diff --git a/src/CameraImageWrapper.cpp b/src/CameraImageWrapper.cpp
index 026cfb5..a51dd8c 100644
--- a/src/CameraImageWrapper.cpp
+++ b/src/CameraImageWrapper.cpp
@@ -9,7 +9,11 @@ CameraImageWrapper::CameraImageWrapper() : LuminanceSource(0,0), image(NULL)
 
 CameraImageWrapper::CameraImageWrapper(const QImage &sourceImage) : LuminanceSource(sourceImage.width(), sourceImage.height())
 {
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 5, 0))
     image = grayScaleImage( &sourceImage );
+#else
+    image = new QImage(sourceImage);
+#endif
     delegate = Ref<GreyscaleLuminanceSource>(
                 new GreyscaleLuminanceSource(getMatrixP(),image->width(), image->height(),0, 0, image->width(), image->height()));
 }
@@ -42,6 +46,7 @@ CameraImageWrapper *CameraImageWrapper::Factory(const QImage &sourceImage, int m
         return new CameraImageWrapper(sourceImage);
 }
 
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 5, 0))
 QImage* CameraImageWrapper::grayScaleImage(const QImage *origin)
 {
     QImage *tmp = new QImage(origin->width(), origin->height(), QImage::Format_Grayscale8);
@@ -58,7 +63,7 @@ QImage* CameraImageWrapper::grayScaleImage(const QImage *origin)
 
     return tmp;
 }
-
+#endif
 QImage CameraImageWrapper::getOriginalImage()
 {
     return *image;
@@ -128,8 +133,14 @@ ArrayRef<char> CameraImageWrapper::getRowP(int y, ArrayRef<char> row) const
         row.reset(ArrayRef<char>(width));
 
     for (int x = 0; x < width; x++)
+    {
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 5, 0))
         row[x] = image->pixel(x,y);
-
+#else
+        QRgb pixel = image->pixel(x,y);
+        row[x] = qGray(pixel);
+#endif
+    }
     return row;
 }
 
diff --git a/src/CameraImageWrapper.h b/src/CameraImageWrapper.h
index 9e37b5b..64904a8 100644
--- a/src/CameraImageWrapper.h
+++ b/src/CameraImageWrapper.h
@@ -32,8 +32,9 @@ public:
 private:
     ArrayRef<char> getRowP(int y, ArrayRef<char> row) const;
     ArrayRef<char> getMatrixP() const;
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 5, 0))
     QImage* grayScaleImage(const QImage *origin);
-
+#endif
     unsigned int gray(unsigned int r, unsigned int g, unsigned int b);
 
     QImage* image;
diff --git a/src/QZXing.pri b/src/QZXing.pri
index 8862bac..7bacf84 100644
--- a/src/QZXing.pri
+++ b/src/QZXing.pri
@@ -258,15 +258,30 @@ symbian {
         Location
 }
 
-unix:!symbian {
-    maemo5 {
-        target.path = /opt/usr/lib
-    } else {
-        target.path = /usr/lib
+!symbian {
+    isEmpty(PREFIX) {
+        maemo5 {
+            target.path = /opt/usr/lib
+        } else {
+            target.path = /usr/lib
+        }
     }
 
     DEFINES += NOFMAXL
-    INSTALLS += target
+
+	# Installation
+	headers.files = qzxing.h QZXing_global.h
+	headers.path = $$PREFIX/include
+	target.path = $$PREFIX/lib
+	INSTALLS += headers target
+
+	# pkg-config support
+	CONFIG += create_pc create_prl no_install_prl
+	QMAKE_PKGCONFIG_DESTDIR = pkgconfig
+	QMAKE_PKGCONFIG_LIBDIR = ${prefix}/lib
+	QMAKE_PKGCONFIG_INCDIR = ${prefix}/include
+
+	unix:QMAKE_CLEAN += -r pkgconfig lib$${TARGET}.prl
 }
 
 win32-msvc*{