Vicon Cameras node

The Vicon Cameras node on the System tab of the Resources pane enables you to manage the identification and configuration settings for each Vicon camera connected to your Vicon system.

Vicon Cameras node context menu

You can select the following commands from the context menu displayed when you right-click on the Vicon Cameras node:

Command	Description
Reorder	Display the Reorder Devices dialog box in which you can change the order in which Vicon cameras are displayed in the System Resources tree.
Reboot Vicon Cameras	Stop and restart all of the Vicon optical cameras in the Vicon system.
Remove Vicon Cameras	Displays a choice of Disconnected or Missing: Disconnected - removes from the Resources tree cameras that are currently unplugged. Missing - removes from the Resources tree cameras that are unplugged, but were previously used in a calibration.
Enable Preview Mode	Displays a video image from the optical sensor of Vicon cameras that offer this option. This enables you to aim cameras more quickly and easily and to check volume coverage by the cameras during setup. Note: This preview feature is for system setup purposes only. You cannot use Preview modewhen you are calibrating, auto masking, capturing, or reviewing data. Tip: If the image produced by Preview mode is too dark, adjust the aperture to maximize the light. After you've finished setting up the cameras, return the aperture to its required setting.

You can select the following commands from the context menu displayed when you right-click on a node for a specific Vicon camera:

Command	Description
Reset Calibration	Remove the selected camera from the current calibration.
Reboot	Start and restart the selected Vicon camera.

Vicon Camera properties

Identification section

Property	Description
Name	A user-defined display name for the entire set of Vicon cameras or for each individual camera. For example, if a camera is placed over a door, you could name it "Over Door." Default: Blank
Device ID	The unique identification number Vicon assigns to each camera during manufacture. The top-level entry for all Vicon cameras takes no value. Default: Identified on connection

Settings section

Property	Description
Enabled	Whether or not the Vicon camera is currently enabled for use. Default: Selected
Strobe Intensity	The amount of light emitted by Vicon camera strobe units. This value can be set between 0-1 to minimize reflections and obtain clear marker images. The higher the setting, the larger the markers appear, but this may cause blobs to be produced from unwanted reflection sources. Lower settings reduce unwanted reflection sources but make the markers themselves less visible to the Vicon cameras. In almost all circumstances, you will want to keep the intensity at its maximum level because the system works by recording light from the strobes that is reflected from the markers, thus the more light the strobes send out the more light the markers reflect. However, there are two significant cases where you may want to lower the intensities: If you see a lot of reflections in the volume, either from other cameras or from other objects in the room, such as shiny equipment, floors, or from the subject. If you are capturing a very fast moving subject. The strobe intensity affects the time the strobe is on for each camera frame. The full strobe intensity corresponds to 1ms for normal frame rates. Lower strobe intensities mean that the markers are captured with the strobes on for less time and, therefore, have less time to move during the frame. Tip: In normal circumstances, it is advisable to use full strobe intensity and deal with reflection problems by closing the camera lens aperture. However, especially when the capture volume is very small, this may be uncomfortable to the patient, so less than the full intensity may be the best setting. Adjust this setting in conjunction with the Threshold setting until reflections are minimized or gone.
Strobe Intensity	Note: If you are using a Vicon system that consists of a mix of MX T-Series cameras and current Vicon cameras, and if it is crucial to your work that the shutter periods for all cameras are precisely aligned, ensure that your firmware is upgraded to version 700 or later, and set the Strobe Intensity for the T-Series camera(s) to its maximum. (Note that lthough you can use T-Series cameras with Nexus 2.15, this is not supported or tested. For information on using these cameras, see the documentation for versions of Nexus earlier than 2.15. Also note that if you add Valkyrie cameras to a system that includes T-Series cameras, the T-Series cameras will not work.) Default: 1
Sensor Mode	Nexus 2.11 and later supports the use of the Vantage+ firmware upgrade, enabling you to use High Speed mode on your Vantage cameras without having to change the field of view (FOV) or lens. When you capture optical data, subsampling (selectively reducing the pixel count) enables you to run at high camera frame rates without reducing the FOV (frame size). In High Speed mode, you can run your Vantage cameras at higher frames rates while maintaining the FOV. You can change frame rates during capture and you do not need to set up your cameras again when you increase the frame rate, as the FOV is unchanged.Because the higher speeds are achieved through subsampling (removing some pixels from the frames), some reduction in resolution is incurred. For details, see Run in High Speed mode and High-speed mode in the Vicon Vantage Reference Guide.
Gain	The digital amplification of the pixel value. Select a displayed value to determine the intensity of the grayscale from the Vicon cameras: x1, x2, x4, or x8. This setting is applied to the camera to change the dynamic range of the recorded image. Increasing the gain means that the marker has less variation in grayscale intensity between its center and its edge, but in certain circumstances, using a higher gain yields markers that are easier for the camera to distinguish. Vicon does not recommend using a gain setting higher than x2. Adjust this setting if the markers appear too faint or if the cameras have trouble distinguishing them; otherwise, leave the this property at the default x1 setting. Default: x1
Grayscale Mode	The type of data for processed grayscale blobs that the Vicon cameras send to Vicon Nexus. The Vicon cameras perform data processing to create 2D data for Vicon markers. They generate grayscale blobs for reflections from objects in the capture volume and then use centroid-fitting algorithms to determine which of these are likely to be markers by comparing the shape of the grayscale blobs to the Minimum Circularity Ratio and Max Blob Height settings. During this processing, Vicon cameras can produce these types of data for grayscale blobs: centroids data (x, y coordinates and the radius of the centroid calculated), grayscale data (pixel and line information), or coordinates data (line information, i.e. grayscale data without pixel values). You can specify which type of processed data Vicon cameras send to Nexus: Auto: Send grayscale data only of the grayscale blobs for which centroids were not generated, that is, those below the threshold specified for Minimum Circularity Ratio.Send coordinates data of grayscale blobs for which one or more line segments, or the total number of lines in the blob, exceeds the value set for Max Blob Height. If a marker can be centroid fitted by the Vicon camera, the centroid is passed to the capture PC. If it cannot, the full grayscale of the image is sent, allowing the data to be post-processed on the PC. This is the default and recommended mode. None: Send no grayscale or coordinates data; send only centroid data. Any grayscale image that cannot be centroid fitted by the camera will be discarded. Select this mode if you are capturing a large number of markers and have redundancy in your capture setup. All: Send grayscale data both of grayscale blobs for which centroids were generated and of those for which centroids were not generated, that is those below the threshold specified for Minimum Circularity Ratio. Send coordinates data of grayscale blobs for which one or more line segments, or the total number of lines in the blob, exceeds the value set for Max blob height. Select this setting if you need to see exactly where the camera calculates the centroid with respect to the grayscale marker image, for example when adjusting parameters. This setting results in much larger data rates and files; it may be useful for diagnostic purposes, but do not use it in normal capture situations. Only: Send all grayscale and coordinates data; send no centroid data.This setting is useful when focusing or making other adjustments to the cameras themselves as you see exactly the image recorded on the sensor. Edges: Send only edge coordinates data; send no centroid or grayscale data.If data rates are very high, for example when there are too many reflections, the camera automatically enters this mode. Use this setting to manually force the camera into this mode. No Edges: Send grayscale data both of grayscale blobs for which centroids were generated and of those for which centroids were not generated; send no coordinates data.Use this setting to prevent the Vicon camera from sending edge coordinates. Default: Auto Caution Even if you have not specified a Grayscale mode setting that would have coordinates data sent to Nexus, a Vicon camera automatically sends coordinates data– either temporarily or permanently– if it is overloaded with data (e.g., too many markers, too many reflections, hand or reflective objects immediately in front of the camera, too low a threshold or too high a gain). If a camera automatically starts to present coordinates data, identify the source of the overload and try to remedy it.
Allow Windowing	Windowing enables Vicon cameras that support windowing to run at a faster frame rate by using letterboxing to reduce the dimensions of the camera sensor area. The configured frame rate affects the field of view. When you select Allow Windowing, if you specify a frame rate greater than the maximum frame rate for the camera at full resolution, image size is automatically reduced in comparison with that for a lower camera frame rate by windowing. This keeps the pixel rate the same by transmitting a greater number of smaller images per second. Cannot be used in calibration mode. Default: Selected
Enable LEDs	Enables you to select whether or not to use the status lights on the Vicon camera strobe unit that provide feedback on the status of the camera (such as its enabled, connection, or selection state and any processing feedback). This is useful for motion capture applications in very dark environments (such as Virtual Reality) where the brightness of these LED status lights can cause problems. Default: Selected
Enable Display	Toggles on or off the display on the front of the camera (of supported Vicon cameras), which gives feedback about the current camera status, eg, when the camera has finished booting, its calibration status, and whether it has been moved since calibration. If Enable Accelerometry is selected (see below), the image on the display rotates based on the orientation of the camera. For more information, see the Vicon Vantage Reference Guide or the Vicon Valkyrie Reference Guide.
Enable Tap to Select	For supported Vicon cameras, enables you to lightly tap the camera in the volume to select it (and deselect the other cameras). This is useful, for example, when you are setting up cameras, before they are calibrated. Default: Selected
Enable Accelerometry	Applies to supported Vicon cameras only. Accelerometers in the Vicon cameras enable bump detection to operate in calibrated cameras to alert you when they have moved from their calibrated positions. If a calibrated camera is knocked, the camera's status LEDs flash blue and in Nexus, the camera's Bumped check box (in its Status properties) displays a check mark. See also Bumped and Bump Detection Sensitivity in the Status section. Default: Selected

Run in High Speed mode

Nexus 2.11 and later supports the use of the Vantage+ firmware upgrade (Firmware 725), enabling you to use High Speed mode on your Vantage cameras without having to change the field of view (FOV) or lens. When you capture optical data, subsampling (selectively reducing the pixel count) enables you to run at high camera frame rates without reducing the FOV (frame size).

Important
To use High Speed mode, you must upgrade to Firmware 725 or later.

In Default mode, to run Vantage cameras at higher frame rates while maintaining their maximum resolution, windowing is used, which reduces the size of the FOV.

In High Speed mode, you can run your Vantage cameras at higher frames rates while maintaining the FOV. You can change frame rates during capture and you do not need to set up your cameras again when you increase the frame rate, as the FOV is unchanged.

Note that because the higher speeds are achieved through subsampling (removing some pixels from the frames), some reduction in resolution is incurred. For details, see High-speed mode in the Vicon Vantage Reference Guide.

To select high-speed mode:

With your Nexus system in Live mode, set the system frame rate to the speed you want to use in High Speed mode.
A warning may temporarily be displayed, alerting you to the discrepancy between the requested frame rate and the actual system frame rate, until you select high speed mode for all the relevant cameras, as explained next.
On the System tab, select one or more cameras.
In the Properties pane, ensure the Advanced properties are displayed and in the Settings section, click the Sensor Mode menu and select High Speed.

In the Camera view pane, notice that the High Speed mode icon is displayed in the bottom left corner of the view .
With Allow Windowing selected (the default), windowing (reducing the size of the field of view) is used above the following frame rates:
- V16: 500 fps
- V8: 900 fps
- V5: 1060 fps
If you don't want to use windowing in addition to High Speed mode, clear the Allow Windowing check box.
After a few moments, the system runs at the new speed.

Centroid Fitting section

Property	Description
Threshold	The threshold for the minimum brightness (intensity) for marker pixels (the setting does nothing to an overall marker, just the individual pixels); pixels of an intensity lower than this threshold are ignored. This value can be set between 0-1 to determine the pixels to be considered for centroid fitting onboard the Vicon cameras. Lower settings enable the camera to detect lower light levels, thus making the markers appear larger, but introduce more noise from unwanted reflections and other light sources. Higher settings reduce the noise, but make the markers themselves less visible. This setting differentiates between markers and ambient light. Vicon cameras record 10-bit grayscale data, which for each sensor pixel is a measure of how much light fell on that pixel during a given amount of time. However, the cameras will almost always pick up some ambient light in the volume. To enable the cameras to distinguish between light that comes from markers and light that does not, a threshold is applied. Anything above this threshold is deemed to be a marker, anything below is deemed to be ambient light. A value in the region of 0.2 to 0.5 is usually appropriate, but Vicon strongly recommends that you use static markers in the volume in order to establish an appropriate setting. If cameras are evenly spaced around the volume, the same Threshold value is usually sufficient for all cameras. Adjust this setting, the Strobe Intensity, and the camera's aperture until reflections are minimized or gone. Default: 0.2
Minimum Circularity Ratio	The circularity threshold used by the centroid-fitting algorithms in a Vicon camera. This value can be set between 0-1 to determine how similar a grayscale blob must be to the internal model of a marker– that is a radially symmetric object that has smooth, sharp edges and whose pixel intensity is brightest at the center and gradually fades towards the edges. The Vicon cameras consider grayscale blobs with circularity equal to or greater than this threshold to be well-formed, circular marker images. The higher the value, the more stringent the centroid fitter is; the lower the value, the less stringent the centroid fitter is. You may wish to apply higher settings for camera calibration to ensure that the Vicon system selects the best markers and thus provides the best possible calibration. A lower value may be appropriate for data capture. Default: 0.5
Maximum Blob Height	The maximum height in pixels of a grayscale blob for a camera to attempt to circle fit it. If the number of pixels exceeds this value, the Vicon camera determines that the grayscale blob is not a marker, stops processing it, and discards the pixel values (it preserves just the coordinates data, which can be sent to Vicon Nexus, depending on the Grayscale mode setting). Set this value between 0-500 to determine how large a grayscale blob can be for a Vicon camera to consider it a candidate marker. The Vicon cameras consider grayscale blobs with horizontal lines containing this number or fewer pixels to be good-sized, circular marker images. The higher the value, the larger a grayscale blob can be; the lower the value, the smaller a grayscale blob must be. Default: 50

Centroid Tracking section

Property

Description

Enable Centroid Tracking

When Nexus recognizes the presence of Vicon cameras, the Enable Centroid Tracking parameter becomes available. Tracking and identifying 2D centroids on an individual camera allows the production of 2D tracks. Tracking and identifying 2D camera centroids provides extra information that maintains marker labels in real time when only one camera can see a marker. When selected, the 2D track calculations are performed by the cameras' onboard sensors. When cleared, the 2D track calculation is performed by the PC (in Nexus).
Click on a Vicon camera to turn on 2D switchable tracks. Clear this option to turn off.
Note: Applies only to Vicon cameras that have the ability to process this information on board the camera.
Default: Off

Marker Velocity

Maximum velocity at which a marker will be tracked, expressed as the percentage of image width per second.
Default: 5

Status section

Property	Description
Connected	Whether or not the Vicon camera is currently connected to the Vicon system. Default: Identified on connection
Sync Source	Whether or not the Vicon camera is designated as the synchronization source for the Vicon system. For more information, see Change the synchronization source in the Vicon Nexus User Guide. Default: Identified on connection
Contributing Centroids	Whether or not the Vicon camera is contributing centroid data during the current motion capture. Default: Identified during capture
Contributing Grayscale	Whether or not there is a socket open to the Vicon camera that is capable of receiving grayscale. This socket may be dropped when the system is under heavy load, therefore this property is useful as a system status monitor. It is not related to Grayscale property under Settings. Default: Selected
Contributing Tracks	Whether or not the camera is contributing tracks. Default: Cleared
Bumped	If selected, indicates that a calibrated camera has moved (usually because it has been accidentally knocked) since it was calibrated. To remove selected camera's bumped status, clear this check box. To clear all cameras' Bumped status, press CTRL+SHIFT+B. Applies only to Vicon cameras that support indicating Bumped status. Default: Cleared
Bump Detection Sensitivity	Enables you to change the sensitivity of the camera to knocks and bumps. Applies only to Vicon cameras that support bump detection. Default: Medium

Hardware section

Property	Description
Type	The type of Vicon camera. The top-level entry for all Vicon optical cameras takes no value. Default: Identified on connection
Strobe Type	The type of strobe unit (if any) attached to the front of the Vicon camera: Visible Red (VR), Near Infrared (NIR), or Infrared (IR). Default: Identified on connection
Camera Body Temp 1 Camera Body Temp 2 or Strobe Temperature	Current operating temperature given in degrees Celsius. A colored temperature indicator on the right changes to reflect a change in temperature: yellow (warming up to the temperature specified by the lower bounds), green (between the specified upper and lower bounds) or red (overheated above the upper bounds). To change the upper and lower bounds, click Camera Temperature Range in list on the left of the Options dialog box (F7). Applies only to Vicon cameras that support temperature sensor display. Default: Identified during connection
Sensor Width	The width (in pixels) of the Vicon camera sensor. Default: Identified on connection
Sensor Height	The height (in pixels) of the Vicon camera sensor. Default: Identified on connection
Revision	Camera revision number.
MAC Address	The Media Access Control (MAC) address assigned to the Vicon camera during manufacture. This is a hexadecimal value in the format ##.##.##.##.##.##. The top-level entry for all Vicon cameras takes no value. Default: Identified on connection
IP Address	The Internet Protocol (IP) address assigned to the Vicon camera on the Vicon Ethernet network. The top-level entry for all Vicon cameras takes no value. Default: Identified on connection
Destination IP Address	The IP address of the network adapter to which data from this camera will be sent. Default: Default

Firmware section

Property	Description
Firmware Version	The version number of the firmware currently installed on the Vicon camera. Default: Identified on connection
Firmware Complete	Whether or not the currently installed firmware is complete. If not, you can reprogram the firmware. See Update firmware in the Vicon Nexus User Guide. Default: Identified on connection

Calibration section

Property	Description
Reset Calibration	Removes the selected camera from the current calibration.
Focal Length (mm)	The focal length (in millimeters) of the Vicon camera lens. The focal length of the lens is automatically calculated by the calibration algorithm. You only need to enter this value manually if you use the Aim Cameras function. Can be set to a value between 2-100. Default: 8

Commands section

Property	Description
Reboot	Stop and restart the selected Vicon camera.

Nexus 2.15 Documentation

Vicon Cameras node