An ImageJ macro to determine False Positive threshold on control images. #BIOP #FIJI #Macro #Coloc

Find_FalsePositive_threshold.ijm

#@File() image_path
#@Integer() ch_idx

table_name = "FP_thresholds";

open(image_path);

img_name = getTitle();
print(img_name);

run("Duplicate...", "title=ch"+ch_idx+" duplicate channels="+ch_idx);
getDimensions(width, height, channels, slices, frames);
if ( bitDepth() == 8){
	greyValue = 256 ; 
} else if ( bitDepth() == 16){
	greyValue = 65536 ; 
} else {
	return;
}


total_pixelNbr = width*height*slices ; 
print ("Total Pixel Number : "+total_pixelNbr);

run("Clear Results");

if (slices >1){
	Stack.setSlice( 1 );
	getHistogram(values, counts, greyValue);

	
	for (slc = 2; slc <= slices; slc++) {
		Stack.setSlice( slc );
		getHistogram(values, counts_v, greyValue);
	
		for (i = 0; i < counts.length; i++) {
			counts[i] += counts_v[i];
		}
	}

}else{
	getHistogram(values, counts, greyValue);
}

// sum content of each bin 
bins_sum = 0;
for ( bin_i = counts.length-1;  bin_i >= 0;  bin_i--) {
	bins_sum += counts[bin_i];
	setResult("Bin", nResults, bin_i);
	setResult("Count", nResults-1, counts[bin_i]);
	setResult("Count (Sum)", nResults-1, bins_sum);
}

bins_sum_array = Table.getColumn("Count (Sum)");
bins_fromTop_array = Table.getColumn("Bin");

// Find value for : False Positive ZERO
idx_FPZero = findThresholdValue(bins_sum_array, 0);
print( "False Positive ZERO : "+bins_fromTop_array[idx_FPZero-1]);// idy is the one who is above threshold, take idx-1

// Find value for : False Positive Tolerance
tol1 	=  0.1	;
tol2 	=  0.01	;
tol3	=  0.001;

pixelCount_tol1 = round (width*height*slices*tol1 /100);
pixelCount_tol2 = round (width*height*slices*tol2 /100);
pixelCount_tol3 = round (width*height*slices*tol3 /100);

idx_FPTol1 = findThresholdValue(bins_sum_array, pixelCount_tol1 );
idx_FPTol2 = findThresholdValue(bins_sum_array, pixelCount_tol2 );
idx_FPTol3 = findThresholdValue(bins_sum_array, pixelCount_tol3 );

if (isOpen(table_name)){
	selectWindow(table_name);
}else {
	Table.create(table_name);
}
row = Table.size;
if (row < 0 ) row =0;


row = Table.size;
Table.set("Image name"										, row, img_name);
Table.set("Channel"											, row, ch_idx);
Table.set("False Positive - %"								, row, tol1);
Table.set("False Positive - Pixel count"					, row, pixelCount_tol1);
Table.set( "Threshold value "								, row, bins_fromTop_array[idx_FPTol1-1]);

row = Table.size;
Table.set("Image name"										, row, img_name);
Table.set("Channel"											, row, ch_idx);
Table.set("False Positive - %"								, row, tol2);
Table.set("False Positive - Pixel count"					, row, pixelCount_tol2);
Table.set( "Threshold value "								, row, bins_fromTop_array[idx_FPTol2-1]);

row = Table.size;
Table.set("Image name"										, row, img_name);
Table.set("Channel"											, row, ch_idx);
Table.set("False Positive - %"								, row, tol3);
Table.set("False Positive - Pixel count"					, row, pixelCount_tol3);
Table.set( "Threshold value "								, row, bins_fromTop_array[idx_FPTol3-1]);

row = Table.size;
Table.set("Image name"										, row, img_name);
Table.set("Channel"											, row, ch_idx);
Table.set("False Positive - %"								, row, 0);
Table.set("False Positive - Pixel count"					, row, 0);
Table.set( "Threshold value "								, row, bins_fromTop_array[idx_FPZero-1] );


run("Close All");


function findThresholdValue(array, threshold){
	continueSearch = true ;
	idx = 0 ;
	while ( continueSearch ){
		if ( bins_sum_array[idx] > threshold ) continueSearch = false ;
		else idx++;
	}
	return idx;	
}