Merge pull request #20367 from augustinmanecy:features2d-rw

**Merge with contrib**: https://github.com/opencv/opencv_contrib/pull/3003

### Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or other license that is incompatible with OpenCV
- [x] The PR is proposed to proper branch
- [ ] There is reference to original bug report and related work
- [x] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
      Patch to opencv_extra has the same branch name.
- [ ] The feature is well documented and sample code can be built with the project CMake

modules/features2d/src/kaze.cpp

@@ -163,6 +163,7 @@ namespace cv
         void write(FileStorage& fs) const CV_OVERRIDE
         {
             writeFormat(fs);
+            fs << "name" << getDefaultName();
             fs << "extended" << (int)extended;
             fs << "upright" << (int)upright;
             fs << "threshold" << threshold;
@@ -173,12 +174,19 @@ namespace cv
 
         void read(const FileNode& fn) CV_OVERRIDE
         {
-            extended = (int)fn["extended"] != 0;
-            upright = (int)fn["upright"] != 0;
-            threshold = (float)fn["threshold"];
-            octaves = (int)fn["octaves"];
-            sublevels = (int)fn["sublevels"];
-            diffusivity = static_cast<KAZE::DiffusivityType>((int)fn["diffusivity"]);
+            // if node is empty, keep previous value
+            if (!fn["extended"].empty())
+                extended = (int)fn["extended"] != 0;
+            if (!fn["upright"].empty())
+                upright = (int)fn["upright"] != 0;
+            if (!fn["threshold"].empty())
+                threshold = (float)fn["threshold"];
+            if (!fn["octaves"].empty())
+                octaves = (int)fn["octaves"];
+            if (!fn["sublevels"].empty())
+                sublevels = (int)fn["sublevels"];
+            if (!fn["diffusivity"].empty())
+                diffusivity = static_cast<KAZE::DiffusivityType>((int)fn["diffusivity"]);
         }
 
         bool extended;