diff --git a/demo/demo/demo3D.cpp b/demo/demo/demo3D.cpp
index e7f909e..b0fe04c 100644
--- a/demo/demo/demo3D.cpp
+++ b/demo/demo/demo3D.cpp
@@ -4,6 +4,7 @@
 //#include <unistd.h>
 #include <mutex>
 
+#include "demo_utils.h"
 #include "CenternetDetection3D.h"
 
 bool gRun;
diff --git a/demo/demo/demoTracker.cpp b/demo/demo/demoTracker.cpp
index 797eb1b..3286ed1 100644
--- a/demo/demo/demoTracker.cpp
+++ b/demo/demo/demoTracker.cpp
@@ -4,6 +4,7 @@
 //#include <unistd.h>
 #include <mutex>
 
+#include "demo_utils.h"
 #include "CenterTrack.h"
 
 bool gRun;
diff --git a/include/tkDNN/demo_utils.h b/include/tkDNN/demo_utils.h
new file mode 100644
index 0000000..06a8970
--- /dev/null
+++ b/include/tkDNN/demo_utils.h
@@ -0,0 +1,22 @@
+#ifndef DEMO_UTILS_H
+#define DEMO_UTILS_H
+
+#include <iostream>
+#include <sstream>
+#include <fstream>
+#include <iomanip>
+#include <stdlib.h>
+
+#ifdef __linux__
+#include <unistd.h>
+#include <opencv2/core/core.hpp>
+#include <opencv2/highgui/highgui.hpp>
+#include <opencv2/imgproc/imgproc.hpp>
+
+#include <yaml-cpp/yaml.h>
+#endif
+
+
+void readCalibrationMatrix(const std::string& path, cv::Mat& calib_mat);
+
+#endif //DEMO_UTILS_H
\ No newline at end of file
diff --git a/include/tkDNN/utils.h b/include/tkDNN/utils.h
index 6ca9b85..5977639 100644
--- a/include/tkDNN/utils.h
+++ b/include/tkDNN/utils.h
@@ -15,11 +15,7 @@
 
 #ifdef __linux__
 #include <unistd.h>
-#include <opencv2/core/core.hpp>
-#include <opencv2/highgui/highgui.hpp>
-#include <opencv2/imgproc/imgproc.hpp>
 
-#include <yaml-cpp/yaml.h>
 #endif
 
 #include <ios>
@@ -137,7 +133,6 @@ void matrixMulAdd(  cublasHandle_t handle, dnnType* srcData, dnnType* dstData,
 void getMemUsage(double& vm_usage_kb, double& resident_set_kb);
 void printCudaMemUsage();
 void removePathAndExtension(const std::string &full_string, std::string &name);
-void readCalibrationMatrix(const std::string& path, cv::Mat& calib_mat);
 static inline bool isCudaPointer(void *data) {
   cudaPointerAttributes attr;
   return cudaPointerGetAttributes(&attr, data) == 0;
diff --git a/src/demo_utils.cpp b/src/demo_utils.cpp
new file mode 100644
index 0000000..dea7077
--- /dev/null
+++ b/src/demo_utils.cpp
@@ -0,0 +1,19 @@
+
+#include "demo_utils.h"
+
+void readCalibrationMatrix(const std::string& path, cv::Mat& calib_mat){
+    YAML::Node config   = YAML::LoadFile(path);
+
+    //read camera matrix
+    int rows = config["camera_matrix"]["rows"].as<int>();
+    int cols = config["camera_matrix"]["cols"].as<int>();
+
+    cv::Mat calib = cv::Mat(cv::Size(rows, cols), CV_32F);
+    float *vals = (float *)calib.data;
+    
+    for(int i=0; i < config["camera_matrix"]["data"].size(); ++i )
+        vals[i] = config["camera_matrix"]["data"][i].as<float>();
+
+    calib_mat = calib;
+
+}
diff --git a/src/utils.cpp b/src/utils.cpp
index 4b3bbb0..7d6c652 100644
--- a/src/utils.cpp
+++ b/src/utils.cpp
@@ -241,20 +241,3 @@ void removePathAndExtension(const std::string &full_string, std::string &name){
     
     // std::cout<<"full string: "<<full_string<<" name: "<<name<<std::endl;
 }
-
-void readCalibrationMatrix(const std::string& path, cv::Mat& calib_mat){
-    YAML::Node config   = YAML::LoadFile(path);
-
-    //read camera matrix
-    int rows = config["camera_matrix"]["rows"].as<int>();
-    int cols = config["camera_matrix"]["cols"].as<int>();
-
-    cv::Mat calib = cv::Mat(cv::Size(rows, cols), CV_32F);
-    float *vals = (float *)calib.data;
-    
-    for(int i=0; i < config["camera_matrix"]["data"].size(); ++i )
-        vals[i] = config["camera_matrix"]["data"][i].as<float>();
-
-    calib_mat = calib;
-
-}