Fig. 1. Construction of a differential pyramid

Fig. 2. Flowchart of the proposed method

Fig. 3. Improved FAST comparison experiment.（a）Fixed threshold（time consumption t=4.5 s）；（b）Adaptive threshold（α=2.5，time consuming t=3.8 s）；（c）Adaptive threshold（α=3.5，time consuming t=1.6 s）；（d）Adaptive threshold（α=4.5，time consuming t=0.9 s）.

Fig. 4. Improved descriptor

Fig. 5. Comparison of the execution time of each algorithm

Fig. 6. Feature point matching accuracy of each algorithm

Fig. 7. Part of the image pairs used for test.（a）Lighting transformation；（b）Viewpoint transformation；（c）Rotation and scale transformation.

Fig. 8. Matching results of each algorithm

Fig. 9. Algorithm matching performance analysis.（a）Matching accuracy of each algorithm；（b）Execution time of each algorithm.

Fig. 10. Image pairs for scale，rotational invariance test.

Fig. 11. Experiment results of image rotation transformation

Fig. 12. Experimental results of light intensity transformation