Alloy Grain Size Measurement 

The particle size distribution of anodized aluminum specimens is measured.

Source

Result

Image Capture

The original image is a polarized micrograph of an aluminum alloy.

To reduce noise, integrated image capture is recommended.

The integrated capture dialog can be accessed by right-clicking the capture icon in the Live Preview window.

It allows removal of random noise from a single captured image, 

resulting in a clean output image.

Pre-Processing

1. Apply Median Filter

The Median Filter is applied to remove speckle noise and small spots, producing a stepwise image.

• The Median Filter is a nonlinear digital filtering technique that is highly effective in eliminating noise from images.

• After filtering, a continuous grayscale image is reconstructed into a grouped stepwise image.

2. Perform Multi-Step Thresholding for Grain Boundary Detection

• Define grayscale ranges for each step.

• Steps 1–5 are interrelated; adjusting the range of one step will automatically affect neighboring steps.

• This process directly influences measurement results and therefore requires precise adjustment.

• Once a step range is defined, it is stored and can be reapplied to other images.
  Here, “other images” refers to images captured under the same conditions (identical specimen type, magnification, illumination, and operator).

• Images captured under different conditions require separate management of grayscale ranges for each step.

Operation Procedure

1.

                   Press the Start button and wait while the Median Filter is being processed.
                   [ Select filter matrix: 3×3, 5×5, or 7×7 / Specify the number of iterations ] 

2. For grain boundary detection, perform a Multi-Step Threshold operation and define grayscale ranges for each step.

       Steps 1–5 are interrelated; when the range of one step is adjusted, the ranges of neighboring steps are automatically updated.

       Since this process directly affects the measurement, precise adjustment is required.

       While holding down this button, the overlay color will be hidden.
       By pressing and releasing repeatedly, you can closely inspect the boundaries of the objects.

3.  Click the Circle icon to perform the measurement.

4.

You can choose to display the measurement results on either the source image or the filtered image. After measurement, to add or remove points, check Tracking. Click on the measurement circle orbit with the mouse to add a point, or use Ctrl + Click to remove a point.

                    *To exit the orbit, press the ESC key.