We propose a new guidance system for the blind. An optical triangulation method is used in the system. The main components of the proposed system comprise of a notebook computer, a camera, and two laser modules. The track image of the light beam on the ground or on the object is captured by the camera and then the image is sent to the notebook computer for further processing and analysis. Using a developed signal-processing algorithm, our system can determine the object width and the distance between the object and the blind person through the calculation of the light line positions on the image. A series of feasibility tests of the developed blind guidance system were conducted. The experimental results show that the distance between the test object and the blind can be measured with a standard deviation of less than 8.5% within the range of 40 and 130 cm, while the test object width can be measured with a standard deviation of less than 4.5% within the range of 40 and 130 cm. The application potential of the designed system to the blind guidance can be expected.
KEYWORDS: Solar cells, Solar concentrators, Solar energy, Tolerancing, Fresnel lenses, Energy efficiency, Beam shaping, Modulation, Diamond turning, Assembly tolerances
In this paper, we proposed a new configuration of concentrator in solar PV system. A special optical system in the
concentrator used in focusing sun light to solar cell is proposed, the system compose of an aspherical surface and a
specific diffusing surface. The uniform-squared light pattern is obtained on the solar cell, the shape and size of light
pattern can be modulated by the parameters of the diffusing surface. In order to decrease the weight of the lens, the
concentrator in Fresnel lens type is built at last. Besides, the optical efficiencies formed by the aspherical concentrator
and Fresnel concentrator are about 92% and 77%, the concentrations are about 720mW/mm2 and 640mW/mm2, and the
acceptance angles are about 0.35° and 0.30°, respectively. The tolerances in assembling the component of the
concentrator are also discussed in detail.
A new apparatus for blind-guide is proposed in this paper. Optical triangulation method was used to realize the system.
The main components comprise a notebook computer, a camera and two laser modules. One laser module emits a light
line beam on the vertical axis. Another laser module emits a light line beam on the tilt horizontal axis. The track of the
light line beam on the ground or on the object is captured by the camera, and the image is sent to the notebook computer
for calculation. The system can calculate the object width and the distance between the object and the blind in terms of
the light line positions on the image. Based on the experiment, the distance between the test object and the blind can be
measured with a standard deviation of less than 3% within the range of 60 to 150 cm. The test object width can be
measured with a standard deviation of less than 1% within the range of 60 to 150 cm. For saving the power consumption,
the laser modules are switched on/off with a trigger pulse. And for reducing the complex computation, the two laser
modules are switched on alternately. Besides this, a band pass filter is used to filter out the signal except the specific
laser light, which can increase the signal to noise ratio.
An improved arterial pulsation measurement (APM) system that uses three LED light sources and a CCD image sensor
to measure pulse waveforms of artery is presented. The relative variations of the pulses at three measurement points near
wrist joints can be determined by the APM system simultaneously. The height of the arterial pulsations measured by the
APM system achieves a resolution of better than 2 μm. These pulsations contain useful information that can be used as
diagnostic references in the traditional Chinese medicine (TCM) in the future.
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