Authors:
Sergio L. Carrasco-Ortiz
;
Eduardo Valero
;
Maria Morant
and
Roberto Llorente
Affiliation:
Universitat Politècnica de València, Spain
Keyword(s):
Computational Sensing, Photonic Sensor, Imaging, CMOS, Multiphase Water Flow, Cavitation, Air Fraction, Bubble Speed.
Related
Ontology
Subjects/Areas/Topics:
Computational Optical Sensing and Imaging
;
Optical Instrumentation
;
Optics
;
Photonics, Optics and Laser Technology
Abstract:
This paper presents and demonstrates experimentally a photonic sensor based on laser excitation and CMOS array detection of light interactions in a bubbling water column. Bubbling water columns are multiphase water flows, which can be produced by cavitation effect in screws and pump-jets, or by water-air mixing in the dam intakes and spillways in hydroelectric energy generation plants. The proposed optical sensor comprises a CMOS array with a polymeric tuneable optical lens sampling the area illuminated by a diode laser operating at 532 nm. By computational imaging, the sensor is able to measure the size, shape and speed of the bubbles inside the water column and the corresponding bubble concentration. The developed laser-assisted sensor is demonstrated experimentally in the laboratory with a water column at 0.05 MPa with good results employing Optical Flow, SIFT and SURF computational methods.