Merge pull request #21453 from sturkmen72:bigtiff

modules/imgcodecs/src/grfmt_tiff.cpp

@@ -112,6 +112,8 @@ static bool cv_tiffSetErrorHandler()
 
 static const char fmtSignTiffII[] = "II\x2a\x00";
 static const char fmtSignTiffMM[] = "MM\x00\x2a";
+static const char fmtSignBigTiffII[] = "II\x2b\x00";
+static const char fmtSignBigTiffMM[] = "MM\x00\x2b";
 
 TiffDecoder::TiffDecoder()
 {
@@ -140,7 +142,9 @@ bool TiffDecoder::checkSignature( const String& signature ) const
 {
     return signature.size() >= 4 &&
         (memcmp(signature.c_str(), fmtSignTiffII, 4) == 0 ||
-        memcmp(signature.c_str(), fmtSignTiffMM, 4) == 0);
+        memcmp(signature.c_str(), fmtSignTiffMM, 4) == 0 ||
+        memcmp(signature.c_str(), fmtSignBigTiffII, 4) == 0 ||
+        memcmp(signature.c_str(), fmtSignBigTiffMM, 4) == 0);
 }
 
 int TiffDecoder::normalizeChannelsNumber(int channels) const

modules/imgcodecs/test/test_tiff.cpp

@@ -455,6 +455,29 @@ TEST(Imgcodecs_Tiff, read_multipage_indexed)
     }
 }
 
+TEST(Imgcodecs_Tiff, read_bigtiff_images)
+{
+    const string root = cvtest::TS::ptr()->get_data_path();
+    const string filenamesInput[] = {
+        "readwrite/BigTIFF.tif",
+        "readwrite/BigTIFFMotorola.tif",
+        "readwrite/BigTIFFLong.tif",
+        "readwrite/BigTIFFLong8.tif",
+        "readwrite/BigTIFFMotorolaLongStrips.tif",
+        "readwrite/BigTIFFLong8Tiles.tif",
+        "readwrite/BigTIFFSubIFD4.tif",
+        "readwrite/BigTIFFSubIFD8.tif"
+    };
+
+    for (int i = 0; i < 8; i++)
+    {
+        const Mat bigtiff_img = imread(root + filenamesInput[i], IMREAD_UNCHANGED);
+        ASSERT_FALSE(bigtiff_img.empty());
+        EXPECT_EQ(64, bigtiff_img.cols);
+        EXPECT_EQ(64, bigtiff_img.rows);
+        ASSERT_EQ(CV_8UC3, bigtiff_img.type());
+    }
+}
 
 #endif