// Original code by Vytas Bindokas; Oct 2006, Univ. of Chicago
// https://digital.bsd.uchicago.edu/docs/imagej_macros/_graybalancetoROI.txt
// This macro white balances RGB to a selected region (equal R,G,B =gray)
//    draw a region prior to running the macro

// Code modified by Patrice Mascalchi, 2014, Univ. of Cambridge UK
// Ask for region to be drawn / Check region existence / check RGB at start / compaction of code (loop)

// chose the destination directory and create the destinations for amplitude and phase
dest_dir=getDirectory("Choose the destination directory");

setTool(0);
waitForUser("Draw a region over background");
run("Set Measurements...", "  mean redirect=None decimal=3");
if (selectionType==-1) exit("you must draw a region first");

ti = getTitle;
Stack.getDimensions(width, height, channels, slices, frames); 
print("width:",width," height:",height," channels:",channels," slices:",slices," frames:",frames);
//newImage(ti+"_Corrected", "RGB", width, height, 0);


for (k=1;k<frames+1;k++){
for(j=1;j<slices+1;j++){
selectWindow(ti);
setSlice(j);

run("Select None");
//setBatchMode(true);

run("Duplicate...", "title=rgbstk-temp");
origBit = bitDepth;
if (bitDepth() != 24) exit("Active image is not RGB");
run("RGB Stack");
run("Restore Selection");

val = newArray(3);
for (s=1;s<=3;s++) {
	setSlice(s);
	run("Measure");
	val[s-1] = getResult("Mean");
}

run("Select None");

run("16-bit");
run("32-bit");
Array.getStatistics(val, min, max, mean);

for (s=1; s<=3; s++) {
	setSlice(s);
	dR = val[s-1] - mean;
	if (dR < 0) {
		run("Add...", "slice value="+ abs(dR));
	} else if (dR > 0) {
		run("Subtract...", "slice value="+ abs(dR));
	}
}

run("16-bit");
run("Convert Stack to RGB");

rename(ti + "-corrected_"+k+"__"+j);
saveAs("Tiff", dest_dir+File.separator+ti + "-corrected_"+k+"__"+j);
close();

//closeWin("Results");
closeWin("rgbstk-temp");

setBatchMode("exit and display");

//run("Tile");			// Can be removed
} // end j loop (slices)
} // end k loopn (frames)
// ------------------------------------------------------------------------------------------
// close any window without returning any error
function closeWin(name) {
	if (isOpen(name)) {
	     selectWindow(name);
	     run("Close");
	}
}