5.3 CAPTURING!
Finally we reached to the capture process, which is the main goal of the 3D Motion Captor. The following points will go through all the necessary steps to carry out motion captures:
New capture
1. Select Capture under the File menu.
2. Select the capture type. The capture type can be either Normal or Large Time. Large time mode is recommended.
Figure 5-13: Select number of models and capture
type.
Normal Mode:
Normal mode works in non-paged RAM memory. It stores all images from all cameras. The time limit depends on the amount of non-paged memory available (available time is not higher than 15 seconds).
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Large Time Mode:
Large time mode uses standard RAM memory. Captures may last for minutes, and the time for the capture is set under options (page 27). Image storage can be customized to be done from whatever cameras. Image storage frequency can also be set. Large Time capture mode is strongly recommended.
Select the Capture Model
There are many available capture models. Check the capture models available on your documentation and select the most appropriate one for your needs.
Start the process
By pressing ok on the dialog shown in Figure 5-13, the capture algorithms start. A new dialog appears while the system recognizes the markers and performs the capture.
Before pressing the ok button, please take into account the following:
�� There are not extra markers on the room.
�� There are not missing markers (the actor/actress has all the markers on)
�� All the markers are correctly placed
�� The actor/actress is standing in the filming area with the right position (each marker configuration has its own reference position).
Performer: Set Up Position
There are two parameters to be considered, the performer’s location within the capture area and his or her body position.
1) Performer location within the capture area
The performer must be located at the center of the capture area. Viewing the scene from the top (Error! Reference source not found.), the performer's head must be located at the center of the capture area.
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2) Body Set Up Position.
The system user must keep special care of the performer’s Set up Position. Incorrect Set up Position may lead to capture errors.
Figure 5-14: For the Set up Position, it is recommended not to face any camera like in the right view. The left view shows the
The performer can face anywhere although it is recommended not to face a camera like the sample shown in Figure 5-14.
Capture Process
The Capture Process consists of the recording phase and the processing images phase. During the first one, the system records the filming area for a period of time previously set as the Capture Time. During the second phase, all recorded images are processed to obtain the performer’s motion.
The recording phase starts when the OK button from the Capture Dialog (Figure 5-13) is pressed. The following sounds will come from the computer:
�� READY…: The word Ready informs the performer that the system is about to start the recording phase.
�� …GO…: The word Go informs that the system has just already started the recording phase.
�� ….O.K.: The recording phase has ended and the processing images phase starts.
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�� During the capture process a motion slider will appear on the scene showing the development of the capture.
Validation Process
After the Capture Process, a validation is required. The Validation Process consists of checking that the Capture Process was successful. As soon as the Capture Process finishes, a representation of the performer viewed from all cameras is shown in the Set Up Position (Figure 5-14). This is called the Capture Validation View.
Figure 5-17: Validation View at Set Up
Figure 5-16 shows the human representation in more detail. The Validation Process consists of checking that the representation shown in all cameras matches that representation.
Finally, press on the Play Forward button (see page 24) to check that the capture has been successful. The human representation shown in all views must be similar to the one shown in Figure 5-16. Figure 5-18 and Figure 5-19 show a valid and a not-valid capture.
Figure 5-15: Capture progress bar
Figure 5-16
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Figure 5-18: Valid Capture. The representation must be coherent throughout the whole motion.
Figure 5-19: Not-Valid capture. Look at frames 30, 40 and 50. The capture missed a foot marker.
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Validation Options
Validation Options are Validation Play Options and Validation View Options.
Validation Play Options
These allow you to move the recorded movie forward and backwards in different ways. Play Options are under the Play menu and are also available in the play toolbar (if not present, the play toolbar can be activated under the edit menu). Play Options are:
Play Forward Performs the movie forward.
Play Backwards Performs the movie backwards
Step Forward Performs the movie one frame forward.
Step Backwards Performs the movie one frame backwards.
Pause Stops the movie.
Validation View Options
For validation purposes, several view modes are provided in order to make the validation process as easy and quick as possible. Validation View modes are images, segments, points or any combination between them. The following describes in detail all view modes:
Images: Setting the Images option on allows you to view black and white images on the Capture Validation View.
Points: The 3D Motion Captor application allows you to view which points are considered as markers. These are highlighted as numbered red dots.
Segments: The Segments option draws lines between the captured markers. Enabling the Segments option helps very much on the motion Capture Validation Process.
Several View Modes can be selected at the same time. Some view mode combinations are shown in Figure 5-20. The default option shows points and segments.
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Figure 5-20: Four different view modes for camera 1 view.
3D VIEW
Figure 5-21: 3D View.
The Motion Captor application has a 3D advanced module that allows 3D capture visualization. This view will allow you to get some 3d feedback. In order to open the 3D view, select 3D View under the Biomechanics menu (or click on the 3D icon).
Set the 3D view on / off
In order to open the 3D view, select 3D View under the Biomechanics menu (or click on the 3D icon).
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Rotation wheels and zoom slider
3D point of view control can be modified with any of the following:
• Rotation Wheel: Just drag the mouse any of the two rotation wheels (in red color) and you will be able to rotate the scene horizontally and vertically.
• Rotation buttons: Rotation buttons allow you rotate step by step the scene. Rotation wheels are shown in the figure bellow.
• Zoom operations: Zoom operations can be carried out by using the zoom slider (on the right hand side of the 3d window), but also with the zoom buttons.
• Z Translation. The point of view can either move forward and backward with the translation buttons.
Mouse mode
The mouse mode defines how the point of view is modified when the mouse is dragged within the view. You can access to the mouse mode by selecting mouse mode under the View Control menu.
Reset view
In order to set the point of view to the default one just select Fit view to scene under the View Control menu or click on the icon .
Other 3D options
The background color can be changed by selecting background color from the Configuration menu. Axis and markers can also be activated from this menu.
Finally with the right mouse button, you will be able to set different render modes, camera tracking, and so on.
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5.4 GENERAL OPTIONS
The options dialog can be opened from the View menu. The use of some of these options requires some knowledge about computer and memory management, and we recommend asking our technical staff before any change.
Options are grouped under:
Calibration: Number of points in the calibration rod, calibration tool, distance between points, and so on.
Capture: Number of cameras, sensor size, focal length, and some other options are grouped under capture.
Directories: The path where temporary files are stored and the calibration folder can be set. Please take into account that these folder must be under the 3D Motion Captor folder.
Image disk saving options: This option only affects normal capture mode in stand alone working mode (page 19).
Image Preservation: These options allow customizing the images to be stored when large time is being used (page 19).
• RAM: Amount of RAM memory used for storing images from the cameras.
• Camera image preservation code. This code is a sequence of n and s letters, and defines how the images from that camera will be stored. For example:
o n : no images
o s : all images
o ns : one image out of two frames.
o nns : one image out of three frames.
… and so on.
Miscellaneous: Automatic lights can be set to on/off, use of image holes (for hiding extra brights), select video code option, and the frame grabber starting slot.
Figure 5-22: Options Dialog
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Figure 6-1: Real time configuration
