Showing papers on "Image sensor published in 1993"

Enhanced image capture through fusion

Abstract: The authors present an extension to the pyramid approach to image fusion. The modifications address problems that were encountered with past implementations of pyramid-based fusion. In particular, the modifications provide greater shift invariance and immunity to video noise, and provide at least a partial solution to the problem of combining components that have roughly equal salience but opposite contrasts. The fusion algorithm was found to perform well for a range of tasks without requiring adjustment of the algorithm parameters. Results were remarkably insensitive to changes in these parameters, suggesting that the procedure is both robust and generic. A composite imaging technique is outlined that may provide a powerful tool for image capture. By fusing a set of images obtained under restricted, narrowband, imaging conditions, it is often possible to construct an image that has enhanced information content when compared to a single image obtained directly with a broadband sensor. >

Active Pixel Sensors: Are CCD's Dinosaurs?

Abstract: Charge-coupled devices (CCDs) are presently the technology of choice for most imaging applications. In the 23 years since their invention in 1970, they have evolved to a sophisticated level of performance. However, as with all technologies, we can be certain that they will be supplanted someday. In this paper, the Active Pixel Sensor (APS) technology is explored as a possible successor to the CCD. An active pixel is defined as a detector array technology that has at least one active transistor within the pixel unit cell. The APS eliminates the need for nearly perfect charge transfer--the Achilles' heel of CCDs. This perfect charge transfer makes CCD's radiation 'soft,' difficult to use under low light conditions, difficult to manufacture in large array sizes, difficult to integrate with on-chip electronics, difficult to use at low temperatures, difficult to use at high frame rates, and difficult to manufacture in non-silicon materials that extend wavelength response. With the active pixel, the signal is driven from the pixel over metallic wires rather than being physically transported in the semiconductor. This paper makes a case for the development of APS technology. The state of the art is reviewed and the application of APS technology to future space-based scientific sensor systems is addressed.

Digital micro-mirror based image simulation system

Abstract: An image simulation system 20 for testing sensor systems 26 and for training image sensor personnel wherein synthetic image data is generated by a scene generator 21 and projected by an image projector 23. The image projector 23 uses a digital micromirror device array 27 to modulate the incident energy and create an image. Four modulation schemes are discussed including digital pulse-width modulation, phase contrast modulation, full complex modulation, and analog modulation. The digital pulse width modulation technique will typically require synchronizing the image sensor and the image projector. Phase contrast modulation, full complex modulation, and analog modulation do not require synchronizing the image projector 23 and the sensor system 26. Phase contrast modulation and full complex modulation have the capability to produce phase information within the image. The image simulation system 20 can produce high contrast images and is more flexible than prior art system.

Image recovery from data acquired with a charge-coupled-device camera

Abstract: A model for data acquired with the use of a charge-coupled-device camera is given and is then used for developing a new iterative method for restoring intensities of objects observed with such a camera. The model includes the effects of point spread, photoconversion noise, readout noise, nonuniform flat-field response, nonuniform spectral response, and extraneous charge carriers resulting from bias, dark current, and both internal and external background radiation. An iterative algorithm is identified that produces a sequence of estimates converging toward a constrained maximum-likelihood estimate of the intensity distribution of an imaged object. An example is given for restoring images from data acquired with the use of the Hubble Space Telescope.

An obstacle detecting device for a vehicle

Abstract: An obstacle detecting device for a vehicle comprises a pair of image sensors for taking an image of an object surrounding a vehicle, a display image plane for displaying an image data taken by said pair of image sensors as an image, and a plurality of windows designating regions of said image on said display image plane. The device further comprises an optical obstacle detecting device for detecting distances from said vehicle to said object in said regions of the image designated by said plurality of windows for the respective windows to thereby detect an obstacle, a laser radar device mounted on the vehicle for radiating a radar beam to the object surrounding the vehicle to thereby detect said obstacle, and an obstacle selecting device for selecting either the obstacle detected by said optical obstacle detecting device or the obstacle detected by said laser radar device mounted on the vehicle.

Focal plane imaging systems for millimeter wavelengths

Abstract: The authors discuss critical aspects of imaging system design and describe several different imaging systems employing focal plane array receivers operating in the 3-mm-2-mm wavelength range. Recent progress in millimeter-wavelength optics, antennas, receivers and other components permits greatly enhanced system performance in a wide range of applications. A radiometric camera for all-weather autonomous aircraft landing capability and a high sensitivity cryogenically cooled array for use in radio astronomical spectroscopy are presented. A near-focus system for identification of plastic materials concealed underneath clothing employs a two element lens, and has been demonstrated in active (transmitting) and passive (radiometric) modes. A dual-mode imaging system for plasma diagnostics utilizes both active and passive modes at its approximately=140-GHz operating frequency to study small-scale structure. The radiometric imaging systems employ between 15 and 256 Schottky barrier diode mixers, while the imaging receivers for the active systems include 64-element video detector arrays. >

Linear theory of nonuniformity correction in infrared staring sensors

Abstract: Correction of photoresponse nonuniformity in IR staring sensors is investigated. Spatial noise expressions for uncorrected, one-point corrected, and two-point corrected imaging are developed. These theoretical results take into account the properties of the IR source, sensor constants, and spatial variations in the IR imaging device. To demonstrate the application of these results, both theoretical and actual spatial noise curves for a platinum silicide IR sensor are presented.

Apparatus and method for adaptively interpolating a full color image utilizing luminance gradients

Abstract: Adaptive interpolation is performed by apparatus operating upon a digitized image signal obtained from an image sensor having color photosites that generate a plurality of color values, but only one color per photosite. A digital processor obtains gradient values from the differences between luminance values in vertical and horizontal image directions. The gradient values are compared to a programmable threshold in order to select one of the directions as the preferred orientation for the interpolation of additional luminance values. The interpolation is then performed upon values selected to agree with the preferred orientation.

Electronic camera with memory card interface to a computer

Abstract: An electronic camera (20) operates with a small, portable computer (10) having a card interface (12, 22) of the type used for communicating with a removable memory card. The camera includes an image sensor for converting an image into an electrical signal, an A/D converter for converting the electrical signal into a digital signal, and a signal processor for interfacing the digital signal to the card interface (22), ordinarily a slot (16) receptacle, on the computer. By defining the interface to include a mechanical extender (24) that physically interconnects the camera to the card slot (16) on the computer, the camera and computer are linked in a high speed interface as a convenient, hand-held unit.

Computer input system and method of using same

Abstract: A computer input system for a computer generating images appearing on a screen. For the purpose of modifying the images appearing on the screen, a light generating device causes an auxiliary light image to appear on the screen. An image sensor responds to the auxiliary image, and a circuit responds to the sensor for causing auxiliary image information to be stored concerning the auxiliary light image. Another circuit responds to the stored auxiliary image information to supply the auxiliary light image information to the computer for utilization therein.

A 128/spl times/128 CMOS active pixel image sensor for highly integrated imaging systems

Abstract: A new CMOS-based image sensor that is intrinsically compatible with on-chip CMOS circuitry is reported. The new CMOS active pixel image sensor achieves low noise, high sensitivity, X-Y addressability, and has simple timing requirements. The image sensor was fabricated using a 2 /spl mu/m p-well CMOS process, and consists of a 128/spl times/128 array of 40 /spl mu/m/spl times/40 /spl mu/m pixels. The CMOS image sensor technology enables highly integrated smart image sensors, and makes the design, incorporation and fabrication of such sensors widely accessible to the integrated circuit community. >

Electronic still camera with improved picture resolution by image shifting in a parallelogram arrangement

Abstract: An electronic still camera comprises a solid state image sensor for outputting a color picture signal corresponding an incident optical image, a signal processor for signal-processing the color picture signal from the solid state image sensor to produce a color still picture signal, a recorder for recording the color still picture signal produced by the signal processor, and a driver for moving at least one of the optical image and the solid state image sensor from an original position in a horizontal direction by a pixel pitch and in an oblique axial direction defined by horizontal and vertical lines extending respectively from the original position in the horizontal and vertical directions by half the pixel pitch.

Contact type image sensor, producing method of the same, and information processing apparatus

Abstract: A contact type image sensor, which includes a transparent member which can contact an original to be read, a light source for radiating light onto the original via the transparent member, a sensor for receiving light reflected by the original, an imaging element for imaging the reflected light on a light-receiving portion of the sensor, and a support unit for supporting the sensor, the imaging element, the transparent member, and the light source. The imaging element and the light source are supported by the transparent member and the support unit.

Cordless image scanner

Abstract: An image scanner comprises an image sensor for inputting image data, a rotary encoder, LED and read out window for reading image data, a buffer D RAM, ROM and S RAM for storing image data, a LCD display for displaying input image data, a power source for supplying electrical power, and a memory card for communicating stored image data to a host, wherein the above elements are formed as a cordless, card-shaped unit.

A programmable artificial retina

Abstract: An artificial retina is a device that intimately associates an imager with processing facilities on a monolithic circuit. Yet, except for simple environments and applications, analog hardware will not suffice to process and compact the raw image flow from the photosensitive array. To solve this output problem, an on-chip array of bare Boolean processors with halftoning facilities is proposed, with versatility provided by programmability. For a pixel memory size of 3 b, the authors demonstrate both the technological practicality and the computational efficiency of this programmable Boolean retina concept. Using semistatic shifting structures together with some interaction circuitry, a minimal retina Boolean processor can be built with less than 30 transistors and controlled by as few as six global clock signals. The successful design, integration, and test of a 65*76 Boolean retina on a 50-mm/sup 2/ CMOS 2- mu m circuit are described. >

A 128 x 128 CMOS Active Pixel Image Sensor for Highly Integrated Imaging Systems

Abstract: A new CMOS-based image sensor that is intrinsically compatible with on-chip CMOS circuitry is reported. The new CMOS active pixel image sensor achieves low noise, high sensitivity, X-Y addressability, and has simple timing requirements. The image sensor was fabricated using a 2 micrometer p-well CMOS process, and consists of a 128 x 128 array of 40 micrometer x 40 micrometer pixels. The CMOS image sensor technology enables highly integrated smart image sensors, and makes the design, incorporation and fabrication of such sensors widely accessible to the integrated circuit community.

Image sensing and processing by a bacteriorhodopsin-based artificial photoreceptor

Abstract: Sensing and processing of optical information have been conducted with a unique bioelectronic image sensor that immobilizes bacteriorhodopsin (bR) as a photosensitive retinal protein. A thin film of bR-containing purple membranes was coated on a two-dimensional pixel array of electrodes and was made into a junction with an electrolyte gel layer having a counterelectrode to form an-artificial photoreceptor. Photocurrent signals from each pixel showed a differential responsivity to light intensity, intrinsic to this liquid-junction photocell. Images detected and processed by the bR-based artificial photoreceptor were simultaneously displayed on a light-emitting-diode monitor panel through parallel signal-transmission circuitry. The experiment revealed that the photoreceptor is, as a retina model, capable of selectively detecting motion of images in real time and of performing vectorial extraction of their edge components, similar to the visual processing function of biological photoreceptors.

Charge multiplying detector (CMD) suitable for small pixel CCD image sensors

Abstract: Generally, and in one form of the invention, a method for multiplying charge in a CCD cell is disclosed comprising the step of causing impact ionization of charge carriers in the CCD cell. Other devices, systems and methods are also disclosed.

Micro non-imaging light concentrators for image sensors with a lenslet array

Abstract: An array of micro-sized converging light transmissive channels is positioned between a lenslet array and an array of pixel detectors. The result is that the detectors are substantially smaller than upper portions of the channels and non-optical components may be positioned between the detectors. The side walls of the channels are reflective and have a hyperbolic or parabolic shape to maximize the acceptance angle of rays entering the device for maximum efficiency. A method of producing the channels employing a micro-sized machine bit is also disclosed.

High-performance infrared thermal imaging with monolithic silicon focal planes operating at room temperature

Abstract: This paper describes the nature, operating principles and status of Honeywell's room-temperature infrared imaging focal planes >

Video imaging system with image processing optimized for small-diameter endoscopes

Abstract: An output video signal is derived from an input video signal generated by an image sensor in response to an image formed on only part of the image sensor. The output video signal is derived in response to only the portion of the input video signal generated by the part of the image sensor on which the image is formed. The input video signal additionally includes a portion generated by the part of the image sensor on which the image is not formed. An image signal generating apparatus is provided in which the image sensor is mounted, and which includes a detachably-attached image-forming device. When attached to the image signal generating apparatus, the image-forming device forms the image on the part of the image sensor. A frame of the input video signal is received from the image sensor. The frame of the input video signal has a structure and includes an image portion generated by the part of the image sensor on which the image is formed, and an external portion generated by the part of the image sensor on which the image is not formed. The image portion of the frame of the input video signal is identified, and the identified image portion is extracted from the frame of the input video signal to provide the image portion of a frame of the output signal which has a frame structure substantially similar to the frame structure of the input video signal.

Precision tracking with segmentation for imaging sensors

Abstract: Precision target tracking based on data obtained from imaging sensors when the target is not fully visible during tracking is addressed. The image is divided into several layers of gray level intensities and thresholded. A binary image is obtained and grouped into clusters using image segmentation. The association of the various clusters to the track to be estimated relies on both the motion and pattern recognition characteristics of the target. The centroid measurements of the clusters and the probabilistic data association filter (PDAF) are employed for state estimation. Expressions for the single-frame-based centroid measurement noise variance of the target cluster and the optimal parameters for cluster segmentation are given. Simulation results validate the expressions for the measurement noise variance as well as the performance predictions of the tracking method. For a dim synthetic target with strong background noise, subpixel accuracy in the range of 0.3-0.4 pixel RMS error with moderate

Design of a low-light-level image sensor with on-chip sigma-delta analog-to-digital conversion

Abstract: The design and projected performance of a low-light-level active-pixel-sensor (APS) chip with semi-parallel analog-to-digital (A/D) conversion is presented. The individual elements have been fabricated and tested using MOSIS* 2 micrometer CMOS technology, although the integrated system has not yet been fabricated. The imager consists of a 128 x 128 array of active pixels at a 50 micrometer pitch. Each column of pixels shares a 10-bit A/D converter based on first-order oversampled sigma-delta (Sigma-Delta) modulation. The 10-bit outputs of each converter are multiplexed and read out through a single set of outputs. A semi-parallel architecture is chosen to achieve 30 frames/second operation even at low light levels. The sensor is designed for less than 12 e^- rms noise performance.

Inter-vehicle distance detecting device

Abstract: An inter-vehicle distance detecting device comprising: a pair of image sensors on which an image of an object in front of a driving car is formed by a pair of optical systems; an image display means for displaying a first image information taken by one of the pair of image sensors; a window setting means for setting a plurality of windows partitioning a region of the image on the first image information; a distance detecting means for calculating respective distances from the driving car to the object surrounded by the respective windows by comparing a second image information in the respective windows set by the window setting means with a third image information taken by the other of the pair of image sensors corresponding to the second image information and by detecting a shift between the second image information and the third image information; a determining means for determining the object for measurement based on the distances to the respective windows provided by the distance detecting means; a gate setting means for setting a gate partitioning the region such that the gate approximately surrounds the object for measurement based on the distances corresponding to the object for measurement; a symmetry determining means for determining symmetry of a fourth image information surrounded by the gate and selected from the first image information and for obtaining a position of a symmetry line; and a predicting means for predicting the presence of a preceding car in front of the driving car by determining a first stability of a movement of the symmetry line provided by the symmetry determining means in the horizontal direction and by determining a second stability of the distances provided by a calculation result of the distance determining means over time.

Amplifier type image sensor with shutter operation

Abstract: The present invention is directed to a solid state image sensor in which one horizontal line from an image sensor section is selected as a line in which a signal is read out from a pixel, a signal is read out to a vertical signal line by a vertical scanning in which selected horizontal lines are sequentially switched, and pixel the signal of the horizontal line, processed in a correlation double sampling fashion, is read out to a horizontal signal line in a constant order. This solid state image sensor has an electronic shutter function includes an electronic shutter scanning means for resetting a horizontal line spaced apart from a horizontal line currently read out by a shutter time in the vertical scanning direction.

Color sequential camera in which chrominance components are captured at a lower temporal rate than luminance components

Abstract: A color sequential electronic camera includes an RGB light source in which the R and G sources are activated in combination to provide a luminance light beam, and the R and B sources separately to provide separate chrominance light beams. Image light reflected by a subject is captured by an image sensor, which generates a color sequential signal comprising a sequence of luminance and chrominance image components. By activating the light sources such that chrominance light beams alternate between luminance light beams, the chrominance image components are captured at a lower temporal rate than the luminance image components. Furthermore, by binning the sensor photosites together for the chrominance image, the chrominance components are captured at a lower spatial resolution than the luminance image components.

Solid-state image pickup apparatus having a defect detecting mode

Abstract: A solid-state image pickup apparatus for use as a video camera has a defect detecting mode and an operation mode The solid-state image pickup apparatus includes a solid-state image sensor having pixels arranged in rows and columns for producing an output signal representing a detected image The solid-state image sensor operates in a field reading mode for reading electric charges from the pixels in approximately one field period such that the electric charges of the pixels of two adjacent rows are summed before being outputted from the solid-state image sensor, the summed electric charges being different in even- and odd-numbered fields, and also operates in a frame reading mode for reading electric charges from the pixels in approximately one frame period such that the electric charges of the pixels of one of two vertically adjacent rows are read in even-numbered fields and the electric charges of the pixels of the other of two adjacent rows are read in odd-numbered fields The positions of defective pixels of the solid-state image sensor are detected in the defect detecting mode, the defective pixels causing noise in the output signal at corresponding times in sampled data of the output signal The detected positions of the defective pixels are stored in a memory When the defect detecting mode is selected, the solid-state image sensor is controlled to operate in the frame reading mode

Target follow-up device and camera comprising the same

Abstract: The target follow-up device of the present invention is adapted quickly and reliably to follow up the position of a target which is moving at high speed. It incorporates an imaging sensor having a number of imaging elements, which performs photometry over the photographic field and which outputs input image data. Based upon this imaging sensor output, input image data for the target to be followed up are stored as reference image data by a memory device. Based upon minimum residue calculation between the input image data and the reference image data, the target follow-up device of the present invention determines the position of the target. In this determination operation, the target follow-up device selects at least one color from a plurality of colors contained in common by the input image data and the reference image data, and calculates the minimum residue for the selected color component.

Two-dimensional contact-type image sensor using amorphous silicon photo-transistor

Abstract: We propose a novel two-dimensional contact-type image sensor using amorphous silicon photo-transistors (APTs) in order to form a compact image scanner Each pixel of the sensor consists of an APT, a storage capacitor, and an amorphous silicon thin-film transistor (a-Si TFT) We have made a prototype 140×240-pixel sensor with a pixel size of 160 µm square It is confirmed that the prototype APT sensor can detect an image under room light Exposure for gray scale images is in the range of 10-1 to 7 lxs This TFT-switched, two-dimensional contact-type image sensor is promising for large-area applications because the process for APTs is fully compatible with that for conventional a-Si TFTs