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Rationale:[edit]

Bubble Counter attempts to abstract the time intensive modified point count (Procedure A in ASTM C457) into a simpler and equally accurate semi-automatic routine. As with the ASTM C457 procedure, Bubble Counter requires carefully prepared samples that have as sharply defined voids as can be produced. Once the sample is properly polished, it is treated such that there is a large contrast difference between air voids and solid. This is done by first inking the prepared surface with a black marker and then pressing a bright white, fine and cohesive powder into the voids. We have found wollastonite powder to perform this role quite nicely.

The present incarnation of Bubble Counter operates with Photoshop and was developed with ExtendScript Toolkit CS5. The script has been written employing JS objects so as to improve extensibility and tweaking. The JS object files are stored in the BC_Classes folder.

Bubble Counter writes a number of files as it evaluates the images. Upon running the BC Set White Balance script, a property file in csv format is written. The property file contains data related to the image such as the location of the white and black intensity peaks and the locations of the lines extracted for evaluation. The file is interrogated frequently by the various scripts, not least of which, the optimization script. It is your friend as it will greatly speed any future analyses you might wish to perform and so shouldn't be deleted or tweaked once written. Two other files are also written, a composite tif image consisting of the lines extracted from the analysis area and a tab delimited text version of that composite. Once again, these files are your friends and subsequent analyses will run in a fraction of the time required for the initial analysis if they are left intact and in their original location.

bc_settings.csv will be created in the folder containing the images upon running BC Analyze. It stores the settings made for the analysis and is intended to reduce redundant entry of data for subsequent analysis of images in that same folder. It will always contain the settings selected for the last image analyzed in that folder.

The BC Set White Balance script determines the intensity of the black and white peaks in the histogram representing the selected area. Photoshop automatically updates the intensity histogram when a selection is made, and this script iterates through the upper and lower ends of the histogram looking for the intensity having the greatest population in each range. If the selected area encloses both black and white areas of the white balance card, then the "true" black and white intensities of the scan are known. These intensities are the limits for a linear stretch that is performed on the composite image prior to analysis.