Options

The Options group provides access to the many Motion Tracking options that allow you to adjust the appearance of track lines and labels and configure the auto-tracking feature.  There are also tools for loading and saving tracks and for resetting all options to their factory defaults.

Load tracks: Clicking this button loads saved tracks from *.TRC  files,  and appends these tracks to the existing list.

Save tracks: Clicking this button saves the tracks in *.TRC  files.

Reset:  Clicking this button resets all Motion Tracking options to their default settings.

Options: Clicking this button opens the Options dialog box for the Motion Tracking feature.  Options are grouped on the Options dialog box as follows:

• Appearance Options: For adjusting the appearance of track lines and labels
• Segmentation Options: For adjusting the segmentation definition
• View Options: For adjusting what and how vectors are shown
• Auto Tracking Options: For fine tuning the automatic track detection routine
• Advanced Tracking Options: Additional controls for fine tuning the automatic track detection routine

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Appearance Options

The options in this group allow you to adjust the appearance of track lines and labels.

Font: The Font group provides standard font style and color options for adjusting the appearance of track labels.

Labels: The Labels group provides display options for the positioning of track labels.

Text:  Defines the text to be displayed with measurements.  You can select "None" (no labels will be shown), "Measurement" (measurement data will be shown), "Name" (the measurement name will be shown), or "Name and Measurement."

Position:  Defines the position for the track label text.  The position options are either relative to a track point (e.g., "first point" or "last point") or relative to the bounding box of the track (e.g., "bottom left outside").

Dynamic: When this option is selected, overlapped labels are not shown in order to prevent crowding.  When this option is not selected, all labels are visible.

Outlines: The Outlines group provides options for modifying the appearance of track lines overlay.  The tools in this group box allow you to set the line style, end point shape, line width, and fill property of measurement features drawn in the image.  The selections you make are applied to all tracks in the image.

Segmentation Options

Segmentation is used by the auto-tracking feature to automatically identify objects to be tracked.  The options in this group allow you to fine tune your segmentation definitions to improve the results of your automatic motion tracking attempts.

Connectivity: Defines the pixel connectivity to use for segmentation -- that is, the number of pixel neighbors segmenting the objects.

Clean Borders: Use this control to specify which borders, if any, are out of bounds for the purposes of counting objects. Objects touching the selected borders will not be counted.

Fill Holes: Defines if the holes inside objects should be included into the object area measurements. Check this checkbox to tell to fill holes -- i.e., ignore holes for the sake of area measurements.

Smoothing: Defines the degree of smoothing to be applied to object outlines. Enter a number between 0 and 100, where 100 applies the maximum amount of smoothing and 0 indicates no smoothing.

Bias %S: This control is only meaningful when you use the Auto Bright or Auto Dark segmentation method to have Image-Pro automatically calculate a threshold to use for segmentation. The Bias control allows you to have Image-Pro automatically adjust the Auto Bright/Dark threshold by a given amount. You must specify both a bias method (RangeMax, Best Fit Range, or Standard Deviation), and a value indicating the degree to which you want the threshold adjusted according to that bias method. There are 3 bias methods:

• Range Max – The bias is calculated as a percentage of the full range of possible intensities of the image. For example, the max range for 8-bit images is 0 to 255. If the Bias value was specified as 10, then the threshold would be adjusted by 10% of 256.
• Best Fit Range – The bias is calculated as a percentage of best-fit range for the image. For example, if the best-fit range for a given image is 25 to 200, then the bias would be calculated as a percentage of 175 (or 200 minus 25). If the Bias was specified as 10, then the threshold would be adjusted by 10% of 175.

Standard Deviation – The bias is calculated by multiplying the bias value and the standard deviation of the image intensity distribution. For example, if the standard deviation of image intensities was 56.51, and the Bias value was specified as .10, then the threshold would be adjusted by .10 * 56.51

Tip: Use the Bias control in combination with the Mean, Mode, Median, Minimum, Maximum, Best Fit Min, or Best Fit Max option of the Auto-Threshold control. These Auto-Threshold options allow you to have Image-Pro set the segmentation threshold at or relative to an upper or lower limit to the intensity distribution range; the Bias control can then be used to adjust the threshold in a consistent way relative to the unique distribution of intensities in each image. These methods can be used with batch macros to count and measure objects with intensities above or below a threshold by fixed value.

Auto-Threshold: This control is only meaningful when you use the Auto Bright or Auto Dark segmentation method to have Image-Pro automatically calculate a threshold to use for segmentation. The Auto-Threshold controls how that threshold is calculate. Use the following options to have the threshold calculated in a way that tries to distinguish objects of interest from noise.

• Min Variance - The ratio of between-phase to total variances minimized (method of Otsu). This is the default method.
• - A legacy version of Minimum Variance method with a bias towards low values.

Use one of the following options in combination with the Bias control. These options set the threshold at various limits or median positions relative to these limits. Refer to the Bias control description for more information about how they can be used with the Bias control.

• Mean - Threshold is the Mean value of histogram.
• Mode - Threshold is the Mode value of histogram.
• Median - Threshold is the Median value of histogram.
• Minimum - Threshold is the Minimum value of histogram.
• Maximum - Threshold is the Maximum value of histogram.
• Best Fit Min - Threshold is the Minimum of best-fit range of histogram.
• Best Fit Max -Threshold is the Maximum of best-fit range of histogram.

Grow: Use this option to have Image-Pro erode or dilate (shrink or grow) segmented objects prior to applying the count size measurements. Enter a positive number to ‘grow’ the segmented objects by the specified value, in pixels. Enter a negative number to ‘shrink’ the segmented objects by the specified value, in pixels.

Load: Click this tool to load previously saved threshold segmentation settings and options.

Save: Click this tool to save the currently configured threshold segmentation settings and options to a file. The file can then be loaded at a later time to restore the settings in a new session.

View Options

This group defines how the tracks are shown on the image.

Show Object Outlines: Select this option to show the outline of the object of interest as it was detected via your segmentation settings.  

Show Partial Tracks: If this option is selected, only a portion of each track will be shown.  This option should be used on long sequences. The section of track that gets displayed is determined by the Tail and Head specifications.  The Head spin box identifies the number of frames before the active frame to show the track for; the Tail spin box identifies the number of frames after the active frame to show the track for.  For example, if Head is 5 and Tail is 4, and the active frame is 10, the portion of the track displayed will be from frames 5 to 14.  

If your sequence is relatively short, you can clear the Show Partial Tracks option to show tracks in their entirety.

Smoothing: The Smoothing option defines whether or not the point coordinates will be filtered using a running average filter. If the value is 0 (default),  no filtering is applied. In other cases, a running average filter is applied with a filter size of Smoothing*2+1. The smoothing can be used when objects move from frame to frame by a very small distance (0-2 pixels). Because of rounding to nearest pixel position small movements produce a very jagged graph of velocities and accelerations. The filtering smoothes the and improves readability of the graphs.

Auto Tracking Options

The options in this group allow you to configure Image-Pro's auto-tracking feature to optimally auto-detect your object(s) of interest.

Velocity Limit: The Velocity Limit defines the maximum distance in calibrated units between object positions on neighboring frames.   

The Velocity Limit parameter defines the search radius used with automatic tracking.  It tells Image-Pro how far away to expect to find the object of interest on the next frame relative to its position on the current frame.  

If you use the fully-automated method of motion tracking and no object is found within the search radius on a given frame, then the track will be closed.  If you use the semi-automated method of motion tracking and no object is found within the search radius, then you will be prompted to click on the position of the object manually.

NOTE: Instead of typing a value in the Velocity Limit field, you can optionally click on the tool to draw a circle directly in the image representing the desired search radius.  In this case, the Velocity Limit value is calculated from the circle you draw.

Acceleration Limit: The Acceleration Limit defines the maximum change in velocity of an object between the frames.  Starting from the third frame, the estimated position of the object is calculated based on the movement vector in the first two frames. The search area is defined as a circle with the center in the estimated position and the radius of the acceleration limit.

If you use the fully-automated method of motion tracking and no object is found within the search radius on a given frame, then the track will be closed.  If you use the semi-automated method of motion tracking and no object is found within the search radius, then you will be prompted to click on the position of the object manually.

Auto:  If the Auto option is selected, the Acceleration Limit is taken as half of the Velocity Limit.

Minimum total track length: The Minimum total track length defines the minimum track length in calibrated units. The tracks that are shorter than this value will not be accepted during automatic and semi-automatic tracking. The default value is 0.

Motion Type: Use this control to tell Image-Pro the predominant type of the objects’ movement:

• Chaotic: Select Chaotic if there is no directional movement of the objects, and the direction of the movement can be changed abruptly. In this case,  the search area on all frames is defined only by the speed limit, the acceleration limit is ignored.
• Straight: If the objects move following straight monotonous trajectories, choose the Straight type of motion.
• Directional: Select the Directional type of motion if the object’s movement is predominantly directional, but not always straight.
• Calculate: Clicking the Calculate button will then analyze the existing tracks and calculate the Velocity limit, Acceleration limit and Predominant motion type , which will be used for further automatic and semi-automatic track detection.

1. Preview Outlines:  This option controls the outline preview behavior for automatic and semi-automatic tracking -- that is, when you click on either the Auto All or Single tools in the Segmentation Tracks group.  A preview outline is an outline of an auto-detected object that was found based on threshold segmentation settings.  If you select either "Active Frame" or "All Frames," Image-Pro will display the outlines for the objects it found (either in only the active frame or across all frames) and prompt you to confirm that they are correct before it continues with the auto-tracking operation.   If you select "None," no confirmation prompts will be given.

Advanced Tracking Options

The controls in this group provide additional options for configuring Image-Pro's auto-tracking feature.

Tracking Prediction Depth: Tracking Prediction Depth defines the number of frames ahead of the current frame which are used to find the most suitable track for the given object (default is 2). This parameter also defines the maximum number of consecutive occlusions -- frames where the object of interest disappears from view -- to allow on the track. The occlusions number will be less than the Prediction Depth by 1. For example, if the Prediction Depth is 3 the maximum number of consecutive object occlusions is 2.  This means that if the object of interest cannot be located for 2 consecutive frames but is found on the third consecutive frame, the third frame will be considered part of the track.  If however, the object is not found on the third frame, the track will be closed (or you will be prompted to click on it if you are doing semi-automated motion tracking).

The track points of missed objects do not have outlines and Count/Size measurement values. High prediction depth values increase computation time significantly.

Allow Shared Objects Between Tracks: If some objects on the image, which belong to different tracks, can not be separated (overlapped, clustered, etc)  theAllow shared objects between tracks  option can be checked. This will include merged objects in several tracks. If this option is unchecked,  a single object can belong to only one track.

Allow Partial Tracks: If the track length is less than the number of active frames in the sequence, the sequence may have entries and exits, where some objects appear in the field of view after the first frame and leave the area before the last frame. These tracks can be taken into account by checking the Allow Partial Tracks option.  If this option is selected, use the spin box to tell Image-Pro the minimum number of consecutive frames a track must traverse to be considered a partial track.  Tracks shorter than the specified number of frames will be ignored.

Track Only Biggest Object:  If the sequence contains only one object that is generally the biggest feature of its kind (i.e., according to your segmentation definition), then the Track Only Biggest Object option can be checked to tell Image-Pro to ignore other objects on the image that are within the threshold levels, but insignificant for tracking.

Coherence Filtering: If the sequence represents coherent motion, in which spatially close particles are likely to have similar velocity vectors, the Coherence Filtering option should be activated. If checked, Image-Pro discards those velocity vectors whose orientation is incompatible with the dominant orientation of the surrounding vectors. The dominant orientation is the median in a window centered on the origin of the vector being considered.  Use the Size and Angle spin boxes (described below) to define the threshold of 'coherence'.