نوع مقاله : علمی- ترویجی

نویسندگان

1 مربی، گروه مهندسی نقشه برداری، دانشگاه آزاد اسلامی، واحد تهران جنوب، تهران، ایران

2 استادیار، دانشکده مهندسی نقشه برداری و اطلاعات مکانی ، پردیس دانشکده های فنی، دانشگاه تهران، تهران، ایران

چکیده

امروزه، بکارگیری سنجنده‌های تصویربرداری غیرمتریک در سکوهای بدون سرنشین بسیار متداول شده است. ‌‌بطوریکه می‌توان این روش را جایگزینی برای نقشه‌برداری زمینی در تهیه نقشه‌های بزرگ مقیاس دانست. به دلیل محدودیت‌هایی مانند ماهیت سکوی پهپاد، ابعاد و وزن سکو، استفاده از سنجنده‌های اپتیکی متریک با حجم و وزن بالا امکان‌پذیر نمی‌باشد. ‌‌اغلب سنجنده‌های مورد استفاده در سکوهای پهپاد دوربین‌های سبک با ماهیت غیرمتریک می‌باشد. ‌‌دانستن مقادیر پارامترهای توجیه داخلی سنجنده به منظور پایش تغییرات آنها و بهبود نتایج مثلث‌بندی این تصاویر نقش اساسی دارد. ‌‌بنابراین، انجام کالیبراسیون هندسی آزمایشگاهی برای سنجنده‌های ذکر شده در شرایط مشابه در شرایط عملیاتی، نتایج مناسبتری را در مراحل بعدی تولید می‌نماید. ایستگاه موردنظر توانایی انجام مشاهدات کالیبراسیون طیف وسیعی از انواع دوربین‌های غیرمتریک را دارا بوده و با امکان ارزیابی صحت نتایج حاصل از روند کالیبراسیون، هم اکنون در حال خدمت‌رسانی است. 

کلیدواژه‌ها

عنوان مقاله [English]

Construction of Non-metric Camera Calibration Station for Use in Unmanned Aerial Vehicles (UAV's)

نویسندگان [English]

  • Nikrouz Mostofi 1
  • Mahdi Hasanlou 2

1 Instructor, Department of Surveying, Islamic Azad University, South Tehran Branch, Tehran, Iran

2 Assistant Professor, Department of Geomatics, Faculty of Engineering, University of Tehran, Tehran, Iran

چکیده [English]

In recent years, use of non-metric imaging sensors is becoming increasingly common in unmanned vehicles. ‌‌This can be considered as an alternative to terrestrial mapping. ‌‌Due to the limitations such as dimension, system weight, and the nature of UAV platform, it is not possible to use high volume and heavy metric sensors. Consequently, most sensors used in UAV platforms are light weight non-metric cameras. ‌‌Determining the values of the internal parameters of the sensor is important in monitoring the variations of these sensors and improving the triangulation results of these images. ‌‌Therefore, laboratory geometric calibration for these sensors under similar operating conditions produces better results in later stages. Our station is capable of performing calibration observations and also the calculations of a wide range of non-metric cameras and is currently serving in related organizations with ability to evaluate the accuracy of calibration results. 

کلیدواژه‌ها [English]

  • Non-metric Camera
  • Camera Calibration
  • Quality Assessment
  • UAV
[1] Atkinson, K.B., Close Range Photogrammetry and Machine Vision, Whittles Publishing, Scotland, 1998. ‌‌
[2] Samdzadegan, F., Hahn, M., Sarpulakic, M., and Mostofi, N., "Geometric and Radiometric Evaluation of the Potential of a High Resolution CMOS-Camera", The 20th International Congress for Photogrammetry and Remote Sensing, ISPRS, Istanbul, Turkey, 2004.
[3] Beyer, H.A. "Geometric and Radiometric Analysis of a CCD-camera Based Photogrammetric Close-Range System", Dissertation, ETH, Zurich, Switzerland, 1992.
[4] Cai, B.L., Wang, Y.W., Wu, J.J. and Wang, M.Y., “An Effective Method for Camera Calibration in Defocus Scene with Circular Gratings,” Opt. Lasers Eng., Vol. 114, pp. 44–49, 2019.
[5] Tarabanis, K., Tsai, R.Y., and Allen, P.K., "Analytical Characterization of the Feature Detectability Constraints of Resolution, Focus, and Field-of View for Vision Sensor Planning", CVGIP: Image Understanding, Vol. 59, pp. 340–358, 1994.
[6]Usamentiaga R and Garcia, D.F., "Multi-Camera Calibration for Accurate Geometric Measurements in Industrial Environments", Measurement, Vol. 134, pp. 345–58, 2019.
[7] Tang, R., Fritsch, D., and Cramer, M., "New Rigorous and Flexible Fourier Self-Calibration Models for Airborne Camera Calibration", ISPRS Journal of Photogrammetry and Remote Sensing, Vol. 71, pp. 76–85, 2012.
[8] Fraser, C.S., Network Design, Whittles Publishing, Scotland, UK, 1996.
[9] Fraser, C.S., "Limiting Error Propagation in Network Design", Photogrammetric Engineering and Remote Sensing, Vol. 48, No. 4, pp. 561-570, 1987.
[10] Fraser, C.S., "Digital Camera Self-Calibration", ISPRS Journal of Photogrammetry and Remote Sensing, Vol. 52, No. 4, pp. 149–159, 1997.
[11] Brown D.C., "The Bundle Adjustment - Progress and Prospects", International Archive of Photogrammetry, Vol. 21, No. 3, pp. 303-336, 1976.
[12] Fraser, C.S. and Veres, S. A., "Self-Cali bration of a Fixed-Frame Multiple-Camera System", Photogrammetric Engineering and Remote Sensing, Vol. 46, No. 11, pp. 1439-1445, 1980.
[13] Fraser, C.S. "Network Design Considerations for Non-Topographic Photogrammetry", Photogrammetric Engineering and Remote Sensing, Vol. 50, No. 8, pp. 1115-1126, 1984.
[14] Fraser, C.S. "Automated Processes in Digital Photogrammetric Calibration, Orientation, and Triangulation", Digital Signal Processing, Vol. 8, No. 4, pp. 277-283, 1998.
[15] Abzal, A., Saadatseresht, M., and Varshosaz, M., "Development of a Novel Simplification Mask for Multi-Shot Optical Scanners", ISPRS Journal of Photogrammetry and Remote Sensing, Vol. 142, pp.12–20, 2018.
[16] Olague G. and Mohr, R., "Optimal Camera Placement for Accurate Reconstruction", Pattern Recognition, Vol. 35, pp. 927–944, 2002.
[17] Vanícek, P. and Krakiwsky, E.J., Geodesy, 2nd Edition, Elsevier Science, Amsterdam, Netherlands, 1986.
[18] Gruen A. and Huang T.S., "Calibration and Orientation of Cameras in Computer Vision", Springer Science & Business Media, Berlin, Germanny, 2013.
[19] Krotkov, E. and Kories, R., "Adaptive Control of Cooperating Sensors: Focus and Stereo Ranging with an Agile Camera System", 1988 IEEE International Conference on Robotics and Automation Proceedings, 1988.
[20]Saadatseresht, M., "To Developing the Automation of Vision Metrology Network Design via Vision Constraint Uncertainty Modeling and Camera Placement", Ph.D. Dissertation, school of surveying and geospatial engineering, University of Tehran, Tehran, Iran, 2004 (In Persian).