Merge pull request #29288 from abhishek-gola:doc_v3

Documentation fixes, Added How to use pre-built opencv doc #29288

closes: https://github.com/opencv/opencv/issues/29263

co-authored by: @kirtijindal14 @Akansha-977 
### 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 another license that is incompatible with OpenCV
- [x] The PR is proposed to the proper branch
- [ ] There is a reference to the original bug report and related work
- [ ] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
      Patch to opencv_extra has the same branch name.
- [x] The feature is well documented and sample code can be built with the project CMake

modules/ptcloud/include/opencv2/ptcloud.hpp

@@ -13,7 +13,15 @@
 #include "opencv2/ptcloud/odometry_settings.hpp"
 
 /**
-@defgroup ptcloud Point Clound Processing
+@defgroup ptcloud Point Cloud Processing
+
+Point-cloud and mesh processing: reading/writing point clouds and meshes,
+triangle rasterization, octree partitioning, and RGB-D / volumetric 3D
+reconstruction (odometry, TSDF volumes).
+
+@{
+    @defgroup ptcloud_rgbd RGB-D and Volumetric Reconstruction
+@}
 */
 
 //! @addtogroup ptcloud

modules/ptcloud/include/opencv2/ptcloud/depth.hpp

@@ -10,7 +10,7 @@
 
 namespace cv
 {
-//! @addtogroup rgbd
+//! @addtogroup ptcloud_rgbd
 //! @{
 
 /** Object that can compute the normals in an image.

modules/ptcloud/include/opencv2/ptcloud/odometry.hpp

@@ -13,6 +13,9 @@
 namespace cv
 {
 
+//! @addtogroup ptcloud_rgbd
+//! @{
+
 /** These constants are used to set a type of data which odometry will use
 * @param DEPTH     only depth data
 * @param RGB       only rgb image
@@ -108,5 +111,7 @@ private:
     Ptr<Impl> impl;
 };
 
+//! @}
+
 }
 #endif //OPENCV_3D_ODOMETRY_HPP

modules/ptcloud/include/opencv2/ptcloud/odometry_frame.hpp

@@ -9,6 +9,9 @@
 
 namespace cv
 {
+
+//! @addtogroup ptcloud_rgbd
+//! @{
 /** Indicates what pyramid is to access using getPyramidAt() method:
 */
 
@@ -104,5 +107,7 @@ public:
     class Impl;
     Ptr<Impl> impl;
 };
+//! @}
+
 }
 #endif // !OPENCV_3D_ODOMETRY_FRAME_HPP

modules/ptcloud/include/opencv2/ptcloud/odometry_settings.hpp

@@ -10,6 +10,9 @@
 namespace cv
 {
 
+//! @addtogroup ptcloud_rgbd
+//! @{
+
 class CV_EXPORTS_W_SIMPLE OdometrySettings
 {
 public:
@@ -61,5 +64,7 @@ private:
     Ptr<Impl> impl;
 };
 
+//! @}
+
 }
 #endif //OPENCV_3D_ODOMETRY_SETTINGS_HPP

modules/ptcloud/include/opencv2/ptcloud/volume.hpp

@@ -13,6 +13,9 @@
 namespace cv
 {
 
+//! @addtogroup ptcloud_rgbd
+//! @{
+
 class CV_EXPORTS_W Volume
 {
 public:
@@ -168,5 +171,7 @@ private:
     Ptr<Impl> impl;
 };
 
+//! @}
+
 }  // namespace cv
 #endif // include guard

modules/ptcloud/include/opencv2/ptcloud/volume_settings.hpp

@@ -12,6 +12,9 @@
 namespace cv
 {
 
+//! @addtogroup ptcloud_rgbd
+//! @{
+
 enum class VolumeType
 {
     TSDF = 0,
@@ -203,6 +206,8 @@ private:
     Ptr<Impl> impl;
 };
 
+//! @}
+
 }
 
 #endif // !OPENCV_3D_VOLUME_SETTINGS_HPP