2012.10
About Instruments Today No. 190
Instrumentation and Measurement Technology
Using Ensemble Empirical Mode Decomposition Method to Analyze Mixing Fringe in Optical Testing [ 下載 PDF ]
Yu-Ta Chen, Mang Ou-Yang, Shuen-De Wu, Shiou-Gwo Lin, Cheng-Chung Lee, Jin-Chern Chiou, Sing-Tsung Lee
Fringe analysis is an important technique in optical testing, and optical testing can bring high quality and high precise optics. In the optical lens measuring, the fringe of the optical lens is analyzed as the interferometer acquiring the interferogram and the influence of the mixing fringe usually affects the interferogram. In this paper, the mixed image is simulated by the tilt aberration, and several methods of the reducing mixing fringe are utilized to reconstruct the optical paths difference (OPD) profile of the mixed image. The ensemble empirical mode decomposition (EEMD) method is used to decompose the mixed image into several intrinsic mode functions (IMFs), and then removing one or more IMFs to reduce the influence of the mixing fringe in the mixed image. After the procedure of reducing influence of the mixing fringe, the noisy fringe can reconstruct the OPD profile easily. Using EEMD method to reduce the influence of the mixing fringe in the simulation, the root mean square (RMS) value of the OPD is 0.081 waves as the residue image subtracted from the OPD profi les of original image. In the experiment, the EEMD method reducing the noise of the mixing fringe has the advantage on the straighter fringe, but the crooked fringe is difficult to be separated from the noisy interferogram after the procedure of the EEMD.
The Development of Measurement/Monitoring by Mobile Devices and Systems [ 下載 PDF ]
Chi-Hung Hwang, Yu-Chieh Chen, Chih-Chieh Wu, Tai-Shan Liao, Shu Wen Li, Din-Ping Tsai
Mobile devices, such as smart phones and tablets have become widely popular as an access to the internet and an easier approach to deal with and share real-time digital information. Mobile devices are in general consisted of the integral design and fabrication of optical, electronic, mechanical and MEMS sensors. Expanding the utilities of such sensors to perform easier instrumentation and measurement can be achieved by adding internal programs, commonly known as applications or apps in the device or additional external sensing facilities. The prevalence of mobile devices lately has made it an emerging yet indispensable fraction and has created a strong niche for the future of instrumentation and measurement. In this paper, we investigate several examples of how mobile devices perform measurement and monitoring in real life situations.
The Vernier-Based TDC Empolying Soft-Injection- Locked Ring Oscillators [ 下載 PDF ]
Chia-Yu Yao, Wei-Chun Hsia, Pei-Jung Tsai, Yu-Jou Wen
A time-to-digital converter (TDC) plays an important role in time interval measurement. Among various TDC structures, the vernier-based TDC is promising because it can possess highly accurate time resolution. However, the oscillators used in the conventional vernier-based TDC require complicated calibration procedure. This makes the TDC difficult in use. In this paper, we purpose a new soft-injection-locked ring oscillator as the clock source for the vernier-based TDC. The proposed oscillator can oscillate immediately and accurately right after the trigger signal arrives. The TDC structure employing the purposed oscillators is verified by the TSMC 0.18 µm CMOS process. Experimental results show that the equivalent resolution less than ±1 LSB can be achieved.
Leukocyte Nucleus Segmentation and Recognition in Color Blood-Smear Images [ 下載 PDF ]
Der-Chen Huang, Kun-Ding Hung
In this paper, a leukocyte segmentation and recognition method is proposed for leukocyte differential counting. In general, leukocytes are usually manually classified in laboratories by using microscopes. It is a painstaking and subjective task for biologists. An automatic method is essential to reduce the overhead for biologists. The nuclei are used to identify five types of leukocyte in this paper. The leukocyte cell nucleus enhancer is proposed to segment the region we are interested in by enhancing the region of the leukocyte nucleus and suppressing the other region of the blood smear images. In the recognition steps, we reduce features by principle component analysis (PCA) to obtain suitable features. The genetic algorithm based K-means clustering approach is used to classify the five kinds of leukocyte in the reduced dimensions. The experimental results show that even though only leukocyte nucleus features are used for classification in our method, we achieve a high and promised accurate recognition rate.
Coin Detection by Mobile Devices [ 下載 PDF ]
Wu-Ja Lin, Chih-Wei Tseng, Sin-Sin Jhuo
In this manuscript, a system which automatically measures the number of coins by using mobile devices is proposed. The proposed system converts the color space of captured image from RGB to Lab, applies feature-preserving clustering algorithm to quantize the transformed image plane, finds edges and circles in quantized image, and finally determines the number of coins. The experimental results show that the proposed system can successfully detect coins in the given images.
Crystalline Silicon Solar Cells Passivated by Amorphous Silicon Films [ 下載 PDF ]
Likarn Wang
Hydrogenated amorphous silicon (a-Si) is a material that can passivate crystalline silicon (c-Si) solar cells, when deposited on the surfaces of the cells. The passivation results from the movement of hydrogen atoms residing in the a-Si toward the a-Si/c-Si interface to fix dangling bonds at a proper temperature and to form Si-H bonds. Besides, a field can be built between the a-Si/c-Si interface, repelling photogenerated electrons to combine with holes and henceforth reducing surface recombination rate. In this article,we present two types of a-Si films (hydrogenated and non-hydrogenated) that prove to improve the performance of crystalline silicon solar cells. Hydrogenated a-Si can be grown on the surface of a silicon solar wafer by PECVD, while non-hydrogenated a-Si can be grown by LPCVD, both improving Voc. One of our earlier experiments revealed that the conversion efficiency of a solar cell with LPCVD grown a-Si deposited on two-side surfaces of the cell was enhanced from 18.1% to 18.4%.
Metal-Ge-Metal Photodetector Fabricated by Rapid-Melting-Growth Method with Surface Passivation [ 下載 PDF ]
Chih-Kuo Tseng, Ting-Hsiao Wu, Wei-Cheng Hung, Jhong-Da Tian, Neil Na, Ming-Chang Lee
Over decades, silicon semiconductor industry grew rapidly due to the advancement of CMOS fabrication technology, as well as the relatively low cost and good material stability. Recently, silicon-based optoelectronics that is capable of being integrated with modern IC receives a lot of attention. One of the key applications is high-speed photodetector for telecommunication and optical interconnect. However, Si is transparent at infrared wavelengths that are usually used in optical communication. Other materials should be used in adjunction with Si substrate to detect infrared signals. Ge is an ideal material for long wavelength absorption; moreover, Ge process is CMOS process-compatible, indicating the possibility of mass production. Ge-based photodetectors on silicon substrate have been studied by several research groups. One of the key issues is the difficulty in epitaxy growth of Ge on silicon due to lattice mismatch (4%). In this paper, we apply rapid melting growth method to grow high-quality singlecrystal metal-semiconductor-metal Ge photodetectors on oxide with low thermal budget. By carefully selecting the metal contact and Ge passivation, the device dark current is significantly reduced by three orders of magnitude compared to the state-of-art literature data.
Line-Scanning Chromatic Confocal Three- Dimensional Microscopic Surface Profilometry [ 下載 PDF ]
Liang-Chia Chen, Tsung-yi Lin, Yi-Wei Chang, Shyh-Tsong Lin
An on-line 3D surface profilometer for micro surface profiles with a long range and high resolution measurement was successfully developed using innovative slit-scan multi-wavelength confocal microscopy. In conventional confocal microscopy, vertical scanning of the object's surface by either mechanical depth movement or objective shifting is extremely time-consuming, thus resulting in unacceptable efficiency for on-line inspection. In this paper, a multi-wavelength confocal microscope employing a broadband light source in combination with a chromatic dispersion objective was developed to generate an accurate wavelength-to-depth conversion for microscopic 3D profile measurement. By using the point spread function (PSF) detected with its corresponding wavelength detected at its matching focal depth, the proposed deconvolution method has been proved effective theoretically and experimentally in greatly minimizing the full width half maximum (FWHM) of the depth response curve. Using the developed deconvolution algorithms, to the measurement resolution of the line-scanning chromatic confocal system can reach the same level of the single point measurement. Using pre-calibrated standard bandwidth and step height targets, the measurement accuracy of the developed method can reach up to 0.1 µm.
Probing in vivo Mechanical Properties of Bone Tissues by Reference Point Indentation Technique [ 下載 PDF ]
Po-Yu Chen
A novel indentation technique which can probe the mechanical properties of bone tissues in vivo is introduced in this paper. The reference point indentation (RPI) instrument consists of a reference probe and a testing probe. By inserting the probes through the skin onto tibia bone, various mechanical properties such as hardness, elastic modulus, maximum indentation distance, indentation distance increase (IDI) can be measured non-invasively. The results showed that IDI were significantly higher in patients who suffered from bone fracture than in controls and can be used to evaluate fracture risk. The technique has a great potential in the medical field and can provide better understanding of the in vivo mechanical properties of bone tissues.
A Brief Introduction to the Principles of Thermal Therapy for Cancer Using External Ultrasonic Sources [ 下載 PDF ]
Kung-Shan Cheng
Irradiating the diseased site of a patient having cancer using external ultrasonic sources could enhance the efficacy of radiotherapy or chemotherapy, and these kinds of treatments by themselves could be an option of therapies treating cancer. The aforementioned therapies require no surgical operation and general anesthetization, and thus they have lower risk and fewer complications associated with them. The article briefly introduced the major components of the devices for these kinds of therapies, the principles of heating, the methods for calculation of the thermal dose, the principles of energy focusing, the principles of computer-aided treatment planning, and the biochemical principles for applying these therapies to human; this introduction would help the readers understand the related multi-disciplinary principles associated with these kinds of therapies.
Instrument Environment Technology Using Smart Mobile Devices and Cloud Services [ 下載 PDF ]
Yu-Hsuan Lin, Da-Ren Liu, Fong-Zhi Chen, Chi-Hung Hwang
In order to operate or control instruments in the traditional labs, the use of numerous PCs, monitors and wires are inevitable. For the transmission and backup of the experimental files, flash drives, DVDs and portable hard disks are also burdens to labs maintenance. The above mentioned various necessaries of traditional labs may lead to the problems such as the waste, disorder and risk of the experimental environment. With the rapid development of smart mobile devices and cloud technology, the problems can be solved. In this article, we proposed several feasible approaches to create a good instrument environment.
