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    Particle Tracking

    The Particle Tracking recipe in Aivia detects subcellular particles and tracks their motility over time in fluorescence time-lapse microscopy images.

    This recipe measures intensity and motion attributes of the detected objects for comprehensive characterization of intracellular dynamics.

    Parameters and Presets

    Parameters

    Recipe parameters for Particle Tracking and their descriptions are summarized in the table below.

    Preset Group

    Parameter Name

    Min Value

    Max Value

    Description

    Preset Group

    Parameter Name

    Min Value

    Max Value

    Description

    Detection

    Background Removal Factor

    0

    100

    Adjusts the sensitivity of the background removal operation; a lower value will preserve larger objects and more background variations

    Object Enhancement Factor

    0

    50

    Adjusts the sensitivity of the bright peak enhancement operation; a lower value will enhance smaller, individual peaks

    Contrast Threshold

    0

    255

    Adjusts the detection sensitivity on the background-removed image; a lower value will detect more objects

    Motion vs Intensity

    Motion vs Intensity

    0

    10

    Adjusts the relative weighting between motion and object intensity for track-point matchmaking between successive frames; a value of 5 will apply equal weights to motion and intensity for matchmaking

    Tracking

    Gap Length

    0

    10

    Specifies the maximum number of time frames for linking tracks that are spatially colocated; a higher value will preserve particle tracks for longer

    Min Track Length

    0

    50,000

    Specifies the minimum number of time frames before a detected object is considered a valid track; a lower value will generate more, and often shorter, tracks

    Max Search Range

    0

    50,000 px or µm

    Specifies the maximum distance for track-point matchmaking between successive time frames; a higher value will expand the search distance for fast-moving cells

     

    Presets

    There are three preset groups in the recipe: Detection, Motion vs Intensity, and Tracking. Each group has three pre-configured parameter groupings to help you get started on the analysis. The default preset values are in the subsections to follow.

     

    Detection

    Parameter Name

    Low

    Medium

    High

    Background Removal Factor

    75

    75

    75

    Object Enhancement Factor

    2

    2

    2

    Contrast Threshold

    125

    65

    15



     

    Motion vs Intensity

    Parameter Name

    Motion

    Mixed

    Intensity

    Parameter Name

    Motion

    Mixed

    Intensity

    Motion vs Intensity

    0

    5

    10

     

     

    Tracking

    Parameter Name

    Low

    Medium

    High

    Gap Length

    5

    5

    5

    Min Track Length

    3

    3

    3

    Max Search Range

    5 px or µm

    5 px or µm

    65 px or µm



     

    Tutorial (written steps)

    Before beginning the tutorial, please download the Particle Tracking Demo image. For information on how to select presets or modify parameter values, please refer to the tutorial on how to use the Recipe Console.

    1. Unzip the demo file and load the demo image, “ParticleTrackDemo.tif,” into Aivia.

    2. In the Recipe Console, click on the Recipe selection dropdown menu and select the Particle Tracking recipe.

    3. Select the following presets for each preset group:

      • Detection: Medium

      • Motion vs Intensity: Motion

      • Tracking: Low

    4. Click on the caret to the left of the Tracking preset group to show the preset parameters.

    5. Modify the parameter value as follows, leaving the other parameters intact:

      • Max Search Range: 0.7

    6. Click the Start button or press the F4 key on your keyboard to begin applying the recipe to the image.

    The detected particle tracks will be overlaid on the image.

     

     

    Particle Tracking Tutorial Results


    Tutorial (video)

     

    Video: Particle Tracking Recipe Tutorial Worked Example (54s)

     

    Measurements

    The Particle Tracking recipe generates intensity and position measurements for each detected particle. You can add additional measurements to the analysis results with the Measurement Tool in Aivia and explore measurement definitions on the Measurement Definitions page. The measurements generated by the recipe are in the table below.

    Intensity

    Position

    • Pixel-based Mean Intensity

    • Pixel-based Total Intensity

    • Pixel-based Standard Deviation Intensity

    • Total Time

    • First Frame

    • Last Frame

    • Centroid X

    • Centroid Y

    • Velocity Magnitude

     

     

    Image Credits

    Laura Anne Lowery, Boston College, Boston MA; David Van Vactor, Harvard Medical School, Boston MA

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