diff --git a/hgdriver/hgdev/hg_scanner.cpp b/hgdriver/hgdev/hg_scanner.cpp
index 2a47c6d..c511333 100644
--- a/hgdriver/hgdev/hg_scanner.cpp
+++ b/hgdriver/hgdev/hg_scanner.cpp
@@ -3138,6 +3138,9 @@ hg_imgproc::IMGPRCPARAM hg_scanner::get_image_process_object(int model)
 		param.width = mat_width;
 		param.height = mat_height;
 	}
+	param.is_sup_real_300dpi_ = firmware_sup_dpi_300;
+	param.is_sup_real_600dpi_ = firmware_sup_dpi_600;
+
 	param.device_7010 = firmware_sup_device_7010;
 	//img_conf_.brightness = (float)bright_;
 	//img_conf_.contrast = (float)contrast_;
diff --git a/hgdriver/hgdev/hg_scanner_239.cpp b/hgdriver/hgdev/hg_scanner_239.cpp
index 06b73a6..a6790df 100644
--- a/hgdriver/hgdev/hg_scanner_239.cpp
+++ b/hgdriver/hgdev/hg_scanner_239.cpp
@@ -1338,6 +1338,7 @@ void hg_scanner_239::thread_get_dves_image(void)
 
 	svdevs_err_.clear();
 	StopWatch sw;
+	StopWatch sw1;
 	bool is_quit_wait_paper_scan = false;
 
 	while (run_)//&& !user_cancel_
@@ -1354,7 +1355,7 @@ void hg_scanner_239::thread_get_dves_image(void)
 		if (ret == SCANNER_ERR_TIMEOUT)
 		{
 			std::this_thread::sleep_for(std::chrono::milliseconds(400));
-			if (sw.elapsed_s() > 60 && !is_auto_scan())
+			if (sw.elapsed_s() > 120 && !is_auto_scan())
 			{
 				status_ = ret;
 				notify_ui_working_status(from_default_language(STATU_DESC_SCANNER_ERR_DEVICE_GET_IMAGE_OUTTIME), SANE_EVENT_ERROR, ret);	// 取图通信超时
@@ -1362,7 +1363,7 @@ void hg_scanner_239::thread_get_dves_image(void)
 				break;
 			}
 
-			if (is_auto_scan() && sw.elapsed_s() >= is_auto_paper_scan_exit_time && is_auto_paper_scan_exit_time != 0)
+			if (is_auto_scan() && sw1.elapsed_s() >= is_auto_paper_scan_exit_time && is_auto_paper_scan_exit_time != 0)
 			{
 				is_quit_wait_paper_scan = true;//标记待纸扫描时间到了自动结束
 				do_stop();
@@ -1504,7 +1505,10 @@ void hg_scanner_239::thread_get_dves_image(void)
 				str += ":" + to_string(++auoto_paper_indx);
 
 				if (!user_cancel_ && is_auto_scan() && svdevs_err_.empty() && !is_quit_wait_paper_scan)
+				{
+					sw1.reset();
 					notify_ui_working_status(str.c_str(), SANE_EVENT_ERROR, status_);
+				}
 				else
 					break;
 			}
diff --git a/hgdriver/hgdev/image_process.cpp b/hgdriver/hgdev/image_process.cpp
index 728f7f4..a877467 100644
--- a/hgdriver/hgdev/image_process.cpp
+++ b/hgdriver/hgdev/image_process.cpp
@@ -431,7 +431,22 @@ namespace hg_imgproc
 			int ret = SCANNER_ERR_OK;
 
 			float scale = img_conf_.fillhole.fillholeratio / 100.0;
-			float val = img_conf_.resolution_dst / 10;
+			int dpi = img_conf_.resolution_dst;
+			
+			if (!param_.is_sup_real_300dpi_)
+			{
+				dpi = 200;
+			}
+			else
+			{
+				if (!param_.is_sup_real_600dpi_)
+				{
+					if (dpi >= 300)
+						dpi = 300;
+				}
+			}
+
+			float val = dpi / 10;
 			cv::Vec4f edgeScale;
 			edgeScale[0] = top;
 			edgeScale[1] = low;
diff --git a/hgdriver/hgdev/image_process.h b/hgdriver/hgdev/image_process.h
index 47dbfec..945c747 100644
--- a/hgdriver/hgdev/image_process.h
+++ b/hgdriver/hgdev/image_process.h
@@ -153,6 +153,8 @@ namespace hg_imgproc
 		int			width;		// in pixel
 		int			height;		// in pixel
 		unsigned	total_bytes;// total bytes
+		bool		is_sup_real_300dpi_;
+		bool		is_sup_real_600dpi_;
 		bool		device_7010;
 	}IMGPRCPARAM, *LPIMGPRCPARAM;
 	typedef struct _img_header
diff --git a/hgdriver/hgdev/usb_manager.cpp b/hgdriver/hgdev/usb_manager.cpp
index efb385f..887fd76 100644
--- a/hgdriver/hgdev/usb_manager.cpp
+++ b/hgdriver/hgdev/usb_manager.cpp
@@ -70,7 +70,7 @@ int LIBUSB_CALL usb_manager::usb_pnp_callback(libusb_context* ctx, libusb_device
     usb_manager* obj = (usb_manager*)monitor;
 
 //    if (event == LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED)
-        libusb_ref_device(device);  // keep the object until handle it
+        //libusb_ref_device(device);  // keep the object until handle it
     //else if(event == LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT)
     //    libusb_unref_device(device);
 
@@ -187,17 +187,22 @@ void usb_manager::thread_notify_usb_event()
                 }
             }
 
+            libusb_ref_device(pd.dev);      // for re-enter the queue pnp_events_
             notify_usb_event(pd, &retry);
             if (retry)
             {
-                if(std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::system_clock::now() - pd.happen_time).count()
+                if (std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::system_clock::now() - pd.happen_time).count()
                     <= 5000)
                     pnp_events_.Put(pd, sizeof(pd));
+                else
+                    retry = false;
                 if(pnp_events_.Size() == 1)
                     this_thread::sleep_for(chrono::milliseconds(1000));
                 else
                     this_thread::sleep_for(chrono::milliseconds(delay));
             }
+            if (!retry)
+                libusb_unref_device(pd.dev);
         }
     }
 }
@@ -283,6 +288,7 @@ int usb_manager::on_usb_pnp_event(libusb_context *ctx, libusb_device *device, li
     PNPDEV pd;
     unsigned ms = std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::system_clock::now() - born_).count();
 
+    libusb_ref_device(device);
     pd.ctx = ctx;
     pd.dev = device;
     pd.event = event;
@@ -295,9 +301,12 @@ int usb_manager::on_usb_pnp_event(libusb_context *ctx, libusb_device *device, li
     else
     {
         bool retry = false;
+        libusb_ref_device(device);
         notify_usb_event(pd, &retry);
         if(retry)
             pnp_events_.Put(pd, sizeof(pd));
+        else
+            libusb_unref_device(device);
     }
 
     return 0;