Skip to main content
Log in

Evaluation of Interest Point Detectors and Feature Descriptors for Visual Tracking

  • Published:
International Journal of Computer Vision Aims and scope Submit manuscript

Abstract

Applications for real-time visual tracking can be found in many areas, including visual odometry and augmented reality. Interest point detection and feature description form the basis of feature-based tracking, and a variety of algorithms for these tasks have been proposed. In this work, we present (1) a carefully designed dataset of video sequences of planar textures with ground truth, which includes various geometric changes, lighting conditions, and levels of motion blur, and which may serve as a testbed for a variety of tracking-related problems, and (2) a comprehensive quantitative evaluation of detector-descriptor-based visual camera tracking based on this testbed. We evaluate the impact of individual algorithm parameters, compare algorithms for both detection and description in isolation, as well as all detector-descriptor combinations as a tracking solution. In contrast to existing evaluations, which aim at different tasks such as object recognition and have limited validity for visual tracking, our evaluation is geared towards this application in all relevant factors (performance measures, testbed, candidate algorithms). To our knowledge, this is the first work that comprehensively compares these algorithms in this context, and in particular, on video streams.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

References

  • Adams, A., Gelfand, N., & Pulli, K. (2008). Viewfinder alignment. Computer Graphics Forum, 27(2), 597–606. doi:10.1111/j.1467-8659.2008.01157.x.

    Article  Google Scholar 

  • Agrawal, M., Konolige, K., & Blas, M. R. (2008). CenSurE: Center surround extremas for realtime feature detection and matching. In Proceedings of the European conference on computer vision (ECCV’08) (Vol. 5305, pp. 102–115). doi:10.1007/978-3-540-88693-8_8.

    Google Scholar 

  • Baker, S., & Matthews, I. (2001). Equivalence and efficiency of image alignment algorithms. In Proceedings of the IEEE conference on computer vision and pattern recognition (CVPR’01) (Vol. 1, pp. 1090–1097).

    Google Scholar 

  • Baker, S., Scharstein, D., Lewis, J. P., Roth, S., Black, M. J., & Szeliski, R. (2007). A database and evaluation methodology for optical flow. In Proceedings of the IEEE intl. conference on computer vision (ICCV’07) (pp. 1–8). doi:10.1109/ICCV.2007.4408903.

    Google Scholar 

  • Bay, H., Ess, A., Tuytelaars, T., & Van Gool, L. (2008). Speeded-up robust features (SURF). Computer Vision and Image Understanding, 110, 346–359. doi:10.1016/j.cviu.2007.09.014.

    Article  Google Scholar 

  • Beaudet, P. R. (1978). Rotationally invariant image operators. In Proceedings of the intl. joint conference on pattern recognition (pp. 579–583).

    Google Scholar 

  • Belongie, S., Malik, J., & Puzicha, J. (2002). Shape matching and object recognition using shape contexts. IEEE Transactions on Pattern Analysis and Machine Intelligence, 24(4), 509–522. doi:10.1109/34.993558.

    Article  Google Scholar 

  • Benhimane, S., & Malis, E. (2004). Real-time image-based tracking of planes using efficient second-order minimization. In Proceedings of the IEEE/RSJ intl. conference on intelligent robots and systems (pp. 943–948).

    Google Scholar 

  • Bleser, G., & Stricker, D. (2008). Advanced tracking through efficient image processing and visual-inertial sensor fusion. In Proceedings of the IEEE virtual reality conference (VR’08) (pp. 137–144). doi:10.1109/VR.2008.4480765.

    Chapter  Google Scholar 

  • Brown, M., & Lowe, D. (2002). Invariant features from interest point groups. In Proceedings of the British machine vision conference (BMVC’02).

    Google Scholar 

  • Calonder, M., Lepetit, V., & Fua, P. (2008). Keypoint signatures for fast learning and recognition. In Proceedings of the 11th European conference on computer vision (ECCV’08), Marseille, France.

    Google Scholar 

  • Campbell, J., Sukthankar, R., & Nourbakhsh, I. (2004). Techniques for evaluating optical flow for visual odometry in extreme terrain. In Proceedings of the IEEE/RSJ intl. conference on intelligent robots and systems (Vol. 4, pp. 3704–3711).

    Google Scholar 

  • Carneiro, G., & Jepson, A. D. (2003). Multi-scale phase-based local features. In Proceedings of the IEEE conference on computer vision and pattern recognition (CVPR’03) (Vol. 1, pp. 736–743).

    Google Scholar 

  • Carrera, G., Savage, J., & Mayol-Cuevas, W. (2007). Robust feature descriptors for efficient vision-based tracking. In Proceedings of the 12th Iberoamerican congress on pattern recognition (pp. 251–260). doi:10.1007/978-3-540-76725-1_27.

    Google Scholar 

  • Chekhlov, D., Pupilli, M., Mayol-Cuevas, W., & Calway, A. (2006). Real-time and robust monocular SLAM using predictive multi-resolution descriptors. In Proceedings of the 2nd intl. symposium on visual computing.

    Google Scholar 

  • Chekhlov, D., Pupilli, M., Mayol, W., & Calway, A. (2007). Robust real-time visual SLAM using scale prediction and exemplar based feature description. In Proceedings of the IEEE conference on computer vision and pattern recognition (CVPR’07) (pp. 1–7). doi:10.1109/CVPR.2007.383026.

    Google Scholar 

  • Cheng, Y., Maimone, M. W., & Matthies, L. (2006). Visual odometry on the mars exploration rovers—a tool to ensure accurate driving and science imaging. IEEE Robotics & Automation Magazine, 13(2), 54–62. doi:10.1109/MRA.2006.1638016.

    Article  Google Scholar 

  • Chum, O., & Matas, J. (2005). Matching with PROSAC—progressive sample consensus. In Proceedings of the IEEE conference on computer vision and pattern recognition (CVPR’05) (pp. 220–226). doi:10.1109/CVPR.2005.221.

    Google Scholar 

  • Davison, A. J., Reid, I. D., Molton, N. D., & Stasse, O. (2007). MonoSLAM: Real-time single camera SLAM. IEEE Transactions on Pattern Analysis and Machine Intelligence, 29(6), 1052–1067. doi:10.1109/TPAMI.2007.1049.

    Article  Google Scholar 

  • DiVerdi, S., & Höllerer, T. (2008). Heads up and camera down: A vision-based tracking modality for mobile mixed reality. IEEE Transactions on Visualization and Computer Graphics, 14(3), 500–512. doi:10.1109/TVCG.2008.26.

    Article  Google Scholar 

  • DiVerdi, S., Wither, J., & Höllerer, T. (2008). Envisor: Online environment map construction for mixed reality. In Proceedings of the IEEE virtual reality conference (VR’08) (pp. 19–26). doi:10.1109/VR.2008.4480745.

    Chapter  Google Scholar 

  • Eade, E., & Drummond, T. (2006a). Edge landmarks in monocular SLAM. In Proceedings of the 17th British machine vision conference (BMVC’06), Edinburgh (Vol. 1, pp. 7–16).

    Google Scholar 

  • Eade, E., & Drummond, T. (2006b). Scalable monocular SLAM. In Proceedings of the IEEE conference on computer vision and pattern recognition (CVPR’06) (Vol. 1, pp. 469–476). doi:10.1109/CVPR.2006.263.

    Google Scholar 

  • Ebrahimi, M., & Mayol-Cuevas, W. (2009). SUSurE: Speeded up surround extrema feature detector and descriptor for realtime applications. In Workshop on feature detectors and descriptors: the state of the art and beyond. IEEE conference on computer vision and pattern recognition (CVPR’09).

    Google Scholar 

  • Fiala, M. (2005). ARTag, a fiducial marker system using digital techniques. In Proceedings of the IEEE conference on computer vision and pattern recognition (CVPR’05) (Vol. 2, pp. 590–596), Washington, DC, USA. doi:10.1109/CVPR.2005.74.

    Google Scholar 

  • Fischler, M. A., & Bolles, R. C. (1981). Random sample consensus: a paradigm for model fitting with applications to image analysis and automated cartography. Communications of the ACM, 24(6), 381–395. doi:10.1145/358669.358692.

    Article  MathSciNet  Google Scholar 

  • Förstner, W. (1994). A framework for low level feature extraction. In Proceedings of the 3rd European conference on computer vision (ECCV’94), Secaucus, NJ, USA (Vol. II, pp. 383–394).

    Google Scholar 

  • Freeman, W. T., & Adelson, E. H. (1991). The design and use of steerable filters. IEEE Transactions on Pattern Analysis and Machine Intelligence, 13(9), 891–906. doi:10.1109/34.93808.

    Article  Google Scholar 

  • Gauglitz, S., Höllerer, T., Krahwinkler, P., & Roßmann, J. (2009). A setup for evaluating detectors and descriptors for visual tracking. In Proceedings of the 8th IEEE intl. symposium on mixed and augmented reality (ISMAR’09).

    Google Scholar 

  • Gauglitz, S., Höllerer, T., & Turk, M. (2010). Dataset and evaluation of interest point detectors for visual tracking (Technical Report 2010-06). Department of Computer Science, UC Santa Barbara.

  • Harris, C., & Stephens, M. (1988). A combined corner and edge detector. In Proceedings of the 4th ALVEY vision conference (pp. 147–151).

    Google Scholar 

  • Hartley, R., & Zisserman, A. (2004). Multiple view geometry in computer vision (2nd ed.). Cambridge: Cambridge University Press.

    MATH  Google Scholar 

  • Horn, B. K. P. (1987). Closed-form solution of absolute orientation using unit quaternions. Journal of the Optical Society of America, A, Optics, Image Science & Vision, 4(4), 629–642.

    Article  MathSciNet  Google Scholar 

  • Julier, S. J., & Uhlmann, J. K. (1997). New extension of the Kalman filter to nonlinear systems. In I. Kadar (Ed.), Proceedings of the SPIE conference on signal processing, sensor fusion, & target recognition VI (Vol. 3068, pp. 182–193). doi:10.1117/12.280797.

    Google Scholar 

  • Kadir, T., Zisserman, A., & Brady, M. (2004). An affine invariant salient region detector. In Proceedings of the 8th European conference on computer vision (ECCV’04) (pp. 228–241).

    Google Scholar 

  • Kato, H., & Billinghurst, M. (1999). Marker tracking and HMD calibration for a video-based augmented reality conferencerencing system. In Proceedings of the 2nd IEEE and ACM intl. workshop on augmented reality (IWAR’99) (p. 85), Washington, DC, USA.

    Chapter  Google Scholar 

  • Ke, Y., & Sukthankar, R. (2004). PCA-SIFT: A more distinctive representation for local image descriptors. In Proceedings of the IEEE conference on computer vision and pattern recognition (CVPR’04) (Vol. 2, pp. 506–513). doi:10.1109/CVPR.2004.183.

    Google Scholar 

  • Kitchen, L., & Rosenfeld, A. (1982). Gray-level corner detection. Pattern Recognition Letters, 1(2), 95–102. doi:10.1016/0167-8655(82)90020-4.

    Article  Google Scholar 

  • Klein, G., & Murray, D. (2007). Parallel tracking and mapping for small AR workspaces. In Proceedings of the 6th IEEE and ACM intl. symposium on mixed and augmented reality (ISMAR’07), Nara, Japan.

    Google Scholar 

  • Klein, G., & Murray, D. (2008). Improving the agility of keyframe-based SLAM. In Proceedings of the 10th European conference on computer vision (ECCV’08), Marseille, France (pp. 802–815).

    Google Scholar 

  • Klein, G., & Murray, D. (2009). Parallel tracking and mapping on a camera phone. In Proceedings of the 8th IEEE intl. symposium on mixed and augmented reality (ISMAR’09) (pp. 83–86). doi:10.1109/ISMAR.2009.5336495.

    Chapter  Google Scholar 

  • Lee, S., & Song, J. B. (2004). Mobile robot localization using optical flow sensors. International Journal of Control, Automation, and Systems, 2(4), 485–493.

    Google Scholar 

  • Lee, T., & Höllerer, T. (2008). Hybrid feature tracking and user interaction for markerless augmented reality. In Proceedings of the IEEE virtual reality conference (VR’08) (pp. 145–152). doi:10.1109/VR.2008.4480766.

    Chapter  Google Scholar 

  • Lepetit, V., & Fua, P. (2006). Keypoint recognition using randomized trees. IEEE Transactions on Pattern Analysis and Machine Intelligence, 28(9), 1465–1479. doi:10.1109/TPAMI.2006.188.

    Article  Google Scholar 

  • Levin, A., & Szeliski, R. (2004). Visual odometry and map correlation. In Proceedings of the IEEE conference on computer vision and pattern recognition (CVPR’04) (Vol. 1, pp. 611–618). doi:10.1109/CVPR.2004.266.

    Google Scholar 

  • Lieberknecht, S., Benhimane, S., Meier, P., & Navab, N. (2009). A dataset and evaluation methodology for template-based tracking algorithms. In Proceedings of the IEEE intl. symposium on mixed and augmented reality (ISMAR’09).

    Google Scholar 

  • Lindeberg, T. (1994). Scale-space theory: A basic tool for analysing structures at different scales. Journal of Applied Statistics, 21(2), 224–270.

    Google Scholar 

  • Lowe, D. G. (1999). Object recognition from local scale-invariant features. In Proceedings of the IEEE intl. conference on computer vision (ICCV’99), Corfu (pp. 1150–1157).

    Chapter  Google Scholar 

  • Lowe, D. G. (2004). Distinctive image features from scale-invariant keypoints. International Journal of Computer Vision, 60(2), 91–110.

    Article  Google Scholar 

  • Matas, J., Chum, O., Urban, M., & Pajdla, T. (2002). Robust wide baseline stereo from maximally stable extremal regions. In Proceedings of the British machine vision conference (BMCV’02) (pp. 384–393).

    Google Scholar 

  • Matthies, L., & Shafer, S. A. (1987). Error modeling in stereo navigation. IEEE Journal of Robotics and Automation, 3(3), 239–248.

    Article  Google Scholar 

  • McCarthy, C. D. (2005). Performance of optical flow techniques for mobile robot navigation (Master’s thesis). Department of Computer Science and Software Engineering, University of Melbourne.

  • Mikolajczyk, K., & Schmid, C. (2001). Indexing based on scale invariant interest points. In Proceedings of the IEEE intl. conference on computer vision (ICCV’01) (Vol. 1, p. 525). doi:10.1109/ICCV.2001.10069.

    Google Scholar 

  • Mikolajczyk, K., & Schmid, C. (2002). An affine invariant interest point detector. In Proceedings of the 7th European conference on computer vision (ECCV’02) (pp. 128–142), London, UK.

    Google Scholar 

  • Mikolajczyk, K., & Schmid, C. (2004). Scale & affine invariant interest point detectors. International Journal of Computer Vision, 60(1), 63–86. doi:10.1023/B:VISI.0000027790.02288.f2.

    Article  Google Scholar 

  • Mikolajczyk, K., & Schmid, C. (2005). A performance evaluation of local descriptors. IEEE Transactions on Pattern Analysis and Machine Intelligence, 27(10), 1615–1630. doi:10.1109/TPAMI.2005.188.

    Article  Google Scholar 

  • Mikolajczyk, K., Tuytelaars, T., Schmid, C., Zisserman, A., Matas, J., Schaffalitzky, F., Kadir, T., & van Gool, L. (2005). A comparison of affine region detectors. International Journal of Computer Vision, 65(7), 43–72.

    Article  Google Scholar 

  • Mohanna, F., & Mokhtarian, F. (2006). Performance evaluation of corner detectors using consistency and accuracy measures. Computer Vision and Image Understanding, 102(1), 81–94. doi:10.1016/j.cviu.2005.11.001.

    Article  Google Scholar 

  • Montemerlo, M., Thrun, S., Koller, D., & Wegbreit, B. (2002). FastSLAM: A factored solution to the simultaneous localization and mapping problem. In Proceedings of the AAAI national conference on artificial intelligence (pp. 593–598).

    Google Scholar 

  • Montemerlo, M., Thrun, S., Koller, D., & Wegbreit, B. (2003). FastSLAM 2.0: An improved particle filtering algorithm for simultaneous localization and mapping that provably converges. In Proceedings of the intl. joint conference on artificial intelligence (IJCAI’03) (pp. 1151–1156).

    Google Scholar 

  • Moravec, H. (1980). Obstacle avoidance and navigation in the real world by a seeing robot rover (Technical Report CMU-RI-TR-80-03). Robotics Institute, Carnegie Mellon University.

  • Moreels, P., & Perona, P. (2007). Evaluation of features detectors and descriptors based on 3D objects. International Journal of Computer Vision, 73(3), 263–284. doi:10.1007/s11263-006-9967-1.

    Article  Google Scholar 

  • Moreno-Noguer, F., Lepetit, V., & Fua, P. (2007). Accurate non-iterative o(n) solution to the pnp problem. In Proceedings of the IEEE international conference on computer vision (ICCV’07) (pp. 1–8). doi:10.1109/ICCV.2007.4409116.

    Google Scholar 

  • Neira, J., & Tardos, J. D. (2001). Data association in stochastic mapping using the joint compatibility test. IEEE Transactions on Robotics and Automation, 17(6), 890–897. doi:10.1109/70.976019.

    Article  Google Scholar 

  • Nistér, D., Naroditsky, O., & Bergen, J. (2004). Visual odometry. In Proceedings of the IEEE conference on computer vision and pattern recognition (CVPR’04) (Vol. 1, pp. 652–659). doi:10.1109/CVPR.2004.1315094.

    Google Scholar 

  • Özuysal, M., Fua, P., & Lepetit, V. (2007). Fast keypoint recognition in ten lines of code. In Proceedings of the IEEE conference on computer vision and pattern recognition (CVPR’07), Minneapolis, Minnesota, USA. doi:10.1109/CVPR.2007.383123.

    Google Scholar 

  • Park, Y., Lepetit, V., & Woo, W. (2008). Multiple 3D object tracking for augmented reality. In Proceedings of the 7th IEEE and ACM intl. symposium on mixed and augmented reality (ISMAR’08) (pp. 117–120). doi:10.1109/ISMAR.2008.4637336.

    Chapter  Google Scholar 

  • Rosten, E., & Drummond, T. (2005). Fusing points and lines for high performance tracking. In Proceedings of the IEEE intl. conference on computer vision (ICCV’05) (Vol. 2, pp. 1508–1511). doi:10.1109/ICCV.2005.104.

    Google Scholar 

  • Rosten, E., & Drummond, T. (2006). Machine learning for high-speed corner detection. In Proceedings of the IEEE European conference on computer vision (ECCV’06) (Vol. 1, pp. 430–443). doi:10.1007/11744023_34.

    Google Scholar 

  • Schaffalitzky, F., & Zisserman, A. (2002). Multi-view matching for unordered image sets, or “How Do I Organize My Holiday Snaps?”. In Proceedings of the 7th European conference on computer vision (ECCV’02) (Vol. 1, pp. 414–431), London, UK.

    Google Scholar 

  • Schmid, C., & Mohr, R. (1997). Local greyvalue invariants for image retrieval. IEEE Transactions on Pattern Analysis and Machine Intelligence, 19, 530–535.

    Article  Google Scholar 

  • Schmid, C., Mohr, R., & Bauckhage, C. (2000). Evaluation of interest point detectors. International Journal of Computer Vision, 37(2), 151–172.

    Article  MATH  Google Scholar 

  • Se, S., Lowe, D., & Little, J. (2002). Mobile robot localization and mapping with uncertainty using scale-invariant visual landmarks. The International Journal of Robotics Research, 21(8), 735–758. doi:10.1177/027836402761412467.

    Article  Google Scholar 

  • Seitz, S. M., Curless, B., Diebel, J., Scharstein, D., & Szeliski, R. (2006). A comparison and evaluation of multi-view stereo reconstruction algorithms. In Proceedings of the IEEE conference on computer vision and pattern recognition (CVPR’06) (Vol. 1, pp. 519–528). Los Alamitos: IEEE Computer Society. doi:10.1109/CVPR.2006.19.

    Google Scholar 

  • Shi, J., & Tomasi, C. (1994). Good features to track. In Proceedings of the IEEE conference on computer vision and pattern recognition (CVPR’94) (pp. 593–600). doi:10.1109/CVPR.1994.323794.

    Google Scholar 

  • Skrypnyk, I., & Lowe, D. G. (2004). Scene modelling, recognition and tracking with invariant image features. In Proceedings of the 3rd IEEE and ACM intl. symposium on mixed and augmented reality (ISMAR’04) (pp. 110–119). doi:10.1109/ISMAR.2004.53.

    Chapter  Google Scholar 

  • Taylor, S., Rosten, E., & Drummond, T. (2009). Robust feature matching in 2.3us. In Workshop, IEEE conference on computer vision and pattern recognition (pp. 15–22). doi:10.1109/CVPRW.2009.5204314.

    Chapter  Google Scholar 

  • Torr, P. H. S., & Zisserman, A. (2000). MLESAC: A new robust estimator with application to estimating image geometry. Computer Vision and Image Understanding, 78(1), 138–156. doi:10.1006/cviu.1999.0832.

    Article  Google Scholar 

  • Trajkovic, M., & Hedley, M. (1998). Fast corner detection. Image and Vision Computing, 16(2), 75–87. doi:10.1016/S0262-8856(97)00056-5.

    Article  Google Scholar 

  • Tuytelaars, T., & van Gool, L. (2000). Wide baseline stereo matching based on local, affinely invariant regions. In Proceedings of the British machine vision conference (BMVC’00) (pp. 412–425).

    Google Scholar 

  • Viola, P., & Jones, M. (2001). Rapid object detection using a boosted cascade of simple features. In Proceedings of the IEEE conference on computer vision and pattern recognition (CVPR’01) (Vol. 1, p. 511). Los Alamitos: IEEE Computer Society. doi:10.1109/CVPR.2001.990517.

    Google Scholar 

  • Wagner, D., Reitmayr, G., Mulloni, A., Drummond, T., & Schmalstieg, D. (2008). Pose tracking from natural features on mobile phones. In Proceedings of the 7th IEEE and ACM intl. symposium on mixed and augmented reality (ISMAR’08), Cambridge, UK.

    Google Scholar 

  • Wagner, D., Schmalstieg, D., & Bischof, H. (2009). Multiple target detection and tracking with guaranteed framerates on mobile phones. In Proceedings of the 8th IEEE intl. symposium on mixed and augmented reality (ISMAR’09) (pp. 57–64). doi:10.1109/ISMAR.2009.5336497.

    Chapter  Google Scholar 

  • Wagner, D., Mulloni, A., Langlotz, T., & Schmalstieg, D. (2010). Real-time panoramic mapping and tracking on mobile phones. In Proceedings of the IEEE virtual reality conference (VR’10).

    Google Scholar 

  • Williams, B., Klein, G., & Reid, I. (2007). Real-time SLAM relocalisation. In Proceedings of the IEEE intl. conference on computer vision (ICCV’07) (pp. 1–8). doi:10.1109/ICCV.2007.4409115.

    Google Scholar 

  • Winder, S., & Brown, M. (2007). Learning local image descriptors. In Proceedings of the IEEE conference on computer vision and pattern recognition (CVPR’07) (pp. 1–8). doi:10.1109/CVPR.2007.382971.

    Google Scholar 

  • Winder, S., Hua, G., & Brown, M. (2009). Picking the best daisy. In Proceedings of the IEEE conference on computer vision and pattern recognition (CVPR’09) (pp. 178–185). doi:10.1109/CVPRW.2009.5206839.

    Google Scholar 

  • Yilmaz, A., Javed, O., & Shah, M. (2006). Object tracking: A survey. ACM Computing Surveys, 38. doi:10.1145/1177352.1177355.

  • Zhang, Z. (1997). Parameter estimation techniques: a tutorial with application to conic fitting. Image and Vision Computing, 15, 59–76.

    Article  Google Scholar 

  • Zimmermann, K., Matas, J., & Svoboda, T. (2009). Tracking by an optimal sequence of linear predictors. IEEE Transactions on Pattern Analysis and Machine Intelligence, 31, 677–692. doi:10.1109/TPAMI.2008.119.

    Article  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Steffen Gauglitz.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Gauglitz, S., Höllerer, T. & Turk, M. Evaluation of Interest Point Detectors and Feature Descriptors for Visual Tracking. Int J Comput Vis 94, 335–360 (2011). https://doi.org/10.1007/s11263-011-0431-5

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s11263-011-0431-5

Keywords

Navigation