diff --git a/envi/bil.h b/envi/bil.h
index 21dfdfa..9bdb7b7 100644
--- a/envi/bil.h
+++ b/envi/bil.h
@@ -309,7 +309,7 @@ public:
 	}
 		
 	// normalize the BIL file
-	bool normalize(std::string outname, double w)
+	bool normalize(std::string outname, double w, double t = 0.0)
 	{
 		unsigned int B = R[2];		//calculate the number of bands
 		unsigned int Y = R[1];
@@ -337,7 +337,10 @@ public:
 			{
 				for(unsigned m = 0; m < X; m++)
 				{
-					c[m + i * X] = c[m + i * X] / b[m + j * X];
+					if( b[m + j * X] < t )
+						c[m + i * X] = (T)0.0;
+					else
+						c[m + i * X] = c[m + i * X] / b[m + j * X];
 				}								
 			}
 			target.write(reinterpret_cast<const char*>(c), L);   //write normalized data into destination
diff --git a/envi/bip.h b/envi/bip.h
index 2f75e5f..33ff222 100644
--- a/envi/bip.h
+++ b/envi/bip.h
@@ -401,7 +401,7 @@ public:
 	}
 		
 	// normalize the BIP file
-	bool normalize(std::string outname, double w)
+	bool normalize(std::string outname, double w, double t = 0.0)
 	{
 		unsigned int B = R[2];		//calculate the number of bands
 		unsigned int Y = R[1];
@@ -431,7 +431,10 @@ public:
 				unsigned iB = i * B;		
 				for(unsigned m = 0; m < B; m++)
 				{
-					c[m + iB] = c[m + iB] / b[i + jX];			//perform normalization
+					if( b[i+jX] < t )
+						c[m + iB] = (T)0.0;
+					else
+						c[m + iB] = c[m + iB] / b[i + jX];			//perform normalization
 				}								
 			}
 			target.write(reinterpret_cast<const char*>(c), L);   //write normalized data into destination
diff --git a/envi/bsq.h b/envi/bsq.h
index 8c475cb..154e549 100644
--- a/envi/bsq.h
+++ b/envi/bsq.h
@@ -252,7 +252,10 @@ public:
 	}
 
 	// normalize the BSQ file
-	bool normalize(std::string outname, double w)
+	//	outname - output file name
+	//	w - band to normalize to
+	//	t - threshold (if w<t, all pixel bands are set to zero)
+	bool normalize(std::string outname, double w, double t = 0.0)
 	{
 		unsigned int B = R[2];		//calculate the number of bands
 		unsigned int XY = R[0] * R[1];	//calculate the number of pixels in a band
@@ -274,7 +277,10 @@ public:
 			band_index(c, j);                     //get the current band into memory
 			for(unsigned i = 0; i < XY; i++)
 			{
-				c[i] = c[i] / b[i];
+				if(b[i] < t)
+					c[i] = (T)0.0;
+				else
+					c[i] = c[i] / b[i];
 			}
 			target.write(reinterpret_cast<const char*>(c), S);   //write normalized data into destination
 		}
diff --git a/envi/envi.h b/envi/envi.h
index f87f601..0882f53 100644
--- a/envi/envi.h
+++ b/envi/envi.h
@@ -96,13 +96,13 @@ public:
 	}
 
 	//perform normalization
-	bool normalize(std::string outfile, double band){
+	bool normalize(std::string outfile, double band, double threshold = 0.0){
 	
 		if(header.interleave == envi_header::BSQ){		//if the infile is bsq file
 			if(header.data_type ==envi_header::float32)
-				return ((bsq<float>*)file)->normalize(outfile, band);
+				return ((bsq<float>*)file)->normalize(outfile, band, threshold);
 			else if(header.data_type == envi_header::float64)
-				return ((bsq<double>*)file)->normalize(outfile,band);
+				return ((bsq<double>*)file)->normalize(outfile,band, threshold);
 			else
 				std::cout<<"ERROR: unidentified data type"<<std::endl;
 		}
--
libgit2 0.21.4