diff --git a/openbr/plugins/cuda/MatManager.cu b/openbr/plugins/cuda/MatManager.cu
index 1e80cd8..41d1137 100644
--- a/openbr/plugins/cuda/MatManager.cu
+++ b/openbr/plugins/cuda/MatManager.cu
@@ -41,7 +41,7 @@ namespace br { namespace cuda {
     sem_init(_matSemaphore, 0, _numMats);
   }
 
-  int MatManager::reserve(Mat *mat) {
+  MatManager::matindex MatManager::reserve(Mat *mat) {
     int reservedMatIndex = 0;
     //std::cout << "Reserving" << std::endl << std::flush;
 
@@ -82,7 +82,7 @@ namespace br { namespace cuda {
     return reservedMatIndex;
   }
 
-  void MatManager::upload(int reservedMatIndex, Mat& mat) {
+  void MatManager::upload(MatManager::matindex reservedMatIndex, Mat& mat) {
     // upload the image
     /*
     pthread_mutex_lock(_matsDimensionLock);
@@ -95,7 +95,7 @@ namespace br { namespace cuda {
     cudaMemcpy(reservedMat, mat.ptr<uint8_t>(), mat.rows * mat.cols, cudaMemcpyHostToDevice);
   }
 
-  void MatManager::download(int reservedMatIndex, Mat& dstMat) {
+  void MatManager::download(MatManager::matindex reservedMatIndex, Mat& dstMat) {
     /*
     pthread_mutex_lock(_matsDimensionLock);
     reservedMat->download(dstMat);
@@ -108,7 +108,7 @@ namespace br { namespace cuda {
     cudaMemcpy(dstMat.ptr<uint8_t>(), reservedMat, dimension, cudaMemcpyDeviceToHost);
   }
 
-  void MatManager::release(int reservedMatIndex) {
+  void MatManager::release(MatManager::matindex reservedMatIndex) {
     uint8_t* reservedMat = _mats[reservedMatIndex];
     pthread_mutex_lock(_matTakenLock);
     bool foundMatch = false;
@@ -185,7 +185,7 @@ namespace br { namespace cuda {
     std::cout << "can't release mat at address: " << gpuMat << std::endl << std::flush;
   }
 */
-  uint8_t* MatManager::get_mat_pointer_from_index(int matIndex) {
+  uint8_t* MatManager::get_mat_pointer_from_index(MatManager::matindex matIndex) {
     return _mats[matIndex];
   }
 
diff --git a/openbr/plugins/cuda/MatManager.hpp b/openbr/plugins/cuda/MatManager.hpp
index 2da9741..b7713eb 100644
--- a/openbr/plugins/cuda/MatManager.hpp
+++ b/openbr/plugins/cuda/MatManager.hpp
@@ -25,13 +25,14 @@ namespace br { namespace cuda {
     sem_t* _matSemaphore;
 
   public:
+    typedef int matindex;
     MatManager(int num);
 
     int reserve(Mat *mat);
-    void upload(int reservedMatIndex, Mat& mat);
-    void download(int reservedMatIndex, Mat& dstMat);
-    void release(int matIndex);
-    uint8_t* get_mat_pointer_from_index(int matIndex);
+    void upload(matindex reservedMatIndex, Mat& mat);
+    void download(matindex reservedMatIndex, Mat& dstMat);
+    void release(matindex matIndex);
+    uint8_t* get_mat_pointer_from_index(matindex matIndex);
 
     ~MatManager();
     //void printMats();
diff --git a/openbr/plugins/cuda/cudalbp.cpp b/openbr/plugins/cuda/cudalbp.cpp
index dccd90c..d7756a8 100644
--- a/openbr/plugins/cuda/cudalbp.cpp
+++ b/openbr/plugins/cuda/cudalbp.cpp
@@ -154,8 +154,8 @@ class CUDALBPTransform : public UntrainableTransform
     void project(const Template &src, Template &dst) const
     {
         Mat& m = (Mat&)src.m();
-        int a;
-        int b;
+        cuda::MatManager::matindex a;
+        cuda::MatManager::matindex b;
         a = matManager->reserve(&m);
 //        std::cout << "m: " << m.size() << ", " << m.type() << std::endl << std::flush;
 //        std::cout << "a: " << a->size() << ", " << a->type() << std::endl << std::flush;