Blob Measurements  
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Toolbar:   measblobs  
Menu:   Measure > Blobs & Fields > Interactive  
Script:   measBlobs  

Use this command to perform interactive blob measurements and collect information about geometrical, optical and topological properties of objects that are represented by blobs. A blob is an area of connected pixels in the Input image, which can only be of a multiphase type. Such an image is usually created as a result of the segmentation of the original Photo image. ImageWarp takes intensity measurements from the Photo image, using the Input image as a binary mask. 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 blob measurements, make sure your image is calibrated with the proper spatial and intensity scales, and the background is corrected for transmission and optical density measurements.

When you choose this command, the Blob Measurements dialog box will appear, and the objects in the Input image will change their colors to white. Note that the Input image can only be of the multiphase type. Select the desired measurement Parameters and move the cursor over the Input image frame. The cursor will take shape of a cross. To select the blob feature, choose the appropriate object in the image and click the left mouse button. The object will change its color from white to the phase color determined by the Class option, and will be measured. The measurement results will be displayed in the Measurement table. As you define more blobs, the table will be updated with new rows of data. If you click a row in the table, the corresponding object in the image will blink.

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 Blob Measurements dialog box:

Input
 
Displays the number of the multiphase 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.  
 
Photo
 
Displays the number of the image frame used for intensity measurements. This is usually an original real-color or grayscale image from which the Input image was derived as a result of image processing and segmentation. When measuring intensity parameters, ImageWarp treats the Input image as a binary mask for the Photo image. If you do not need to perform the intensity measurements, you can set this value to the number of the Input frame and work with the multiphase image only.  
 
Open data
 
Lets you open a data file with the results saved during the previous sessions of blob 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 Blob 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 blob currently selected 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 blob 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.  
ImageWarp uses two different approaches to blob measurements: a geometric approach based on coordinates of the area and a pixel counting approach. Geometric based parameters such as AreaOut and PerimOut use the integration of the object's bounding polygon. The vertices of the boundary fall on pixel centers thus slightly underestimating areas and perimeters. For example, if the object is a 5 by 5 block of pixels, it will be only 4 pixel width wide and 4 pixel heights tall, so its AreaOut will be 16 square units as opposed to 25 ones given by the pixel based Area.  
 
The following parameters are available in the Blob measurements:  
 
AngleMajor
the angle between the major axis of an object and X-axis
AngleMinor
the angle between the minor axis of an object and X-axis
AngleDMax
the angle between the maximum diameter of an object and X-asix
AngleDMin
the angle between the minimum diameter of an object and X-asis
AngleFMax
the angle between the longest caliper of an object and X-axis
AngleFMin
the angle between the shortest caliper of an object and X-axis
AngleRMax
the angle between the maximum radius of an object and X-axis
AngleRMin
the angle between the minimum radius of an object and X-axis
Area
the area of an object in calibrated units
AreaBox
the area of the box bounding an object in calibrated units
AreaConv
the area of object's convex hull in calibrated units
AreaEll
the area of the equivalent ellipse of an object in calibrated units
AreaOut
the area of an object measured by integrating its outside boundary
AreaRatio
the ratio of the area of an object to the reference area
AreaRef
the reference area of the image or selection in calibrated units
Aspect
the ratio between the major and minor axes of an object
AxisMajor
the length of the major axis of object's equivalent ellipse in calibrated units
AxisMjnor
the length of the minor axis of object's equivalent ellipse in calibrated units
BlueAvrg
the average value of the scaled blue component of an object
BlueSD
the standard deviation of the blue component within an object
BoxLength
the length of object's bounding box along its major axis in calibrated units
BoxWidth
the width of object's bounding box along its minor axis in calibrated units
BoxRatio
the ratio between the length and width of obejct's bounding box
CenterX
the X-coordinate of object's binary weighted centroid in calibrated units
CenterY
the Y-coordinate of object's binary weighted centroid in calibrated units
CenterDist
the distance between object's centroid and the origin of the image
CenterAngle
the polar angle of object's centroid
CenterConvX
the X-coordinate of the binary weighted centroid of object's convex hull
CenterConvY
the Y-coordinate of the binary weighted centroid of object's convex hull
CenterGrayX
the X-coordinate of object's intensity weighted center of gravity
CenterGrayY
the Y-coordinate of object's intensity weighted center of gravity
Circularity
the circular form-factor of an object
Class
the class ID of a object or field
Convexity
the ratio of the outline area and convex area of an object
Count
the ordinal number of a object or field in the current session
 
DCircle
the diameter of the circle with the same area as object's area
DAvrg
the average diameter of an object passing through its centroid
DMax
the maximum diameter of an object passing through its centroid
DMin
the minimum diameter of an object passing through its centroid
DRatio
the ratio between the maximum and minimum diameters of an object
Ellipticity
the elliptical form-factor of an object
FeretAvrg
the average caliper length of an object in calibrated units
FeretMax
the maximum caliper length of an object in calibrated units
FeretMin
the minimum caliper length of an object in calibrated units
FeretRatio
the ratio between the maximum and minimum calipers of an object
FeretX
the length of the horizontal projection of an object in calibrated units
FeretY
the length of the vertical projection of an object in calibrated units
 
GrayAvrg
the average scaled intensity of an object
GrayI
the integral scaled intensity of an object
GrayMax
the maximum scaled intensity within an object
GrayMin
the minimum scaled intensity within an object
GraySD
the standard deviation of scaled intensity within an object
GreenAvrg
the average value of the scaled green component of an object
GreenSD
the standard deviation of the green component within an object
Holes
the number of holes within an object
HoleArea
the total area of holes within an object in calibrated units
MaxX
the maximum X coordinate of an object in calibrated units
MinX
the minimum X coordinate of an object in calibrated units
MaxY
the maximum Y coordinate of an object in calibrated units
MinY
the minimum Y coordinate of an object in calibrated units
OptdAvrg
the average optical density of an object
OptdI
the integral optical density of an object
OptdSD
the standard deviation of the optical density within an object
 
Perim
the length of the boundary of an object in calibrated units
PerimCirc
the perimeter of a circle with the area equal to the area of an object
PerimConv
the perimeter of the convex hull of an object in calibrated units
PerimEll
the perimeter the object's equivalent ellipse in calibrated units
PerimOut
the length of the outside boundary of an object not including inside
PerimX
the horizontal component of the length of an object boundary
PerimY
the vertical component of the length of an object boundary
Pixels
the number of pixels within an object, not calibrated
RBest
the radius of the circle that most closely fits an object's boundary
Rectangularity
the rectangular form-factor of an object
RedAvrg
the average value of the scaled red component of an object
RedSD
the standard deviation of the red component within an object
RAvrg
the average radius of an object measured from its centroid
RMax
the maximum radius of an object measured from its centroid
RMin
the minimum radius of an object measured from its centroid
RRatio
the ratio between the maximum and minimum radii of an object
Roughness
the ratio between the outline perimeter and convex perimeter of an object
StartX
the X-coordinate of the first found point of an object in pixels
StartY
the Y-coordinate of the first found point of an object in pixels
TransmAvrg
the average value of the scaled optical transmission of an object
TransmSD
the standard deviation of the optical transmission within an object
YatMaxX
the associated Y-value at the maximum X coordinate of an object
YatMinX
the associated Y-value at the minimum X coordinate of an object
XatMaxY
the associated X-value at the maximum Y coordinate of an object
XatMinY
the associated X-value at the minimum Y coordinate of an object
 
 
Select All (Ctrl-A)
 
Click this button to select all blob features in the input image and measure them. The blobs will be measured in the order from top to bottom, left to right. Note that this command will automatically clear the Measurement table before filling it out with measurement results for all blob features.  
 
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 select a new blob 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 object in the input image will blink. Click the same row again to stop blinking of the object. 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 object in the input image will change its color back to white.  
 
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 Blob Measurements dialog box and restores original colors of objects in the Input image. 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.