.mcal XML Calibration Files
An overview of the data available in the .mcal calibration file.
Overview
Beginning with Motive 3.2, calibration data is stored in an XML file with the file extension .mcal. XML is a human-readable format that can be imported for use in end-user applications.
This page defines the properties in the .mcal file that could be used in third-party applications.
Properties in the calibration file that are not relevant for use outside of Motive are listed and noted as such. These properties may be used by OptiTrack Support for troubleshooting.
Camera Serial
The serial number of the camera. In Motive, this information is located in the Camera Details section of the Camera Properties.
Camera Properties
Properties related to the specified camera, as defined in the Camera Properties pane in Motive.
Camera ID
The camera number assigned by Motive. In the Properties pane, this is shown in the Number field.
ImagerIndex
This value corresponds to the letter prefix in the device serial number, when present. Pre-set values are used for USB-connected devices.
Prime Cameras
M
00
USB Cameras
None
00
Tracking Bar Cameras Primary
None
01
Tracking Bar Cameras Secondary
None
02
Tracking Bar Cameras Tertiary
None
03
OptiTrack IO X Duo & Trio Device Break-out Connectors
None
0F
eSync Devices
ES
10
Golftec Cameras
GT
20
Color Cameras
C
30
Active Devices
A
40
Leyard Cameras
L
50
Exposure
The amount of time, in microseconds, that the camera exposes per frame.
Threshold
The minimum brightness required for a camera to detect a pixel. All pixels below the stated threshold will be ignored.
Intensity
This is a legacy setting related to LED power.
ContinuousIR
Indicates whether the camera's infrared lights are set to strobe (0) or to remain on continuously (1).
VideoType
Indicates the video mode of the camera.
2
Object
4
Precision
1
Grayscale
6
MJPEG
FrameRate
The camera system frame rate.
FrameDecimation
Indicates the ratio of frames displayed per total frames captured.
Frame Decimation is not supported in all devices.
0
1:1
3
1:4
7
1:8
15
1:16
GrayscaleDecimation
Indicates the ratio of frames displayed per total frames captured when in Grayscale mode.
Grayscale decimation is not supported in all devices.
0
1:1
2
1:4
4
1:16
JPEGQua
For cameras in MJPEG mode, this value indicates the quality of the video recording.
25
Minimum
50
Low
75
Medium
100
High
IRFilter
Indicates whether the camera is set to view infrared spectrum (0) or visible (1) light.
AutoGainControl
This is a legacy property that no longer affects the system calibration.
AutoExposureControl
This is a legacy property that no longer affects the system calibration.
HighPower
Indicates if high power mode is on (1) or off (0) for applicable cameras.
High power mode is only available on Flex 3 and Slim3u USB cameras when used with an OptiHub2.
Orientation
Indicates the angle of the camera's view. This property can be adjusted in Motive from the Camera Settings menu in the Cameras View of the Viewport.
ImagerGain
Indicates the imager gain level for the selected camera. Gain settings can be adjusted to amplify or diminish the brightness of the image.
The valid range for gain values in the calibration file is 0 - 7. In the Motive user interface, gain values are increased by 1 for a more user-friendly experience. Thus, a gain of 3 in the .mcal file will show as a gain of 4 in Motive.
Enabled
Indicates whether the camera is enabled (1) or disabled (0) from contributing to the reconstruction of 3D data, when recording in object mode.
EnabledForRecording
Indicates whether the Reconstruction setting is enabled (1) or not (0).
Attributes
These values are found in the Details section of the Camera Properties in Motive.
Revision
Internal reference information for the camera.
Model
The internal camera model number.
Group
The camera group number that the selected camera is in.
ImagerPixelWidth
Defines the center point of the imager on the x-axis.
ImagerPixelHeight
Defines the center point of the imager on the y-axis.
Intrinsic Values
Intrinsic values are fixed characteristics of the lens and are used to adjust for lens distortion. These values are not displayed in Motive.
The calibration file contains two types of intrinsic values:
OptiTrack Internal Model. Values optimized for Motive's internal calibration calculation. This model is not applicable for use in other contexts.
Standard Camera Model. Standardized values that provide accurate results when exported to the OpenCV model.
LensCenterX
The location of the lens center on the imager, on the X axis.
LensCenterY
The location of the lens center on the imager, on the Y axis.
HorizontalFocalLength
The Focal Length of the imager along the Y axis, in pixels.
VerticalFocalLength
The Focal Length of the imager along the X axis, in pixels.
Distortion: K1 / K2 / K3 Values
K values control the amount of radial distortion applied to the image.
Tangential X / Y
Tangential values account for the distortion that occurs when the imager and the lens are not aligned in parallel. TangentialX is the amount of tilt off the X axis, while TangentialY is the amount of tilt off the Y axis.
Extrinsic Values
Extrinsic values define the physical location of the camera. In Motive, the position values are shown in the Details section of Camera Properties.
Position: X / Y / Z
The camera's location in X/Y/Z coordinates.
Rotation: OrientMatrix 0 - 8
Values that comprise the rotation matrix where the camera's rotation values are stored. Motive uses Row Major rotation matrices.
Camera Software Filters
Camera Software filter properties are found on the Settings Panel > Live Pipeline > Camera tab. Some are advanced settings.
FilterLevel
Indicates the Filter Type to apply to a 2D object for it to be included in the Point Cloud reconstruction. Possible choices are Size & Roundness (2). or None (0).
MarkerMinSize
The minimum pixel size for a 2D object to be included in the Point Cloud reconstruction.
MarkerMaxSize
The maximum pixel size for a 2D object to be included in the Point Cloud reconstruction.
MarkerMinRoundness
The minimum circularity threshold a 2D object must meet to be included in the Point Cloud reconstruction.
Camera Hardware Filters
Camera Hardware filter properties are found on the Settings Panel > Live Pipeline > Camera tab. All are advanced settings.
GrayscaleFloor
The pixel intensity of the grayscale floor.
ObjectMargin
The minimum number of pixels required between objects before they begin to overlap.
ObjectSkew
The number of pixels a 2D object is allowed to lean.
AspectTolerance
The maximum allowable aspect tolerance to process a 2D object (width:height).
AspectBase
The allowable aspect tolerance for very small objects.
Aspect Step
The rate at which the aspect tolerance relaxes as object size increase.
RIOIntrusion
Indicates whether the intrusion band setting is on (1) or off (0).
RIOGuardBand
The size of the guard region beyond the object margin for neighbor detection. Corresponds to the Intrusion Band property.
Continuous Calibration
Camera properties relevant to continuous calibration are found in the Camera Properties pane.
PartitionID
The partition group assigned to the camera for continuous calibration.
Color Camera Properties
Additional properties specific to Color Cameras are located in the Camera Properties pane. These properties are not included in the .mcal file if there are no color cameras present.
CameraResolution
This property sets the resolution of the images captured by the selected camera.
0
1080
1
720
2
540
3
272
ColorCompressionMode
The type of compression that will be applied to the captured images.
1
Constant Bit-Rate
0
Variable Bit-Rate
ColorCompression
The percentage of the maximum data transmission speed to allocate for the camera.
ColorBitRate
The selected color camera's output transmission rate, as a fraction of the maximum (100 MB/s).
This value is applicable only when the ColorCompressionMode is set to 1 (Constant Bit-Rate).
ColorGamma
The amount of gamma correction applied to the selected camera's output image.
SubModel
The camera sub-model, as shown in the Camera details.
Export for OpenCV Use
The .mcal XML file can be exported for use with the OpenCV platform.
From the File menu, select Export Calibration...
Browse to the directory where you would like the file exported to.
The default file name includes the timestamp of the export, not for the calibration itself.
For instructions on importing the .mcal file into your OpenCV project, please consult the documentation for the applicable platform.
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