add resetting the offset variable after setting a new image

modules/objdetect/src/cascadedetect.cpp

@@ -677,6 +677,10 @@ void HaarEvaluator::computeOptFeatures()
     copyVectorToUMat(*optfeatures_lbuf, ufbuf);
 }
 
+bool HaarEvaluator::setImage(InputArray _image, const std::vector<float>& _scales){
+    tofs = 0;
+    return FeatureEvaluator::setImage(_image, _scales);
+}
 
 bool HaarEvaluator::setWindow( Point pt, int scaleIdx )
 {

modules/objdetect/src/cascadedetect.hpp

@@ -347,6 +347,7 @@ public:
     virtual Ptr<FeatureEvaluator> clone() const;
     virtual int getFeatureType() const { return FeatureEvaluator::HAAR; }
 
+    virtual bool setImage(InputArray _image, const std::vector<float>& _scales);
     virtual bool setWindow(Point p, int scaleIdx);
     Rect getNormRect() const;
     int getSquaresOffset() const;