diff --git a/src/ITANumericUtils.cpp b/src/ITANumericUtils.cpp
index 9d64799265d820087b2f3cd252394f073b168b29..991977858e1f70d94fe98fc43455b78af960722e 100644
--- a/src/ITANumericUtils.cpp
+++ b/src/ITANumericUtils.cpp
@@ -256,7 +256,7 @@ float anglef_proj_NPI_PI( const float alpha )
 
 float anglef_proj_NPIH_PIH( const float alpha )
 {
-	float alpha_temp = fmodf( alpha, PI_F );
+	float alpha_temp = fmodf( alpha + PI_F / 2.0f, PI_F ) - PI_F / 2.0f;
 	if( alpha_temp < -PI_F/2.0f )
 		alpha_temp += PI_F;
 	return alpha_temp;