diff --git a/src/CascadeClassifierWrap.cc b/src/CascadeClassifierWrap.cc
index 3950c04..6dbf68d 100755
--- a/src/CascadeClassifierWrap.cc
+++ b/src/CascadeClassifierWrap.cc
@@ -61,10 +61,10 @@ class AsyncDetectMultiScale : public NanAsyncWorker {
 
       if(this->im->mat.channels() != 1) {
         cvtColor(this->im->mat, gray, CV_BGR2GRAY);
+        equalizeHist( gray, gray);
       } else {
         gray = this->im->mat;
       }
-      equalizeHist( gray, gray);
       this->cc->cc.detectMultiScale(gray, objects, this->scale, this->neighbors, 0 | CV_HAAR_SCALE_IMAGE, cv::Size(this->minw, this->minh));
       res = objects;
     }