diff --git a/modules/core/src/image/private/vpImageConvert_impl.h b/modules/core/src/image/private/vpImageConvert_impl.h
index f5d7a17485..b3fce17d6c 100644
--- a/modules/core/src/image/private/vpImageConvert_impl.h
+++ b/modules/core/src/image/private/vpImageConvert_impl.h
@@ -93,7 +93,7 @@ BEGIN_VISP_NAMESPACE
 #endif
 
   const unsigned int val_0x10000 = 0x10000;
-  for (int i = 2; i < val_0x10000; ++i) {
+  for (unsigned int i = 2; i < val_0x10000; ++i) {
     histogram[i] += histogram[i - 1]; // Build a cumulative histogram for the indices in [1,0xFFFF]
   }
   dest_depth.resize(src_depth.getHeight(), src_depth.getWidth());
@@ -151,7 +151,7 @@ void vp_createDepthHistogram(const vpImage<uint16_t> &src_depth, vpImage<unsigne
 #endif
 
   const unsigned int val_0x10000 = 0x10000;
-  for (int i = 2; i < val_0x10000; ++i) {
+  for (unsigned int i = 2; i < val_0x10000; ++i) {
     histogram[i] += histogram[i - 1]; // Build a cumulative histogram for the indices in [1,0xFFFF]
   }
   dest_depth.resize(src_depth.getHeight(), src_depth.getWidth());
@@ -196,15 +196,16 @@ void vp_createDepthHistogram(const vpImage<float> &src_depth, vpImage<vpRGBa> &d
   }
 
   const unsigned int val_0x10000 = 0x10000;
-  for (int i = 2; i < val_0x10000; ++i) {
+  for (unsigned int i = 2; i < val_0x10000; ++i) {
     histogram[i] += histogram[i - 1]; // Build a cumulative histogram for the indices in [1,0xFFFF]
   }
-#ifdef VISP_HAVE_OPENMP
-#pragma omp parallel for
-#endif
+
   const unsigned char val_uc_5 = 5;
   const unsigned char val_uc_20 = 20;
   const unsigned char val_uc_255 = 255;
+#ifdef VISP_HAVE_OPENMP
+#pragma omp parallel for
+#endif
   for (int i = 0; i < src_depth_size; ++i) {
     uint16_t d = static_cast<uint16_t>(src_depth.bitmap[i]);
     if (d) {
@@ -247,13 +248,13 @@ void vp_createDepthHistogram(const vpImage<uint16_t> &src_depth, vpImage<vpRGBa>
   for (unsigned int i = 2; i < val_0x10000; ++i) {
     histogram[i] += histogram[i - 1]; // Build a cumulative histogram for the indices in [1,0xFFFF]
   }
-#ifdef VISP_HAVE_OPENMP
-#pragma omp parallel for
-#endif
 
   const unsigned char val_uc_5 = 5;
   const unsigned char val_uc_20 = 20;
   const unsigned char val_uc_255 = 255;
+#ifdef VISP_HAVE_OPENMP
+#pragma omp parallel for
+#endif
   for (int i = 0; i < src_depth_size; ++i) {
     uint16_t d = src_depth.bitmap[i];
     if (d) {
diff --git a/modules/core/src/image/vpImageTools.cpp b/modules/core/src/image/vpImageTools.cpp
index 8056c746cd..9e591d7ac8 100644
--- a/modules/core/src/image/vpImageTools.cpp
+++ b/modules/core/src/image/vpImageTools.cpp
@@ -1217,10 +1217,11 @@ int vpImageTools::inRange(const unsigned char *hue, const unsigned char *saturat
   unsigned char v_high = static_cast<unsigned char>(hsv_range[index_5]);
   int size_ = static_cast<int>(size);
   int cpt_in_range = 0;
+
+  const unsigned char val_uc_255 = 255;
 #if defined(_OPENMP)
 #pragma omp parallel for reduction(+:cpt_in_range)
 #endif
-  const unsigned char val_uc_255 = 255;
   for (int i = 0; i < size_; ++i) {
     bool check_h_low_high_hue = (h_low <= hue[i]) && (hue[i] <= h_high);
     bool check_s_low_high_saturation = (s_low <= saturation[i]) && (saturation[i] <= s_high);