Ji Qi, Yingzhong Tian, Wenjun Zhang, Albert Weckenmann, Minglun Fang
3D SURFACE MICRO TOPOGRAPHY RECOVERY FROM MULTI-FOCUS IMAGES USING MODIFIED LAPLACIAN OPERATOR

Optical microscopy enables the observation of highly magnified objects and material structures on micro surfaces, however with the weakness that it can only acquire 2D images. In order to observe the areal features more accurately and intuitively, 3D surface micro topography recovery is applied to form a 3D surface model of an object from its 2D image sequence. Optical microscope has a limited depth of focus in large magnification, which makes the area within the depth of focus cleared and other area blurred. So this paper firstly acquires image sequence which obtains all useful information in one view by vertical scanning of the microscope. Secondly, each image is calculated by an appropriate focus measure operator to find the maximum focus measure value and form a 2D fused image. Then the maximum value of each pixel is accurately transferred into a distance value, forming a discrete depth map. After conducting interpolation, fitting and color mapping, a smooth and authentic 3D color model of the measured surface is obtained. Various focus measure operators such as grey level variance are used to compare their performances in 3D model recovery. The superiority of the modified Laplacian operator proposed in this paper is proved by experimenting on measured objects with different micro topography features such as ditch shaped and slope shaped structure. In addition, surface roughness information of R_a and R_z is extracted from the formed 3D models.

J. Escande, P. Gajan, A. Strzelecki
3D VELOCITY PROFILE RECONSTRUCTION OF GAS FLOW IN A PIPE WITH ULTRASONIC TOMOGRAPHY

Beyond possibilities of simple flowmeters, ultrasonic tomography allows to reconstitute the three-dimensional velocity field over a circular pipe cross section. The differences of transit times between transducers distributed around the pipe are used in an iterative algebraic reconstruction algorithm in order to reconstruct the three velocity components. This experimental method has been tested successfully to quantify the 3D velocity field of various flows (fully developed, asymmetric and swirling air flows).

Shang Wei Lu, Li Tao, Cheng Yong Pei, Wang Yan, Qian Zhao Jun
50 kNm TORQUE STANDARD MACHINE

The paper introduces the working principle of dead-weight balance type 50kNm torque standard machine , which was developed recently. The paper describes in detail the key technique , etc. such as the knife edge supporting technique with high load , the force magnifing technique , the alignment technique and the computer control automatic loading technique , etc. The paper analyses the uncertainty of the machine and the compared and verifyed data with LNE . The uncertainty of the 50kNm torque standard machine arrives at 0.023%(tp=3.1).

Maria Gabriella Masi, Lorenzo Peretto, Roberto Tinarelli, Luigi Rovati
A  PUPIL SIZE MEASUREMENT SYSTEM FOR THE ANALYSIS OF THE IMPACT OF FLICKER ON HUMAN BEING

The validation of any new model of the human response to flicker requires proper experimental data. Recently, studies have been carried out with the intent of achieving information relevant to the state of annoyance of a human being subjected to light flicker by analyzing the modification of the pupil size. Indeed, it is well known that pupil diameter changes according to the luminous flux variation. According to such a theory the authors developed a measurement system capable of tracing the pupil size variations in time under flicker conditions. This will result of help for further developing the above theory and confirming its correctness and robustness. The presented measurement system will allow measuring the pupil diameter when subjected to flicker with given amplitude, frequency and colour. The technique and the relative system will be examined through the description of some tests executed to evaluate its performance. The good behaviour of the measurement system suggests its future employment for the analysis of flicker effects on human beings.

Mustafa Keskin, Un-Ku Moon, Gabor C. Temes
A 0.9-V 10.7-MHz 3.6-mW Bandpass ∆Σ Modulator Using Unity-Gain-Reset Opamps

A low-voltage and low-power bandpass ∆Σ modulator is described. In this design, two novel ideas are incorporated: unity-gain-reset and integrating-two-path techniques. A test chip, realized in a 0.35- µ m CMOS process and clocked at both 20 and 40 MHz, provided a dynamic range DR = 45 dB and a signal-to-noise+distortion-ratio SNDR = 36 dB for a 100-kHz signal bandwidth at 5MHz center frequency, and DR = 30 dB and SNDR = 32 dB for a 200-kHz BW at 10MHz center frequency. The supply voltage was 0.8 V for 20 MHz clock, and 0.9 V for 40 MHz clock.