CCD Image Sensor Research Articles

Simulation of the Mechanism of Insect Bionic Compound Eye Super-Resolution Restoration Technology of Copper Strip Surface Defect Images

In view of the problem that in traditional copper strip surface defect inspection process, the low resolution of the collected images will greatly decrease the accuracy of the detect defects, through the study of biological bionic imaging technology, combined with insect bionic compound eye imaging technology, this paper proposes a visual simulation insects bionic mechanism of the copper strip surface defect image super-resolution reconstruction technique. Through the study of biological bionic imaging technology, and take the advantage of insect compound eye visual imaging mechanism, this paper uses multiple linear array CCD image sensors to collect images aimed at getting defect images in all perspectives. The actual input images are restored by the method of super-resolution reconstruction using the sample library to improve the resolution of the image. Through the large amount of experiments of different copper strip surface defect images, and then compare the results, it can be seen that taking this papers method to dispose the defect images, will improve the images PSNR value, and has greatly improved the images quality, which will do good to improve the accuracy of the copper strip surface defect detection.

Design on Embedded Driving and Control System for Direct Current Servo Motor

Analyzed working principle of servo control system and applications of direct current (i.e. DC) servo motor in the two-dimensional (i.e. 2D) digital control system, used embedded PC104 processor as the central processing unit, selected DC servo motor whose model was J320LYX04C as azimuth axis motor, and DC servo motor whose model was J215LYX03E as pitch axis motor, constituted the executive body for servo system, and designed a driving and control system which can control the two-dimension turntable rotating precisely in space and lead CCD image sensor to catch and track target. Tests show that the system positioning accuracy meet the given requirements and the system with high reliability runs smoothly in the real application.

Development of Stiffness Measurement Instrument for Precise Elastic Elements in Electro-Hydraulic Servo Valve Based on Charge-Coupled Device

According to stiffness measurement of feedback rod and spring tube in electro-hydraulic servo valve, this paper proposed the measured piece displacement method based on CCD image sensors. On this basis, developing a stiffness measurement instrument based on CCD and giving the overall program design. Because ambient noise affect the image quality seriously, reduce measurement accuracy, image pre-processing is the core of software systems. The system can achieve automatic loading, measure, evaluate and output the result. This article select three types measured piece to experiment and calculation, then, calculate and analysis of experimental data.

Image demosaicing using content and colour-correlation analysis

Most digital cameras of today use a single CCD image sensor with alternating arrangement of red, blue and green colour filters in what is known as a Bayer pattern. To extract a full colour image, a demosaicing strategy has to be applied. In this paper we propose a content adaptive demosaicing strategy utilising structure analysis and correlation between the red, green and blue planes. These two aspects are used for the classification of a block of pixels to generated trained filters. The proposed method aims to reconstruct a high quality demosaiced image from a Bayer pattern in a colour filter array efficiently. Experimental results show that the proposed strategy performs comparatively as more expensive methods.

CMOS Imager With Focal-Plane Analog Image Compression Combining DPCM and VQ

CMOS imagers, in comparison to CCD image sensors, have the great advantage of allowing for the implementation of signal processing circuitry inside the pixel matrix. We can extract information of interest from an image prior to analog-to-digital conversion. In this work, we present a 32 × 32 imaging integrated circuit that captures and compresses gray scale images on the focal plane of the image sensor using analog circuits that implement, for every 4 × 4 pixel block, differential pulse-code modulation, linear transform, and vector quantization. Theoretical details and circuit design are carefully described, as well as the test setup and details of the chip that was fabricated in a 0.35 μm CMOS technology. To validate the technique, we present tests and experimental results including overall modulation transfer function and photographs captured by the chip. The CMOS imager features focal-plane data compression based on DPCM and VQ with bit rate below 0.94 bpp and peak signal-to-noise ratio values around 18 dB. The overall power consumption is 37 mW (white image), which is equivalent to approximately 36 μW per pixel. Using photographs taken from bar-target pattern inputs, it is shown that details up to 2 cycles/cm are preserved in the decoded images.

Network security camera system and its application for consumer electronics in ubiquitous environment

This paper presents a network security camera system and its application to provide visual information to consumer electronics devices in ubiquitous environment. For this system, we developed a network camera processor chip and a network security board. The processor includes a digital camera processor, a motion JPEG encoder, an Ethernet controller and an ARM processor, which serve to enhance the quality of raw images from a CCD image sensor, compress the image data size and transmit the compressed data via Internet. The processor was fabricated with 0.25um CMOS technology. The die area is 60.84 mm2 and the gate count is approximately 1.2 million. The network security board consists of the board driving the network camera processor chip and the CCD image sensor board. To demonstrate the applicability of the network security system to consumer electronics, we applied the proposed system to a vacuum cleaner.

Design and Implementation of a Soft-Measuring System for High-Temperature Field Based on Color CCD Image Sensor

The soft-measuring system consists of an optical lens, a color CCD camera, an image acquisition card, a computer and associated measuring software based on colorimetric temperature measurement. Using the system, the temperature distribution of a high-temperature field can be measured and then displayed on the screen. A method of adjusting the intensity of light is developed to expand the range of the measuring temperature of the system, and the calibration experiments through blackbody furnace are adopted to calibrate the soft-measuring system. The errors of the measurement caused by the non-ideal spectrum response of CCD image sensor are corrected. Multi-spectral segmenting is applied on the image of the high-temperature field, thus various high-temperature noises in the color image can be reduced or even eliminated. The experiment indicates the soft-measuring instrumentation meets the high-temperature detecting requirements of industrial production due to its high accuracy and reliability.

Digging supplementary buried channels: investigating the notch architecture within the CCD pixels on ESA's Gaia satellite

The European Space Agency (ESA) Gaia satellite has 106 CCD image sensors which will suffer from increased charge transfer inefficiency (CTI) as a result of radiation damage. To aid the mitigation at low signal levels, the CCD design includes Supplementary Buried Channels (SBCs, otherwise known as `notches') within each CCD column. We present the largest published sample of Gaia CCD SBC Full Well Capacity (FWC) laboratory measurements and simulations based on 13 devices. We find that Gaia CCDs manufactured post-2004 have SBCs with FWCs in the upper half of each CCD that are systematically smaller by two orders of magnitude (<50 electrons) compared to those manufactured pre-2004 (thousands of electrons). Gaia's faint star (13 < G < 20 mag) astrometric performance predictions by Prod'homme et al. and Holl et al. use pre-2004 SBC FWCs as inputs to their simulations. However, all the CCDs already integrated onto the satellite for the 2013 launch are post-2004. SBC FWC measurements are not available for one of our five post-2004 CCDs but the fact it meets Gaia's image location requirements suggests it has SBC FWCs similar to pre-2004. It is too late to measure the SBC FWCs onboard the satellite and it is not possible to theoretically predict them. Gaia's faint star astrometric performance predictions depend on knowledge of the onboard SBC FWCs but as these are currently unavailable, it is not known how representative of the whole focal plane the current predictions are. Therefore, we suggest Gaia's initial in-orbit calibrations should include measurement of the onboard SBC FWCs. We present a potential method to do this. Faint star astrometric performance predictions based on onboard SBC FWCs at the start of the mission would allow satellite operating conditions or CTI software mitigation to be further optimised to improve the scientific return of Gaia.

The Research of High-Precision Turntable’s Countertop Tilting Dynamic Testing Technology

The dynamic tilting of high-precision turntable has a very significant impact on the parameters of measurement and processing during the operation.In order to achieve long-term stability and control the turntable’s dynamic tilting angle at the second level, only improving the mechanical precision of the turntable is not realistic, and it may greatly enhance the cost of the turntable. A precision turntable dynamic tilting test method based on laser and CCD technology is put forward in this paper. The system uses laser as the light source, and uses CCD image sensor to receive the reflected signal of the turntable. According to the amount movement of the laser spot on the CCD target surface and the corresponding geometric relationships, we can measure the inclination error of the turntable. During debugging analysis and practical application, it proves that the system can achieve differentiate accuracy at the second level and meet the needs of online measurement.

Experiments With Three-Dimensional Integral Imaging Under Low Light Levels

We experimentally demonstrate the possibility of reconstructing 3-D scenes using integral imaging from very photon-starved scenes. It is shown that by using an iterative reconstruction algorithm, it is possible to reconstruct 3-D objects captured with an optical signal just above the CCD image sensors' noise level. Three-dimensional scene reconstruction with integral images with only a few photons per pixel of the image sensor is demonstrated. Optical experimental results are presented.

A novel telecentricity measuring method for illumination system in lithography based on pinhole imaging

A methodology for measuring the telecentricity of illumination system in lithography tool based on the pinhole imaging is proposed. Illumination light goes through the pinhole located on the reticle plane and forms the pupil-fill image in CCD image sensor. Based on the Fresnel diffraction theory, the image intensity of source in CCD photosurface and the optimization of pinhole size are discussed. By simulating, effects of the stability of telecentricity measuring from non-uniformity of light field and pinhole defocus in different illumination patterns are analyzed respectively. Simulation results prove the effectiveness of this new method.

Synchronous phase-demodulation and harmonic rejection of 9-step pixelated dynamic interferograms

We propose a novel synchronous phase-demodulation of pixelated interferograms using squared 3x3 phase-shifted unit-cells. This 3x3 unit-cell is tiled over the CCD image sensor to create a two-dimensional (2D) pixelated carrier. Our synchronous phase-demodulation uses this 2D carrier to demodulate the pixelated interferogram as in the standard 2x2 unit-cell case. The main motivation behind the use of a 3x3 pixelated carrier (instead of the usual 2x2) is its higher harmonic robustness, allowing one to demodulate intensity-distorted fringe patterns. The harmonic rejection robustness of our spatial 3x3 configuration equals the robustness of the temporal least-squares 9-step phase-shifting algorithm (PSA). In other words, extending from the usual 2x2 phase-shifting unit-cell to 3x3 unit-cells, one extends the harmonic rejection of the demodulation algorithm. Finally we also prove that our proposed 9-step, 3x3 pixelated carrier uses the 2D available spectral space more efficiently than using these 9-steps in a linear spatial-carrier configuration.

Optical readout method based on a narrow-strip filter for microcantilever array sensing

An effective optical readout approach based on a narrow-strip filter is presented to detect bends of a bimaterial microcantilever focal plane array, by which light intensity of the image plane (CCD image sensor plane) can be increased and its uniformity on the image plane effectively enhanced. It reduces the noise equivalent temperature difference of the microcantilever focal plane array IR imaging system and improves uniformity of the IR images. A comparative experiment is designed to verify effectiveness. The experimental results show that the proposed method has advantages of preferable effect.

Design and Implementation of a Soft-Measuring System for High-Temperature Field Based on Color CCD Image Sensor

not Available.

Motion Detection: A Biomimetic Vision Sensor Versus a CCD Camera Sensor

We compare a traditional CCD imaging sensor with a biomimetic vision sensor (based on Musca domestica, the common house fly) with regard to detecting small moving objects at various speeds and levels of contrast. The patent-pending biomimetic vision sensor described is shown to be capable of reliable object detection in spite of challenging movement and low contrast conditions in which a typical commercial CCD camera sensor failed to properly detect the object.

Modeling and design of micromachined optical Söller collimators for lensless CCD-based fluorometry

To address the needs of medical diagnostics in resource-poor settings, it is necessary to develop low cost, simple and portable Point of Care detectors for integrated medical diagnostics. Previously, we have described a simple lensless fluorometer with sensitivity in the range of current ELISA plate readers. The key to the lensfree fluorometer is the uniform spatial distribution of light, which we achieved using a simple optical collimator based on a "stack of pinholes" (a stack of black PMMA plates with arrays of pinholes machined via laser) enabling the light to be collimated from the LED light source through the necessary wavelength filters and the assay's microfluidics directly onto the CCD without a lens. In this paper, we describe the optical principle for designing these Söller collimators for lensfree CCD-based fluorometry. The illuminating surface was modeled as a collection of differential areas emitting uniformly and spherically, and the intensity contribution of each emitting area was summed over the detector surface. To compute the final light intensity distribution from such a differential model we derived an integral equation to sum the individual intensity contributions from the two-dimensional emitting surface. The equation is for a single-hole collimator. Light intensity measurements were taken by placing a collimator with a particular aspect ratio (the ratio of hole length to diameter (L/d)) over the CCD image sensor and capturing an image. The resulting image is the 2D light intensity profile generated by the collimator. As the aspect ratio is increased the slope of the light intensity profile increases, corresponding to an increased degree of collimation. To test the model, the measured maximum and mean light intensities were compared with the theoretical predictions generated from the model. There was an agreement between the variation of the mean (R(2) = 0.990) and maximum (R(2) = 0.938) values of light intensities with aspect ratios based modeling. These profile measurements suggest an excellent agreement with the theoretical predictions. The integral equation presented here can be used to perfect the design of the optical Söller collimator. These results may lead to the development of more effective Söller collimators for lensfree CCD-based fluorometry for use in simple low cost lensfree optical detectors with the potential to enhance the accessibility and the quality of health care for underserved populations.

Towards High-Resolution X-Ray Imaging Using a Structured Scintillator

Structured scintillators, by light-guiding secondary emitted visible photons to a pixel in a CCD or CMOS image sensor, improve the lateral resolution of X-ray imaging detectors. In this work we have fabricated pore arrays in a silicon wafer and subsequently filled them with CsI(Tl) by a melting process. The goal was to down-scale the pore geometry for increased resolution. The results show that although pore depth must be reduced to comply with achievable aspect ratio of the Inductively Coupled Plasma (ICP) etching, melting into the pores is possible. The time and temperature has, however, to be optimized to prevent thallium loss during the melting. By correlating light yield measurements with the X-ray absorption in samples of various geometries, we find that the efficiency is slightly reduced for pore diameters approaching one micron. Nevertheless, the increased absorption in deep pores will lead to a significantly improved quantum efficiency compared to thin films currently used to achieve the same lateral resolution.

High-resolution X-ray Imaging Based on Pixel-structured CsI:Tl Scintillating Screens for Indirect X-ray Image Sensors

We introduce the development of pixel-structured screens with a thallium-doped CsI (CsI:Tl) scintillator for indirect digital X-ray imaging sensors. The indirect-conversion detection method based on the pixel-structured CsI:Tl scintillator provides high spatial resolution X-ray imaging without sacrificing the light spread in thick scintillation layers. The scintillation screens were fabricated by using a vacuum deposition process and filling the CsI:Tl scintillating powders into a two-dimensional pixel-structured silicon array. Pixel structures with 100 μm and 50 μm pixel sizes with wall widths of 20 μm and 200 μm thickness were prepared and the fabricated CsI:Tl scintillating powders were filled into the trench of the pixel structure through a vacuum process. The final scintillation screens with 2.5 cm × 2.5 cm size were prepared and directly coupled to a CCD image sensor with an optical lens for performance evaluation of X-ray imaging. The imaging performance of the samples was investigated in terms of the relative light intensity, the X-ray linearity and the spatial resolution under practical X-ray exposure conditions. These preliminary results imply that pixel-structured CsI:Tl scintillating screens show high spatial resolution by less lateral spread of the emitted visible photons within pixel-structured silicon arrays. However, these X-ray detectors still require improved X-ray sensitivity by coating the reflective layer onto an inner silicon wall surface and filling the scintillating power into pixel structures completely.

Image Acquisition of Drivers' Fatigue State Based on Fuzzy Evaluation

The research on monitoring and predicting drivers’ fatigue state has remarkable effect on prevention of traffic accidents, using the CCD image sensor camera as the image acquisition device of driver’s face and the 940nm infrared emitting diode as the light supplementary device and 3-points light supplementary had been utilized, the light supplementary system had been optimized by the experiment of infrared light supplementary which proceeded by means of combining the orthogonal experiment and expert fuzzy evaluation. The research result makes great sense to the monitoring of drivers’ fatigue state and traffic safety

Fluorescence detection by miniaturized instrumentation based on non-cooled CCD minicamera and dedicated for lab-on-a-chip applications

Due to high specificity and sensitivity, fluorometric detection is one of the main detection methods applied in analytical microsystems commonly known as lab-on-a-chip (LOC). In most cases, optical instrumentation for fluorescence induction and detection is based on configuration and components “borrowed” from large laboratory instruments based on an epifluorescence microscope. As a result, the optical instrumentation surrounding lab-on-a-chip is bulky, expensive and dedicated for operation only inside laboratories. In this paper a brief discussion on fluorescence detection in lab-on-a-chip is presented. Next, novel low-cost detection instrumentation utilising noncooled CCD image sensor and semiconductor laser light source is described. The instrumentation is dedicated for operation in portable and low-cost devices for different LOC-based life science applications. Finally, an example of application of the novel method and instrumentation co-working with lab-on-a-chip for real-time PCR detection of food pathogens is briefly described.