Solution of topical spectroradiometric problems using synchrotron radiation

Atmospheric turbulence and aerosol scattering can produce the blurring of the remotely sensed image. The degrading effect is usually quantified by atmospheric modulation transfer function (MTF). However, this effect behaves differently with different remote sensors. The effort of this article is to study the different degrading effects of aerosol MTF and turbulence MTF between charge-coupled device (CCD) camera on China–Brazil Earth Resources Satellite-02b (CBERS-02b) and on Huan Jing-1A/1B satellite (HJ-1A/1B). Specifically, a corrected aerosol MTF model is established based on classical solution of small-angle approximation (SAA) model by considering the MTF and the effective instantaneous field of view (EIFOV) of CCD cameras. By assuming many different atmospheric conditions, the aerosol MTF and turbulence MTF for two CCD cameras are evaluated. It is found that the output aerosol MTF of CCD camera on HJ-1A/1B causes more degrading effect than that of CBERS-02b under the same atmospheric condition. However, the situation reverses for the turbulence MTF. Furthermore, CCD images acquired over Beijing, China, by CBERS-02b and HJ-1A/1B on four different dates are selected. The overall atmospheric MTF for these images are determined based on the aerosol products from Aerosol Robotic Network (Aeronet) and radiosounding data. Results indicate that the overall atmospheric MTF of CBERS-02b CCD camera reduces image quality more seriously than that of HJ-1A/1B CCD camera. Additionally, the atmospheric MTF compensation is performed and evaluated for these CCD images based on the overall atmospheric MTF.

In the wider field of image processing and analysis the most common source of greylevel images is the CCD (Charge-Coupled Device) camera. This quite closely resembles a standard photographic camera; a lens at the front of the unit focuses light from the viewed environment onto a light sensitive surface within the camera body. In photography that surface is a section of photographic film. In CCD cameras, film is replaced by a rectangular array of light sensitive cells. When the shutter opens, each cell generates an electrical signal proportional to the amount of light falling upon it. These signals are fed out of the camera and into the computer via special purpose hardware which converts the analogue signals generated by the CCD array into a digital raster image.

In this work we have proposed a new configuration based on a tilted charged coupled device (CCD) camera and bandpass sampling theorem which not only decreases the spectrometer size but also operates in the traditional spectrometers wavelength range of 400 nm – 1100 nm. The static Michelson interferometer is built by attaching a quartz cube and a prism together, and a CCD camera is attached to the quartz cube in 45 degree to record path length differences (PLD). An algorithm is developed to process the signal and calculate the Fourier transform of the recorded interferograms on the CCD camera.

The report describes the research contract proposal concerning the development of a neutron imaging system for real time and tomography investigations that is based on LiF-ZnS scintillator and Charge Coupled Devices (CCD) camera like light-electrical signal converter. The necessary components of such a type of detector: scintillating screen, aluminized mirror and CCD camera with proper lenses are presented. It is intended to use the imaging system with large scale objects under static and dynamic investigations under various neutron fluencies obtained from Annular Core Pulsing Reactor (ACPR) in steady state and pulsing mode.

To analyze Bragg-peak beams in SOBP (spread-out Bragg-peak) beam using CCD (charge-coupled device) camera - scintillation screen system. We separated each Bragg-peak beam using light output of high sensitivity scintillation material acquired by CCD camera and compared with Bragg-peak beams calculated by Monte Carlo simulation. In this study, CCD camera - scintillation screen system was constructed with a high sensitivity scintillation plate (Gd2O2S:Tb) and a right-angled prismatic PMMA phantom, and a Marlin F-201B, EEE-1394 CCD camera. SOBP beam irradiated by the double scattering mode of a PROTEUS 235 proton therapy machine in NCC is 8 cm width, 13 g/cm2 range. The gain, dose rate and current of this beam is 50, 2 Gy/min and 70 nA, respectively. Also, we simulated the light output of scintillation plate for SOBP beam using Geant4 toolkit. We evaluated the light output of high sensitivity scintillation plate according to intergration time (0.1 - 1.0 sec). The images of CCD camera during the shortest intergration time (0.1 sec) were acquired automatically and randomly, respectively. Bragg-peak beams in SOBP beam were analyzed by the acquired images. Then, the SOBP beam used in this study was calculated by Geant4 toolkit and Bragg-peak beams in SOBP beam were obtained by ROOT program. The SOBP beam consists of 13 Bragg-peak beams. The results of experiment were compared with that of simulation. We analyzed Bragg-peak beams in SOBP beam using light output of scintillation plate acquired by CCD camera and compared with that of Geant4 simulation. We are going to study SOBP beam analysis using more effective the image acquisition technique.

The ability to determine its positions and orientations accurately is very important for a mobile robot when performing tasks such as free-range path tracking and navigation. In this paper, a cost-effective method is proposed for localization of a mobile robot, where a low-resolution charge-coupled device (CCD) camera, a stepping motor, and three artificial landmarks are used. The CCD camera is mounted on the robot and its rotation is controlled by the stepping motor. Then, from the images captured by the CCD camera, image-processing techniques are used to determine the distances between the CCD camera and the three landmarks. On the basis of these distances, it can be proved that the position of the robot is determined uniquely provided that the three artificial landmarks observed are not installed in a line. Moreover, the heading angle of the robot is determined from the rotation angle of the stepping motor. To account for possible installation errors, a non-linear programming method is proposed. Meanwhile, a least-squares method is also used to increase the accuracy of localization. To show the feasibility of the proposed method, experimental results are included for illustration.

The equipment that the payload electronic control box matches the satellite Charge-Coupled Device (CCD) camera must be rigorously tested before being put into use. The traditional testing process is to make it with the bulky CCD camera system docking and then to capture a certain image to analyze, this will cause a waste of time and material. In consideration for the above problems, a simulative CCD camera image resource system is proposed in this paper. The control signal of a simulative CCD camera image resource is usually implemented in the Field Programmable Gate Array (FPGA), thus increasing the complexity of the hardware language, and stability will fall and making post-adjustment is more trouble. This paper presents a system which is controlled based on the host computer software. It makes complex code integrate into the host computer and sets aside a adjust interface to the software in advance, achieving with the FPGA circuit board to send the picture generated by the system cycle together. Sending images, image display and serial communication are usually for a thread in the general simulative CCD camera image resource system, this will inevitably cause some problems that often appear in the process. However, the system utilizes a three-run thread synchronization mode which makes the system more flexible, very easy to adjust. Extensive tests show that the simulative CCD camera image resource system has been running with satisfactory results. So it can replace CCD camera to test the payload electrical control box, which is stable and reliable test for the project and provides a strong support.

Comparison of detection limits of direct-counting CMOS and CCD cameras in EELS experiments

Charged-Coupled Device (CCD) Camera can be used as an optical position sensor to determine the location of the hot spot on the sensor surface in two dimensions. A CCD camera is a video camera with a coupled device (CCD), which is an integrated circuit transistor light sensor with a high quantum efficiency, minimal noise, large dynamic range, linear response, and little geometric distortion. The CCD camera is a digital camera that enables taking visual information and converting it into an image or video. CCD cameras are widely used due to their ability to take images in low light. The control system employed in this study is based on a novel and modern closed-loop algorithm that allows for precise tracking of the hotspot's location and speed used in the measurement of a specific physical process. The proposed control model is controlled around the brightest area using two controllers, the Proportional-Integral-Derivative controller (PID) and the Neuro-Fuzzy controller with feedback through the CCD sensor, as well as the use of a Brushless Direct Current (BLDC) motor for position and speed control with two feedback loops. To verify the validity of the proposed system, it was found that the algorithm will achieve a better rise time and reduce the maximum overshoot.

An instantaneous phase stepping and subsequent phase analysis method, using a charge-coupled device (CCD) camera with a pixelated form-birefringent microretarder array, is proposed for 2-D birefringence distribution measurement. A birefringent sample placed behind a polarizer and a quarter-wave plate is analyzed by the proposed method. Light emerging from the sample is recorded using a CCD camera that has a pixelated microretarder array on the CCD plane. This microretarder array has four different principal directions. That is, an image obtained by the CCD camera contains four data corresponding to four different optical axes of the retarder. The four images separated from the image recorded by the CCD camera are reconstructed using gray-level interpolation. Then, the distributions of the Stokes parameters that represent the state of polarization are calculated from the four images. The birefringence parameters, that is, the angle of the principal axis and the phase retardation, are then obtained from these Stokes parameters. This method is applicable to real-time inspection of optical elements as well as the study of the mechanics of time-dependent materials, because multiple exposures are unnecessary for sufficient data acquisition in the completion of data analysis.

Contrast medium causes side effects such as contrast-induced nephropathy, and the dose of contrast medium is a risk factor in their occurrence. To reduce doses of contrast medium, we developed an angiographic system with high definition and high sensitivity and reviewed its effectiveness. The system entails synchrotron radiation, which is characterized by high photon density and straightness of beam that together result in high resolution, and a high-gain avalanche rushing amorphous photoconductor receiver, which is 100 times more sensitive than conventional charge-coupled device cameras. Diluted contrast medium was administered, and angiography of rat hindlimbs was performed with synchrotron radiation and the high-gain photoconductor receiver. The difference in gray-scale value between the background and contrast medium was calculated. Images were evaluated by counting of arteries. The difference in contrast at low levels was detected with the high-gain photoconductor receiver but not with the charge-coupled device camera. The photon density of synchrotron radiation with the high-gain photoconductor receiver was one-fifth that with the charge-coupled device camera. The high-gain photoconductor receiver had approximately 5 times the sensitivity of the charge-coupled device camera. Use of the synchrotron radiation and high-gain photoconductor receiver makes it possible to perform angiography with an extremely low concentration of contrast medium.

Chapter 3 Cooled CCD Versus Intensified Cameras for Low-Light Video---Applications and Relative Advantages

The authors first discuss the physical and mathematical model of CCD (charge coupled device) cameras on which the standard photogrammetric calibration of the cameras is based. Then they introduce artificial neural networks in order to improve the classical calibration of the CCD cameras, and thus develop a new method to calibrate CCD cameras. In this set-up, a feedforward artificial neural network is used. Three advantages of the hybrid calibration are discussed: feasibility, applicability, and efficiency. In order to judge the quality of the calibration, the calibration error of a camera is defined. It is shown experimentally that the accuracy of the image frame coordinates has been improved by a factor two through the hybrid calibration. It appears to be a new idea to add an artificial neural network to the physical and mathematical model of a system in order to improve the overall description of the system. >

A digital image processing system based on a charge-coupled device (CCD) camera interfaced to a Texas Instruments Professional Computer (TIPC) has been implemented on the Cameca IMS-3F Ion Microscope to improve lateral imaging capabilities. The CCD sensor, produced at TI, generates a 376 × 288 pixel image, and a hardware interface to the TIPC provides an 8-bit grayscale (256 levels) for subsequent storage and display. The Cameca ion microscope projects secondary ions from the sample onto a microchannel plate/fluorescent screen combination. The CCD array images the screen directly and no vacuum modifications to the Cameca are required. Nitrogen cooling of the CCD imager to reduce thermal noise allows low light levels to be integrated for several minutes and displayed on the TIPC, providing a substantial increase in sensitivity over the standard optics. False color imaging enhances the contrast of various features in the ion image to provide ease of identification. A variety of software options, such as frame mosaicking, multiple frame overlays, color threshold modification and histogram equalization are available. The TIPC has also been interfaced to the Cameca controlling computer to allow display of ion images during depth profiling.

Purpose: To compress the quality assurance time for the scanned carbon-ion beam system, we have been developed the novel range verification system using scintillator and CCD (charge-coupled device) camera. Methods: A cylindrical plastic scintillator block and a CCD camera were installed on the black box. The range was determined by image processing. Reference range for each energy beam was determined the 80 percent of distal dose of the depth dose distribution that were measured by a large parallel-plate ionization chamber. Carbon beams ranging from 151.9 to 430 MeV/n were tested and compared with reference range. The common reference point of range is distal 80% of the dose distribution. In order to select the best reference point on a light distribution, the authors compared two range detection. Methods: threshold method (TH); the threshold positions set by the range from 10 to 90% of maximum value on the projected line are identified and difference of Gaussian (DOG) method. Using DOG method, range position is determined by zero-crossing position in the difference between small-Gaussian smoothed data and large-Gaussian smoothed data. Results: The 1 mm range difference was clearly detected. Standard deviation of discrepancy from the range measured by the ionization chamber was less than 0.1 mm. A 1 mm setup error in the any direction was less than 0.2 mm range error. Conclusion: We have shown that the range of carbon beam can be determined with sub-millimeter accuracy using scintillator and CCD camera. The 80 percent of maximum value is minimized discrepancies between expected and measured ranges for carbon beam. It was supposed to be a Result of the change of shape due to quenching effect. Since the system determine the range with short time and sufficient accuracy, it seems be that the system has potential to play the daily range check system.