By using binocular stereoscopic vision and planar images, this paper details the process of obtaining 3D information for interested objects and obtains the world and pixel coordinates of any point on the object. The m...
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ISBN:
(纸本)9789811089718;9789811089701
By using binocular stereoscopic vision and planar images, this paper details the process of obtaining 3D information for interested objects and obtains the world and pixel coordinates of any point on the object. The main contents of this article are focus on camera calibration, image correction, stereo matching, and parallax extraction. Furthermore, various algorithms and implementation methods are studied and analyzed. Finally, by comparing correction and stereo matching algorithms, more effective correction algorithm and matching algorithm are achieved.
Field of view (FOV) of the fisheye lens is close to or even higher than 180 degrees, which brings about extraordinary imaging effect that the visual range would be far wider than the human eye perspective. However, th...
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ISBN:
(数字)9781510614062
ISBN:
(纸本)9781510614062;9781510614055
Field of view (FOV) of the fisheye lens is close to or even higher than 180 degrees, which brings about extraordinary imaging effect that the visual range would be far wider than the human eye perspective. However, the wide visual range of the fisheye lens is always at the expense of image quantity, so that the images obtained by fisheye lens would inevitably show a large degree of distortion aberration. In this paper, we propose an improved distortion calibration algorithm of longitude-latitude mapping to eliminate the image distortion aberration caused by fisheye lens. This method does not need to depend on a specific physical camera and has general and universal significance. By using Matlab as a mathematical analysis tool, the verified experiment and the corresponding write code is performed to correct a specific fisheye lens' image based on the previously proposed algorithm. A reverse mapping is used to avoid cross-border problems, and comparative experiments are also analyzed to show the difference between the image processing with the traditional and the proposed algorithm. Experimental results demonstrate that the proposed algorithm can better achieve the correction of fisheye lens distortion. The twisted lines that are not expected can be well corrected into the straight lines. This method can not only reduce the problem of horizontal stretching of the image, but also make the processing results visually consistent with people's viewing habits.
Cutting tool machining quality and accuracy calibration has always been an important indicator of the performance of machine tools, machine tool testing technology is particularly the key point. In this paper, an opti...
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ISBN:
(纸本)9781538663011
Cutting tool machining quality and accuracy calibration has always been an important indicator of the performance of machine tools, machine tool testing technology is particularly the key point. In this paper, an optical based non-contact five-axis machine tool calibration system with IOT feature is presented. It can be obtained once the three-dimensional detection signals, combined with embedded systems for data calculation and communication using Wi-Fi wireless. Test hardware includes two sets of laser light source, two sets of photoelectric sensors and spherical lens and DSP processor. The proposed calibration IOT system has simple for setup, low cost, high precision features for calibration five-axis motor and static error.
A concurrent dual-band receiver based on a single multiport correlator is proposed in this brief to down-convert dual-band radio frequency signals. The system configuration, output power, as well as its spectrum analy...
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A concurrent dual-band receiver based on a single multiport correlator is proposed in this brief to down-convert dual-band radio frequency signals. The system configuration, output power, as well as its spectrum analysis are discussed, and then a generalized baseband signal recovery theory is put forward. Next, the calibration algorithm based on real-valued time-delay neural network, which can take the system impairments and signal distortions into consideration, is proposed to retrieve two baseband signals, simultaneously. Finally, the six-port receiver is tested under the common modulated signals, and the measured error vector magnitudes between the transmitted and the received signals are all less than 2%.
To approach wide-field optical properties quantification in real heterogeneous biological tissue, we developed a Dual-Step setup that couples a punctual diffuse reflectance spectroscopy (DRS) technique with multispect...
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To approach wide-field optical properties quantification in real heterogeneous biological tissue, we developed a Dual-Step setup that couples a punctual diffuse reflectance spectroscopy (DRS) technique with multispectral imaging (MSI). The setup achieves wide-field optical properties assessment through an initial estimation of scattering with DRS, which is used to estimate absorption with MSI. The absolute quantification of optical properties is based on the ACA-Pro algorithm that has been adapted both for DRS and for MSI. This paper validates the Dual-Step system not only on homogeneous Intralipid phantoms but also on a heterogeneous gelatine phantom with different scattering and absorbing properties. (C) 2018 Society of Photo-Optical Instrumentation Engineers (SPIE)
Complexity and computation effective design of multiport-based receiver system is proposed in this paper, and a simple calibration algorithm based on modified memory polynomial for the five-port receiver is used to de...
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Complexity and computation effective design of multiport-based receiver system is proposed in this paper, and a simple calibration algorithm based on modified memory polynomial for the five-port receiver is used to demodulate the desired baseband signals from the received radio frequency signals. The theoretical foundation for the baseband signal recovery for the multiport system, basic circuit theory of the five-port receiver, and the proposed algorithm about how to retrieve the baseband signals from three output voltage signals are discussed. Finally, common modulated signals are used in the five-port receiver to validate the proposed calibration algorithm, and the measured performance in terms of error vector magnitude between the transmitted and the received signals are all less than 2%. Also, the performance comparison with the state-of-the-art multiport receivers is made to conclude that the five-port receiver with the proposed model can be one of the best cost and computation effective choices to accurately complete the signal recovery.
In this paper, the non-ideal factors, which include spatial noise and temporal noise, are analyzed and suppressed in the high-speed spike-based image sensor, which combines the high-speed scanning sequential format wi...
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In this paper, the non-ideal factors, which include spatial noise and temporal noise, are analyzed and suppressed in the high-speed spike-based image sensor, which combines the high-speed scanning sequential format with the method that uses the interspike time interval to indicate the scene information. In this imager, spatial noise contains device mismatch, which results in photo response non-uniformity (PRNU) and the non-uniformity of dark current. By multiplying the measured coefficient matrix the photo response non-uniformity is suppressed, and the non-uniformity of dark current is suppressed by correcting the interspike time interval based on the time interval of dark current. The temporal noise is composed of the shot noise and thermal noise. This kind of noise can be eliminated when using the spike frequency to restore the image. The experimental results show that, based on the spike frequency method, the standard deviation of the image decreases from 18.4792 to 0.5683 in the uniform bright light by using the calibration algorithm. While in the relatively uniform dark condition, the standard deviation decreases from 1.5812 to 0.4516. Based on interspike time interval method, because of time mismatch and temporal noise, the standard deviation of the image changes from 27.4252 to 27.4977 in the uniform bright light by using the calibration algorithm. While in the uniform dark condition, the standard deviation decreases from 2.361 to 0.3678.
The backstage calibration method based on LMS-FIR and interpolation filter for a four-channel time-interleaved analog-to-digital converter(TI-ADC) is presented in this *** analysis is made for the mismatch between sub...
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ISBN:
(纸本)9781509066261;9781509066254
The backstage calibration method based on LMS-FIR and interpolation filter for a four-channel time-interleaved analog-to-digital converter(TI-ADC) is presented in this *** analysis is made for the mismatch between sub-channels of multi-channel TI-ADC,such as offset mismatch,gain mismatch,and sampling *** the LMS calibration algorithm can reduce the performance loss caused by the mismatch *** proposed four-channel TI-ADC is designed in a 90 nm CMOS *** pre-corrected input is 12.55 MHz and sampling frequency is 200 MHz with mismatch errors,SNDR is 44.0 d B,the effective number of bit(ENOB) is 7.0 bit,and SFDR is 53.4 d *** correction,the spurious performance is significantly reduced and the overall noise reduction is decreased,the SNDR is 65.6 d B and ENOB is 10.6 *** calibration effect is obvious with ENOB inproved by 3.6 bit and the spurious performance decreased by 30.7 d BFS.
The radiometric calibration equations for the thermal emissive bands (TEB) and the reflective solar bands (RSB) measurements of the earth scenes by the polar satellite sensors, (Terra and Aqua) MODIS and Suomi NPP (VI...
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The radiometric calibration equations for the thermal emissive bands (TEB) and the reflective solar bands (RSB) measurements of the earth scenes by the polar satellite sensors, (Terra and Aqua) MODIS and Suomi NPP (VIIRS), and geostationary sensors, GOES Imager and the GOES-R Advanced Baseline Imager (ABI) are analyzed towards calibration algorithm harmonization on the basis of SI traceability which is one of the goals of the NOAA National calibration Center (NCC). One of the overarching goals of NCC is to provide knowledge base on the NOAA operational satellite sensors and recommend best practices for achieving SI traceability for the radiance measurements on-orbit. As such, the calibration methodologies of these satellite optical sensors are reviewed in light of the recommended practice for radiometric calibration at the National Institute of Standards and Technology (NIST). The equivalence of some of the spectral bands in these sensors for their end products is presented. The operational and calibration features of the sensors for on-orbit observation of radiance are also compared in tabular form. This review is also to serve as a quick cross reference to researchers and analysts on how the observed signals from these sensors in space are converted to radiances.
The dynamic envelope measurement plays very important role in the external dimension design for high-speed train. Recently there is no digital measurement system to solve this problem. This paper develops an optoelect...
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ISBN:
(数字)9781510617544
ISBN:
(纸本)9781510617544;9781510617537
The dynamic envelope measurement plays very important role in the external dimension design for high-speed train. Recently there is no digital measurement system to solve this problem. This paper develops an optoelectronic measurement system by using monocular digital camera, and presents the research of measurement theory, visual target design, calibration algorithm design, software programming and so on. This system consists of several CMOS digital cameras, several luminous targets for measuring, a scale bar, data processing software and a terminal computer. The system has such advantages as large measurement scale, high degree of automation, strong anti-interference ability, noise rejection and real-time measurement. In this paper, we resolve the key technology such as the transformation, storage and calculation of multiple cameras' high resolution digital image. The experimental data show that the repeatability of the system is within 0.02mm and the distance error of the system is within 0.12mm in the whole workspace. This experiment has verified the rationality of the system scheme, the correctness, the precision and effectiveness of the relevant methods.
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