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Optical metrology has experienced a fast development in recent years—cross laser-pattern has become a common cooperative measuring marker in optical metrology equipment, such as infrared imaging equipment or visual 3D measurement system. The rapid and accurate extraction of the center point and attitude of the cross-marker image is the first prerequisite to ensure the measurement speed and accuracy. In this paper, a cross laser-pattern is used as a cooperative marker, in view of the high resolution of the cross laser-pattern image in the project and the vulnerability to adverse environmental effects, such as stray light, smoke, water mist and other interference in the environment, resulting in poor contrast, low signal-to-noise ratio (SNR), uneven energy distribution. As a result, a method is proposed to detect the center point and attitude of cross laser-pattern image based on Gaussian fitting and least square fitting. Firstly, the distortion of original image is corrected in real time, the corrected image is smoothed by median filter, and the noise is suppressed while preserving the edge sharpness and detail of the image. In order to adapt to different environments, the maximum inter-class variance method of threshold automatic selection is used to determine the threshold of image segmentation to eliminate the background interference caused by different illumination intensities. To improve the real-time performance of the algorithm, the four cross laser edge pixels are obtained by line search, and then fitted by least square. With the edge lines, the transverse and portrait line of the cross-laser image are separated, then we calculate Gaussian center points of all Gaussian sections of transverse and portrait lines based on Gaussian fitting method, respectively. Based on the traditional line fitting method, the sub-pixel center of the transverse and portrait laser strip images are fitted by removing the Outlying Points, and the center coordinates and attitude information of the cross laser-pattern are calculated by using the center equation of the laser strip, realizing cross laser-pattern center and attitude accurate positioning. The results show that the method is robust, the center positioning accuracy is better than 0.6 pixels, the attitude positioning accuracy is better than ±15” under smoke and water mist environment and the processing speed is better than 0.1 s, which meets the real-time requirements of the project.

High precision reducer is the core component of industrial robot. Its performance test is the key to improve product quality and ensure the accuracy of robot operation. One of the basic geometric parameters in performance test is the angle, which refers to the angular displacement of the input or output of the tested reducer. Based on a vertical instrument, angular measurement systems are designed in this article. In order to ensure the precision of results, the angle encoder is as close as possible to the measured object, which shortens the measurement chain and reduces the number of error sources. A cylindrical and disk structure improves the structural stiffness, ensures regular deformation patterns, and minimizes the angular errors caused by weak stiffness supports in the conventional instrument. Another system consisting of an autocollimator and a regular polyhedron, whose output is taken as angular standard, calibrates absolute circular gratings in the instrument. The model based on back propagation neural network can compensate the errors over the whole circumference, and finally get the angular displacement of input and output of the tested reducer in the drive process accurately. After compensation, the angular measurement errors of the instrument are within ±2 arc seconds.

In rotating machines, misaligned shafts increase vibrations and friction, which can increase the energy consumption considerably and cause premature bearing and seal damage. Laser-based alignment systems can realize quick shaft alignment with high accuracy, consisting of laser transmitting unit, charge-coupled device (CCD) or position sensitive detector (PSD) receiving unit and display unit. Their resolution can reach 1 μm or higher, and the accuracy can be even up to ± (0.5%|L| + 1 resolution). In the paper, the principle of a laser-based alignment system is presented. In order to calibrate laser-based alignment systems, a set of measurement device is established. The receiving unit is fixed on a high precision one-dimensional linear stage, while the transmitting unit remains stationary. So, the relative displacement between the two units can be measured. A laser interferometer is used as the standard value of the linear stage displacement, which is traceable to the definition of meter. The layout of the calibration system is complied with Abbe's principle, reducing the measurement error. In addition, several key influencing factors for calibration are given. At last, the uncertainty of the calibration result is analyzed. The result indicates that the calibration apparatus is practical and efficient during the routine work.

To obtain a method for measuring thread functional diameter, a new probe based on the synthetic measurement principle is designed to quantify the practical effect of each parameter in all axial sections. The probing element is an axial slice of a standard thread with a certain thickness; hence, the slice has a determined lead angle and curvature radius. When threads with different diameters are measured by slices, the maximum error caused by the lead angle and curvature radius can approach 99 μm according to the simulation results. To solve this problem, a measurement error model is established by analyzing the relationship between the contact points of the measuring tip and thread. By simulations and experiments, our results show that most of the effect of lead angle and curvature radius can be compensated. Using six slices with different pitches, a precise detection of 192 kinds of threads is achieved after error compensation within the range of M65–M300.

The calibration and error compensation techniques for an Articulated Arm Coordinate Measuring Machine (AACMM) with two parallel rotational axes are proposed. An improved six-parameter D–H model is established. The reversal techniques are used to calibrate the parallelism errors, arm lengths and zero position of the AACMM. The effects of the bending and torsion deformations caused by the gravity of the arms are removed. The experiments prove that the calibration method is simple and the measurement expanded uncertainty ( 2 u c ) of the developed AACMM with a measuring range of (∅200–∅1000 mm) × 250 mm is less than 10 μm after error compensation.

A coordinate measuring machine (CMM) with two linear axes and an articulated arm has been developed for on machine in situ measurement of just machined workpieces. Some techniques for calibrating the CMM parameters, such as the arm and stylus lengths, offsets, parallelism and squareness errors between axes, as well as zero positions of the articulated arm and stylus, have been worked out, which are essential for assuring high accuracy of the CMM. The effectiveness of the proposed calibration techniques has been proved by experiments and practice.

The Precision Micro-Assembly Machine was developed to manufacture the ICF targets, which have submillimeter-sized components with micrometer sized features. The machine provides simultaneous manipulation of three objects in a 3-cm3 operating arena and can stitch together multiple millimeter-scales operating arenas over distances spanning tens of centimeters with micrometer-level accuracy. In this report, we will discuss the technologies that are merged to help assist the research community with micro-component fabrication. Furthermore, we also present the design of the online monitoring system, which contains two kinds of non-contact measurement system, microscopic image and laser confocal. The online monitoring system can characterize the positions of the target components during the assembly process. The effect and mathematic model of on-line measuring was analyzed. The results of target assembly experiments show position tolerance of the assembly is not more than 10μm.

In order to set up a controller of good dynamic response for the laser tracking system, special requirements of laser tracking system to its controller are analyzed in this article. One is exact position track and the other is rapid and steady speed response. The overall design strategy of the control system is put forward on the condition that the startup torque and Coulomb torque difference a lot and the system works at relative low speed (typically -10rpm to 10rpm). It is pointed out that the PWM method is effective to reduce system startup torque and increase steadiness of startup. In position loop a fuzzy PI controller is designed to decrease the position overshoot to 1.5mm and increase the smoothness of the tracking. The experimental results show that the tracking control system can accurately and rapidly follow movement of the target.

Considering the measurement system for the suspended position of the transparent film in the water, an image processing method based on watershed transform for contour detection has been proposed. The difference between the film and water has been researched by obtaining the image information through the image sensor under special light source. An algorithm of watershed which uses minima imposition to solve the problem of over segmentation for the detection is applied. Depending upon the improved algorithm, which aims to obtain the contour of the film, the target areas in the image integrate together. The result of the position is gained by the image processing technology, which provides the technical basis for automatic operation of catching film in the water.

A method for measuring the angle of two elements separated at a large distance by using a common optical reference is proposed. A common light plane or several parallel light planes are projected on these elements. The angles between these elements and the projections of light planes are measured and thereafter the angle between these two elements is determined. A practical example of measuring the angle formed by two elements separated at a distance of 7 m is shown. Its calibration method is also discussed.

To ensure that the liquid drop is slowly delivered under quasi-equilibrium condition in drop analysis, a microflow feeding pump actuated by a single stepping motor and controlled by the computer software is improved. The function of switching and injecting can be effectively realized and the cost is reduced. It can exclude the influence of bubbles. The photo signal of an embedded photoelectric sensor is used to control the movement of the syringe so as to avoid the step-missing condition. The computer software is used to solve the possible problems caused by the accidental mechanical block or sudden power cut. A kind of one-time syringe is designed for some liquids difficult to clean. Average method in the dynamic drop monitoring process is used to smooth the signals with high-frequency noise. A representation of the liquid drop fingerprint based on equivalent drop volume percentage is developed by normalizing the capacitive signal to solve the problem of magnification variation.

To achieve the aim of precise measurement of a target micro‐sphere, approximately 0.2 mm in diameter, a laser confocal probe was designed. To improve the output signal, a mathematical model of the photoelectric signal was proposed. The diameter of the pinhole was determined, and the optical path was adjusted; the oscillating units were designed. The performance of the probe was validated by experiments using gauge blocks combined with a micro‐motion measuring mount model. Besides, a more accurate signal processing method was suggested.

To achieve the aim of precise position measurement of a target micro-sphere, approximately 0.2mm in diameter, a laser confocal probe, on an active focus adjusting principle, was introduced in this paper. For finding the effect way to improve the output signal, a mathematical modal of the photoelectric signal was proposed. Based on the mathematical modal, the diameter of the pinhole was decided and the optical path was adjusted, which forward the performance of the probe. The tuning fork stimulating, inductive coils and the pinhole adjuster device were designed according to the theoretical analysis, which were more convenient to the measure task. The stability of the intact oscillating unit was tested; and the optical and mechanical performance of the probe was validated by experiments using gage blocks combining with a calibrated micro-driven table. Besides, a more accurate signal processing method was suggested in this paper.

Dual-wavelength optical signals are injected into the liquid drop through optical fibers in order to study the light intensity variation during the drop growth. Modulation and demodulation are used to reduce the influence of ambient light on the valuable optical signals. HA17555 chip composes the oscillating circuit for light modulation, with different high oscillating frequency for different light source. The light signal collected by a fiber detector after propagation inside the drop is changed into electric signal through the OPA2111 photoelectric circuit. The second-order band-pass filter composed of MAX275 chip is used for signal-separation. The high-pass filter is used to prevent the low frequency signal of ambient light. The valuable signal related to the drop is demodulated by a linear demodulation circuit including a half-wave rectifier, full-wave composition and low-pass filter.

CCD camera is used in the liquid signature analyzer system to capture images of the liquid drop of the tested sample. The digital image processing work is presented. CCD camera records the variation of the liquid drop during growth. The outline information of the drop is available through image processing. The instantaneous volume of the liquid drop can be gained through mathematical calculation. With the use of CCD camera, the information of the tested sample we can get during the measurement is enhanced. The function of the liquid signature analyzer is enriched and the discrimination ability of this technology is improved.

An instrumental method for measuring the properties of liquids has been developed. The instrument, called the fiber-capacitive drop analyzer (FCDA), is based on a specially designed drop sensor by means of the fiber drop analyzing technology and the capacitive drop analyzing technology, and produces a volume-based fiber drop trace (VFDT), which shows the relation between the light intensity passing through the liquid drop and the instant drop volume. Preliminary experiments have been carried out and these prove that VFDT externalizes the overall properties of tested liquids and is suitable for fine discrimination among different kinds of liquids. In this paper, a multi-wavelength drop analysis (MWDA) method is described. In this case, the light source of the FCDA is developed from a single wavelength to a multi-wavelength. A special filter is employed to sort out the signals from the mixed multi-wavelength signals and it becomes possible to get two or three VFDT with different light wavelength at the same time. As one knows, a material will absorb the light on certain wavelengths. It means that, for a mixed liquid, one can get different VFDTs by MWDA at the same time. By this way, the resolution capability of a FCDA is enhanced very much due to more information including in those VFDTs. A special signal process circuit, the key technology of the MWDA, is described in this paper. The test results show that the new circuit had satisfied the MWDA method well and will be very useful to an instrument of the FCDA with MWDA.

A single‐wavelength liquid signature analyzer can only reveal a part of the characteristics of some liquids, because the same liquid has different absorption in the light signal with different wavelengths and different liquids have different absorption in the light signal with the same wavelength. So dual‐wavelength light signals from two LEDs are introduced into the liquid drop. In the processing circuit, two light signals are modulated with different high frequencies. The collected signal is separated by band‐pass filters and demodulated by a linear precision demodulation circuit. Bubbles make the drop shape and volume become unstable, so a seal cavity is specially designed. The drop sensor is separable, thus, the drop head can be cleaned thoroughly, which reduces the mutual interference among different tested liquids. The penetration depth of fibers into the liquid drop can be adjusted quantitatively. Furthermore fibers, diodes, and the preamplifier circuit are integrated into the liquid drop ...

Fiber drop analysis reveals the variation regularity of the light signal passing through the liquid drop during the drop growth. The coupled light signal reflects mechanical and optical properties of the tested liquids, but it is not only dependent on the profile and volume of the drop, but it is also dependent on the liquid absorption. Thus, spectral drop analysis is introduced into the drop analyzer to study the liquid composition by studying the absorption spectrum of the multi‐wavelength light signal passing through the liquid. A three‐dimensional (3‐D) liquid drop fingerprint (LDF) can be obtained by merging the light intensity signal from the fiber drop sensor, the drop volume signal from the capacitive drop sensor or CCD image processing, and the absorption spectrum signal from the fast Fourier transform (FFT) infrared spectrum analyzer. The 3‐D LDF covers a more extensive range of physical and chemical properties of liquids, and it enhances the capability of drop analysis for fine discrim...

A low cost confocal probe based on time difference measurement has been developed. A tuning fork is used to modulate the focal length of the probe. An auxiliary arm is introduced to the optical system. This arm can be utilized for carrying out lateral measurement or for providing a reference signal. The position of the surface is determined by measuring the time difference between two successive peak intensities of the measuring signal or that between peak intensities of measuring and reference signals. Some key problems in probe design are discussed. A correlation based technique for determining the time difference between two peak pulses is developed. Error compensation technique for nonlinearity and other errors is introduced. The excellent performance of the probe has been proven by experiments.

A photoelectric multiple‐wavelength liquid drop sensor (PMWLDS) is introduced in this paper. Being employed in the liquid signature analyzer (LSA), the PMWLDS has improved much of LSAs characteristics, compared to the previous models. The PMWLDS is constructed of two integrated parts and can be separated during its cleaning. When separated, all the surfaces contacting liquid samples become open surfaces, by which the liquid head can be cleaned easily. A small chamber is designed for the elimination of the bubbles existing in the test liquid. Otherwise, the unique drop forming process will be destroyed and the LSAs test results will become meaningless. Due to a multiple‐wavelength light source integrated into the sensor, liquid drop traces can be obtained based on different light wavelengths. Being a newly developed drop sensor, PMWLDS shortens the length of the fiber sensor, makes an adjustable couple between liquid drop and fiber sensor, avoids the capacitor sensor's signature loss, etc. All the...

A flexible coordinate measuring system based on multi-lateration with tracking laser Interferometers has been built. The problems related to the optimal design of the system are studied. The principle of redundancy and its application in self-calibration, error compensation, system optimization, lost Information recovery, and measuring range extension are discussed. A new tracking system with Independent drives and a new design of the cat's eye are proposed. The optimal arrangement of the multi-lateration system, which is essential for improving its accuracy, is studied in detail. All the studies combine computer simulations and experiments.

In the process of microtarget assembling, the geometrical parameters of the microtarget need to be measured in real-time by the online detection system with four-axis linkage. So the moving performance and positioning accuracy of every motorized axis are crucial to the measurement. This paper proposed a new motion control technique for linear translation stages with stepper motor. The control algorithm was realized on field programmable gate array (FPGA) and digital signal processor (DSP), and met the high-efficiency and high-precision measurement requirements. An efficient and optimized speed control performance was achieved by using a method that was based on speed-difference driving and speed-table supplying, and a high-precision, closed-loop positioning control performance which has an error less than +0.3μm was achieved by using a method that was based on position feedback, position-window restriction and time-window restriction.

Oxygen is one of the prominent parameters characterized the quality of water, how to detect the precise content of oxygen is paid much attention nowadays. Lately the method of fluorescence quenching has been the hotspot practice to detect the oxygen in the international. This paper based on the principle of fluorescence quenching has designed the DO(dissolved oxygen)detecting system. Through choosing dissolved oxygen sensing head and photoelectric receiving devices rationally and determining appropriate circuit parameters after experiment, it can realize the detecting of the DO preliminarily, laying the foundation for the instrumentation of the system.

The article is taken from the research of real-time detection of Plastic Calendar roll-gap by the three-point and the minimum distance two ways which based on CCD image measurement technology. It has been found that the minimum distance measurement method meets the accuracy of 5um after experiencing on analysis, calculation and verification of measurement errors arising from the two methods.

An optical method is proposed for in-situ measurement of angles of space elements separated at a distance of several or several tens of meters. When it is necessary to measure large objects or geometrical elements within a large scale space, it is not always possible to bring these workpieces to conventional coordinate measuring machines (CMMs) which are widely used in industries. Mobile measuring systems provide ideal solutions for these applications. The basic idea of the presented research work is to set up the multiple common optical references through which the dimensional inspections of separation angles of bifacial lines in a large scale space can be fulfilled. The angles between the projection light and each element can be captured through a machine vision system, and thereafter the angles between those corresponding elements can be determined using the geometrical principles. The method and the calibration approach have been validated on our designed work station.

Non-linear friction is one of the main factors that effect both dynamic and static performance of high-precision mechanical servo system, and model-based friction compensation is the basic method of eliminating the impact of friction. This paper focuses on modeling, identification, and compensation of non-linear friction with simulation and experiment on ball screw drive system. Firstly, a simulation platform of the servo system according to high-precision experimental platform is established, based on dynamic model of the ball screw drive system and the LuGre friction model. Secondly, both static and dynamic parameters of the friction model are identified using genetic algorithm. Finally, the simulation and experiments of the friction feed-forward compensation are performed based on the friction model, utilizing by both the simulation platform and experimental platform. It shows that the experimental results are basically consistent with the simulation results without and with compensation. The feasibility and advantage of LuGre model based feed-forward compensation is verified by simulation and experiment, and it can decrease the tracking error of the system and improve the positioning accuracy.

Micro-sphere is the key element in ICF (Inertial Confinement Fusion).The relative position between micro-sphere and cylindrical gold hohlraum is required to be critically accurate so that the motivation energy and transition efficiency of the ICF can be significantly improved. Accurate detection of micro-target assembly (especially the center position error) is necessary and indispensable to ascertain the qualities of ignitions. The micro-sphere and cylindrical gold hohlraum have tiny dimensions and are flimsy and easy to deform. To resolve such problems, a non-contact method based on digital image progressing is proposed to detect the center position error of micro-sphere in this paper. Canny operator is employed to detect the gray-level gradient image. After removing the fake edge points, the images are transformed into binary images by a dual-threshold. To increase the operation speed, a region of interest (ROI) containing only parts of the detected target is selected by alternating manual work. A Hough transform is then selectively applied to the chosen sub-area. The equations of the target circles and the lines can be gotten by fitting these edge points. The center position error of micro-sphere can be obtained based on axial and radial position errors of micro-sphere. Experimental results show that the proposed method is independent of binary thresholds and robust to additional noises. The standard deviation of the center position error is about 2μm, and the maximum error (3σ) is less than 6μm.

Basing on the principle of dynamic active confocal measuring method, a non-contact probe was introduced. The relation between the displacement of the object measured and the displacement of the oscillating unit was established by applying to the measure principle. To find the effect way to improve the output signal, a mathematical modal of the photoelectric signal was proposed. According to the mathematical modal, the diameter of the pinhole was decided and the optical path was adjusted, which improved the performance of the probe. It valuable to emphasize that the double lens oscillating unit was the crucial parts of the mechanical and optical structure. The tuning fork stimulating, inductive coils and the pinhole and photodiode adjuster device were designed according to the theoretical analysis, which were more convenient to the measure task. The stability of the oscillating unit was tested; and the optical and mechanical performance of the probe was validated by experiments using gage blocks combining with a micro-motion measuring mount model. The cost of a micro-displacement testing sensor was saved in designing of this kind of probe. A more accurate signal processing method was discussed in this paper.

A study on Chemical Oxygen Demand (COD) measuring method is reported, in which the COD value is measured by an integrated liquid drop monitor sensor without any reagent and chemical treatment. The integrated drop sensor consists of a liquid head, an integrated fiber sensor and a capacitor sensor. The capacitor sensor is composed of a drop head and a ring electrode. As the part of the drop head, the outline of the drop will be changed during the drop forming, which result in the variation of the capacitance. The fiber sensor is composed of two fibers that are positioned into the liquid drop. The light signal goes into the liquid drop from one fiber and out from the other one. A unique fingerprint of the liquid drop can be got by the data processing. The matching between the COD value of a liquid and the codes of the fingerprints in the database are presented and discussed.

The drop profile is one of the evident differences for different liquids. An image drop sensor is developed for capturing the drop profile images real-timely in various stages during the drop growth. The drop head for forming the uniform and satiated liquid drop is designed. The original profile records of pure water and 100% ethanol during their drop growth will be presented. Edge extraction methods on drop profile are discussed. Curve fitting based on third-order polynomial linear regression is used to mathematically describe the detected edge curves of the drop profile in sequential drop formation.

The multi-wavelength liquid signature analyzer (MWLSA) is used to analyze the characteristics of liquid. It adopts two kinds of transmitter diodes with different peak wavelengths as the light sources of the system. With MWLSA not only the light intensity signal reflecting the optical characteristic of the sample liquid under different wavelengths can be obtained, but also the volume and outline information of the corresponding liquid drop are acquirable. The application of the multi-wavelength light sources makes it possible for us to get more information about the liquid sample, which enriches the function of the liquid signature analyzer and improves its discrimination ability of different liquids so as to have more application fields.

An on-line operation of micro-spectrometer and liquid drop analyzer is proposed in this paper. Comparing with a full spectral range spectrometer system, a micro-spectrometer has narrow spectral range that results in its inefficiency or inability in qualitative analysis of a mixed liquid since more than one function group of the mixed liquid might cause a peak or valley in the spectrogram at almost the same wavelength. A liquid drop analyzer (LDA) is an instrument that detects the characters of a liquid by monitoring its drop forming process. The LDA gives a fingerprint that is unique for certain liquid due to its specific chemical, physical and mechanical characters. An approach of combining micro-spectrometer with a fiber drop analyzer, by which a virtual 3D liquid fingerprint is formed, is described and it functions like a full range spectrum. The signals obtained from the micro-spectrometer and liquid drop analyzer, the method of on-line operation and database setting up, the experimental device and test results are described and discussed in the paper.

This paper describes a multispectral liquid drop analyzer for liquid chemical and physical propertiesanalysis. Liquid drops formed at the tip of a liquid head are measured in parallel by a fiber sensor and acapacitive sensor. The fiber sensor works as follows: multispectral light sources are injected into the dropthrough an optical fiber and the total internal reflections and absorptions are detected by a photo detector.By combining fiber and capacitive sensor outputs, a drop speed independent one-dimensional waveform(liquid fingerprint) is generated. Liquid surface tension, refractive index and di-electric constant can beestimated from the fingerprint. To compare two fingerprints, the sensor outputs are normalized to have thesame unit of measurement and drop starting position. After that, a reference liquid based calibration isapplied to correct of fingerprint distortion due to variations in environmental conditions, such as changes intemperature and humidity. Finally, a normalized correlation algorithm analyses the fingerprint difference.The repeatability and sensitivity of the system are demonstrated using different liquid samples. On-lineapplications show that the analyzer is able to detect 2% change in alcohol density.Key words: liquid drop, liquid classification, liquid fingerprint, fiber sensor, opto-mechanical device

An optical liquid drop sensor(OLDS) which can be used to distinguish different liquids is presented in this paper. The main block ofthis system are a light path and a drop-forming head sensor. We can gain three kinds ofiniormation about the liquid to be measured with this OLDS system. That is optical signal representing light intensity information, electrical signal revealing volume information ofthe liquid drop and spectral signal displaying ingredient information of the liquid individually. Colligate this three kinds of information and after data-processing the fingerprint of the measured liquid can be derived. Due to different characteristics of various liquids, the fingerprint of one liquid differs from that of others. This difference has been proved through experiment. Thus the OLDS is valuable for the discrimination of different liquids and the measurement ofthe liquid's parameters.

The confocal probe is a kind of non-contact measurement probes. Through an optical system containing an oscillating tuning fork, it converts displacement measurement to time difference measurement. For the measuring precision, the oscillation stability and swing of the tuning fork are important. Based on analysis, the relationship between the measuring precision and the frequency and amplitude of the tuning fork is described, and the means to obtain stable frequency and amplitude is introduced.

This article describes an online detection system for measuring the geometrical parameters of the microtarget in inertial confinement fusion (ICF). The measurement can be done during the microtarget’s assembly process and then the message, according to the online detection results, can be sent to the assembly robots as the adjustment order. This detection system consists of three parts: a laser confocal system, a machine-vision system, and a motion-control system. During the real-time monitoring in the assembly process, the machine-vision system detects the position information of each part and the laser confocal system detects the reference points which have higher-precision requirements. The laser confocal system and the machine-vision system can be operated by the motion-control system so as to achieve the best measurement effect. The test data got by the two systems are then unified in the calibrated coordinate system. Using various fitting algorithms, the authors can find the parameter status, make t...

In the formation of liquid drops, different kinds of liquids may have different outer profiles; the change of volume and shape in the process of drop formation can indirectly reflect liquid's physical and chemical properties, such as surface tension and viscosity, etc. Real-time detection the size of drops in the forming process is on the basis of drop analysis technique. Previous researchers have studied that optic fiber and capacitance drop sensor fusion technology can indirectly gain drop's form and the volume. This article is based on the optic fiber and capacitance drop sensor theory, designing the system based on the LabVIEW software to realize the LDF (Liquid Drop Fingerprint) data acquisition function. The experiment results show that the system can well realize the acquisition, compared with the traditional VC programming technology, this data acquisition system is high efficiency.