Describe the feature and motivation

samples is one of the main faces of the library. Currently, we have a lot of poorly organized, mainly obsolete samples in OpenCV. We need to clean it up in OpenCV 5 and maybe even in OpenCV 4.

• C++ samples:
  • bgfg_segm.cpp - old and low-quality
  • camshiftdemo.cpp - old and low-quality. Deep-learning based object detection and tracking demos can be used instead
  • cloning_demo and cloning_gui - low-quality. Deep-learning based computational photography demos could be added later.
  • contours2.cpp, convexhull.cpp - old. can easily be removed. Example how to call convexHull can be added to documentation.
  • create_mask.cpp is almost useless example. can be removed.
  • dbt_face_detection.cpp - obsolete
  • delaunay2 - obsolete. Delaunay triangulation might still be useful, but it's quite stupid way to demonstrate it.
  • demhist - we can retain it, but it shall definitely be improved. For now we can keep it as-is.
  • detect_blob - too specialized. Can be removed.
  • detect_mser - possibly retain, but make more useful.
  • dft - too artificial example. Can be removed.
  • digits_lenet - keep, but make it more entertaining, let user to draw digits with mouse.
  • digits_svm - remove
  • dis_opticalflow - remove. We now support RAFT deep learning model.
  • distrans - keep, but need to improve.
  • drawing - keep, but need to significantly improve.
  • edge - we can retain it if we demonstrate many different methods, including deep learning based.
  • ela - looks almost useless. remove
  • em - demo for ML. move to opencv_contrib.
  • epipilar_lines - remove it in favor of essential_mat_reconstr
  • facedetect - remove in favor of deep learning-based demo
  • facial_features - remove in favor of deep learning-based demo
  • falsecolor - probably keep for now, improve later
  • fback - another old demo of optical flow. Remove in favor of deep learning-based demo
  • ffilldemo - we can keep it as long as it's more educative. There should be a gallery of special sample images.
  • filestorage - can be kept, but should be improved
  • fitellipse - looks nice. probably can be kept and extended to demonstrate other figures like convex hull etc.
  • flann_search_dataset - remove it. Probably should have face recognition demo (or place recognition demo) instead.
  • ... (skip several)
  • inpaint - remove. Need to replace it with deep learning-based demo.
  • kalman - remove. We already have very fast deep-learning based trackers
  • kmeans - too primitive. Remove.
  • laplace - too primitive. Remove.
  • letter_recog - remove in favor of deep learning-based demo working with real images.
  • lkdemo - classic. Keep it for now, but we need a better point tracking algorithm and demo. Something like PTAM.
  • logistic_regression - move to opencv_contrib/ml/samples.
  • lsd_lines - remove. Add deep learning-based demo as soon as we have such an algorithm.
  • mask_tmpl - remove.
  • matchmethod_orb_... - remove. It's enough to have planar object tracking demo using SIFT/A-SIFT.
  • minarea - too primitive, remove.
  • morphology2 - entertaining but primitive. May be kept, but should be improved. E.g. it can be converted to object counting demo.
  • neural_network - it's obsolete. remove.
  • npr_demo - keep and improve.
  • pca - somewhat old, but might be useful for education purposes. Can keep, but need to be improved.
  • peopledetect - remove in favor of deep learning-based demo.
  • phase_corr - remove
  • points_classifier - move to opencv_contrib/ml/samples
  • polar_transforms - remove perhaps
  • segment_objects - replace with a demo of SAM or a similar model.
  • simd_basic - may keep, but needs to be extended perhaps to demonstrate more useful stuff.
  • smile_detect - remove. The feature (smile detection) would be a useful addition to the deep learning-based face detection example.
  • squares - too old. remove.
  • stereo_calib - keep, but probably improve.
  • stereo_match - same.
  • stitching_detailed and stitching - good demos, but need improvements. Do we need 2 variants of image stitching demo?
  • text_skeweness_correction - remove. replace with text detection and recognition demo.
  • train_HOG - obsolete. Remove.
  • train_svmsgd - move to opencv_contrib/ml/samples.
  • travelsalesman - move to opencv_contrib/ml/samples.
  • tree_engine - same.
  • video_capture_* - combine multiple examples into 1-3 examples. For example, conventional 2D capture and 3D capture (using depth sensor).
  • warpperspective_demo - remove. Probably, we need a demo of various image augmentations using OpenCV.
  • watershed - probably, keep or combine with grabcut demo.
• Python samples:
  • Python samples are generally better, but need to remove obsolete demos, demos for ML or simple demos which are duplicates of C++ samples.
• DNN samples:
  • Mostly they are fine, but we can consolidate text detection/recognition examples and also merge "tf_" examples into the respective examples for ONNX (since ONNX is now our main format).
• do we need dedicated "java/" if we have "android/"?
• winrt, winrt_universal and wp8 should probably be removed
• example of HAL should be non-trivial. We need to polish Carotene, we need to move IPP-based HAL from 'embedded HAL' to 3rdparty. They will be much more realistic examples for HAL than opencv/samples/hal.
• openvx shall be removed, we no longer support it.
• probably, put directx, opengl, sycl, va_intel, opencl under "interoperability" directory. Are they all still relevant?
• since non-CPU HAL and, correspondingly, UMat, will evolve, tapi and gpu samples could probably be put to cpp/python directories.

Additional context

No response