diff --git a/rtengine/EdgePreservingDecomposition.cc b/rtengine/EdgePreservingDecomposition.cc
index 7bc292c3f..43a68f024 100644
--- a/rtengine/EdgePreservingDecomposition.cc
+++ b/rtengine/EdgePreservingDecomposition.cc
@@ -21,7 +21,7 @@ Takes less memory with OkToModify_b = true, and Preconditioner = nullptr. */
 float *SparseConjugateGradient(void Ax(float *Product, float *x, void *Pass), float *b, int n, bool OkToModify_b,
                                float *x, float RMSResidual, void *Pass, int MaximumIterates, void Preconditioner(float *Product, float *x, void *Pass))
 {
-    int iterate, i;
+    int iterate;
 
     float* buffer = (float*)malloc(2 * n * sizeof(float) + 128);
     float *r = (buffer + 16);
@@ -411,7 +411,7 @@ bool MultiDiagonalSymmetricMatrix::CreateIncompleteCholeskyFactorization(int Max
 
     //How many diagonals in the decomposition?
     MaxFillAbove++; //Conceptually, now "fill" includes an existing diagonal. Simpler in the math that follows.
-    int i, j, mic, fp;
+    int j, mic, fp;
     mic = 1;
     fp = 1;
 
@@ -441,8 +441,8 @@ bool MultiDiagonalSymmetricMatrix::CreateIncompleteCholeskyFactorization(int Max
     }
 
     //It's all initialized? Uhkay. Do the actual math then.
-    int sss, ss;
-    int MaxStartRow = StartRows[m - 1];  //Handy number.
+    int sss;
+   // int MaxStartRow = StartRows[m - 1];  //Handy number.
     float **l = ic->Diagonals;
     float  *d = ic->Diagonals[0];       //Describes D in LDLt.
     int icm = ic->m;
diff --git a/rtengine/FTblockDN.cc b/rtengine/FTblockDN.cc
index d075ec5bc..abcb896ad 100644
--- a/rtengine/FTblockDN.cc
+++ b/rtengine/FTblockDN.cc
@@ -125,7 +125,7 @@ void ImProcFunctions::Median_Denoise(float **src, float **dst, const int width,
         medBuffer[1] = dst;
     }
 
-    float ** medianIn, ** medianOut;
+    float ** medianIn, ** medianOut = nullptr;
     int BufferIndex = 0;
 
     for (int iteration = 1; iteration <= iterations; ++iteration) {
@@ -454,10 +454,10 @@ SSEFUNCTION void ImProcFunctions::RGB_denoise(int kall, Imagefloat * src, Imagef
     const bool useNoiseLCurve = (noiseLCurve && noiseLCurve.getSum() >= 7.f);
     const bool autoch = (settings->leveldnautsimpl == 1 && (dnparams.Cmethod == "AUT" || dnparams.Cmethod == "PRE")) || (settings->leveldnautsimpl == 0 && (dnparams.C2method == "AUTO" || dnparams.C2method == "PREV"));
 
-    float** lumcalc;
-    float* lumcalcBuffer;
-    float** ccalc;
-    float* ccalcBuffer;
+    float** lumcalc = nullptr;
+    float* lumcalcBuffer = nullptr;
+    float** ccalc = nullptr;
+    float* ccalcBuffer = nullptr;
 
     bool ponder = false;
     float ponderCC = 1.f;
@@ -518,7 +518,7 @@ SSEFUNCTION void ImProcFunctions::RGB_denoise(int kall, Imagefloat * src, Imagef
             ccalc[i] = ccalcBuffer + (i * wid);
         }
 
-        float cn100Precalc;
+        float cn100Precalc = 0.f;
 
         if (useNoiseCCurve) {
             cn100Precalc = SQR(1.f + ponderCC * (4.f * noiseCCurve[100.f / 60.f]));
diff --git a/rtengine/previewimage.cc b/rtengine/previewimage.cc
index 891186d8a..4d0fd59b6 100644
--- a/rtengine/previewimage.cc
+++ b/rtengine/previewimage.cc
@@ -141,7 +141,7 @@ PreviewImage::PreviewImage (const Glib::ustring &fname, const Glib::ustring &ext
 
             if (data) {
                 int w, h;
-                double scale = 1.;
+             //   double scale = 1.;
                 w = output->getWidth();
                 h = output->getHeight();
                 previewImage = Cairo::ImageSurface::create(Cairo::FORMAT_RGB24, w, h);