Line Measurements  
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Toolbar:   measlines  
Menu:   Measure > Lines…  
Script:   measLines  

Use this command to perform interactive line measurements that allow you to define line features and collect information about their geometrical properties. You can save the results into an ImageWarp data file and open it later as a data table
, or you can export the results to Microsoft Excel for further analysis. Before performing line measurements, make sure your image is calibrated with the proper spatial scale.

When you choose this command, the Line Measurements dialog box will appear. Select the desired measurement Parameters and move the cursor over the Input image frame. To define the line feature, choose the appropriate place in the image, click the left mouse button to anchor the start point of the line, and move the cursor to the location of the endpoint. If you want to constrain the feature to a vertical or horizontal line, hold down the CTRL key while moving the cursor. As you draw the line, its current length and angle will be displayed at the bottom of the dialog box. To complete the line feature definition, click the left mouse button again. The line will be measured and the results will be displayed in the Measurement table. As you define more features, the table will be updated with new rows of data. If you click a row in the table, the corresponding feature in the image will blink. You can redefine any line feature by holding the SHIFT key, pressing the left mouse button, and moving one of the endpoints of the line or the entire line to the new location in the image. When you release the left mouse button, the corresponding row in the Measurement table will be updated to reflect the new measurement results.

You can change the size of the dialog box by positioning the cursor near an edge or corner and dragging the two-way arrow to the desired position.

The following options are available in the Line Measurements dialog box:

Input
 
Displays the number of the image frame for which the measurements are taken. If you want to perform measurements of another image, type or select the corresponding value. You can perform measurements on different images switching between them, while ImageWarp will continually add the results to the Measurement table.  
 
Open data
 
Lets you open a data file with the results saved during the previous sessions of line measurements. When you click this button, the Open dialog box will appear allowing you to select a data file from the list of files and folders. If a data file contains measurement parameters compatible with the parameters available in the Line Measurements dialog box, the saved results will be loaded into the beginning of the Measurement table, and parameters stored in the data file will be added to the set of the parameters being measured. Note that the results loaded from a data file will appear gray, indicating that they do not relate to any line feature currently highlighted in the input image.  
 
Class
 
Allows you to select the class for the features being measured. A class is a numerical identifier that you assign to the features having similar properties. If you select a new class and continue performing measurements, the new features will be highlighted in a different color corresponding to the related index in the multiphase palette.  
 
Parameters
 
Lets you select parameters for line measurements. When you click this button, the Parameters dialog box will appear with the list of available parameters. To select a parameter for measurements, click the corresponding check box. If you click a selected parameter, it will be deselected. To deselect all parameters, click Clear. As you step through the list of parameters by using the mouse or arrow keys, a brief textual and graphic description of each parameter will appear in the pane on the right. The following parameters are available in the Line measurements:  
 
Angle
the angle between a line and X-axis
StartX
the X-coordinate of the starting point of a line in pixels
StartY
the Y-coordinate of the starting point of a line in pixels
EndX
the X-coordinate of the endpoint of a line in pixels
EndX
the Y-coordinate of the endpoint of a line in pixels
CenterX
the X-coordinate of the center of a line in calibrated units
CenterY
the Y-coordinate of the center of a line in calibrated units
CenterDist
the length of the radius vector of the center of a line feature
CenterAngle
the angle between the radius-vector of the center of a line and X-axis
Class
the class ID of a line feature
Count
the ordinal number of a line feature in the current session
FeretX
the length of the horizontal projection of a line in calibrated units
FeretY
the length of the vertical projection of a line in calibrated units
Length
the length of a line in calibrated units
MaxX
the maximum X coordinate of a line in calibrated units
MinX
the minimum X coordinate of a line in calibrated units
MaxY
the maximum Y coordinate of a line in calibrated units
MinY
the minimum Y coordinate of a line in calibrated units
 
 
Measurement table
 
Displays measurement results. The topmost row of the table lists the currently selected parameters. If spatial or intensity calibration has been applied to the current image, the corresponding units will be displayed next to the parameters' names. The first column of the table displays the ordinal number of a feature, while the second column shows the class ID. As you define a new feature in the input image, this feature will be measured, and the results will be added to the table. If you click a row in the table, the corresponding feature in the image will blink. Click the same row again to stop blinking of the feature. Note that if you use the Open Data option to load stored results from a data file, they will appear gray, and they will not relate to any feature in the image.  
 
Delete row
 
Click this button to delete the currently selected row from the Measurement table. When you delete a row of data from the table, the corresponding feature will be erased from the input image.  
 
Clear all
 
Click this button to clear the entire Measurement table and initialize the count of features. This command does not affect the data loaded from a data file and displayed in gray color.  
 
Export to Excel
 
Click this button to transfer data to Microsoft Excel for further analysis. If the Excel application is not open, ImageWarp will attempt to start it automatically before transferring data. If you receive an error message, make sure Microsoft Excel is installed in the system and you have enough memory to run both Excel and ImageWarp.  
 
Copy to Grid
 
Click this button to copy the data from the Measurement Table to the Global Grid and display it. If the Global Grid already contains some data, they will be overwritten.  

Save data
 
Click this button to save the measurement results into an ImageWarp data file. When you click this button, the Open dialog box will appear allowing you to enter a file name or select a data file from the list of files and folders. If you select a file in the list, its name will appear in the File Name box, and ImageWarp will ask if you want to replace this file with the one you would like to save. Note that data file stores the parameters' names along with the results. This allows you to resume performing measurements by simply opening the data file which you previously saved. You can also open a data file for further analysis by choosing Open Data on the File menu.  
 
Close
 
Closes the Line Measurements dialog box. If you have not saved the session results to a data file, ImageWarp will offer you to do it.  
 
Note – ImageWarp maintains backup logs during all interactive measurements. This ensures that data will not be lost due to a sudden hardware or software failure. If the system fails or application stops responding, restart ImageWarp and choose the measurement command that was interrupted. All results from the last session will be restored and loaded into the measurement table.