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ControlDescription
Strobe Intensity (for cameras with strobes), or Optical Shutter Duration (for cameras without strobes)

For cameras with strobes, enables you to specify the duration that the camera's strobes are on and the shutter is open.

For cameras without strobes, enables you to specify the duration that the shutter is open.

Default: 1.00

Threshold

The minimum brightness (intensity) for markers; pixels of an intensity lower than this threshold are ignored. This value can be set between 0 and 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 may pick up 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. A Vicon camera records 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: 0.20

Grayscale Mode

The type of data that the Vicon cameras send to Vicon Tracker. By default Low Jitter is enabled so this setting will be read-only.

The Vicon cameras can 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 Circularity Threshold and Maximum Blob Height settings. During this processing, Vicon cameras can produce the following 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, that is, grayscale data without pixel values).

Default: Only (read-only)

You can specify which type of processed data Vicon cameras send to Tracker (ensure Low Jitter is disabled):


Auto

Send grayscale data only of the grayscale blobs for which centroids were not generated, that is, those below the threshold specified for Circularity Threshold.

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 Maximum Blob Height.

If a marker can be centroid fitted by the 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 data; send only centroid data (i.e, x, y, and radius data).

Any ambiguous grayscale data will be discarded.


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 Circularity Threshold.

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 Maximum 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.

When Low Jitter mode is selected (its default setting) in the Processing panel, Grayscale Mode is locked to this setting.


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.

Caution: Even if you have not specified a Grayscale Mode setting that would have coordinates data sent to Tracker, 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 attempt to remedy it.

Sensor Mode

Tracker 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 Vicon Vantage camera performance comparison in the Vicon Vantage Reference Guide .

Default: Default mode

Gain

The amplification of the pixel value. Select a displayed value to determine the intensity of the grayscale from the Vicon cameras: 1x, 2x, 4x, or 8x. (The available values are those supported by the camera.)

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.

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 setting.

Default: 1x

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