diff --git a/twain/twain/huagaods.cpp b/twain/twain/huagaods.cpp
index 7f7962c..133a280 100644
--- a/twain/twain/huagaods.cpp
+++ b/twain/twain/huagaods.cpp
@@ -1000,7 +1000,12 @@ Result huagao_ds::imageInfoGet(const Identity&, ImageInfo& data)
 		if (m_compression == Compression::Group4)
 			data.setPixelType(PixelType::BlackWhite);
 		else
-			data.setPixelType(head.format == SANE_FRAME_RGB ? PixelType::Rgb : PixelType::Gray);
+		{
+			if (head.format == SANE_FRAME_RGB)
+				data.setPixelType(PixelType::Rgb);
+			else if(head.format == SANE_FRAME_GRAY)
+				data.setPixelType(head.depth == 1 ? PixelType::BlackWhite : PixelType::Gray);
+		}
 		data.setPlanar(false);
 		data.setWidth(head.pixels_per_line);