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This PR adds performance regression baseline data for the new estimateTranslation2D() function introduced in opencv/opencv#27950

@ismailabouzeidx ismailabouzeidx force-pushed the feat/estimate-translation2d branch from f212aed to 64e1be5 Compare November 6, 2025 13:42
@asmorkalov asmorkalov merged commit ac1c964 into opencv:4.x Nov 8, 2025
asmorkalov pushed a commit to opencv/opencv that referenced this pull request Nov 8, 2025
…ion2d

 [calib3d] Add estimateTranslation2D() #27950

Merge with opencv_extra PR: opencv/opencv_extra#1286

### **Description**

This PR adds a new API, `cv::estimateTranslation2D()`, to the **calib3d** module.  
It computes a **pure 2D translation** between two sets of corresponding points using robust methods (`RANSAC` and `LMedS`).  
The function mirrors the interface and behavior of `estimateAffine2D()` and `estimateAffinePartial2D()`, but constrains the transformation to translation only.

This model is particularly useful for cases where the motion between images is purely translational, such as:
- Aerial stitching and planar mosaics.  
- Image alignment in fixed-camera systems.  
- Lightweight pipelines where affine or homography models are unnecessarily complex.

The implementation introduces a new internal class `Translation2DEstimatorCallback` and integrates seamlessly into OpenCV’s existing robust estimation framework (`PointSetRegistrator`).

---

### **Key Features**
- Implements `cv::estimateTranslation2D()` in the `calib3d` module.
- Supports robust methods **RANSAC** and **LMedS**.  
- Adds accuracy and performance tests.  
- Provides full **C++ and Python bindings**.  
- Includes **Doxygen documentation** consistent with OpenCV’s standards.  
- Verified correctness across noise, outlier, and datatype variations.

---
### **Testing & Verification**

**Unit Tests** (`modules/calib3d/`)

- **Minimal sample:**  
  `test1Point` validates that a single correspondence recovers the correct translation under both **RANSAC** and **LMedS** across 500 randomized trials.  
- **Robustness to noise and outliers:**  
  `testNPoints` generates 100 correspondences, injects noise and outliers (≤40% for RANSAC, ≤50% for LMedS), and verifies that:  
  - Estimated **T** closely matches ground truth (`cvtest::norm(..., NORM_L2)`).  
  - Inlier mask consistency and correctness are maintained.  
- **Datatype conversion:**  
  `testConversion` checks mixed input datatypes (integer → float) to ensure correct conversion and consistent results.  
- **Input immutability:**  
  `dont_change_inputs` confirms that input arrays remain unchanged after function execution, mirroring affine behavior.

**Performance Tests** (`modules/calib3d/`)

- `EstimateTranslation2DPerf` benchmarks **RANSAC** and **LMedS** using:  
  - Point counts: 1000  
  - Confidence levels: 0.95  
  - Refinement iterations: 10, 0  
  
These tests confirm **numerical stability**, **performance scaling**, and **consistency** across datatypes and noise levels.

---
### 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 (`4.x`)
- [x] There is a clear description, motivation, and validation summary in this PR
- [x] There are accuracy and performance tests in the calib3d module
- [x] The feature is well documented and sample code can be built with CMake
- [x] The feature has Python bindings and verified documentation output
- [x] There is test data or sample code in the opencv_extra repository (if applicable)
- [ ] There is a reference to the original bug report or related issue (if applicable)
@asmorkalov asmorkalov mentioned this pull request Nov 17, 2025
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2 participants