Versatile Wand

An ImageJ magic wand with selectable tolerance, variable hue or grayscale preference for RGB, gradient detection for grayscale, 4-connected, 8-connected or non-contiguous operation and preview.

Value Tolerance

• The selection is expanded to all image points as long as the difference between the pixel value of the point clicked and the image point is less than the Value Tolerance.
• Value Tolerance is ignored for thresholded images; there the thresholded (red) area is selected instead. For 16-bit and float images, note that rounding errors occur, thus the red area displayed is only an approximation to the exact thresholded area. In contrast to the ImageJ wand, you must click into the thresholded area; clicking outside will create a beep.
• For color images, see the color slider below.
• The selection can be further restricted by the Gradient Tolerance.
• For calibrated images, the Gray Value Tolerance is in calibrated units (e.g., 'lux'); for color images, the gray level is used (See Edit>Options>Conversions for pixel weights)

Color

• For RGB images, this slider determines the relative weight of the gray value and the color hue/saturation for the evaluation of the tolerance.
• With a value of -100, only the gray value is taken into account (with weights of the color channels depending on the Edit>Options>Conversions>Weighted RGB checkbox).
• With a value of 0, the vector distance between the (unweighted) RGB vectors is used, and
• with a value of 100, only the difference of hue/saturation is taken into account, independent of the gray value.
• Use a large value (e.g. 80) if you want to select one color independent of brightness. If you use the maximum, 100, also black and (with some tolerance) almost-black areas will be selected.

Gradient Tolerance

• Irrespective of Value Tolerance, the selection is not expanded if the gray level gradient is larger than the Gradient Tolerance.
• Gradient Tolerance is also active if a threshold is used instead of the Value Tolerance; in this case visual inspection is easier with the Threshold display in 'Over/Under' mode.
• Gradient detection is less sensitive to noise than in 4-connected mode than in 8-connected mode.
• For calibrated images, the gradient tolerance is in calibrated units, e.g., 'lux/mm'. For RGB images, gradient tolerance works on the gray value (brightness) only.

Eyedropper Color

• Uses the current foreground color (color of the eyedropper tool) as reference color (or pixel value), instead of the pixel color (value) where the user has clicked.
• In 4-connected and 8-connected mode (see 'connectedness', below) the starting pixel is selected irrespective of its color (value). In non-contiguous mode, an empty selection may result if no pixel matches the eyedropper color within the tolerance.

Connectedness

• In Eight-Connected mode, the selection proceeds to neighboring pixels touching each other at a side or a corner.
• Four-Connected means that the selection proceeds only to neighboring pixels sharing a side with the previous pixel.
• Non-Contiguous mode selects all pixels of the image within the tolerance irrespective of connectedness.
• In non-contiguous mode, the 'Gradient Tolerance' and 'Include Holes' options are ignored.

Include Holes

• When checking this option, the selection created by this wand operation will not have interior holes. Nevertheless, holes may arise from combining/subtracting selections with the SHIFT or ALT keys; also edge holes may be present.

Install Tool

• Installs the tool into the ImageJ toolbar. This replaces all other custom tools, e.g. those from the Startup Macros.
• This option is present only if the plugin is called from the plugins menu.

x, y

• Start point of the wand for preview or 'Do Wand on OK'.
• Always in uncalibrated units (pixels).
• These values default to the last point where the wand has been used.
• This input field is present only if there is an open image.

Do Wand on OK

• After clicking 'OK', performs a wand operation at point x,y.
• Deselect it if you want to set the options only.
• This checkbox is present only if there is an open image.

Preview

• Shows the result of a wand operation at x,y.
• Useful for trying different parameters.
• This checkbox is present only if there is an open image.

• Copy Versatile_Wand.java into the ImageJ plugins folder or a subfolder thereof. Make sure that you name the downloaded file ”Versatile_Wand.java”; uppercase/lowercase matters.
• If using a version of ImageJ before 1.42p, remove (comment out) the line ”gd.addHelp…” in showDialog.
• Compile with “Compile and Run” and press “OK”. Disregard any deprecation warning.
• Use Help>Update Menus to make it appear in the menus.
• You can install the tool by running 'Versatile Wand' from the menu and checking 'Install Tool'.
• Alternatively, put the following into your StartupMacros.txt file to have the Versatile Wand as a standard tool:

    macro 'Versatile Wand Tool-Cf00Lee55O2233' {
        getCursorLoc(x, y, z, flags);
        call('Versatile_Wand.mousePressed', x, y);
    }
    macro 'Versatile Wand Tool Options' {
        call('Versatile_Wand.setOptions');
    }

If you like a more fancy icon, this one has a gradient in the background:

    macro 'Versatile Wand Tool-C333F8082C555F8282C777F8482C999F8682CbbbF8882CdddF8a82C00fLee44O1133' {

• Left-click the tool icon for selecting the tool.
• Right-click or double-click the tool icon for the options menu.

• 2009-Jun-03 First version
• 2009-Jun-04 inserted missing import ij.gui.Wand. Still available.
• 2009-Jul-09 added color, non-contiguous mode, help button
• 2009-Jul-10 fixed NullPointerException on options dialog if no image open.
• 2010-Sep-10 Can use eyedropper (foreground) color instead of the color (value) of the pixel.
• 2012-Dec-07 Bugfix, tolerance was incorrect for RGB images (incomplete)
• 2012-Dec-09 Bugfix again, tolerance was still inconsistent for RGB images download