diff --git a/src/filterSample/inlay.cc b/src/filterSample/inlay.cc
index c9b5022..b23ab6b 100644
--- a/src/filterSample/inlay.cc
+++ b/src/filterSample/inlay.cc
@@ -4,9 +4,9 @@
 static inline bool is_inlay(int strict, cv::Vec3b ref, cv::Vec3b pix)
 {
   return (strict && ref == pix) || (!strict &&
-    ((ref[0] > 0 && pix[0] > 127 && pix[0] > pix[1] && pix[0] > pix[2])
-      || (ref[1] > 0 && pix[1] > 127 && pix[1] > pix[0] && pix[1] > pix[2])
-      || (ref[2] > 0 && pix[2] > 127 && pix[2] > pix[0] && pix[2] > pix[1])));
+    ((ref[0] > 0 && pix[0] - pix[1] > 30 && pix[0] - pix[2] > 30)
+      || (ref[1] > 0 && pix[1] - pix[0] > 30 && pix[1] - pix[2] > 30)
+      || (ref[2] > 0 && pix[2] - pix[0] > 30 && pix[2] - pix[1] > 30)));
 }
 
 void* Inlay::operator()(void* para)
diff --git a/src/main.cc b/src/main.cc
index a76029b..b5bd4ae 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -77,6 +77,11 @@ bool parse_cli(Configuration& conf, int argc, char** argv)
     for (auto it = vs.begin(); it != vs.end(); ++it)
       conf.input.push_back(std::string(*it));
   }
+  else
+  {
+    std::cerr << "Please provide an input file" << std::endl;
+	return false;
+  }
 
   if (vm.count("filter"))
   {
@@ -111,8 +116,6 @@ int main (int argc, char** argv)
   {
     if (!pipe.add_filter(filter.first, filter.second))
     {
-      std::cerr << argv[0] << ": Unknown filter `"
-                << filter.first << "'" << std::endl;
       return 2;
     }
   }
diff --git a/src/pipeline.cc b/src/pipeline.cc
index 6f0713a..d2487c9 100644
--- a/src/pipeline.cc
+++ b/src/pipeline.cc
@@ -43,11 +43,19 @@ bool Pipeline::add_filter(std::string filter, std::vector<int> args)
   else if (filter == "rotate-v")
     this->pipeline_.add_filter(*(new Rotate(2)));
   else if (filter == "color" && args.size() >= 3)
-    this->pipeline_.add_filter(*(new Color(cv::Vec3b {
-            (unsigned char) args[0],
-            (unsigned char) args[1],
-            (unsigned char) args[2]
-          })));
+  {
+    if (args.size() < 3)
+    {
+      std::cerr << "Missing parameters for filter color" << std::endl;
+      return false;
+    }
+    else
+      this->pipeline_.add_filter(*(new Color(cv::Vec3b {
+              (unsigned char) args[0],
+              (unsigned char) args[1],
+              (unsigned char) args[2]
+            })));
+  }
   else if (filter == "sepia")
   {
     this->pipeline_.add_filter(*(new Grey()));
@@ -60,44 +68,93 @@ bool Pipeline::add_filter(std::string filter, std::vector<int> args)
     else
       this->pipeline_.add_filter(*(new Blur()));
   }
-  else if (filter == "merge" && this->input_it_ != this->input_.end())
+  else if (filter == "merge")
   {
-    this->pipeline_.add_filter(*(new Compose(*this->input_it_)));
-    this->input_it_++;
-    this->pipeline_.add_filter(*(new Merge()));
+    if (this->input_it_ != this->input_.end())
+    {
+      this->pipeline_.add_filter(*(new Compose(*this->input_it_)));
+      this->input_it_++;
+      this->pipeline_.add_filter(*(new Merge()));
+    }
+    else
+    {
+      std::cerr << "Missing additional input file argument for filter merge"
+        << std::endl;
+      return false;
+    }
   }
-  else if (filter == "interlace" && this->input_it_ != this->input_.end())
+  else if (filter == "interlace")
   {
-    this->pipeline_.add_filter(*(new Compose(*this->input_it_)));
-    this->input_it_++;
-    this->pipeline_.add_filter(*(new Interlace()));
+    if (this->input_it_ != this->input_.end())
+    {
+      this->pipeline_.add_filter(*(new Compose(*this->input_it_)));
+      this->input_it_++;
+      this->pipeline_.add_filter(*(new Interlace()));
+    }
+    else
+    {
+      std::cerr << "Missing additional input file argument for filter "
+       "interlace" << std::endl;
+      return false;
+    }
   }
-  else if (filter == "inlay" && this->input_it_ != this->input_.end()
-    && args.size() >= 3)
+  else if (filter == "inlay")
   {
-    this->pipeline_.add_filter(*(new Compose(*this->input_it_)));
-    this->input_it_++;
-    this->pipeline_.add_filter(
-      *(new Inlay(cv::Vec3b {
-            (unsigned char) args[0],
-            (unsigned char) args[1],
-            (unsigned char) args[2]
-          }, 0)));
+    if (this->input_it_ == this->input_.end())
+    {
+      std::cerr << "Missing additional input file argument for filter inlay"
+        << std::endl;
+      return false;
+    }
+    else if (args.size() < 3)
+    {
+      std::cerr << "Missing parameters for filter inlay"
+        << std::endl;
+      return false;
+    }
+    else
+    {
+      this->pipeline_.add_filter(*(new Compose(*this->input_it_)));
+      this->input_it_++;
+      this->pipeline_.add_filter(
+        *(new Inlay(cv::Vec3b {
+              (unsigned char) args[0],
+              (unsigned char) args[1],
+              (unsigned char) args[2]
+            }, 0)));
+    }
   }
-  else if (filter == "strictinlay" && this->input_it_ != this->input_.end()
-    && args.size() >= 3)
+  else if (filter == "strictinlay" && args.size() >= 3)
   {
-    this->pipeline_.add_filter(*(new Compose(*this->input_it_)));
-    this->input_it_++;
-    this->pipeline_.add_filter(
-      *(new Inlay(cv::Vec3b {
-            (unsigned char) args[0],
-            (unsigned char) args[1],
-            (unsigned char) args[2]
-          }, 1)));
+    if (this->input_it_ == this->input_.end())
+    {
+      std::cerr << "Missing additional input file argument for filter "
+        "strictinlay" << std::endl;
+      return false;
+    }
+    else if (args.size() < 3)
+    {
+      std::cerr << "Missing parameters for filter strictinlay" << std::endl;
+      return false;
+    }
+    else
+    {
+      this->pipeline_.add_filter(*(new Compose(*this->input_it_)));
+      this->input_it_++;
+      this->pipeline_.add_filter(
+        *(new Inlay(cv::Vec3b {
+              (unsigned char) args[0],
+              (unsigned char) args[1],
+              (unsigned char) args[2]
+            }, 1)));
+    }
   }
   else
+  {
+    std::cerr << ": Unknown filter `"
+      << filter << "'" << std::endl;
     return false;
+  }
 
   return true;
 }