Fast four step digital demodulation for multiplexed fibre laser sensors

2008 ◽  
Author(s):  
M. Milnes ◽  
A. Tikhomirov ◽  
S. Foster ◽  
S. Goodman
Keyword(s):  
Fibre Laser ◽  
Laser Sensors ◽  
Digital Demodulation

Polarimetric fibre laser sensors using Er-doped fibre

1995 ◽  
Vol 27 (5) ◽  
pp. 481-485 ◽  
Author(s):  
H. K. Kim ◽  
S. K. Kim ◽  
B. Y. Kim
Keyword(s):  
Fibre Laser ◽  
Laser Sensors ◽  
Er Doped

scholarly journals Gradient–Index Fibre Based Miniature Gas Cell For Intra–Cavity Fibre Laser Sensors

2012 ◽  
Author(s):  
Li Mo ◽  
Asrul Izam Azmi ◽  
Gang–Ding Peng
Keyword(s):  
Gas Sensing ◽  
Small Diameter ◽  
Single Mode ◽  
Fibre Laser ◽  
Gradient Index ◽  
Gaussian Field ◽  
Coupling Loss ◽  
Gas Cell ◽  
Laser Sensors ◽  
Index Fibre

This paper presents a new and simple design of gas cell for the use of intra–cavity fibre laser sensors. This design utilizes gradient–index fibres for collimation to realize a miniature gas cell of very small diameter. By using the Gaussian field approximation and ray transformation, the gas cell is analyzed and optimized. It is found that gradient–index fibre based cells could achieve lower coupling loss of nearly 10 dB at a separation of 20 mm and allow for additional tolerance to certain misalignments, in comparison with those single–mode fibre based cells. A new–design cell is fabricated and its coupling loss is tested with a 1550 nm laser. Good agreement in the analysis and experimental results is obtained, indicating that the design could be feasible in practical gas sensing. Key words: Gradient–index fibre based cell; gradient–index fibre collimator (GIFC); coupling loss; misalignments; intra–cavity fibre gas sensor

Developing Algorithms for a Berry Recognition System Used in Robotized Harvesting of Garden Strawberry

2020 ◽  
Vol 67 (1) ◽  
pp. 133-141
Author(s):  
Dmitriy O. Khort ◽  
Aleksei I. Kutyrev ◽  
Igor G. Smirnov ◽  
Rostislav A. Filippov ◽  
Roman V. Vershinin
Keyword(s):  
Computer Vision ◽  
Technological Process ◽  
Degrees Of Freedom ◽  
Computer Control ◽  
Recognition System ◽  
Raspberry Pi ◽  
Laser Sensors ◽  
Lighting Conditions ◽  
Systems Research ◽  
Degree Of Maturity

Technological capabilities of agricultural units cannot be optimally used without extensive automation of production processes and the use of advanced computer control systems. (Research purpose) To develop an algorithm for recognizing the coordinates of the location and ripeness of garden strawberries in different lighting conditions and describe the technological process of its harvesting in field conditions using a robotic actuator mounted on a self-propelled platform. (Materials and methods) The authors have developed a self-propelled platform with an automatic actuator for harvesting garden strawberry, which includes an actuator with six degrees of freedom, a co-axial gripper, mg966r servos, a PCA9685 controller, a Logitech HD C270 computer vision camera, a single-board Raspberry Pi 3 Model B+ computer, VL53L0X laser sensors, a SZBK07 300W voltage regulator, a Hubsan X4 Pro H109S Li-polymer battery. (Results and discussion) Using the Python programming language 3.7.2, the authors have developed a control algorithm for the automatic actuator, including operations to determine the X and Y coordinates of berries, their degree of maturity, as well as to calculate the distance to berries. It has been found that the effectiveness of detecting berries, their area and boundaries with a camera and the OpenCV library at the illumination of 300 Lux reaches 94.6 percent’s. With an increase in the robotic platform speed to 1.5 kilometre per hour and at the illumination of 300 Lux, the average area of the recognized berries decreased by 9 percent’s to 95.1 square centimeter, at the illumination of 200 Lux, the area of recognized berries decreased by 17.8 percent’s to 88 square centimeter, and at the illumination of 100 Lux, the area of recognized berries decreased by 36.4 percent’s to 76 square centimeter as compared to the real area of berries. (Conclusions) The authors have provided rationale for the technological process and developed an algorithm for harvesting garden strawberry using a robotic actuator mounted on a self-propelled platform. It has been proved that lighting conditions have a significant impact on the determination of the area, boundaries and ripeness of berries using a computer vision camera.

Erratum: Saturable absorber modelocked polarisation maintaining erbium-doped fibre laser

1993 ◽  
Vol 29 (9) ◽  
pp. 825
Author(s):  
E.A. de Souza ◽  
M.N. Islam ◽  
C.E. Soccolich ◽  
W. Pleibel ◽  
R.H. Stolen ◽  
...  
Keyword(s):  
Saturable Absorber ◽  
Fibre Laser ◽  
Erbium Doped

scholarly journals Optical soliton molecular complexes in a passively mode-locked fibre laser

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Z. Q. Wang ◽  
K. Nithyanandan ◽  
A. Coillet ◽  
P. Tchofo-Dinda ◽  
Ph. Grelu
Keyword(s):  
Molecular Complexes ◽  
Optical Soliton ◽  
Fibre Laser

scholarly journals Analysis and optimization of laser drilling process during machining of AISI 303 material using grey relational analysis approach

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
V. Chengal Reddy ◽  
Thota Keerthi ◽  
T. Nishkala ◽  
G. Maruthi Prasad Yadav
Keyword(s):  
Surface Roughness ◽  
Process Parameters ◽  
Grey Relational Analysis ◽  
Pulse Frequency ◽  
Laser Drilling ◽  
Simultaneous Optimization ◽  
Fibre Laser ◽  
Drilling Process ◽  
Relational Analysis ◽  
Grey Relational

AbstractSurface roughness and heat-affected zone (HAZ) are the important features which influence the performance of the laser-drilled products. Understanding the influence of laser process parameters on these responses and identifying the cutting conditions for simultaneous optimization of these responses are a primary requirement in order to improve the laser drilling performance. Nevertheless, no such contribution has been made in the literature during laser drilling of AISI 303 material. The aim of the present work is to optimize the surface roughness (Ra) and HAZ in fibre laser drilling of AISI 303 material using Taguchi-based grey relational analysis (GRA). From the GRA methodology, the recommended optimum combination of process parameters is flushing pressure at 30 Pa, laser power at 2000 W and pulse frequency at 1500 Hz for simultaneous optimization of Ra and HAZ, respectively. From analysis of variance, the pulse frequency is identified as the most influenced process parameters on laser drilling process performance.

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