Approximate bandpass and frequency response models of the difference of Gaussian filter

2010 ◽  
Vol 283 (24) ◽  
pp. 4942-4948 ◽  
Author(s):  
Philip Birch ◽  
Bhargav Mitra ◽  
Nagachetan M. Bangalore ◽  
Saad Rehman ◽  
Rupert Young ◽  
...  
Keyword(s):  
Frequency Response ◽  
Gaussian Filter ◽  
Response Models ◽  
Difference Of Gaussian ◽  
The Difference

scholarly journals Small Infrared Target Detection via a Mexican-Hat Distribution

2019 ◽  
Vol 9 (24) ◽  
pp. 5570 ◽  
Author(s):  
Yubo Zhang ◽  
Liying Zheng ◽  
Yanbo Zhang
Keyword(s):  
Target Detection ◽  
Signal To Noise Ratio ◽  
Infrared Image ◽  
Small Target ◽  
Gaussian Filter ◽  
Adjacent Region ◽  
Detection Rates ◽  
Mexican Hat ◽  
Difference Of Gaussian ◽  
The Difference

Although infrared small target detection has been broadly used in airborne early warning, infrared guidance, surveillance and tracking, it is still an open issue due to the low signal-to-noise ratio, less texture information, background clutters, and so on. Aiming to detect a small target in an infrared image with complex background clutters, this paper carefully studies the characteristics of a target in an IR image filtered by the difference of Gaussian filter, concluding that the intensity of the adjacent region around a small infrared target roughly has a Mexican-hat distribution. Based on such a conclusion, a raw infrared image is sequentially processed with the modified top-hat transformation and the difference of Gaussian filter. Then, the adjacent region around each pixel in the processed image is radially divided into three sub-regions. Next, the pixels that distribute as the Mexican-hat are determined as the candidates of targets. Finally, a real small target is segmented out by locating the pixel with the maximum intensity. Our experimental results on both real-world and synthetic infrared images show that the proposed method is so effective in enhancing small targets that target detection gets very easy. Our method achieves true detection rates of 0.9900 and 0.9688 for sequence 1 and sequence 2, respectively, and the false detection rates of 0.0100 and 0 for those two sequences, which are superior over both conventional detectors and state-of-the-art detectors. Moreover, our method runs at 1.8527 and 0.8690 s per frame for sequence 1 and sequence 2, respectively, which is faster than RLCM, LIG, Max–Median, Max–Mean.

scholarly journals Markerless Image Alignment Method for Pressure-Sensitive Paint Image

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 453
Author(s):  
Kyosuke Suzuki ◽  
Tomoki Inoue ◽  
Takayuki Nagata ◽  
Miku Kasai ◽  
Taku Nonomura ◽  
...  
Keyword(s):  
Computational Cost ◽  
Measurement Data ◽  
Image Alignment ◽  
Feature Points ◽  
Alignment Method ◽  
Pressure Sensitive Paint ◽  
Pressure Sensitive ◽  
Difference Of Gaussian ◽  
Tracing Algorithm ◽  
The Difference

We propose a markerless image alignment method for pressure-sensitive paint measurement data replacing the time-consuming conventional alignment method in which the black markers are placed on the model and are detected manually. In the proposed method, feature points are detected by a boundary detection method, in which the PSP boundary is detected using the Moore-Neighbor tracing algorithm. The performance of the proposed method is compared with the conventional method based on black markers, the difference of Gaussian (DoG) detector, and the Hessian corner detector. The results by the proposed method and the DoG detector are equivalent to each other. On the other hand, the performances of the image alignment using the black marker and the Hessian corner detector are slightly worse compared with the DoG and the proposed method. The computational cost of the proposed method is half of that of the DoG method. The proposed method is a promising for the image alignment in the PSP application in the viewpoint of the alignment precision and computational cost.

Vibration Analysis of Diesel’s Undercarriage by Virtual Measure and Actual Measure

2011 ◽  
Vol 228-229 ◽  
pp. 621-626
Author(s):  
Peng Liu ◽  
Ying Yun Huang ◽  
Hao Peng Gao ◽  
Da Sheng Ou
Keyword(s):  
Frequency Response ◽  
Time Domain ◽  
Vibration Analysis ◽  
Response Characteristics ◽  
Amplitude Frequency Response ◽  
Actual Measure ◽  
Frequency Response Characteristics ◽  
The Difference

This paper proposes to verify and test the vibration of diesel’s undercarriage got by virtual measure and actual measure through the analysis of time domain characteristics and amplitude frequency response characteristics of three-orientation vibrant speed of diesel’s undercarriage, represents the difference in time domain characteristics and amplitude frequency response characteristics got by virtual measure and actual measure, expounds the reasons of difference and puts forward a method to diminution the difference. It proves that virtual measure can replace actual measure in a way, though there are some difference in existence, we can erase these difference to the best of ours’ abilities through enough analysis.

scholarly journals Static and dynamic operating characteristics of a pericardial balloon

2001 ◽  
Vol 90 (4) ◽  
pp. 1481-1488 ◽  
Author(s):  
Douglas R. Hamilton ◽  
Gwyneth Devries ◽  
John V. Tyberg
Keyword(s):  
Frequency Response ◽  
Diastolic Pressure ◽  
Ventricular Volume ◽  
Left Ventricular ◽  
Operating Characteristics ◽  
Minimum Diameter ◽  
Before And After ◽  
Unity Gain ◽  
Dynamic Operating ◽  
The Difference

Previously, we developed a balloon transducer to measure the constraint of the pericardium (i.e., pericardial pressure) on the surface of the heart. It was validated physiologically in that it was shown to measure a pressure equal to the difference between the left ventricular end-diastolic pressure measured before and after pericardiectomy at the same left ventricular volume. To define its static operating characteristics, we loaded the balloon nonuniformly with weights that covered fractions of the balloon surface and found that the balloon accurately recorded the average stress if the stress was applied over at least 23% of its surface. To test its performance when curved, we placed it in large and small cylinders (minimum diameter 31 mm) and found that the balloon accurately recorded the stress. To define its dynamic operating characteristics, we applied sinusoidal stresses and found that its frequency response was limited only by that of the connecting catheter. When better dynamic response is required, we introduce a micromanometer-tipped catheter to obtain a unity-gain frequency response that is flat to 200 Hz.

Bio-MEMS Circular Plate Sensors Under Electrostatic Hard Excitations: Frequency Response of Superharmonic Resonance of Fourth Order

2020 ◽  
Author(s):  
Julio Beatriz ◽  
Dumitru I. Caruntu
Keyword(s):  
Frequency Response ◽  
Circular Plate ◽  
Fourth Order ◽  
Multiple Scales ◽  
Superharmonic Resonance ◽  
Electrostatically Actuated ◽  
Amplitude Frequency Response ◽  
Elastic Circular Plate ◽  
Modes Of Vibration ◽  
The Difference

Abstract This paper investigates the frequency-amplitude response of electrostatically actuated Bio-MEMS clamped circular plates under superharmonic resonance of fourth order. The system consists of an elastic circular plate parallel to a ground plate. An AC voltage between the two plates will lead to vibrations of the elastic plate. Method of Multiple Scales, and Reduced Order Model with two modes of vibration are the two methods used in this work. The two methods show similar amplitude-frequency response, with an agreement in the low amplitudes. The difference between the two methods can be seen for larger amplitudes. The effects of voltage and damping on the amplitude-frequency response are reported. The steady-state amplitudes in the resonant zone increase with the increase of voltage and with the decrease of damping.

scholarly journals Balanced gain for a square metaloop antenna

2019 ◽  
Vol 6 ◽  
pp. 3
Author(s):  
Hisamatsu Nakano ◽  
Ittoku Yoshino ◽  
Tomoki Abe ◽  
Junji Yamauchi
Keyword(s):  
Frequency Response ◽  
Radiation Pattern ◽  
Free Space ◽  
Loop Antenna ◽  
Circularly Polarized ◽  
Left Handed ◽  
The Difference

A square loop antenna implemented using a metamaterial line, referred to as a metaloop, is discussed. The metaloop radiates a counter circularly polarized (CP) broadside beam when the loop circumference equals one guided wavelength. The frequency response of the gain shows two different maximum values: gain G Lmax for a left-handed CP wave at frequency fGLmax and gain GRmax for a right-handed CP wave at frequency fGRmax, where GLmax is smaller than GRmax. In order to increase GLmax, while not affecting the original GRmax as much as possible (i.e. balance the gain), a parasitic natural conducting loop (paraloop), whose circumference is one free-space wavelength at fGLmax, is placed at height Hpara above the metaloop. It is found that the difference in the gains can be reduced by choosing an appropriate Hpara. The radiation pattern at fGLmax is narrowed by the paraloop, while the VSWR is not remarkably affected.

The Revised Method of Quantitative Detection of Animal-Origin Bovine and Porcine Gelatin Difference Using Surface Plasmon Resonance Based Biosensor

2019 ◽  
Vol 948 ◽  
pp. 146-152
Author(s):  
Devy Pramudyah Wardani ◽  
Muhammad Arifin ◽  
Kamsul Abraha
Keyword(s):  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Sensor Response ◽  
Animal Origin ◽  
Quantitative Detection ◽  
Response Models ◽  
Gelatin Concentration ◽  
The Difference ◽  
Different Characteristics

We have previously reported the surface plasmon resonance (SPR)-based biosensor ability for quantitatively differentiating bovine and porcine gelatin has been done by us before. However, it has some inaccuracies. By improving the method of detection, the results of this study shows that the difference between bovine and porcine gelatin was more distinguishable. The sensor response models acquired were nonlinear as in the previous study. However, they show different characteristics. The sensitivities of the sensor obtained are higher than those of the previous ones, i.e., 3.04o and 4.29o for bovine and porcine gelatin concentration change of 0.1%, respectively. And the sensor’s LOD and LOQ towards both gelatin concentrations were 0.22% and 0.74% (w/w), respectively.

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