Showing papers on "Image sensor published in 1996"

Apparatus and method for rotating the display orientation of a captured image

Abstract: The apparatus of the present invention preferably comprises an image sensor, an orientation sensor, a memory and a processing unit. The image sensor is used for generating captured image data. The orientation sensor is coupled to the image sensor, and is used for generating signals relating to the position of the image sensor. The memory, has an auto-rotate unit comprising program instructions for transforming the captured image data into rotated image data in response to the orientation sensor signals. The processing unit, executes program instructions stored in the memory, and is coupled to the image sensor, the orientation sensor and the memory. The method of the present invention preferably comprises the steps of: generating image data representative of an object with an image sensor; identifying an orientation of the image sensor relative to the object during the generating step; and selectively transferring the image data to an image processing unit in response to the identifying step.

Technology and device scaling considerations for CMOS imagers

Abstract: This paper presents an analysis of the impact of device and technology scaling on active pixel CMOS image sensors. Using the SLA roadmap as a guideline, we calculate the device characteristics that are germane to the image sensing performance of CMOS imagers, and highlight the areas where the CIMOS imager technology may need to depart from "standard" CMOS technologies. The impact of scaling on those analog circuit performance that pertain to image sensing performances are analyzed. Our analyses suggest that while "standard" CMOS technologies may provide adequate imaging performance at the 2-1 /spl mu/m generation without any process change, some modifications to the fabrication process and innovations of the pixel architecture are needed to enable CMOS to perform good quality imaging at the 0.5 /spl mu/m technology generation and beyond. Finally, the challenges to the CMOS imager research community are outlined.

Real-time focus range sensor

Abstract: Structures of dynamic scenes can only be recovered using a real-time range sensor. Depth from defocus offers an effective solution to fast and dense range estimation. However, accurate depth estimation requires theoretical and practical solutions to a variety of problems including recovery of textureless surfaces, precise blur estimation, and magnification variations caused by defocusing. Both textured and textureless surfaces are recovered using an illumination pattern that is projected via the same optical path used to acquire images. The illumination pattern is optimized to maximize accuracy and spatial resolution in computed depth. The relative blurring in two images is computed using a narrow-band linear operator that is designed by considering all the optical, sensing, and computational elements of the depth from defocus system. Defocus invariant magnification is achieved by the use of an additional aperture in the imaging optics. A prototype focus range sensor has been developed that has a workspace of 1 cubic foot and produces up to 512/spl times/480 depth estimates at 30 Hz with an average RMS error of 0.2%. Several experimental results are included to demonstrate the performance of the sensor.

256/spl times/256 CMOS active pixel sensor camera-on-a-chip

Abstract: A CMOS imaging sensor is described that uses active pixel sensor (APS) technology and permits the integration of the detector array with on-chip timing, control, and signal chain electronics. This sensor technology has been used to implement a CMOS APS camera-on-a-chip. The camera-on-a-chip features a 256/spl times/256 APS sensor integrated on a CMOS chip with the timing and control circuits, and signal-conditioning to enable random-access, low power (/spl sim/5 mW) operation, and low read noise (13 e/sup -/ rms). The chip features simple power supplies, fast readout rates, and a digital interface for commanding the sensor, as well as for programming the window-of-interest readout and exposure times. Excellent imaging has been demonstrated with the APS camera-on-a-chip, and the measured performance indicates that this technology will be competitive with charge-coupled devices (CCD's) in many applications.

Multi-mode digital camera with computer interface using data packets combining image and mode data

Abstract: A digital camera, which captures images and transfers the captured images to a host computer, includes an image sensor exposed to image light for capturing the images and generating image signals; an A/D converter for converting the image signals into digitized image data; a digital interface for transferring the digitized image data to the host computer; means for controlling the image sensor in at least two different camera configurations, each configuration including configuration information defining a plurality of camera parameters; and means for communicating at least part of the configuration information along with the digitized image data to the computer via the digital interface.

Electronic still camera having automatic orientation sensing and image correction

Abstract: An electronic still camera is provided with an electronic image sensor for generating an image signal corresponding to a still image of a subject and an orientation determination section for sensing the orientation of the camera relative to the subject. The orientation determination section provides an orientation signal recognizing either the vertical or the horizontal orientation of the camera relative to the subject. An image processor is responsive to the orientation signal for processing the image signal and correcting the orientation thereof so that the still image is output from the image processor in a predetermined orientation. In this way, the electronic still camera can be positioned in a variety of orientations relative to a subject, including both clockwise and counterclockwise vertical "portrait" orientations and a horizontal "landscape" orientation, without affecting the orientation of the images output by the camera.

Combined electronic/silver-halide image capture system with cellular transmission capability

Abstract: A combined electronic/silver-halide image capture system is capable of transmitting electronic image data using conventional cellular telephone transmission technology. The system includes a camera unit and a cellular telephone that can be electrically coupled to the camera unit. The camera unit has both a photographic film plane and an electronic image sensor. A mechanism is provided for directing scene light from a scene to be imaged to at least one of the photographic film plane and the electronic image sensor, wherein the electronic image sensor generates analog image signals in response to incident scene light. A processing unit receives the analog image signals generated by the electronic image sensor and generates digital image signals represented of the scene to be imaged. A memory unit is provided to selectively store the digital image signals generated by the processing unit. The camera unit also preferably includes a display so that the digital image signals generated by the processing means can be viewed by the operator of the system. The digital image signals are supplied to a cellular telephone which transmits the digital image signals to a remote location when the camera unit is electrically coupled to the cellular telephone.

Electronic imaging system capable of image capture, local wireless transmission and voice recognition

Abstract: A system for digital image capture and transmission, includes a digital camera that has an electronic image sensor for sensing an image and producing a digital image; a memory for storing digital images produced by the image sensor in digital image files, the digital image files having associated information for controlling a remote image fulfillment server; a voice recorder for digitizing voice commands relating to control of the image fulfillment server; and a transmitter for transmitting the digital image file to the image fulfillment server. Either the camera or the fulfillment server includes a voice recognition module responsive to the digitized voice commands for producing control signals for the image fulfillment server. The image fulfillment server includes a receiver for receiving the digital image file and control signals; a memory for storing the received digital image file; and a file manager for managing the digital image file in response to the control signals.

Pixel structure, image sensor using such pixel, structure and corresponding peripheric circuitry

Abstract: A pixel structure for CMOS imaging applications, the pixel structure including a photosensitive element, a load transistor in series with the photosensitive element, a first reading transistor, coupled to the photosensitive element and to the load transistor, for reading out signals acquired in the photosensitive element and converting the signals to a voltage drop across the load transistor. The gate length of at least the load transistor is increased by at least 10% compared to a gate length of transistors manufactured according to layout rules imposed by a CMOS manufacturing process, thereby increasing the light sensitivity of the pixel structure.

Solid-state image sensor with focal-plane digital photon-counting pixel array

Abstract: A solid-state focal-plane imaging system comprises an N×N array of high gain, low-noise unit cells, each unit cell being connected to a different one of photovoltaic detector diodes, one for each unit cell, interspersed in the array for ultralow level image detection and a plurality of digital counters coupled to the outputs of the unit cell by a multiplexer (either a separate counter for each unit cell or a row of N of counters time shared with N rows of digital counters). Each unit cell includes two self-biasing cascode amplifiers in cascade for a high charge-to-voltage conversion gain (>1 mV/e - ) and an electronic switch to reset input capacitance to a reference potential in order to be able to discriminate detection of an incident photon by the photoelectron (e - ) generated in the detector diode at the input of the first cascode amplifier in order to count incident photons individually in a digital counter connected to the output of the second cascode amplifier. Reseting the input capacitance and initiating self-biasing of the amplifiers occurs every clock cycle of an integratng period to enable ultralow light level image detection by the array of photovoltaic detector diodes under such ultralow light level conditions that the photon flux will statistically provide only a single photon at a time incident on any one detector diode during any clock cycle.

Multichannel vision system for estimating surface and illumination functions

Abstract: This paper describes a set of experimental measurements and theoretical calculations designed to recover both the surface-spectral reflectance function and the illuminant spectral-power distribution from the image data. A multichannel vision system comprising six color channels was created with the use of a monochrome CCD camera and color filters. The spectral sensitivity of each color channel is calibrated, and the dynamic range of the camera is extended for sensing a wide range of intensity levels. Three algorithms and the corresponding results are introduced. First, a method of choosing the appropriate dimension of the linear model dimensions is introduced. Second, the illuminant parameters are estimated from the sensor measurements made at multiple points within separate objects. Third, the sensor responses are corrected for highlight and shading variations. The body reflectance parameters, unique to each surface, are recovered from these corrected values. Experimental results with a small number of test surfaces and a simple illumination geometry demonstrate that the illuminant spectrum and the surface-spectral reflectance functions can be recovered to within typical deviations of 1% and 4%, respectively.

New false color mapping for image fusion

Abstract: A pixel based colour mapping algorithm is presented that produces a fused false colour rendering of two gray level images representing different sensor modalities. The result-ing fused false colour images have a higher information content than each of the original images and retain sensor-specific image information. The unique component of each image modality is enhanced in the resulting fused colour image representation. First, the common component of the two original input images is determined. Second, the common component is subtracted from the original images to obtain the unique component of each image. Third, the unique component of each image modality is subtracted from the image of the other modality. This step serves to enhance the representation of sensor specific details in the final fused result. Finally, a fused colour image is produced by displaying the images resulting from the last step through respec-tively the red and green channels of a colour display. The method is applied to fuse thermal and visual images. The results show that the colour mapping enhances the visibility of certain details and preserves the specificity of the sensor information. The fused images also have a fairly natural appearance. The fusion scheme involves only operations on corresponding pixels. The resolution of a fused image is therefore directly related to the resolution of the input images. Before fusing, the contrast of the images can be enhanced and their noise can be reduced by standard image processing techniques. The colour mapping algorithm is computational simple. This implies that the investi-gated approaches can eventually be applied in real time and that the hardware needed is not too complicated or too voluminous (an important consideration when it has to fit in an aeroplane for instance).

Digital imaging device optimized for color performance

Abstract: A digital imaging device captures an image and generates a color signal from the image for application to an output device having specific color sensitivities, the imaging device further being one of many devices of the same type useful with the output device. The digital imaging device, for example a digital camera, includes a color sensor for capturing the image and generating a color signal from the captured image, the color sensor having predetermined spectral sensitivities, and an optical section that is interposed in the image light directed to the color sensor, the optical section also having predetermined spectral characteristics. The combination of the spectral sensitivities of the color sensor and the spectral characteristics of the optical section uniquely distinguish this particular imaging device from other imaging devices of the same type. By providing a set of matrix coefficients uniquely determined for this imaging device, the matrix coefficients optimally correct the spectral sensitivities of the color sensor and the spectral characteristics of the optical section for the color sensitivities of the output device.

Optical imaging assembly having improved image sensor orientation

Abstract: An imaging assembly having a 2D image sensor so oriented in relation to its supporting structure that, when a reader including the imaging assembly is held in its normal operating position during the reading of a 1D bar code symbol, the image of that 1D symbol is aligned with a diagonal of the image sensor, thereby increasing the resolution with which the 1D symbol is read. An image sensor including a generally rectangular 2D array of photosensitive elements is secured to a mounting structure so that the plane of the array is generally parallel to and approximately in the focal plane of an associated 2D imaging optics assembly. The angular orientation of the image sensor with respect to its mounting structure is selected so that, when a reader including the imaging assembly is held in its normal reading position during the reading of a 1D symbol, the image of the 1D symbol is formed along a diagonal of the array.

VLSI implementation of a focal plane image processor-a realization of the near-sensor image processing concept

Abstract: The near-sensor image processing concept, which has earlier been theoretically described, is here verified with an implementation. The NSIP describes a method to implement a two-dimensional (2-D) image sensor array with processing capacity in every pixel. Traditionally, there is a contradiction between high spatial resolution and complex processor elements, In the NSIP concept we have a nondestructive photodiode readout and we can thereby process binary images without loosing gray-scale information. The global image processing is handled by an asynchronous Global Logical Unit. These two features makes it possible to have efficient image processing in a small processor element. Electrical problems such as power consumption and fixed pattern noise are solved. All design is aimed at a 128/spl times/128 pixels NSIP in a 0.8 /spl mu/m double-metal single-poly CMOS process. We have fabricated and measured a 32/spl times/32 pixels NSIP. We also give examples of image processing tasks such as gradient and maximum detection, histogram equalization, and thresholding with hysteresis. In the NSIP concept automatic light adaptivity within a 160 dB range is possible.

Electronic camera having a printer

Abstract: In an electronic camera including optics for focusing an image of a subject at an image plane; an area image sensor disposed at the image plane for receiving the image subject and producing a digital image representing the subject; storage memory coupled to the area image sensor for storing the digitized image of the subject; and a moveable display being moveable between a user viewable position to a print position and adapted to be selectively coupled to the storage means for displaying an image of the subject. The camera further includes an optical printer being adapted to be optically coupled to the display when in its print position for producing a hard copy output of the subject represented by the display; and logic and control circuitry being responsive to the display moving to its print position for deenergizing the display after an image to be printed is selected and for reenergizing the display means when in its print position.

A full-body tactile sensor suit using electrically conductive fabric and strings

Abstract: We present design and implementation of a tactile sensor system, sensor suit, that covers the entire body of a robot. The sensor suit is designed to be soft and flexible and to have a large number of sensing regions. We have built the sensor suit using electrically conductive fabric and string. The current version of the sensor suit has 192 sensing regions. Each sensing region works as a binary switch in the current version. All of the signals from the sensor suit are gathered and superimposed on a visual image of the robot. The video multiplexer for the sensor signals is built on a field programmable gate array set. The construction of sensor suit system and its application with a full-body humanoid are presented.

Optical system for single camera stereo video

Abstract: A mechanism and method for recording stereo video with standard camera system electronics and a uniquely adapted optical assembly is disclosed. The optical assembly comprises left and right optical channels disposed to capture and project separate left and right images onto a single image sensor such that the boundary between the projected images is sharply delineated with no substantial overlap or gap. The viewpoints of the left and right optical channels are separated by a distance, d, such that the captured images are differentiated to produce a stereo image pair. By proper disposition of the left and right optical channels, stereo image pairs exhibiting full stereo overlap without keystone distortion are obtained. One image of the stereo pair is produced for visualization by the left eye and the other image is produced for visualization by the right eye. Alternatively, the images can be interrogated by a computer system for generating three dimensional position data. The image sensor is scanned in a standard fashion such that the left and right images are sampled by the video sampling circuitry of the camera unit at substantially the same time. In one mode, a pair of anamorphic lenses compress the left and right images along the axis of the image sensor scan lines so that each video field represents a stereo pair of images at a substantially unity anamorphic ratio and at an aspect ratio substantially equal to that of the image sensor. In a another mode, a conventional (non-distorting) lens is utilized and each video frame represents a pair of images having an aspect ratio equal to one-half that of the image sensor. A stereo playback mechanism and method is also disclosed.

Image sensor producing at least two integration times from each sensing pixel

Abstract: Designs and operational methods to increase the dynamic range of image sensors and APS devices in particular by achieving more than one integration times for each pixel thereof. An APS system with more than one column-parallel signal chains for readout are described for maintaining a high frame rate in readout. Each active pixel is sampled for multiple times during a single frame readout, thus resulting in multiple integration times. The operation methods can also be used to obtain multiple integration times for each pixel with an APS design having a single column-parallel signal chain for readout. Furthermore, analog-to-digital conversion of high speed and high resolution can be implemented.

Waveguide type compact optical scanner and manufacturing method thereof

Abstract: A waveguide type reduction type image sensor has a waveguide type light source having a light emitting element (6) and a substrate (5) including optical waveguides having a planar waveguide and a tapered waveguide. The waveguide type reduction type image sensor also has a light detecting section having a microlens array (4), an optical waveguide substrate (2) and a CCD array (3). The microlens array (4) converges reflected light from an original (1) onto an incident face of the optical waveguide substrate (2). The optical waveguide substrate (2) has L-shaped optical waveguides for guiding the converged light to the CCD array (3) located on a substrate face perpendicular to the incident face. The CCD array (3) converts the guided light to an electric signal and outputs this electric signal. A manufacturing method of this waveguide type reduction type image sensor is also shown.

Multi-direction camera in combination with a car

Abstract: A multi-direction camera comprising a mirror 3 having a plurality of reflecting surfaces 31 and 32 disposed in front of a lens 4. The lens 4 receives light reflected from the mirror 3 from a plurality of directions and forms an image by the image sensor 7. The mirror 3 can be moved linearly by an actuator 8. The arrangement of the mirror 3 and lens 4 allows the camera to image road conditions of multiple directions at the same time. The camera can also image a road condition in a single direction with a wider scope manually or automatically when the road condition in that direction needs to be confirmed preponderantly.

Video camera with automatic zoom adjustment based on distance between user's eyes

Abstract: An video camera capable of auto-zoom control, where light projector 14 irradiates a subject at fixed periods, a correlation calculator 16 inputs an image signal pre-stored in a memory 6 and an image signal from an image sensor 2 into an adder 7 , and outputs information on bright points, corresponding to the subject's eyes upon light emission period of the light projector 14 , into a zoom controller 18 . The zoom controller 18 controls a zoom driver 12 such that an interval between the subject's eyes, detected based on the input bright point information, is a predetermined value.

Method and device for achieving high contrast surface illumination

Abstract: A method and device for acquiring data related to topography of a medium includes projecting light, allowably from more than one direction, onto the surface of the medium at an angle of less than sixteen degrees relative to the surface and imaging the surface. For example, the imaging sensor may be an array of sensor elements that is used to determine navigation of a hand-held scanner along an original. By introducing light at an angle of less than sixteen degrees, surface irregularities cast shadows that form a high contrast illumination pattern along the surface of the medium. The navigation sensor detects multi-element variations of intensity of scattered light from the surface with respect to positions along the surface, so that the Nyquist criteria are adequately satisfied. Typically, the light is collimated incoherent light, but this is not critical. The illumination angle can be established by using a prism. The prism may have an antireflective thin film coating on one or more prism faces. The employment of a prism provides a number of advantages, such as use of a transparent surface in contact with the media and raising the illumination source(s) away from the media.

A 128/spl times/128-pixel standard CMOS image sensor with electronic shutter

Abstract: A 128/spl times/128-pixel image sensor with a 20 s-10/sup -4/ s electronic shutter has been integrated in a 1.2-/spl mu/m digital CMOS technology. The pixel cell consists of four PMOS transistors and a photodiode with antiblooming suppression. Each pixel measures 24 /spl mu/m by 24 /spl mu/m and has a fill factor of 25%. Current is used to transfer pixel signals to the column readout amplifiers in order to minimize voltage swings on the highly capacitive column lines. Correlated double sampling is used to reduce intracolumn fixed pattern noise. The saturation voltage is 470 mV. The peak output signal to noise ratio is 45 dB, and the optical dynamic range is 56 dB. The frame transfer rate is 1.7 ms per frame.

Electronic camera with dual resolution sensors

Abstract: An electronic camera includes a low resolution image sensor responsive to image light for generating a low resolution output signal that is used for camera control functions, such as image viewing, and a high resolution image sensor responsive to image light for generating a high resolution output signal that is used to produce an output image signal. The camera further includes an electronic display driven by the output signal from the low resolution image sensor, a zoom lens for varying the size of the image incident upon the high resolution image sensor and a zoom interpolator responsive to a zoom setting of the zoom lens. The output signal from the low resolution image sensor is then applied to the zoom interpolator, which processes the output signal so that the size of a display image obtained from the low resolution signal corresponds to the zoom setting of the zoom lens.

Terminal device with built-in image sensor

Abstract: The terminal device with built-in image sensor allows to use a conventional writing tool as the handwritten input means, and facilitates reading of printed document, and incorporates a scanning image sensor composed of a lens member having the optical path disposed parallel to a transparent panel , a prism member for bending the optical path at right angle to match one focal position of the lens member with the surface of the transparent panel , a light source for illuminating the surface of the transparent panel , and a light sensor disposed at other focal position of the lens member , and reads a document placed on the transparent panel ,and conventional writing device is provided in the lid unit, and by closing the lid unit after writing character or picture by the writing device, the character or picture is read by the image sensor .

Panoramic image acquisition

Abstract: This paper is concerned with acquiring panoramic focused images using a small field of view video camera. When scene points are distributed over a range of distances from the sensor, obtaining a focused composite image involves focus computations and mechanically changing some sensor parameters (translation of sensor plane, panning of camera etc.) which can be time intensive. In this paper we present methods to optimize the image acquisition strategy in order to reduce redundancy. We show that panning a camera about a point f (focal length) in front of the camera eliminates redundancy. The non-frontal imaging camera (NICAM) with tilted sensor plane has been previously introduced as a sensor that can acquire focused panoramic images. In this paper we also describe strategies for optimal selection of panning angle increments and sensor plane tilt for NICAM. Experimental results are presented for panoramic image acquisition using a regular camera as well as using NICAM.

Method and apparatus of high dynamic range image sensor with individual pixel reset

Abstract: A wide dynamic range image sensor provides individual pixel reset to vary the integration time of individual pixels. The integration time of each pixel is controlled by column and row reset control signals which activate a logical reset transistor only when both signals coincide for a given pixel.

Image sensing device with different image sensing characteristics for documents and scenery

Abstract: An image sensing device, such as an electronic camera, has different operating modes that are suited for sensing images of documents and sensing images of landscapes and the like In the document mode, since information in the document is important, the image sensor is set at a maximum resolution In the landscape mode, the resolution is varied in accordance with image brightness, to optimize the exposure conditions Additional image processing is carried out in the document mode to enhance the sensed image and increase the efficiency with which memory is utilized

Amorphous silicon x-ray image sensor

Abstract: The design and the performance of a 20 cm by 20 cm flat panel x-ray detector for digital radiography and fluoroscopy is described: Thin film amorphous silicon (aSi) technology has been used to build a 1024 by 1024 photodetector matrix, each pixel including both a photodiode and a switching diode; the pixel size is 196 by 196 micrometers2. A high resolution and high absorption CsI(Tl) scintillator layer covers the top of the photodetector matrix in order to provide for x ray to light conversion. For low electronic noise and 30 fr/s operating rate we developed a custom design charge readout integrated circuit. The detector delivers a 12 bit digital output. The image quality, signal to noise ratio, and DQE are presented and discussed. The flat panel detector provides a MTF in excess of 30% at 2 lp/mm and a high contrast ratio without any distortion on the whole imaging area. The x-ray absorption is 70% for 50 KeV photons. The readout amplifier is optimized to reduce the electronic noise down to 1000 e-. This low noise level, combined with high sensitivity (1150 e-/incident x-ray quantum) provides the capability for fluoroscopic applications. The digital flat panel detector has been integrated in a C-arm system for cardiology and has been used on a regular basis in a European hospital since February 1995. The results are discussed for several operating modes: radiography and fluoroscopy. Conclusions on present detector performances, as well as further improvements, are presented.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.