[1] Koch E, Dietzel A. Surface reconstruction by means of a flexible sensor array[J]. Sensors & Actuators A: Physical, 2017, 267: 293-300.

[2] Schaefer P L, Barrier G, Chagnon G, et al. Strain gauges based 3D shape monitoring of beam structures using finite width gauge model[J]. Experimental Techniques, 2019, 43(5): 599-611.

[3] De Gelidi S, Seifnaraghi N, Bardill A, et al. Torso shape detection to improve lung monitoring[J]. Phys. Meas., 2018, 39(7): 074001.

[4] Porcu M C, Patteri D M, Melis S, et al. Effectiveness of the FRF curvature technique for structural health monitoring[J]. Construction and Building Materials, 2019, 226: 173-187.

[5] Stollenwerk K, Müllers J, Müller J, et al. Evaluating An Accelerometer-based System for Spine Shape Monitoring[M]. Computational Science and Its Applications-ICCSA, 2018: 740-756.

[6] Dementyev A, Kao H-L, Paradiso J A. SensorTape[Z]. Proc. of the 28th Annual ACM Symposium on User Interface Software & Technology, 2015: 649-658.

[7] Plamondon A, Delisle A, Larue C, et al. Evaluation of a hybrid system for three-dimensional measurement of trunk posture in motion[J]. Appl Ergon, 2007, 38(6): 697-712.

[8] Griffith C, Dare P, Danish L. Calibration enhancement of ShapeAccelArray technology for long term deformation monitoring applications[C]// IEEE/ION Position, Location and Navigation Symposium. IEEE, 2010: 621-626.

[9] Green G E, Mikkelsen P E. Deformation measurements with inclinometers[J]. Transportation Research Record, 1988.

[10] Hou X M, Yang X S, Huang Q. Using inclinometers to measure bridge deflections[J]. Bridge Construction, 2005, 10: 564-569.

[11] Stark T D, Choi H. Slope inclinometers for landslides[J]. Landslides, 2008, 5(3): 339-350.

[12] Cha Y-J, Choi W, BüYüKZTüRK O. Deep learning-based crack damage detection using convolutional neural networks[J]. Computer-Aided Civil and Infrastructure Engineering, 2017, 32(5): 361-378.

[13] Ye X W, Dong C Z, Liu T. A review of machine vision-based structural health monitoring: Methodologies and applications[J]. J. of Sensors, 2016, 2016(7): 1-10.

[14] Mullen L J, Vieira A J C. Application of RADAR technology to aerial LIDAR systems for enhancement of shallow underwater target detection[J]. IEEE Trans. on Microwave Theory & Techniques, 1995, 43(9): 2370-2377.

[15] Gentile C, Bernardini G. Radar-based measurement of deflections on bridges and large structures[J]. European J. of Environmental and Civil Engineering, 2011, 14(4): 495-516.

[16] Milillo P, Fielding E J, Shulz W H, et al. COSMO-SkyMed spotlight interferometry over rural areas: The Slumgullion landslide in Colorado, USA[J]. IEEE J. of Sel. Top. in Appl. Earth Observations and Remote Sensing, 2014, 7(7): 2919-2926.

[17] Choi S W, Kim B R, Lee H M, et al. A deformed shape monitoring model for building structures based on a 2D laser scanner[J]. Sensors (Basel), 2013, 13(5): 6746-6758.

[18] Bednarz B, Popielski P, Sienko R, et al. Distributed fibre optic sensing (DFOS) for deformation assessment of composite collectors and pipelines[J]. Sensors (Basel), 2021, 21(17): 5904.

[19] Donder A, Baena F R Y. Kalman-filter-based, dynamic 3-D shape reconstruction for steerable needles with fiber Bragg gratings in multicore fibers[J]. IEEE Trans. on Robotics, 2021: 1-14.

[20] Issatayeva A, Amantayeva A, Blanc W, et al. Design and analysis of a fiber-optic sensing system for shape reconstruction of a minimally invasive surgical needle[J]. Scientific Reports, 2021, 11(1): 8609.

[21] Galloway K C, Chen Y, Templeton E, et al. Fiber optic shape sensing for soft robotics[J]. Soft Robot, 2019, 6(5): 671-684.

[22] Gherlone M, Cerracchio P, Mattone M. Shape sensing methods: Review and experimental comparison on a wing-shaped plate[J]. Progress in Aerospace Sciences, 2018, 99: 14-26.

[23] Ferreira P, Caetano E, Pinto P. Real-time flying shape detection of yacht sails based on strain measurements[J]. Ocean Engineering, 2017, 131: 48-56.

[24] Yin Y, Yu P, Jia Z, et al. An approach of the maximum curvature measurement of dynamic umbilicals using OFDR technology in fatigue tests[J]. Frontiers in Materials, 2021, 8: 717190.

[25] Fu Y, Di H, Liu R. Light intensity modulation fiber-optic sensor for curvature measurement[J]. Optics & Laser Technology, 2010, 42(4): 594-599.

[26] Fu Y, Di H. Fiber-optic curvature sensor with optimized sensitive zone[J]. Optics & Laser Technology, 2011, 43(3): 586-591.

[27] Markovic M Z, Bajic J S, Vrtunski M, et al. Application of fiber-optic curvature sensor in deformation measurement process[J]. Measurement, 2016, 92: 50-57.

[28] Stupar D Z, Bajic J S, Manojlovic L M, et al. Wearable low-cost system for human joint movements monitoring based on fiber-optic curvature sensor[J]. IEEE Sensors J., 2012, 12(12): 3424-3431.

[29] Leal-Junior A G, Frizera A, José Pontes M. Sensitive zone parameters and curvature radius evaluation for polymer optical fiber curvature sensors[J]. Optics & Laser Technol., 2018, 100: 272-281.

[30] Yang Yang, Zhu Xiaotong, Yan Liangjun, et al. A highly accurate curvature sensor based on a rough side-polished single-mode fiber[J]. Acta Optica Sinica, 2020, 40(14): 1406004.

[31] Culshaw B, Gong Y, Liao Y, et al. Fiber-optic curvature sensor based on step-index multimode fiber[Z]. 2011 Inter. Conf. on Optical Instruments and Technology: Optical Sensors and Applications. 2011.10.1117/12.904127.

[32] Ma L, Qi Y, Kang Z, et al. All-fiber strain and curvature sensor based on no-core fiber[J]. IEEE Sensors J., 2014, 14(5): 1514-1517.

[33] Rodríguez-Vera R, Guzman-Sepulveda J R, Díaz-Uribe R, et al. Measurement of curvature and temperature using multimode interference devices[Z]. 22nd Congress of the Inter. Commission for Optics: Light for the Development of the World. 2011.10.1117/12.903448.

[34] Fu X, Wen J, Zhang Y, et al. Experimental and theoretical analysis of curvature sensor based on cladding mode resonance with triple cladding quartz specialty fiber[J]. Optics Communications, 2018, 429: 5-11.

[35] Silva S, FrazO O, Viegas J, et al. Temperature and strain-independent curvature sensor based on a singlemode/multimode fiber optic structure[J]. Measurement Science and Technology, 2011, 22(8): 085201.

[36] Gong H, Song H, Li X, et al. An optical fiber curvature sensor based on photonic crystal fiber modal interferometer[J]. Sensors and Actuators A: Physical, 2013, 195: 139-141.

[37] Herrera-Piad L A, Hernandez-Romano I, May-Arrioja D A, et al. Sensitivity enhancement of curvature fiber sensor based on polymer-coated capillary hollow-core fiber[J]. Sensors (Basel), 2020, 20(13): 3763.

[38] Salceda-Delgado G, Martinez-Rios A, Selvas-Aguilar R, et al. Adaptable optical fiber displacement-curvature sensor based on a modal Michelson interferometer with a tapered single mode fiber[J]. Sensors (Basel), 2017, 17(6): 1259.

[39] Zhao Y, Gao P, Yang Y. Temperature insensitive curvature sensor based on a combination interference structure and an intensity demodulation method[J]. Microwave and Optical Technology Letters, 2015, 57(4): 806-809.

[40] Su B, Zhang F, Zhong L, et al. Temperature compensated curvature sensor with insensitive axial strain based on tapered ring core fiber interferometer[J]. Opt. Communications, 2022, 513: 128067.

[41] Gong H, Song H, Zhang S, et al. Curvature sensor based on hollow-core photonic crystal fiber sagnac interferometer[J]. IEEE Sensors J., 2013, 14(3): 777-780.

[42] Zhao Y, Cai L, Li X G. Temperature-insensitive optical fiber curvature sensor based on SMF-MMF-TCSMF-MMF-SMF structure[J]. IEEE Trans. on Instrumentation and Measurement, 2017, 66(1): 141-147.

[43] Marrujo-García S, Hernndez-Romano I, Torres-Cisneros M, et al. Temperature-independent curvature sensor based on in-fiber Mach-Zehnder interferometer using hollow-core fiber[J]. J. of Lightwave Technol., 2020, 38(15): 4166-4173.

[44] Liu Y, Dong J, Huang L, et al. Investigations on seven-core fiber based interferometric all-fiber sensor for curvature and temperature measurements[J]. Optik, 2022, 254: 168638.

[45] Xiao D, Wang G, Yu F, et al. Optical curvature sensor with high resolution based on in-line fiber Mach-Zehnder interferometer and microwave photonic filter[J]. Opt. Express, 2022, 30(4): 5402-5413.

[46] Ding L, Yu L, Hu G, et al. Knee joint curvature detection system based on fiber optic Mach-Zendler interferometric curvature sensor[J]. IEEE Sensors J., 2021, 21(24): 28017-28024.

[47] Xu S, Chen H, Feng W. Fiber-optic curvature and temperature sensor based on the lateral-offset spliced SMF-FCF-SMF interference structure[J]. Opt. & Laser Technol., 2021, 141: 107174.

[48] Zhang X, Liu C, Liu J, et al. Single modal interference-based fiber-optic sensor for simultaneous measurement of curvature and strain with dual-differential temperature compensation[J]. IEEE Sensors J., 2018, 18(20): 8375-8380.

[49] Liao N, He L, Ma L, et al. A sensitivity-enhanced micro-cavity extrinsic Fabry-Perot interferometric fiber-optic curvature sensor[J]. Optik-Inter. J. for Light and Electron Optics, 2020, 221: 165310.

[50] Novais S, Silva S O, Frazao O. A self-referencing intensity-based Fabry-Perot cavity for curvature measurement[J]. IEEE Sensors Lett., 2019, 3(10): 1-4.

[51] Robalinho P, Frazo O. Fiber microsphere coupled in a taper for a large curvature range[J]. Fibers, 2019, 7(10): 87.

[52] Lin H S, Raji Y M, Lim J H, et al. Packaged in-line Mach-Zehnder interferometer for highly sensitive curvature and flexural strain sensing[J]. Sensors and Actuators A: Physical, 2016, 250: 237-242.

[53] Raji Y M, Lin H S, Ibrahim S A, et al. Intensity-modulated abrupt tapered fiber Mach-Zehnder Interferometer for the simultaneous sensing of temperature and curvature[J]. Optics & Laser Technology, 2016, 86: 8-13.

[54] Meng Q, Dong X, Chen Z, et al. Simultaneous measurement of curvature and temperature based on two waist-enlarged fiber tapers and a fiber Bragg grating[C]// Photonics Global Conference. IEEE, 2012.

[55] Koo B, Kim D H. Directional bending sensor based on triangular shaped fiber Bragg gratings[J]. Opt. Express, 2020, 28(5): 6572-6581.

[56] Liu H-L, Zhu Z-W, Zheng Y, et al. Experimental study on an FBG strain sensor[J]. Optical Fiber Technol., 2018, 40: 144-151.

[57] Zhang Xiongxiong, Song Yanming, Sun Guangkai, et al. Fiber Bragg grating curvature sensor based on flexible composite matrix[J]. Infrared and Laser Engineering, 2019, 48(2).doi:10.378811RLA201948.0222001.

[58] Danisch L A. Fiber Optic Curvature Sensor: WO, WO2000068645 A1[P].

[59] Lewis E, Nascimento I M, Chesini G, et al. LPG-based sensor for curvature and vibration[Z]. Sixth European Workshop on Optical Fibre Sensors. 2016.10.1117/12.2237041.

[60] Wu C, Feng Z W, Liu Z, et al. Curvature sensor based on an LPG written in an air-clad thin-core fiber[C]// 2016 15th Inter. Conf. on Optical Communications and Networks (ICOCN). IEEE, 2016.

[61] Gouveia C, Jorge P A S, Baptista J M, et al. Temperature-independent curvature sensor using FBG cladding modes based on a core misaligned splice[J]. IEEE Photon. Technol. Lett., 2011, 23(12): 804-806.

[62] Ba D, Chen C, Fu C, et al. A high-performance and temperature-insensitive shape sensor based on DPP-BOTDA[J]. IEEE Photon. J., 2018, 10(1): 1-10.

[63] Kreger S T, Gifford D K, Froggatt M E, et al. High resolution distributed strain or temperature measurements in single- and multi-mode fiber using swept-wavelength interferometry[J]. Ofs, 2006. doi: 10.131410FS.2006.ThE42.

[64] Duncan R G, Inaudi D, Raum M T, et al. Characterization of a fiber-optic shape and position sensor[Z]. Smart Structures and Materials 2006: Smart Sensor Monitoring Systems and Applications. 2006.10.1117/12.658535.

[65] Shao C, Yin G, Lv L, et al. OFDR with local spectrum matching method for optical fiber shape sensing[J]. Appl. Physics Express, 2019, 12(8): 082010.1-082010.4.

[66] Koyamada Y, Imahama M, Kubota K, et al. Fiber-optic distributed strain and temperature sensing with very high measure and resolution over long range using coherent OTDR[J]. J. of Lightwave Technol., 2009, 27(9): 1142-1146.

[67] Jovan S B, Markovic M Z, JoA A, et al. Design calibration and characterization of a robust low-cost fiber-optic 2D deflection sensor[J]. Sensors and Actuators A: Physical, 2017, 267: 278-286.

[68] Barrera D, Gasulla I, Sales S. Multipoint two-dimensional curvature optical fiber sensor based on a nontwisted homogeneous four-core fiber[J]. J. of Lightwave Technol., 2015, 33(12): 2445-2450.

[69] Jason M P. Shape sensing using multi-core fiber[C]// Optical Fiber Communications Conference and Exhibition, IEEE, 2015.

[70] Westbrook P S, Kremp T, Feder K S, et al. Continuous multicore optical fiber grating arrays for distributed sensing applications[J]. J. of Lightwave Technol., 2017, 35(6): 1248-1252.

[71] Floris I, Madrigal J, Sales S, et al. Twisting measurement and compensation of optical shape sensor based on spun multicore fiber[J]. Mechanical Systems and Signal Processing, 2020, 140: 106700.1-106700.9.

[72] Floris I, Sales S, CalderóN P A, et al. Measurement uncertainty of multicore optical fiber sensors used to sense curvature and bending direction[J]. Measurement, 2019, 132: 35-46.

[73] Issatayeva A, Amantayeva A, Blanc W, et al. Temperature compensation of the fiber-optic based system for the shape reconstruction of a minimally invasive surgical needle[J]. Sensors and Actuators A: Physical, 2021, 329: 112795.

[74] Xu C, Sharif Khodaei Z. Shape sensing with Rayleigh backscattering fibre optic sensor[J]. Sensors (Basel), 2020, 20(14): 4040.

[78] Erroranalysis of FBG-based shape sensors for medical needle tracking[J]. IEEE/ASME Trans. on Mechatronics, 2014, 19(5): 1523-1531.

[79] Jason P M. Shape sensing using multi-core fiber[C]// 2015 Optical Fiber Communications Conference and Exhibition (OFC), IEEE, 2015.

[80] Al-Ahmad O, Ourak M, Van Roosbroeck J, et al. Improved FBG-based shape sensing methods for vascular catheterization treatment[J]. IEEE Robotics and Automation Letters, 2020, 5(3): 4687-4694.

[81] Cui J, Zhao S, Yang C, et al. Parallel transport frame for fiber shape sensing[J]. IEEE Photon. J., 2018, 10(1): 1-12.

[82] Khan F, Donder A, Galvan S, et al. Pose measurement of flexible medical instruments using fiber Bragg gratings in multi-core fiber[J]. IEEE Sensors J., 2020, 20(18): 10955-10962.

[83] Okamura E, Shahriari N, Roesthuis R, et al. Steering an actuated-tip needle in biological tissue: Fusing FBG-sensor data and ultrasound images[C]// Robotics and Automation (ICRA). IEEE, 2016.

[84] Denasi A, Khan F, Boskma K J, et al. An observer-based fusion method using multicore optical shape sensors and ultrasound images for magnetically-actuated catheters[C]// IEEE Inter. Conf. on Robotics & Automation. IEEE, 2018.