diff --git a/openglcanvas.cpp b/openglcanvas.cpp
index dd34ee0af6353bf31563b52091b7731f4d84e5cc..1a111f83c5e0ed9fb76d0cab44dcb819e5dc3c5c 100644
--- a/openglcanvas.cpp
+++ b/openglcanvas.cpp
@@ -1,6 +1,6 @@
 #include <QtGui>
 #ifdef NEEDGLEE
-#include "GLee.h"
+  #include "GLee.h"
 #endif
 #include "openglcanvas.h"
 #include <cmath>
@@ -34,7 +34,6 @@ OpenGLCanvas::OpenGLCanvas(QWidget *parent) :
     time_timer.setInterval(0);
     connect(&time_timer, SIGNAL(timeout()), this, SLOT(slotTimer()));
     time_start = time_time.time();
-
 }
 
 void OpenGLCanvas::slotTimer(void) {
@@ -104,14 +103,27 @@ void OpenGLCanvas::change_fov_scale_relation(QString name){
 void OpenGLCanvas::change_visualization(QString name){
 
     visualization = name;
-   updateGL();
+    updateGL();
 
 }
 
+void OpenGLCanvas::load_image(const char *new_image){
+    const char * const progname=(char*)(PROGNAME);
+    int textureSize=getTextureSize(progname,new_image);
+    unsigned char * textureBytes=(unsigned char*)malloc(textureSize);
+    int width,height;
+    readTextureBytes(progname,new_image,textureBytes,&width,&height);
+    glPixelStorei(GL_UNPACK_ALIGNMENT,1);
+    GLuint tex;
+    glGenTextures(1,&tex);
+    glBindTexture(GL_TEXTURE_2D,tex);
+    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
+    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
+    glTexImage2D(GL_TEXTURE_2D,0, GL_RGB, width,height,0,GL_RGB,GL_UNSIGNED_BYTE,textureBytes);
+}
+
 void OpenGLCanvas::change_input_image(){
-    QString path = QFileDialog::getExistingDirectory(this,tr("Choose directory"),directory.path());
-    if(path.isNull()==false)
-        directory.setPath(path);
+    load_image(QFileDialog::getOpenFileName(this,tr("Choose Panorama File")).toStdString().c_str());
     updateGL();
 }
 
@@ -137,27 +149,17 @@ void OpenGLCanvas::initializeGL(){
 #endif
 
     fprintf(stderr,"progname=%s\n",progname);
-    fprintf(stderr,"image=%s\n",input_image);
-    // exit if the input file does not exist
+    fprintf(stderr,"default image=%s\n",input_image);
+    // what to do if the input file does not exist
     struct stat testbuf;
     if(stat(input_image,&testbuf)){
-        fprintf(stderr,"the file does not exist!\n");
+        fprintf(stderr,"the default image file does not exist!\n");
         free(input_image);
-        exit(-1);
+        load_image(QFileDialog::getOpenFileName(this,tr("Choose Panorama File")).toStdString().c_str());
+    }else{
+        load_image(input_image);
     }
 
-    int textureSize = getTextureSize(progname,input_image);
-    unsigned char * textureBytes = (unsigned char*)malloc(textureSize);
-    int width, height;
-    readTextureBytes(progname, input_image, textureBytes, &width, &height);
-    glPixelStorei(GL_UNPACK_ALIGNMENT,1);
-    GLuint tex;
-    glGenTextures(1,&tex);
-    glBindTexture(GL_TEXTURE_2D, tex);
-    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
-    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
-    glTexImage2D(GL_TEXTURE_2D,0, GL_RGB, width,height,0,GL_RGB,GL_UNSIGNED_BYTE,textureBytes);
-
     // mesh resolution
     int m,n;
     m = n = 100;
diff --git a/openglcanvas.h b/openglcanvas.h
index 7426b6b3dc79ff409e8fd1cf8c064a67df21d89c..3d3d25bc5149a01d25168c26e3d0ea5e1e640a3c 100644
--- a/openglcanvas.h
+++ b/openglcanvas.h
@@ -33,7 +33,7 @@ extern "C" {
   #include <GL/glext.h>
 #endif
 
-#include <QDir>
+#include <QFile>
 #include <QFileDialog>
 
 class OpenGLCanvas : public QGLWidget
@@ -43,6 +43,7 @@ public:
     explicit OpenGLCanvas(QWidget *parent = 0);
 
 protected:
+    void load_image(const char *new_image);
     void initializeGL();
     void resizeGL(int w, int h);
     void paintGL();
@@ -76,7 +77,6 @@ private:
     double center_phi;
     QString fov_scale_relation;
     QString visualization;
-    QDir directory;
 
     Chronos time_time;
     QTimer time_timer;
diff --git a/panowindow1.h b/panowindow1.h
index 0cff4b6db5dcea5062d83710e56e91b9e33c47d1..05f2b800ab7dbdd6ee9e28d715fa3f887efaf925 100644
--- a/panowindow1.h
+++ b/panowindow1.h
@@ -18,5 +18,4 @@ public:
 private:
     Ui::PanoWindow1 *ui;
 };
-
 #endif // PANOWINDOW1_H
diff --git a/panowindow1.ui b/panowindow1.ui
index 744013851d4794a936c29ed80bf61cb523d6ea07..df1f5d37dcf4a9a0244a08a0bf3f4173f704b0c3 100644
--- a/panowindow1.ui
+++ b/panowindow1.ui
@@ -14,7 +14,7 @@
    <string>PanoWindow1</string>
   </property>
   <layout class="QGridLayout" name="gridLayout">
-   <item row="0" column="0" rowspan="10">
+   <item row="0" column="0" rowspan="12">
     <widget class="OpenGLCanvas" name="GLCanvas" native="true"/>
    </item>
    <item row="0" column="1" colspan="2">
@@ -115,7 +115,7 @@
      </property>
     </widget>
    </item>
-   <item row="7" column="1">
+   <item row="8" column="1">
     <widget class="QDoubleSpinBox" name="doubleSpinBox_3">
      <property name="maximumSize">
       <size>
@@ -134,7 +134,7 @@
      </property>
     </widget>
    </item>
-   <item row="7" column="2">
+   <item row="8" column="2">
     <widget class="QDoubleSpinBox" name="doubleSpinBox_4">
      <property name="maximumSize">
       <size>
@@ -153,7 +153,14 @@
      </property>
     </widget>
    </item>
-   <item row="8" column="2">
+   <item row="9" column="1" colspan="2">
+    <widget class="QPushButton" name="chooseFile">
+     <property name="text">
+      <string>Input Image</string>
+     </property>
+    </widget>
+   </item>
+   <item row="10" column="2">
     <spacer name="verticalSpacer">
      <property name="orientation">
       <enum>Qt::Vertical</enum>
@@ -166,7 +173,7 @@
      </property>
     </spacer>
    </item>
-   <item row="9" column="1" colspan="2">
+   <item row="11" column="1" colspan="2">
     <widget class="QPushButton" name="pushButton">
      <property name="text">
       <string>Close</string>
@@ -180,7 +187,7 @@
   <customwidget>
    <class>OpenGLCanvas</class>
    <extends>QWidget</extends>
-   <header>openglcanvas.h</header>
+   <header location="global">openglcanvas.h</header>
    <container>1</container>
    <slots>
     <slot>change_fov(double)</slot>
@@ -290,5 +297,21 @@
     </hint>
    </hints>
   </connection>
+  <connection>
+   <sender>chooseFile</sender>
+   <signal>clicked()</signal>
+   <receiver>GLCanvas</receiver>
+   <slot>change_input_image()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>566</x>
+     <y>258</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>247</x>
+     <y>249</y>
+    </hint>
+   </hints>
+  </connection>
  </connections>
 </ui>