Papers by Keyword: Calibration

Abstract: In this paper, we present a new calibration technique aimed at blind steganalysis for JPEG images, which can magnify the difference between cover images and stego images. The calibration can be considered as a preprocessing of stego image before extracting the features. So the calibrated features are calculated as the difference between a specific function calculated from the original stego image and the same function obtained from calibrated version. Moreover, the calibrated feature was used to train SVM (support vector machine), a nonlinear classifier, which is effective in class separation. For comparison, a database composed of 6690 cover and stego images (generated by using four different embedding schemes) was established. Based on this database, we conducted extensive experiments and drawn a conclusion that the steganalysis based on our novel calibration can detect the stego images with high accuracy.

Abstract: Laser Diode (LD) tester is widely used in the research, manufacturing and testing of laser diode, but no verification regulation or calibration specification for laser diode tester has been released until now. With the fully using of the standard instruments in our optical communication laboratory, and referring to the operational manual, specification and relevant calibration regulations, we provide approaches to the calibration of the laser diode tester. The evaluation processes and results of measurement uncertainty for optical power measurement, output DC current, and DC voltage measurement are delivered at the end of the paper.

Abstract: Proximate analyzer is broadly used for determination of coal, so it is very important to evaluate its performance, orderly, the proximate analyzer is needed to be calibrated by metrology organizations. But there is no standard or regulation for proximate analyzer calibration in our country. On the basis of the function characteristics of proximate analyzer, the authors have suggested the calibration methods of temperature control performance, indication error and repeatability of ash and volatile, and the general technical requirement which includes appearance, insulation resistance, and insulation strength. The experimental results prove that this method can evaluate the performance of the proximate analyzer accurately and comprehensively.

Abstract: In modern industry the processing quality and precision become the concerned aspects. The cutting force dynamometer could ensure the two points by adjusting the cutting parameters. A piezoelectric dynamometer is introduced. The electric potential of X0 and Y0 crystal wafer has been analyzed by ANSYS under F_z, F_x and M_z. For the F_x and M_z measurement, the charge distribution expression is calculated by nonlinear elasticity and piezoelectric theory. The dynamometer is designed and the calibration experiments have been had. The nonlinearity and repeatability of M_z, F_x, and F_z are 0.77% and 1.05%, 0.46% and 0.58%, 0.34% and 0.69.

Abstract: Specific to the parameters in the process of three-phase smart meter calibration, such as DC offset, AC offset, AC gain, etc. impact on measurement results, a design of a three-phase smart meter based on CS5463 chips is introduced in this paper. Through theoretical analysis, optimized calibration, and experimental verification, parameters such as voltage, current, active power, reactive power, apparent power, power factor can be measured by the meter. After calibrated, the voltage and current measurement accuracy of the three-phase smart meter can reach above 0.2%. It can meet the needs of the practical application.

Abstract: To meet the special requirement of high speed micromouse, FPGA was added into the system. This document explains and demonstrates how to celibate a micromouse based on MCU and FPGA under the help of VB. Micromouse running pictures in the maze illustrate the micromouse prototype and calibration of micromouse very good, which can meet the fast exploration and dashing requirements of micromouse.

Abstract: The traditional virtual assembly technology requires building a true three-dimensional scene of all the assembly data, leading to complex modeling, low sense of reality and efficiency of real-time interaction. An augmented assembly system based on markers is proposed. The camera calibration technique is studied to get its inside and outside parameters first; a 3D registration algorithm based on markers is used to determine the exact location of virtual objects in the real scene then; the augmented assembly system is constructed according to the characteristics of virtual assembly finally. Experimental results show that the augmented reality technology makes the assembly steps appear in front of the staff intuitively and allows them to complete the actual assembly correctly, improving the sense of reality of the operation and interaction efficiency.

Abstract: Due to the instability and low precision of electromagnetic position trackers and the inefficiency of existing calibrating methods, a method with high accuracy and effectiveness for FOB (Flock of Birds) calibration was studied. The components, operational principle, merits and drawbacks of FOB were briefly introduced. The positions of 343 sampling points set in the effective working area were measured and the data was processed for trainings and tests of the calibration model established using genetic algorithm and BP algorithm. Experiments were conducted to verify the effectiveness of the method and the results showed the calibrated tracker’s average errors in the X, Y, and Z direction were 0.86cm, 0.70cm and 0.83cm respectively, meeting the requirements of human-computer interaction.

Abstract: Maxwell coil cannot meet the magnetic sensor calibration when the high uniformity of magnetic gradient is required and the space size is strictly limited. To solve this problem, a magnetic gradient coil with high uniformity was designed as magnetic sensor calibration device. Application of internal series method analyzed the magnetic field that a single axial symmetric coil generated, and then got the general characteristics of the magnetic gradient field distribution. On this basis, the structural parameters and the uniformity of magnetic gradient coil with high uniformity were calculated. Simulation analyses were carried out on the coil model and complete the design and production of magnetic gradient coil device. Finally, the data obtained from actual measurement and simulation proves the correctness of the design.

Abstract: This paper describes calibration principle of the thermal resistance based thermometer, and put forward digital thermometer calibration scheme of thermal resistance. Besides, according to the detailed analysis of the factors affected the accuracy of calibration, this paper supply a measure to solve this problem. This calibration design described in the article can achieve high-precise, digital calibration of the thermal resistance thermometer.