ................................................................................................... 31
Auto-Rescaling for HDMI-Output ......................................................................................... 31
Auto-HIT................................................................................................................................ 31
Motor Control....................................................................................................................... 31
Auto-Interaxial...................................................................................................................... 32
Auto-Convergence................................................................................................................ 32
Depth Plane Parallax Range.................................................................................................. 33
STAN Processing Speed ........................................................................................................ 33
Introduction
The STAN (Stereoscopic Analyzer) is an assistance system for stereo shootings and 3D
productions. An image-based scene analysis estimates in real-time the stereo geometry of
the two cameras in order to allow an optimal alignment of the cameras and lens settings
directly on the set. It automatically eliminates undesired vertical disparities between the two
views, through an electronic image rectification process. In addition it detects the position of
near and far objects in the scene, derives the optimal interaxial distance and gives alerts if
synchronization problems occur.
Figure 1 illustrates the Graphical User Interface of the Stereoscopic Analyzer. The GUI allows
an easy overview about all important stereoscopic parameters. The input images can be
monitored in a variety of visualization modes.

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Figure 1: STAN's Graphical User Interface (GUI)
First Steps
Select Input Device
If your PC system has more than one HD-SDI Input Device, choose the appropriate capture
board from the Drop Down. Figure 2 illustrates this process.
Supported capture boards are:
DVS Centaurus II
DVS Atomix
DVS Atomix LT
Blackmagic Design DeckLink HD Extreme 3D

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Figure 2: Input Device selection: Options  Video  Input Device.
The options menu is automatically opened after the start of the application when no
camera signal matching the current Input Raster could be detected. After changing the
Input Device, click Restart.
Select Input Raster
In a first step, the proper Input Raster needs to be chosen. The Input Raster is a combination
of the resolution, the frame rate, and the scan mode (progressive or interlaced). Select the
Options tab and use the drop-down menu to choose the Input Raster as shown in Figure 3.
Briefly, the Input Raster must match the configuration of the Monitor Output or the
Recording Output of your cameras.
The Input Raster can be selected in the Options tab. Within the Options tab, select the Video
tab.
SDI Input Device

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Figure 3: Input Raster selection: Options  Video  Input Raster
The options menu is automatically opened after the start of the application when no
camera signal matching the current Input Raster could be detected. After changing the
raster, click Restart.
After the first start the STAN shows the video settings in the Options tab. It is necessary to
select the proper Input Raster from the cameras. All supported Input Rasters can be found
in the ANNEX. Please note that some video equipment cannot distinguish between a psF-
Raster (progresseive scan mode using two fields as done in interlaced mode) and an
Interlaced-Raster. The psF-Raster is widely used by Sony cameras but is not specified in
SMPTE 292M.
Adjust Vertical and Horizontal Flip
When using a mirror rig, you will need to flip one or both cameras vertically or horizontally.
Before you can start working with the STAN. Figure 4 shows an example of a stereo pair
which needs a vertical flip to be applied on the left image. The left camera image was flipped
by using a mirror rig.

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Figure 4: Unmodified camera signals. The left image is flipped due to the use of a mirror rig
while shooting the content. Using the Side-by-Side view mode, one can easily perceive
which flipping option is necessary.
We know choose the appropriate flipping in the Options menu as shown in Figure 5 and
Figure 7. In our example we need to flip the left image vertically.
Figure 5: Select the appropriate flipping in the Options menu. In our example, the left
image needs to be flipped vertically. Changes apply immediately.
After applying the flip, we switch back to the Side-by-Side view mode to check the result of
the flipping settings as illustrated in Figure 6. Apparently, we do now have a valid stereo pair.
Figure 6: Stereoscopic image pair. The left image has been flipped vertically to compensate
for flipping introduced by the mirror rig. You can start using the STAN now.
Some stereo rig configurations might require to flip both cameras vertically and one camera
horizontally.

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Figure 7: Vertically or horizontally flip the images when using mirror rigs. You can define
the flipping in the menu:
Options  Video  Flip Left Image / Flip Right Image
As shown in Figure 7 you can also swap the left and right input channel. If for instance, the
left camera is connected to the right STAN input channel (and the right camera to the left
STAN input channel) you can use this feature to compensate this erroneous configuration.
Figure 8 illustrates this process.
Figure 8: Swap the left and right camera input on demand. The changes apply immediately
When you change the flipping settings and/or the swapping settings, these apply apply
immediately, i.e. no restart is required.

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Calibrating your Stereo Rig
Mechanical Alignment
One of the main features of the STAN is to provide assistance for the mechanical alignment
of the rig. In Figure 9 the results of the geometrical analysis are illustrated. In this example,
Roll, Vertical, Keystone, Tilt-Keystone, Y-Offset and Zoom settings are being evaluated and
displayed.
Figure 9: Displaying the parameters for the Mechanical Alignment.
To achieve an optimal mechanical alignment the red marked values in Figure 9 need to be
calibrated as:
Roll –0°
Vertical Offset –0%
Keystone –0%
Tilt Keystone –0%
Y-Offset –0%
Zoom Level –100%
In general, during the setup and calibration phase, you should try to get near the above
mentioned values. Depending on which stereo rig you use, it might happen that you need to
calibrate some values iteratively.
To perform the adjustment, use the appropriate calibration knobs and/or screws on your
stereo rigs, and turn them until all values are near the optimum.
In addition, you might want to get a visual feedback. To do so, choose one of the overlay
modes in the Overlay menu as shown in Figure 10 to Figure 12.

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Figure 10: The Anaglyph Overlay mode can be used to get a visual feedback of the quality
of the mechanical alignment. Red or cyan lines around horizontal object borders in the
image are clear indicators of the presence of vertical disparities and thus a poor
mechanical alignment.
The Anaglyph Overlay mode is widely used to assist the calibration of the stereo rig. Red
and Cyan border indicate differences between the left and the right image. This can be used
to identify vertical disparities indicating a missing calibration of the stereo rig. Moreover,
one can easily detect horizontal disparity and especially the convergence plane. This assists
the stereographer the choose the right convergence angle or Horizontal Image Translation
(HIT). One can choose between three Sub-Options:
Input
Program
Preview
These options define, if the uncorrected image pair sill be shown in the anaglyph overlay
(Input), or if electronically corrected images shall be shown (Program and Preview).
Program refers to the correction parameters which are active on the HDMI-output while
Preview applies correction matrices which become active when hitting the button Rectify.
These Sub-Options are also available for the visualization modes Difference and Opacity
Overlay.