Charge-coupled Device Technology Research Articles

Fully depleted charge‐coupled device design and technology development

AbstractWe describe the advancement of fully depleted charge‐coupled device (CCD) technology for scientific applications. Recent efforts on 650–725 m‐thick CCDs for direct dark‐matter and radiation detection with single‐electron sensitivity are described, as well as the technology transfer of the fully depleted CCD technology to 200 mm‐wafer fabrication facilities.

Адаптивный алгоритм снижения уровня импульсного шума на изображениях с камер видеонаблюдения

An optical signal is usually converted into an electrical one by using photosensitive matrices with a large number of discrete elements based on charge-coupled device (CCD) technology or CMOS technology. One of the disadvantages of CCD and CMOS technologies is the impulse conversion noise that appears on digitized images, impairing visual perception and significantly reducing the likelihood of correct identification in pattern recognition tasks. Traditionally, impulse noise is removed from images using median filters with a fixed aperture within each iteration of full-format processing. However, such filters reduce the sharpness of the reconstructed image at high noise levels or insufficiently suppress the interference under the same noise conditions. These setbacks call for a need to develop an adaptive median filtering algorithm, which would produce a reconstructed image as a joint result of processing with median filters with different apertures. The essence of this algorithm is to select image areas with different noise levels and process these areas with filters with different apertures. As an objective criterion for assessing the efficiency of the proposed filtering algorithm, the authors used the criterion of the maximum correlation coefficient between noise-free and non-noisy images at various values of the noise variance. The mathematical modeling performed in this study allowed finding that with an increase in the impulse noise variance, the gain of the adaptive median filtering algorithm increases exponentially, in comparison with the algorithms using the filters with a fixed aperture value. The proposed algorithm can be used for pre-preprocessing images intended for recognition by machine vision systems, scanning text, and improving subjective image characteristics, such as sharpness and contrast.

Is a Fundamental Design Change for Gastrointestinal Endoscopes Required?

Since the first fiberoptic instruments, gastrointestinal endoscopy has shaped the field of gastroenterology and is now a key diagnostic and therapeutic tool. Compared with the initial fiberoptic endoscopes state-of-the-art optical chips (or charge-coupled device technology) allowed a quantum leap in image quality. Despite these advances, gastrointestinal endoscopy is far from being perfect. The diagnostic yield (eg, for adenoma detection rates) is highly operator dependent and there is still the need for sedation or even anesthesia to address discomfort during the procedure. Despite highly standardized cleaning and high-level disinfection the reuse of contemporary (and difficult to clean) endoscopes with multiple channels exposes patients to the risk of transmission of infections. Artificial intelligence and pattern recognition should eliminate interindividual variability including polyp detection rates, self-propelled, and (potentially remotely controlled) scopes with a soft shaft could reduce the discomfort during procedures and abolish the need for sedation and anesthesia altogether and single-use designs should eliminate the risk of patient-to-patient transmission of infections. While these innovations are feasible and could be implemented rapidly utilizing available technology, they require a paradigm shift affecting all levels of the value chain from the supplier of the instruments to the end-users. Some may negate the need for a paradigm shift, but it is evident that a major redesign of the endoscopic equipment is overdue to fully utilize novel technologies and most importantly ensure the best possible outcomes for patients.

Research on CCD High-speed Data Acquisition and Computer Simulation Processing System Controlled by Single Chip Microcomputer

CCD (charge-coupled device) is a unique performance of the semiconductor photoelectric device, CCD technology applied to displacement, thickness and other geometric measurement, can achieve high precision, online dynamic detection and non-contact measurement requirements. This system USES the method of combining FPGA and single chip microcomputer to measure the thickness of the object using CCD as the sensor. In this design, the CCD driver pulse circuit, control logic and calculation circuit are all integrated in FPGA chip, thus improving the reliability of the system and creating conditions for the system integration. External display and control circuits such as liquid crystal display, keyboard and EEPROM memory are designed by SCM. The whole system embodies the characteristics of high integration, simple structure and superior performance. This paper introduces the principle, design and implementation of the system in detail.

Imaging of the jaws

Introduction The mainstay of dental imaging has traditionally been the intraoral images called periapicals and bitewings, which for many years were made with film that was wrapped in a protective packet. Today these images are taken using small detectors or sensors that are placed inside the patient 's mouth. The first digital intraoral solid-state detector, a charge-coupled device (CCD), was introduced in 1997. These detectors are directly attached to the computer by a wire and give an almost instantaneous image on the computer monitor (Fig. 1). This provides huge savings in time compared with the traditional wet processing needed for films as well as for the ability to manipulate the image and change its brightness and contrast. In addition, because the images appear on a monitor within the operatory it allows for instant feedback to the operator and also the patient. Several manufacturers are now using complementary metal oxide semiconductor technology for their detectors, as it is less expensive to produce than CCD technology. In dentistry these types of detectors are often referred to as “sensors” to differentiate them from an alternate digital intraoral detector, photostimulable phosphor (PSP) plates. PSP plates are thinner and more flexible than the solid-state sensors and are often tolerated better by the patient. They are the same size as traditional intraoral film packets and can be used with the same positioning devices without modification. Exposure to x-rays produces a latent image within the plate in the form of stored energy, which is released when the plates are “processed” by laser light in the manufacturer 's scanning device or reader. The readers are often small enough that they can be placed in the dental operatory (Fig. 2). The image, therefore, like film is not instantaneous as this is a 2-step process. However, once placed in the reader the images can appear on the computer monitor in as little as 3 seconds. Some dental offices still use film-based imaging

Front-end multiplexing—applied to SQUID multiplexing: Athena X-IFU and QUBIC experiments

As we have seen for digital camera market and a sensor resolution increasing to “megapixels”, all the scientific and high-tech imagers (whatever the wave length - from radio to X-ray range) tends also to always increases the pixels number. So the constraints on front-end signals transmission increase too. An almost unavoidable solution to simplify integration of large arrays of pixels is front-end multiplexing. Moreover, “simple” and “efficient” techniques allow integration of read-out multiplexers in the focal plane itself. For instance, CCD (Charge Coupled Device) technology has boost number of pixels in digital camera. Indeed, this is exactly a planar technology which integrates both the sensors and a front-end multiplexed readout. In this context, front-end multiplexing techniques will be discussed for a better understanding of their advantages and their limits. Finally, the cases of astronomical instruments in the millimeter and in the X-ray ranges using SQUID (Superconducting QUantum Interference Device) will be described.

Single-shot compressed ultrafast photography at one hundred billion frames per second.

The capture of transient scenes at high imaging speed has been long sought by photographers, with early examples being the well known recording in 1878 of a horse in motion and the 1887 photograph of a supersonic bullet. However, not until the late twentieth century were breakthroughs achieved in demonstrating ultrahigh-speed imaging (more than 10(5) frames per second). In particular, the introduction of electronic imaging sensors based on the charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS) technology revolutionized high-speed photography, enabling acquisition rates of up to 10(7) frames per second. Despite these sensors' widespread impact, further increasing frame rates using CCD or CMOS technology is fundamentally limited by their on-chip storage and electronic readout speed. Here we demonstrate a two-dimensional dynamic imaging technique, compressed ultrafast photography (CUP), which can capture non-repetitive time-evolving events at up to 10(11) frames per second. Compared with existing ultrafast imaging techniques, CUP has the prominent advantage of measuring an x-y-t (x, y, spatial coordinates; t, time) scene with a single camera snapshot, thereby allowing observation of transient events with temporal resolution as tens of picoseconds. Furthermore, akin to traditional photography, CUP is receive-only, and so does not need the specialized active illumination required by other single-shot ultrafast imagers. As a result, CUP can image a variety of luminescent--such as fluorescent or bioluminescent--objects. Using CUP, we visualize four fundamental physical phenomena with single laser shots only: laser pulse reflection and refraction, photon racing in two media, and faster-than-light propagation of non-information (that is, motion that appears faster than the speed of light but cannot convey information). Given CUP's capability, we expect it to find widespread applications in both fundamental and applied sciences, including biomedical research.

Study on Inspection Methods for High-Speed Progressive-Die Punched Strips

The inspection of sheet strips post high-speed punching mainly relies on the manual off-line inspection with basic inspection equipment or CCD equipment. Such inspections cannot reflect the real-time conformity of strip machining, and in severe cases, lead to rejects in batches, causing a tremendous waste in production. Now that the application of charge-coupled device (CCD) technology in product inspection is relatively mature, it would be a very good thought to adopt the CCD technology to realize real-time online inspection of conformity of the high-speed punched strips. KeyWords: CCD technology; strip; online automatic inspection; progressive die

CCD image sensor induced error in PIV applications

The readout procedure of charge-coupled device (CCD) cameras is known to generate some image degradation in different scientific imaging fields, especially in astrophysics. In the particular field of particle image velocimetry (PIV), widely extended in the scientific community, the readout procedure of the interline CCD sensor induces a bias in the registered position of particle images. This work proposes simple procedures to predict the magnitude of the associated measurement error. Generally, there are differences in the position bias for the different images of a certain particle at each PIV frame. This leads to a substantial bias error in the PIV velocity measurement (∼0.1 pixels). This is the order of magnitude that other typical PIV errors such as peak-locking may reach. Based on modern CCD technology and architecture, this work offers a description of the readout phenomenon and proposes a modeling for the CCD readout bias error magnitude. This bias, in turn, generates a velocity measurement bias error when there is an illumination difference between two successive PIV exposures. The model predictions match the experiments performed with two 12-bit-depth interline CCD cameras (MegaPlus ES 4.0/E incorporating the Kodak KAI-4000M CCD sensor with 4 megapixels). For different cameras, only two constant values are needed to fit the proposed calibration model and predict the error from the readout procedure. Tests by different researchers using different cameras would allow verification of the model, that can be used to optimize acquisition setups. Simple procedures to obtain these two calibration values are also described.

Two-Dimensional Microchemical Observation of Mast Cell Biogenic Amine Release as Monitored by a 128 × 128 Array-Type Charge-Coupled Device Ion Image Sensor

Available array-type, chemical-sensing image sensors generally only provide on/off responses to the sensed chemical and produce qualitative information. Therefore, there is a need for an array sensor design that can detect chemical concentration changes to produce quantitative, event-sensitive information. In this study, a 128 × 128 array-type image sensor was modified and applied to imaging of biogenic amines released from stimulated rat mast cells, providing recordable responses of the time course of their release and diffusion. The imaging tool was manufactured by an integrated circuit process, including complementary metal oxide semiconductor and charge-coupled device technology. It was fitted with an amine-sensitive membrane prepared from plasticized poly(vinyl chloride) including a hydrophobic anion, which allowed the sensor to detect amines, such as histamine and serotonin, in Tyrode's solution. As mast cells were larger in diameter than the pixel hollows, some pixels monitored amines released from single cells. The image from the array responses yielded sequential snapshots at a practical frame speed that followed amine concentration changes over time, after mast cell amine release was synchronized by chemical stimulation. This sensor was shown to be sensitive to amine release at very low stimulus concentrations and was able to detect localized spots of high amine release. The entire time course of the amine release was recorded, including maximum concentration at 4-6 s and signal disappearance at 30 s after stimulation. With further development, this sensor will increase opportunities to study a variety of biological systems, including neuronal chemical processes.

Intraoral Radiology in General Dental Practices – A Comparison of Digital and Film-Based X-Ray Systems with Regard to Radiation Protection and Dose Reduction

The purpose of this study was to gain insight into the distribution and application of digital intraoral radiographic techniques within general dental practices and to compare these with film-based systems in terms of patient dose reduction. 1100 questionnaires were handed out to general dental practitioners. Data was analyzed with respect to the type of system by using descriptive statistics and nonparametric tests, i.e. Kruskal-Wallis, Mann-Whitney and chi-square test (SPSS 20). 64% of the questioned dentists still use film-based radiology, 23% utilize storage phosphor plate (SPP) systems and 13% use a charge-coupled device (CCD). A strong correlation between the number of dentists working in a practice and the use of digital dental imaging was observed. Almost 3/4 of the film users work with E- or F-speed film. 45% of them refuse to change to a digital system. The use of lead aprons was popular, while only a minority preferred thyroid shields and rectangular collimators. A fourfold reduction of exposure time from D-speed film to CCD systems was observed. Due to detector size and positioning errors, users of CCD systems take significantly more single-tooth radiographs in total. Considering the number of radiographs per patient, there is only a slight tendency towards more X-rays with CCD systems. Up to image generation, digital systems seem to be as or even more difficult to handle than film-based systems, while their handling was favored after radiographic exposure. Despite a slight increase of radiographs taken with CCD systems, there is a significant dosage reduction. Corresponding to the decrease in exposure time, the patient dose for SPP systems is reduced to one half compared to film. The main issues in CCD technology are positioning errors and the size of the X-ray detectors which are difficult to eliminate. The usage of radiation protection measures still needs to be improved. ► Responsible use of digital intraoral radiology results in a significant dose reduction in everyday practice. ► The ALARA principle is only achieved by strict implementation of dose-reducing methods. ► The efforts to use dose-reducing devices must be increased.

Witnessing the Birth of VLSI Design

I have had several lucky breaks in my career. One of them was the opportunity to be immersed in the emergence of VLSI technology and its associated design methodology. I got my Ph.D. in Experimental Physics from the University of Basel, Switzerland, in 1969. My first job was with Bell Telephone Laboratories in Murray Hill, New Jersey. Because of my thesis, in which I studied the behavior of Interface States in Metal-Oxide-Semiconductor Field-Effect Transistors, I was placed into Lab 225, which was engaged in building solid state imaging devices based on the brand new CCD (Charge-Coupled Device) technology, which had been conceived there a few months earlier. When I arrived, the group with Mike Tompsett and Gil Amelio had just demonstrated a CCD sensor array with 8 by 8 pixels. Since I have been enamored with geometry ever since high-school, I jumped to the opportunity to design the layouts of much larger imaging arrays, first with 128 by 128 pixels, and eventually (in 1973) with two interlaced fields of 256 scan lines, which was compatible with the American broadcast TV format. The latter device was way larger than any other IC chips of that time: It had ¾ of a million MOS electrodes placed in a rectangle measuring ½ inch by 5/8 of an inch (Figure 1).

Image quality of digital direct flat-panel mammography versus an indirect small-field CCD technique using a high-contrast phantom.

Objective. To compare the detection of microcalcifications on mammograms of an anthropomorphic breast phantom acquired by a direct digital flat-panel detector mammography system (FPM) versus a stereotactic breast biopsy system utilizing CCD (charge-coupled device) technology with either a 1024 or 512 acquisition matrix (1024 CCD and 512 CCD). Materials and Methods. Randomly distributed silica beads (diameter 100–1400 μm) and anthropomorphic scatter bodies were applied to 48 transparent films. The test specimens were radiographed on a direct digital FPM and by the indirect 1024 CCD and 512 CCD techniques. Four radiologists rated the monitor-displayed images independently of each other in random order. Results. The rate of correct positive readings for the “number of detectable microcalcifications” for silica beads of 100–199 μm in diameter was 54.2%, 50.0% and 45.8% by FPM, 1024 CCD and 512 CCD, respectively. The inter-rater variability was most pronounced for silica beads of 100–199 μm in diameter. The greatest agreement with the gold standard was observed for beads >400 μm in diameter across all methods. Conclusion. Stereotactic spot images taken by 1024 matrix CCD technique are diagnostically equivalent to direct digital flat-panel mammograms for visualizing simulated microcalcifications >400 μm in diameter.

A Simple Illustrative Model of a Charge-Coupled Device (CCD)

Many students (as well as the general public) use modern technology without an understanding of how these devices actually work. They are what scientists refer to in the laboratory as “black boxes.” Students often wonder how physics relates to the technology used in the real world and are interested in such applications. An example of one such “black box” is the charge-coupled device (CCD), an electronic imaging sensor invented in 1970 by Bell Labs researchers Willard Boyle and George Smith. Astronomers first embraced CCD technology in the early 1980s because CCDs are very light sensitive, consume low amounts of power, and generate digital images quickly. More than three decades later, CCDs have become ubiquitous, as they are found in consumer digital cameras, scanners, photocopiers, medical imaging devices and spectroscopic detectors. This paper presents a model of a CCD “chip” that can be easily adapted as a classroom demonstration.

Response of a delta-doped charge-coupled device to low energy protons and nitrogen ions

We present the results of a study of the response of a delta-doped charge-coupled device (CCD) exposed to ions with energies less than 10keV. The study of ions in the solar wind, the majority having energies in the 1–5keV range, has proven to be vital in understanding the solar atmosphere and the near Earth space environment. Delta-doped CCD technology has essentially removed the dead layer of the silicon detector. Using the delta-doped detector, we are able to detect H+ and N+ ions with energies ranging from 1to10keV in the laboratory. This is a remarkable improvement in the low energy detection threshold over conventional solid-state detectors, such as those used in space sensors, one example being the solar wind ion composition spectrometer (SWICS) on the Advanced Composition Explorer spacecraft, which can only detect ions with energies greater than 30keV because of the solid-state detector’s minimum energy threshold. Because this threshold is much higher than the average energy of the solar wind ions, the SWICS instrument employs a bulky high voltage postacceleration stage that accelerates ions above the 30keV detection threshold. This stage is massive, exposes the instrument to hazardous high voltages, and is therefore problematic both in terms of price and its impact on spacecraft resources. Adaptation of delta-doping technology in future space missions may be successful in reducing the need for heavy postacceleration stages allowing for miniaturization of space-borne ion detectors.

A temperature-controlled complementary metal oxide semiconductor camera

In recent years, complementary metal oxide semiconductor (CMOS) imaging sensors have been replacing charge-coupled device (CCD) imagers in consumer and industrial markets. Their low cost and high peripheral integration on chip gives new opportunities to those who have not adopted CCD technology due to cost or technical concerns. This paper describes the design of a prototype CMOS camera for use in spectral experiments with noise reduction techniques to improve image quality. We use a Peltier device to cool the sensor, a synchronous dynamic random access memory (SDRAM) frame buffer for storage and a universal serial bus (USB) interface to transfer the data at a high speed.

Determination of the resolution of a digital system for panoramic radiography based on CCD technology

Objectives To determine Line Spread Functions (LSFs) and Modulation Transfer Functions (MTFs) for a digital system for panoramic radiography: the Dimax I (Planmeca Oy, Helsinki, Finland) based on Charge-Coupled Device (CCD) technology. Study design A test object was specially designed having a gold foil positioned vertically. Images of the gold foil created edge functions that were used to determine LSFs and MTFs. The design of the test object made it possible to move the gold foil forward and backward relative to the central plane of the image layer by means of a micrometer screw. The experiment was carried out for different object depths in 5 different regions: the anterior, the canine, the premolar, the molar, and the TMJ regions. LSFs and MTFs were calculated using specially designed software. Results The results are presented graphically. LSFs and MTFs for the central plane were essentially the same for all regions. The MTFs for different object depths in the 5 investigated regions exhibited typical characteristics of MTFs for panoramic radiography with the exception for the functions for the molar region. Conclusions The present findings indicate that the resolution of the Dimax I CCD system is comparable to that of film-based panoramic radiography.

Fluorescence-based array biosensors for detection of biohazards.

Total internal reflection fluorescence (TIRF) is a process whereby fluorophores that are either attached to or are in close proximity with the surface of a waveguide are selectively excited via an evanescent wave. Planar waveguides provide the possibility of immobilizing multiple capture biomolecules onto a single surface and therefore, offer the exciting prospect of multi-analyte detection. The production of arrays and the results of various groups which use TIRF to interrogate such surfaces is reviewed, along with a look at how far the field has advanced toward the production of an automated, portable, multi-analyte array biosensor for real-time biohazard detection. In particular, a miniaturized, fully automated, stand-alone array biosensor developed at the Naval Research Laboratory is reported that monitors interactions between binding partners either as the final image or in real-time. A variety of analytes including toxins, bacteria and viruses have been detected both in buffer and complex matrices, such as blood and soil suspensions, with comparable detection limits. A number of developments have led to a TIRF array biosensor weighing only 5.5 kg which is automated for environmental, clinical and food monitoring or for detection of bioterrorist agents.

Design and characterization of a fast cmos multiple linear array imager for nanosecond light pulse detections

Active pixel sensors (APS) technology offers performance competitive with charge-coupled device technology, and it offers advantages in on-chip functionality, system power reduction, cost, and miniaturization. In this paper, we present the design and characterization of a fast CMOS APS imager for high-speed laser detections, which can replace streak cameras. It produces intensity information as a function of one spatial dimension and time (I=f(x,t)) from a pixel array with two spatial dimensions. The time information is obtained for the first prototype camera by delaying successively the integration phase for each pixel of the same row. The different noise sources of the APS sensors, such as shot noise due to the photo sensor, thermal noise, and flicker noise due to the readout transistors, and the photon shot noise are presented in order to determine the fundamental limits of the image sensor. The first prototype fast MOS imager (FAMOSI) consists of 64/spl times/64 active pixels. The simulation and experimental results show that a conversion gain of 6.73/spl plusmn/0.25 /spl mu/ V/e/sup -/ has been obtained with a noise level of 87/spl plusmn/3 e/sup -/ rms. The power consumption of the chip is 25 mW at 50 frames/s. The time resolution is 0.8 ns for this new concept camera.

Optical-based molecular imaging: contrast agents and potential medical applications.

Laser- and sensitive charge-coupled device technology together with advanced mathematical modelling of photon propagation in tissue has prompted the development of novel optical imaging technologies. Fast surface-weighted imaging modalities, such as fluorescence reflectance imaging (FRI) and 3D quantitative fluorescence-mediated tomography have now become available [1, 2]. These technical advances are paralleled by a rapid development of a whole range of new optical contrasting strategies, which are designed to generate molecular contrast within a living organism. The combination of both, technical advances of light detection and the refinement of optical contrast media, finally yields a new spectrum of tools for in vivo molecular diagnostics. Whereas the technical aspects of optical imaging are covered in more detail in a previous review article in "European Radiology" [3], this article focuses on new developments in optical contrasting strategies and design of optical contrast agents for in vivo diagnostics.