Showing papers on "Image sensor published in 2001"

Solid-state time-of-flight range camera

Abstract: The concept of a real-time range camera without moving parts is described, based on the time-of-flight (TOF) principle. It operates with modulated visible and near-infrared radiation, which is detected and demodulated simultaneously by a 2-D array of lock-in pixels employing the charge-coupled device principle. Each pixel individually measures the amplitude, offset and phase of the received radiation. The theoretical resolution limit of this TOF range camera is derived, which depends on the square root of the detected background radiation and the inverse of the modulation amplitude. Actual measurements of 3-D sequences acquired at 10 range images per second show excellent agreement between our theory and the observed results. A range resolution of a few centimeters over a range of 10 m, with an illumination power of a few hundreds of milliwatts is obtained in laboratory scenes for noncooperative, diffusely reflecting objects.

Reduced area imaging device incorporated within wireless endoscopic devices

Abstract: A reduced area imaging device is provided for use in medical or dental instruments such as an endoscope. In a first embodiment of the endoscope, connections between imaging device elements and between a video display is achieved by hard-wired connections. In a second embodiment of the endoscope, wireless transmission is used for communications between imaging device components, and/or for transferring video ready signals to a video display. In one configuration of the imaging device, the image sensor is placed remote from the remaining circuitry. In another configuration, all of the circuitry to include the image sensor is placed in a stacked fashion at the same location. The entire imaging device can be placed at the distal tip of an endoscope. Alternatively, the image sensor can be placed remote from the remaining circuitry according to the first configuration, and control box is used which communicates with the image sensor and is placed remotely from the endoscope. Further alternatively, the imaging device can be incorporated in the housing of a standard medical camera which is adapted for use with traditional rod lens endoscopes. In any of the configurations or arrangements, the image sensor may be placed alone on a first circuit board, or timing and control circuits may be included on the first circuit board containing the image sensor. The timing and control circuits and one or more video processing boards can be placed adjacent the image sensor in a tubular portion of the endoscope, in other areas within the endoscope, in the control box, or in combinations of these location.

CMOS active pixel sensor type imaging system on a chip

Abstract: Single substrate device is formed to have an image acquistition device and a controller. The controller on the substrate controls the system operation.

An image sensor and an endoscope using the same

Abstract: An endoscope (fig. 2, item 40) having restricted dimensions and comprising at least one image gatherer (48), at least one image distorter and at least one image sensor (46) shaped to fit the limited dimensions, and wherein said image distorter (fig. 13, itel 115) is operable to distort an image receiver (fig. 2, item 40) from the image gatherer so that the image is sensible at said shaped image sensor (fig. 2, item 46).

A 10000 frames/s CMOS digital pixel sensor

Abstract: A 352/spl times/288 pixel CMOS image sensor chip with per-pixel single-slope ADC and dynamic memory in a standard digital 0.18-/spl mu/m CMOS process is described. The chip performs "snapshot" image acquisition, parallel 8-bit A/D conversion, and digital readout at continuous rate of 10000 frames/s or 1 Gpixels/s with power consumption of 50 mW. Each pixel consists of a photogate circuit, a three-stage comparator, and an 8-bit 3T dynamic memory comprising a total of 37 transistors in 9.4/spl times/9.4 /spl mu/m with a fill factor of 15%. The photogate quantum efficiency is 13.6%, and the sensor conversion gain is 13.1 /spl mu/V/e/sup -/. At 1000 frames/s, measured integral nonlinearity is 0.22% over a 1-V range, rms temporal noise with digital CDS is 0.15%, and rms FPN with digital CDS is 0.027%. When operated at low frame rates, on-chip power management circuits permit complete powerdown between each frame conversion and readout. The digitized pixel data is read out over a 64-bit (8-pixel) wide bus operating at 167 MHz, i.e., over 1.33 GB/s. The chip is suitable for general high-speed imaging applications as well as for the implementation of several still and standard video rate applications that benefit from high-speed capture, such as dynamic range enhancement, motion estimation and compensation, and image stabilization.

Data input device

Abstract: A data input device and method including an illuminator operative to illuminate at least one engagement plane by directing light along the at least one engagement plane, a two-dimensional imaging sensor viewing the at least one engagement plane from a location outside the at least one engagement plane for sensing light from the illuminator scattered by engagement of a data entry object with the at least one engagement plane and data entry processor receiving an output from the two-dimensional imaging sensor and providing a data entry input to utilization circuitry.

A device for in vivo imaging

Abstract: The present invention provides a system and method for obtaining in vivo images. The system contains an imaging system and an ultra low power radio frequency transmitter for transmitting signals from the CMOS imaging camera to a receiving system located outside a patient. The imaging system includes at least one CMOS imaging camera, at least one illumination source for illuminating an in vivo site and an optical system for imaging the in vivo site onto the CMOS imaging camera.

Plastic lens system for vehicle imaging system

Abstract: An optical or lens system for use with an imaging system of a vehicle includes a plurality of optical elements. The optical elements include less than five optical elements and, preferably, include four optical elements. Each of the optical elements is formed of a plastic material. At least two of the optical elements include a diffractive element. Preferably, a diffractive element is formed on an outer surface of two of the optical elements. The optical system provides and focuses a field of view of a targeted area of at least approximately 100 degrees to an imaging plane. The imaging plane is at an imaging sensor or camera or other imaging device operable to receive the image from the optical system. The optical system further includes an aperture stop between two of the optical elements.

Image reconstruction and enhanced resolution imaging from irregular samples

Abstract: While high resolution, regularly gridded observations are generally preferred in remote sensing, actual observations are often not evenly sampled and have lower-than-desired resolution. Hence, there is an interest in resolution enhancement and image reconstruction. This paper discusses a general theory and techniques for image reconstruction and creating enhanced resolution images from irregularly sampled data. Using irregular sampling theory, we consider how the frequency content in aperture function-attenuated sidelobes can be recovered from oversampled data using reconstruction techniques, thus taking advantage of the high frequency content of measurements made with nonideal aperture filters. We show that with minor modification, the algebraic reconstruction technique (ART) is functionally equivalent to Grochenig's (1992) irregular sampling reconstruction algorithm. Using simple Monte Carlo simulations, we compare and contrast the performance of additive ART, multiplicative ART, and the scatterometer image reconstruction (SIR) (a derivative of multiplicative ART) algorithms with and without noise. The reconstruction theory and techniques have applications with a variety of sensors and can enable enhanced resolution image production from many nonimaging sensors. The technique is illustrated with ERS-2 and SeaWinds scatterometer data.

Fusion of vision and gyro tracking for robust augmented reality registration

Abstract: A novel framework enables accurate augmented reality (AR) registration with integrated inertial gyroscope and vision tracking technologies. The framework includes a two-channel complementary motion filter that combines the low-frequency stability of vision sensors with the high-frequency tracking of gyroscope sensors, hence achieving stable static and dynamic six-degree-of-freedom pose tracking. Our implementation uses an extended Kalman filter (EKF). Quantitative analysis and experimental results show that the fusion method achieves dramatic improvements in tracking stability and robustness over either sensor alone. We also demonstrate a new fiducial design and detection system in our example AR annotation systems that illustrate the behavior and benefits of the new tracking method.

A generalized approach to parallel magnetic resonance imaging.

Abstract: Parallel magnetic resonance (MR) imaging uses spatial encoding from multiple radiofrequency detector coils to supplement the encoding supplied by magnetic field gradients, and thereby to accelerate MR image acquisitions beyond previous limits. A generalized formulation for parallel MR imaging is derived, demonstrating the relationship between existing techniques such as SMASH and SENSE, and suggesting new algorithms with improved performance. Hybrid approaches combining features of both SMASH-like and SENSE-like image reconstructions are constructed, and numerical conditioning techniques are described which can improve the practical robustness of parallel image reconstructions. Incorporation of numerical conditioning directly into parallel reconstructions using the generalized approach also removes a cumbersome and potentially error-prone sensitivity calibration step involving division of two distinct in vivo reference images. Hybrid approaches in combination with numerical conditioning are shown to extend the range of accelerations over which high-quality parallel images may be obtained.

Methods for identification of images acquired with digital cameras

Abstract: From the court we were asked whether it is possible to determine if an image has been made with a specific digital camera. This question has to be answered in child pornography cases, where evidence is needed that a certain picture has been made with a specific camera. We have looked into different methods of examining the cameras to determine if a specific image has been made with a camera: defects in CCDs, file formats that are used, noise introduced by the pixel arrays and watermarking in images used by the camera manufacturer.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Dosimetric investigation and portal dose image prediction using an amorphous silicon electronic portal imaging device.

Abstract: A two step algorithm to predict portal dose images in arbitrary detector systems has been developed recently. The current work provides a validation of this algorithm on a clinically available, amorphous silicon flat panel imager. The high-atomic number, indirect amorphous silicon detector incorporates a gadolinium oxysulfide phosphor scintillating screen to convert deposited radiation energy to optical photons which form the portal image. A water equivalent solid slab phantom and an anthropomorphic phantom were examined at beam energies of 6 and 18 MV and over a range of air gaps (approximately 20-50 cm). In the many examples presented here, portal dose images in the phosphor were predicted to within 5% in low-dose gradient regions, and to within 5 mm (isodose line shift) in high-dose gradient regions. Other basic dosimetric characteristics of the amorphous silicon detector were investigated, such as linearity with dose rate (+/- 0.5%), repeatability (+/- 2%), and response with variations in gantry rotation and source to detector distance. The latter investigation revealed a significant contribution to the image from optical photon spread in the phosphor layer of the detector. This phenomenon is generally known as "glare," and has been characterized and modeled here as a radially symmetric blurring kernel. This kernel is applied to the calculated dose images as a convolution, and is successfully demonstrated to account for the optical photon spread. This work demonstrates the flexibility and accuracy of the two step algorithm for a high-atomic number detector. The algorithm may be applied to improve performance of dosimetric treatment verification applications, such as direct image comparison, backprojected patient dose calculation, and scatter correction in megavoltage computed tomography. The algorithm allows for dosimetric applications of the new, flat panel portal imager technology in the indirect configuration, taking advantage of a greater than tenfold increase in detector sensitivity over a direct configuration.

Hand-held computers incorporating reduced area imaging devices

Abstract: A reduced area imaging device is provided for use with a miniature hand-held computer referred to in the industry as a PDA. In one configuration of the imaging device, the image sensor is placed remote from the remaining image processing circuitry. In a second configuration, all of the image processing circuitry to include the image sensor is placed in a stacked fashion near the same location. In the first configuration, the entire imaging device can be placed at the distal end of a camera module. In a second configuration, the image sensor is remote from the remaining image processing circuitry wherein available space within the PDA is used to house the remaining circuitry. In any of the embodiments, the image sensor may be placed alone on a first circuit board, or timing and control circuits may be included on the first circuit board containing the image sensor. One or more video processing boards can be stacked in a longitudinal fashion with respect to the first board, or the video processing boards may be placed within the housing of the communication device. The PDA includes a miniature LCD-type video view screen which is capable of viewing not only the images taken by the camera module, but also can show incoming video images received from a personal computer connected to a global communications network. The camera module is of such small size that it can be easily stored within the housing of the PDA, and may be attached thereto as by a small retractable cable.

Compact fluorescence endoscopy video system

Abstract: A fluorescence endoscopy video system includes a multimode light source that produces light for color and fluorescence imaging modes. Light from the light source is transmitted through an endoscope to the tissue under observation. The system also includes a compact camera for color and fluorescence imaging. Images obtained through the endoscope are optically divided and projected onto one or more image sensors by a fixed beam splitter in the camera. The fixed beam splitter eliminates the need for inserting a movable mirror into the light path between the endoscope and the image sensors. Image signals from the camera are processed in the system processor/controller where a contrast enhancement function can be applied. The contrast enhancement function increases the color contrast between normal tissue and tissue suspicious for early cancer. Finally, the system also includes a calibration feature whereby the system performance can be maintained when used with different endoscopes.

Autodiscrimination and line drawing techniques for code readers

Abstract: The disclosure relates to optical image readers having a two-dimensional image sensor and an auto-discrimination function. The auto-discrimination function identifies optical codes by type for pixel clusters and, in some cases, tilt angle and start/stop coordinates. The clustered pixel data is passed to an appropriate decoder identified by the auto-discrimination function based upon a likelihood that the cluster contains an optical code of a particular type. Line drawing techniques provide for adequate sampling of the clustered pixel data code based on the tilt angle of the code relative to a image sensor array.

Image sensor mounting system

Abstract: According to the invention, a multilayered image sensor is back mounted to a plate, and the plate in turn, is installed in a holding pocket of a device. In that the scheme takes advantage of a high controllability of a mounting plate's thickness, the mounting scheme provides a tight control of holding forces with which an image sensor is secured in an imaging device. In that the scheme provides for back mounting of image sensor on a planar surface, the mounting system provides tight control of an imaging assembly's pixel plane to fixed point in space distance.

Swiped aperture capacitive fingerprint sensing systems and methods

Abstract: A fingerprint sensing system includes an image sensor, a rate sensor and a sensor circuit. The image sensor includes a linear array of capacitive sensors for capacitive sensing of ridge peaks and ridge valleys of a fingerprint on a swiped finger. The rate sensor senses the speed of the finger as it is swiped across the image sensor. The sensor circuit supplies image drive signals to the image sensor and detects image signals in response to the drive signals. The sensor circuit supplies rate drive signals to the rate sensor and detects rate signals in response to the rate drive signals. The sensor circuit further coordinates the image signals and the rate signals to provide a fingerprint image. The image sensor may be configured as an image pickup plate and multiple image drive plates formed on a substrate, such as a flexible printed circuit board or other flexible substrate which may conform to the shape of the finger.

Reduced area imaging devices utilizing selected charge integration periods

Abstract: A reduced area imaging device is provided for use in a wide variety of devices including medical or dental instruments such as an endoscope. In one configuration of the imaging device, the image sensor is placed remote from the remaining circuitry. In another configuration, all of the circuitry to include the image sensor is placed in a stacked fashion at the same location. In a first embodiment of the invention, the entire imaging device can be placed at the distal tip of an endoscope. In a second embodiment, the image sensor is remote from the remaining circuitry according to the first configuration, and wherein a control box can be provided which communicates with the image sensor and is placed remotely from the endoscope. In another embodiment, the imaging device can be incorporated in the housing of a standard medical camera which is adapted for use with traditional rod lens endoscopes. In yet another embodiment, the imaging device can be wholly incorporated within the endoscope by placing the image sensor and timing and control circuitry within the distal tip of the endoscope, and placing the remaining processing circuitry within the handle of the endoscope. In any of the embodiments, the image sensor may be placed alone on a first circuit board, or timing and control circuits may be included on the first circuit board containing the image sensor. One or more video processing boards can be stacked in a longitudinal fashion with respect to the first board, or the video processing boards may be placed in the control box or in the handle of the endoscope. The imaging device may be further enhanced by including charge integration capability. Accordingly, the imaging device can be defined as a CMOS-CID device wherein a user may select an appropriate integration period in order to enhance the viewed image to a desired level of brightness. Particularly in fluorescence guided endoscopy and fluorescence assisted surgery, the ability to vary and select particular charge integration periods improves these processes.

Image capture and processing accessory

Abstract: An imager for capturing and processing images for a variety of applications which may be connected to a transceiver such as a cell phone, a personal digital assistant or an internet appliance for transmitting the images over a limited bandwidth network, is described. The imaging applications include bar code and photograph still images, and permanent video and video phone motion images. The imager may be self-contained providing the image signal to be transmitted by the transceiver, or the imager and the transceiver may be combined into a single integrated unit. The imager comprises a high resolution CMOS image sensor, a processor for controlling the image sensor and for processing image data from the image sensor, and an interface for providing commands to the processor and for viewing displays generated by the processor. The method of processing the images includes the steps of determining the bandwidth of the network, selecting an imaging application, determining the image format required, acquiring image data in the image sensor, processing the image data into the format required, and transferring the data for transmission over the network.

Integrated ic chip package for electronic image sensor die

Abstract: An IC chip package for an image sensitive, integrated circuit semiconductor die incorporates all the components typically found in an imaging module of an electronic camera. The IC chip package (80) consists of a plastic substrate base (83) for holding an image sensor die and a separate, plastic upper cover (81) for encapsulating the image sensor die and holding a filter glass (87), an optical lens (89), and providing an aperture for the optical lens. The upper cover (81) has a lower shelf (109) for holding the optical lens (89) in alignment with the aperture opening over the image sensor die, and has an upper shelf (107) for holding the filter glass (87) over the optical lens (89). The lens is attached to the lower shelf using UV cure adhesive, and its focal distance to the image sensor die is determined by first electrically activating the image sensor die, adjusting the lens position to identify the optimal focus sharpness, and then applying UV light to activate the UV cure adhesive and hold the lens in focus.

Vehicle headlight control using imaging sensor identifying objects by geometric configuration

Abstract: A headlamp control system for a motor vehicle includes an imaging array sensor operable to sense light in a field of view forward of the motor vehicle and a control that is responsive to the imaging array sensor. The control is operable to identify at least one object of interest in the field of view by a spectral signature and/or a geometric organization of the object. The control is operable to control a headlamp of the motor vehicle in response to identifying the object as being at least one of a headlamp of another vehicle, a taillight of another vehicle, a traffic sign, a lane marker and a traffic light. The control may be operable to identify a headlamp and/or taillight of another vehicle in response to light sensed by the imaging array sensor during different exposure periods of the imaging array sensor.

A self-calibrating single-chip CMOS camera with logarithmic response

Abstract: A high-dynamic-range CMOS image sensor consisting of nonintegrating, continuously working photoreceptors with logarithmic response is presented. The nonuniformity problem caused by the device-to-device variations is greatly reduced by an implemented analog self-calibration. After performing this calibration, the remaining fixed pattern noise amounts to 3.8% (RMS) of an intensity decade at a uniform illumination of 1 W/m/sup 2/. The sensor provides a resolution of 384/spl times/288 pixels and a dynamic range of 6 decades in the intensity region from 3 mW/m/sup 2/ to 3 kW/m/sup 2/. It contains all components required for operating as a camera-on-a-chip. The image data can be read out either via a single analog line (video standard) or via a digital interface after undergoing an analog-to-digital conversion on the chip. Additional features like automatic exposure control, averaging of adjacent pixels, and digital zoom have been implemented, making the sensor suitable for a wide field of applications.

Stacked package structure of image sensor

Abstract: A stacked package structure of an image sensor for electrically connecting to a printed circuit board includes a first substrate, a second substrate, an integrated circuit, an image sensing chip, and a transparent layer. The second substrate is mounted on the first substrate so as to a cavity formed between the first substrate and second substrate. The integrated circuit is located within the cavity and electrically connected the first substrate. The image-sensing chip is arranged on the second substrate. The transparent layer covers over the image sensing chip, wherein the image sensing chip receives image signals via the transparent layer and transforms the image signals into electrical signals transmitted to the first substrate. Thus, the image sensing chip of the image sensing product and the integrated circuit can be integrally package.

Combined display-camera for an image processing system

Abstract: An image processing system includes a combined display-camera having an array of interspersed display elements and camera elements, arranged substantially in a common plane of a flat panel or other display. Each of at least a subset of the camera elements has one or more imaging angles associated therewith, with the one or more imaging angles being selected to provide a desired imaging operation for the combined display-camera. The imaging angles of the camera elements can be selected to provide an imaging operation which approximates that of a lens-based single-camera system, a pin-hole camera system or other type of system. Each of the camera elements may include multiple image sensors, such that different imaging angles can be set for the different image sensors of a given camera element, and different perspectives of a scene can be generated in the image processing system.

Micro-size led and detector arrays for minidisplay hyper-bright light emitting diodes, lighting, and uv detector and imaging sensor applications

Abstract: A micro-size LED-like optical element has an n-contact, a p-contact, and an optical active structure connected between the n-contact and the p-contact for generating light when forward biased and for detecting light when reverse biased. The optical active structure has a diameter of about 20 νm or smaller. When the optical active structure is forward biased, if forms a micro-size LED (νLED). When the optical active structure is reverse biased, it forms a micro-size detector (νdetector). An array of the micro-size optical active structures may be used as a minidisplay, a detector, or a sensor (when each structure is separately wired), or as a hyperbright LED (when the structures are wired to turn on and off simultaneously). Alternatively, a hyperbright LED may be obtained by forming a plurality of micro-size holes extending into an LED wafer.

A 10,000 Frames/s 0.18 μm CMOS Digital Pixel Sensor with Pixel-Level Memory

Abstract: In a Digital Pixel Sensor (DPS), each pixel has an ADC, all ADCs operate in parallel, and digital data is directly read out of the image sensor array as in a conventional digital memory [1]. The DPS architecture offers several advantages over analog image sensors including better scaling with CMOS technology due to reduced analog circuit performance demands and the elimination of column fixed-pattern noise and column readout noise. With an ADC per pixel, massively parallel conversion and high-speed digital readout become possible, completely eliminating analog readout bottlenecks. This benefits traditional high speed imaging applications and enables new imaging enhancement capabilities such as multiple sampling for increasing sensor dynamic range [2]. Achieving acceptable pixel sizes using DPS, however, requires the use of a 0.18 μm or below CMOS process, which is challenging due to reduced supply voltages and increased leakage currents [3].

Impactron-a new solid state image intensifier

Abstract: This paper describes the theory of operation and up to date achieved performance of a new image sensor concept that is using Impact Ionization to multiply photo-generated charge before sensing. It is shown that the charge multiplication based on a single carrier impact ionization is almost noiseless. This allows detected signal charge to be amplified directly in the charge domain and be always kept above the charge detector amplifier noise floor. Charge is repeatedly transferred in a CCD fashion through high field regions where the impact ionization occurs. Even though the impact ionization has a low probability and the high field regions are short the number of transfers is large and significant charge gains are obtained. The developed charge multiplication structure can be easily incorporated into pixels of any standard CCD image sensor and included in the image sensing area, the memory area, or any other vertical or horizontal CCD register with a minimum area penalty. This feature thus provides high flexibility in designing new sensors with various performance characteristics suitable for an extreme low light level imaging. The paper describes in detail the theory of charge multiplication and excess noise generation that is supported by the measured data obtained form the test image sensors. The measurement methods that are used to characterize the charge multiplication gain and noise are also described in detail.

Dual ported memory for digital image sensor

Abstract: An image sensor architecture that accommodates the relative mismatch of bus width between the image sensor, processor, and memory is disclosed. The preferred embodiment of the invention provides a dual-ported memory structure having a relatively wide data port for receiving data from the image sensor and having a relatively narrow data port for communicating data to and from the processor. In one embodiment of the invention, the memory is organized into banks of a specific width. The banks may be accessed sequentially by the processor, such that the bus width is equivalent to the bank width, and the banks may be accessed simultaneously, such that the bus width is equivalent to the combined bank widths. A simple switching means, operating under processor control, reconfigures the memory on the fly.

Method to reduce reset noise in photodiode based CMOS image sensors

Abstract: A method for controlling a sensor to reduce reset noise is disclosed. The method including the steps of providing a reset command including a RESET signal and a first SAMPLE signal. The method also includes the steps of providing a read command including a first ADDRESS signal, a second SAMPLE signal, and a second ADDRESS signal. An apparatus including a system controller and a sensor controlled by the system controller is also disclosed. In one embodiment, the method and apparatus is provided for a sensor in a sensor array that is read-out in a pipelined fashion.