摘要: This paper presents a method to measure the deformation of large deployable mesh
microwave antenna by using the photogrammetric technology. Because the mesh reflector surface is
controlled by 79 nodes, measuring 3D coordinates of these nodes accurately is the key to test the
deformation of antenna. The technique of camera calibration, the matching method of the image
points, and the solution of measuring 3D points are introduced in this paper. The experimental data is
also provided. This paper proposes a method to calculate the spatial coordinates of microwave
antenna nodes by using the bundle adjustment with distance constraints. This method is capable of
correcting the influences of the lens distortion and improving system measurement accuracy. In
reference to the fact that the surface of this antenna is controlled by 79 nodes, and the design
parameter of these nodes is already known, a method based on digital surface model constrain is used
to solve the image points matching problem. This method efficiently simplifies the computation
procedure and shortens the measurement time.
摘要: The inflatable space antenna is gradually used in various spacecrafts because it is portable
and foldaway. It is usually made of thin-film materials and has a flexible surface, so that measuring
force is not tolerable in measurement process. Close-range photogrammetry is considered as an
optimal solution because of its advantages of non-contact operation and fast data acquisition. To
improve measuring precision, a method combining bundle adjustment algorithm and the distance
constraint is presented in the paper. Two experiments under different conditions are accomplished
and experiment results are compared. One experiment is completed with the distance constraint and
another without. The experiment results are compared by two parameters: tightness and residuals. The
measured object is an inflatable antenna with a 3.5-m diameter.
摘要: This paper describes a method to characterizing the digital camera. The nonlinear
relationship between the RGB signals generated by a digital camera and original image CIEXYZ
values was obtained using the polynomial regression procedures. The reasonable structures of the
polynomial were found for two digital cameras. The better number of polynomial terms was 19,
yielding a modeling accuracy typically averaging 2.1~2.2 E ∆ units and maximally 9.5~10.9 E ∆
units. The experiments results showed that the polynomial regression could be used to characterize
commonly digital camera.
摘要: This paper presents an autofocusing system for an optical microscope (OM) based on a
low-cost, highly-sensitive laser focusing probe integrated with a precision stepper positioning stage.
During the OM measurement procedure, the laser focusing probe detects variations in the distance
between the glass substrate containing the specimen of interest and the OM objective lens and
generates a driving signal to adjust the position of the OM via the precision positioning stage such
that a precisely-focused image is obtained. The experimental results show that the integrated laser
focusing probe and positioning stage complete the autofocusing process within 0.5 seconds.
摘要: Grind gauge is a measuring tool for size of grains or particles included in paint or ink. Its
geometrical specifications and operational procedure are regulated to some extent and partly
standardized in both ISO and JIS. However, only skilled technician can manage to handle it properly
and to obtain correct measurement results. The objective of this study is to develop an automatic
inspection system for the grain or particle size by use of artificial lighting and CCD camera with
image processing techniques. A telecentric lens system was constructed and high resolution CCD
camera was attached to it. Advantages of coaxial illumination and oblique illumination methods were
revealed and their applicability was examined respectively. The optical configuration to cover the
scale and the whole groove width of grind gauge was devised so that the captured image data could
contain both grain/particle distribution and height location. A proper software program followed by
image processing algorithm was established to reveal particle mark and liner mark.
摘要: In this paper, we proposed a method to attain a high sensitivity of weak optical signal
detection by using the multi-wavelength modulation principle. In this method, the optical phase
carrying the measurand is obtained by averaging the phases obtained in various orders of
heterodyne harmonics. The employment of higher heterodyne harmonics reduces the drift effect in
optical detection. The proposed method is demonstrated on the nano-scale displacement
measurement by using a single channel fiber interferometer. In the experiment, the displacement is
simulated by moving a mirror with a piezoelectric tube. The results show that more repeatable
measurements with a resolution of 35nm can be obtained by using the proposed method.
摘要: This paper proposes an improved active homodyne detection technique to compensate for
the drift in homodyne measurement. The technique is implemented on a fiber based Michelson
interferometer where a computer controller is designed to drive a piezoelectric cylinder attached to
one arm of the interferometer. It is shown that the proposed technique can efficiently stabilize the
摘要: This paper presents a new set of estimation formulae for non-contact 2D displacement
measurement by using the principle of triangulation and the position sensitive detector (PSD) as a
2-D range sensor. It has been shown in theory that the new set of formulae outperforms the
conventional formulae by providing much more accurate estimate of the 2D displacement. The
theoretical analysis has been verified by simulation studies.
摘要: The shear force detection by using a tuning fork plays a key role in the implement all
kinds of scanning probe microscopes. This paper presents primary results of modeling dynamics of
a tuning fork. The obtained model considers not only the piezoelectric properties and mechanical
properties of the tuning fork, but also the electric-mechanical coupling between the two prongs of
the tuning fork. It has been shown by theoretical studies and experiment results that the theoretical
model can fit the amplitude and phase responses of a tuning fork.
摘要: Nitric oxide (NO) produced in the endothelial cells and other tissues has been known to
play a range of physiological roles including vasodilation. Thus, direct in vivo measurement of NO is
of great importance for clarification of physiological roles of NO and development of therapeutics
using NO. It has long been assumed that NO is readily oxidized in blood and cannot be detected;
however, some recent reports demonstrated much longer half-life of NO in the blood stream in vivo.
Recently, we reported the basic performance of an NO sensor which is applicable to in vivo
measurement. This sensor can detect NO in the blood stream in an anesthetized rat and some
biological samples including a dialysis solution. In these studies we found that NO itself showed
dynamic changes different from these of oxidative products of NO (nitrite and nitrate) that are
conventionally used as indices of NO level. We have also developed a catheter-type NO sensor and
demonstrated validity of the sensor for in vivo measurement of NO in the aorta and coronary sinus of
anesthetized dogs and rabbits. Both endothelium-dependent and -independent NO productions could
be detected. In conclusion, the NO sensor and the catheter-type NO sensor are applicable to direct
measurement of NO in biological samples even in vivo and will contribute to clarification of
physiological roles of NO.