Showing papers on "Image sensor published in 1989"

Multiple resolution image sensor

Abstract: An image sensor comprised of an array of photo elements (pixels) includes a device for randomly addressing individual pixels and a device for selectively varying the number of pixels which can be read out on any one reading cycle. The random addressing of pixels enables the readout of pixels located in selected regions of interest. Limiting the readout of the images to areas of interest allows an increase in the frame rate of the images. Relatively large groups of pixels can be read out simultaneously and the resulting signals can be merged into superpixel signals to provide high speed data capture, albeit at relatively lower resolution, since there will be a reduced number of data samples in each image. This feature is useful to rapidly scan and analyze a scene being viewed in order to locate an area of interest. Once an area of interest is located, the number of pixels read out on each cycle may be reduced to provide a higher resolution, lower speed, readout of the area of interest.

Visual navigation and obstacle avoidance structured light system

Abstract: A vision system for a vehicle, such as a mobile robot (10) includes at least one radiation projector (14, 16) which projects a structured beam of radiation into the robot's environment. The structured beam of radiation (14a, 16a) preferably has a substantially planar pattern of sufficient width to encompass the immediate forward path of the robot and also to encompass laterally disposed areas in order to permit turning adjustments. The vision system further includes an imaging (12) sensor such as a CCD imaging device having a two-dimensional field of view which encompasses the immediate forward path of the robot. An image sensor processor (18) includes an image memory (18A) coupled to a device (18D) which is operable for accessing the image memory. Image processing is accomplished in part by triangulating the stored image of the structured beam pattern to derive range and bearing, relative to the robot, of an object being illuminated. A navigation control system (20) of the robot inputs data from at least the vision system and infers therefrom data relating to the configuration of the environment which lies in front of the robot. The navigation control system generates control signals which drive propulsion and steering motors in order to navigate the robot through the perceived environment.

Image shake detecting device

Abstract: An image shake detecting device for detecting a shake of an image on an image sensing plane on the basis of a video signal output from an image sensor includes detection circuits arranged to detect image displacement in a plurality of areas set on the image sensing plane, and a control microcomputer which makes a discrimination, on the basis of information output from these detection circuits, between a movement of a camera and a solo movement of a photographed object. The device thus accurately makes compensation for an image shake by judging the state of the image on the basis of information output from these detection circuits. The image shake detecting device further includes a computing circuit arranged to compute a quantity of an image shake on the basis of a difference in detecting timing of a feature point of the image and a sensitivity control circuit arranged to change the detection sensitivity of the shake detection circuits. Further disclosed is an object tracing device to which the invented image shake detecting device is applied.

Automatic image stabilization device

Abstract: An automatic image stabilization device which is arranged to detect image movement information from a sensed image signal produced from an image sensor and to reduce the image movement comprises a movement detecting circuit which obtains movement vector information for each of a plurality of parts of an image plane, and a weight setting circuit arranged to attach weight to each movement vector information and to vary the weighting degree according to photographing conditions. A camera using this device is arranged to correct the shaking of the camera on the basis of the result of a computing operation performed on a camera shake detected from the signal produced from the image sensor together with a camera shake physically detected by means of an accelerometer.

A simple, real-time range camera

Abstract: A simple imaging range sensor is described, based on the measurement of focal error, as described by A. Pentland (1982 and 1987). The current implementation can produce range over a 1 m/sup 3/ workspace with a measured standard error of 2.5% (4.5 significant bits of data). The system is implemented using relatively inexpensive commercial image-processing equipment. Experience shows that this ranging technique can be both economical and practical for tasks which require quick and reliable but coarse estimates of range. Examples of such tasks are initial target acquisition or obtaining the initial coarse estimate of stereo disparity in a coarse-to-fine stereo algorithm. >

Method of recording reproducing data of mesh pattern, and apparatus therefor

Abstract: A data reading apparatus reads data of dots from a recording sheet on which data is recorded in the form of a mesh pattern, and decodes the read data into binary data. The data reading apparatus has an image sensor to read black/white levels of dots of the mesh pattern using the image sensor and to binarize the read levels by a hardware component or CPU processing according to software. An image can have a high recording density by minimizing a dot size.

Portable electronic copying machine

Abstract: An electronic copying machine comprises an optical image forming system for forming an optical image of a remote surface on an image plane, and an image sensor disposed in the image plane and transversely movable in the image plane for scanning the optical image and converting the image into image signals. A scanning area defining device defines the height of the image sensor so as to scan the image plane according to the height of the remote surface. An image printing unit including a printing head is driven according to the image signals for printing an image on paper.

Color scanning system

Abstract: In a color scanning system according to this invention, signals from the detectors of an image sensor for converting a color image into electric signals are subjected to specified processing, thereby to sharply reduce noise at the contour part of the image.

Wide dynamic range camera

Abstract: An image pickup apparatus includes image sensors (70-1, 70-2, ..., 70-n) for receiving an image at various exposure levels and circuitry (74) combining the results into a single image signal. This results in a significantly widened dynamic range of exposure.

Image-enhanced tracking

Abstract: Measurement of the angular orientation of the target or the target designation makes possible the design of high-accuracy tracking and prediction systems. Such measurements are best accomplished with an imaging sensor. A model is presented for the image-based observation link, along with the equations used to convert a sequence of image processor outputs into an estimate of target status. An example examines the interrelationship which exists between the rate of feature changes of a target, the frame rate of the imager, and the sensitivity of the sensor-image processor. It is shown that even at high frame rates, anomalous events may occur. >

Real-time digital processor for producing full resolution color signals from a multi-color image sensor

Abstract: A digital processing system is described for processing luminance and chrominance signals from a single, multi-color image sensor. By concentrating signal improvements and corrections into an application-dependent post-processing phase, the pre-processing functions are isolated in a signle, generic pre-processor integrated circuit that provides fully interpolated color signals in a real-time system by utilizing a fully pipelined architecture. The pre-processor circuit separates luminance and chrominance interpolation so as to operate partly in quantized linear space and partly in quantized logarithmic space. The image signals are processed in a black reference clamp, a defect concealment circuit and a color separation and luminance interpolation circuit in linear space, using right shifts and additions to approximate predetermined multiplications. The signals are then transformed into hue signals and processed in log space for white balance and chroma (hue) interpolation. With the log green signal separately adjusted for gain, quantized red, green and blue signals are output from the pre-processor integrated circuit.

Method of, and apparatus for, controlling the position of an automatically operated door

Abstract: The automatically operated door is controlled in dependence upon the presence and movement conditions of one or more persons present on a support surface within a predeterminate space on a predetermined side of the automatically operated door. A radiation source, particularly an infrared radiation source emits a radiation field along and at a predetermined height above the support surface so that the at least one person present on the support surface is irradiated and infrared reflections originate from the at least one irradiated person. The infrared reflection is received at an active imaging device such as, for example, an infrared camera. Such imaging device contains a liquid crystal display (LCD) unit with an associated microshutter and a linear image sensor arranged in a plane extending substantially parallel to the plane of the liquid crystal display unit. Data representative of the infrared reflection images are processed in a programmable evaluation and control unit with respect to the contour representative of the at least one person and with respect to temporal variations in the reflection images. The recognition capability of the apparatus can be improved by alternatingly producing optical reflection images and infrared reflection images.

The Minnesota Scanner: a prototype sensor for three-dimensional tracking of moving body segments

Abstract: An advanced method for tracking the three-dimensional motion of bodies is presented This system, which is presently being used for human motion tracking, has the potential for dynamically characterizing robot motion and also provides a means for facilitating robot endpoint control Three rotating planes of laser light, fixed and moving photovoltaic diode targets, and a pipelined architecture composed of analog and digital electronics are used to locate multiple targets whose number is only limited by available computer memory Data collection rates are a function of the laser scan rotation speed and are selectable up to 480 Hz The tested performance on a preliminary prototype designed for 01-in accuracy at a 480-Hz data rate includes a resolution of 08 mm, a repeatability of +or-0636 mm, and an absolute accuracy of +or-20 mm within an eight cubic meter volume with all results applicable at the 95% level of confidence along each coordinate direction The system can be used to reduce XYZ target position data to body angular orientation which, for this first prototype, ranges in accuracy from +or-05 degrees to +or-1 degrees Moving targets can be tracked at speeds exceeding 1 m/s with signal integrity tested but not limited to 25-Hz motions >

Image picking-up and processing apparatus

Abstract: An image picking-up and processing apparatus particularly suitable for use in dental treatment comprises a transmission and conversion section including an image sensor for detecting input light from an object, an objective lens, and a light guide for transmitting illumination light; a control section including a control unit for producing an image signal on the basis of an output signal from the image sensor, and a light source for emitting the illumination light; and an interchangeable image processing section detachably connected to the transmission and conversion section for processing the image signal to reproduce image information in a desired form. An interchangeable image picking-up section, for example, an endoscope including an objective lens, an image fiber for transmitting the input light, and a light guide for transmitting the illumination light is detachably connected to the transmission and conversion section.

Optical low-pass filter

Abstract: An optical low pass filter for use in an imaging device including an objective lens and a solid state image sensor forming a plurality of picture elements thereon, which filter comprises a diffraction grating disposed between the objective lens and the solid state image sensor The diffraction grating is of a type which the periodicity of an image of the diffraction grating projected onto the solid state image sensor by the objective lens is selected to be twice or 1/n of the periodicity of the picture element, wherein n represents an integer The applicable imaging device may be of a type comprising an objective lens, a solid state image sensor forming a plurality of picture elements thereon, and a color filter array disposed on the solid state image snesor and including a plurality of sets of different color filter elements, or of a type comprising a single tube type color imaging device having an evacuated glass envelope, an objective lens and a color filter array including a plurality of sets of different color filter elements

Use of measurements from an imaging sensor for precision target tracking

Abstract: The extraction of measurements for precision tracking of the centroid of a target from a forward-looking infrared imaging sensor is presented. The size of the image of the target is assumed to be small, i.e. around 10 pixels. The statistical characterization of the centroid of the target is obtained. Similarly, the statistical properties of the image correlation of two frames, which measures the target offset, are derived. Explicit expressions that map the video noise statistics into measurement noise statistics are obtained. The offset measurement noise is shown to be autocorrelated. State variable models for tracking the target centroid with these measurements are then presented. Simulation results and quantitative conclusions about achievable subpixel tracking accuracy are given. It is shown that the filter that models the autocorrelated measurement noise provides the best performance. >

Low resolution verifier for a still video image

Abstract: Video imaging apparatus provides a relatively lower resolution verification image from a high resolution image sensor (12). By orienting a color filter array (10) so that the luminance (green) elements are arranged in same-color stripes (18) parallel to the horizontal scanning direction, the luminance elements may be subsampled for greater flexibility in generating the lower resolution image. A memory (50) stores the discrete image signals from the image sensor (12) and accesses the signals in two modes: a high resolution recording mode for addressing substantially all the image signals and a low resolution display mode for addressing only those signals from lines of same-color (green) filter elements. The low resolution addressing can be based on a variety of line sampling patterns corresponding to the line capability and horizontal resolution of a display device (54).

Color image processing apparatus.

Abstract: A color image processor that corrects a color image signal for the disagreement of images caused by the vibration of the image sensor when scanning a manuscript. The image sensor delivers an image signal that includes three signals, each one representing the level of brightness of one of the primary colors contained on the scanned image. Each signal includes a discrete value for each pixel reading the sensor and hence, comprises the brightness levels for a plurality of pixels. One of the three signals is called a standard color signal; the other two are called non-standard color signals. Each of the brightness levels of a non-standard color signal is sequentially stored in a register array. Individual levels of the pixels in the register array are examined to determine whether a pixel exists at an edge portion of a letter image. A pixel that exists at an edge portion is called a correction objective pixel. Various detectors connected to the register array are used to determine whether a pixel is a correction objective pixel. If a pixel is determined to be a correction objective pixel, the levels of brightness of neighboring pixels together with the level of brightness of the standard color pixel corresponding to the correction objective pixel are used to calculate a correction factor, which factor is used to adjust the level of brightness of the correction objective pixel. By adjusting the value of the level of brightness of the correction objective pixel of the non-standard color pixels the image signal is corrected for unwanted movements of the image sensor.

Image processor with dark current compensation

Abstract: An CCD image sensor includes a number of detector sites which are shielded from exposure to light so as to produce an output signal indicative of the dark current from the sensor. The output signal from the sensor is digitized into a series of multi-bit numbers. As dark current picture elements are clocked from the sensor, a logic circuit detects when any one of several least significant bits of the multi-bit digitized sensor output signal has a given logic level. A switch, controlled by the logic circuit, applies a constant current to charge a capacitor so that the voltage across the capacitor will represent the magnitude of the dark current in the sensor output signal. The capacitor voltage is subtracted from the sensor output to provide an image signal in which the effects of the dark current are compensated.

Multi-chip type image sensor

Abstract: A multi-chip type image sensor includes, a base, a plurality of sensor chips arranged on the base so as to be staggered so that adjacent sensor chips among the sensor chips partially overlap with each other in the direction perpendicular to a direction in which the sensor chips are arranged. The sensor chips are fastened to the base by an adhesive for use in die bonding. Each of the sensor chips has a plurality of light receiving elements arranged into a line at a predetermined pixel pitch Pd. Each of the sensor chip contains silicon. Therminal pins are supported on the base and electrically coupled to the sensor chips. The following formula is satisfied: Pc=Pd×[1+(Tc-Ta)(α.sub.B -αSi.sub.)] where Tc [°C.] is a curing temperature of the adhesive, Ta [°C.] is an environment temperature at which the image sensor is to be used, α Si is a thermal expansion coefficient of each of the sensor chips comprising silicon, α B is a thermal expansion coefficient of the base, and Pc is a pixel pitch at which the light receiving elements are arranged in each of the sensor chips before the adhesive is cured by die bonding.

A low-noise Bi-CMOS linear image sensor with auto-focusing function

Abstract: A bipolar imaging device consisting of a capacitor-loaded emitter follower circuit for a phototransistor has been implemented in a linear image sensor with two lines of 48-bit array for an autofocus camera system. The sensor, which has self-noise reduction and charge amplification capabilities, has demonstrated excellent performance, such as responsivity of 24 V/x-s, a wide dynamic range of 85.3 dB at a storage time of 10 ms and ambient temperature of 25 degrees C, a high S/N ratio of 27.6 dB at a faceplate light intensity of 1*10/sup -3/ lx, a storage time of 200 ms, an ambient temperature of 25 degrees C, and applicability in a range of light intensity from 1*10/sup -3/ to 1*10/sup 4/ lx. >

Image sensor having multiple horizontal shift registers

Abstract: An image sensor is disclosed which comprises an imaging region and horizontal shift registers which receive charge carriers generated in the imaging region and transfer them to an output circuit for processing. In order to facilitate the transfer of charge carriers out of the sensor and to provide an image sensor which has a simplified structure, dual horizontal transfer registers are used and transfer of charge carriers between the two registers is accomplished without a separate transfer gate electrode. Transfer regions are disposed between alternate storage regions of the registers such that charge carriers in one-half of the storage regions in one register can be transferred to storage regions in the other register. The two registers can then be clocked out in parallel to read out a single line.

Dual operational image reading apparatus

Abstract: An image reading apparatus of the present invention enlarges and reads a small light-permeable document such as a photographic film. In the apparatus of the present invention, an image of a film is divided into strips and is projected on a part of a main-scanning direction of a line image sensor. The film is then moved in a direction corresponding to the main-scanning direction of the line image sensor, thereby reading the image of the whole area of the film.

Optical surveillance assembly and camera

Abstract: A covert surveillance camera assembly comprises a dummy sprinkler head for camouflaging a camera. The sprinkler head has a pair of parallel arms and a mirror is mounted in a predetermined position relative to the camera and between the arms of the sprinkler head. An associated mechanism for scanning an object area may include a rotating component for turning the mirror at a predetermined angular speed in a first direction about an optical axis of the optical device. A dovetail prism is provided for stabilizing an image transmitted from an outlet end of the surveillance assembly, the prism being rotated at one half the angular speed of the rotating mirror in a second direction about the optical device's axis opposite to the first direction. The camera includes (a) a housing, (b) a transducer disposed in the housing for converting incoming electromagnetic radiation into electrical signals, the transducer including a solid state image sensor, (c) an element for movably mounting the image sensor to the housing, and (d) a shifting mechanism operatively connected to the image sensor for reciprocating the image sensor along a substantially linear path in a direction essentially transverse to the incoming electromagnetic radiation.

Image sensor including logarithmic converters

Abstract: A photosensor, or an image sensor made of many such photosensors, including a plurality of photosensor pixels each having a logarithmic converter. The logarithmic converter converts source charges that are produced by a photoreceptor (or a photodiode) and proportional to the amount of the incident light into signal charges logarithmically proportional to the source charges whose amount does not grow so rapid as the amount of source charges grows. Owing to the logarithmic converter, the dynamic range of the photosensor (or image sensor) has a very wide dynamic range.

Image pick-up apparatus

Abstract: A video camera comprises an image sensor for converting a projected light image into an electrical signal, an exposure time setting circuit for setting the exposure time for the image sensor to either one of a normal exposure time and an exposure time longer than the normal exposure time, and an automatic gain control circuit including a variable gain amplifier for amplifying a video signal read out from the image sensor and a detector for detecting an output signal level of the variable gain amplifier and supplying a gain control signal based on the result of detection to the variable gain amplifier. The automatic gain control circuit is controlled so as to make the response speed of the automatic gain control circuit, when the exposure time is set to an exposure time longer than the normal exposure time, lower than that preset when the exposure time is set to the normal exposure time.

System for determining and controlling the attitude of a moving airborne or spaceborne platform or the like

Abstract: A system for determining the attitude of an airborne or spaceborne platform such as a terrain image sensor or an energy beam pointer includes a digital image correlator for comparing successive overlapping, instantaneous images of the terrain which are recorded by a second, two-dimensional image sensor whose image plane is oriented parallel to that of the platform or terrain image sensor. The second sensor generates an instantaneous master image and a subsequent slave image which at least partially overlaps the master image in terms of the terrain which is viewed. The master and slave images are approximately registered and a correlation is performed. A plurality of points on the slave image are correlated with the corresponding terrain points on the master image. The relative orientation of the slave image with respect to the master image characterizes the attitude change of the platform. The technique also reveals changes in altitude and velocity of the platform when mean altitude and velocity are known. The image produced by the terrain image sensor or the attitude of the beam pointer can be altered on a real time basis using the information relating to the change in platform attitude, or the master and slave image data can be recorded for subsequent use in modifying the image data recorded by the terrain image sensor. A multispectral scanner is employed to detect in advance regions that cannot be properly imaged due to clouds and the like and a computer controlled mirror directs images onto the sensor from regions that the scanner has determined to produce meaningful image data.

Electronic endoscope apparatus employing automatic light source control

Abstract: In an electronic endoscope apparatus, a light source such as a xenon lamp is automatically turned off when the endoscope examination is accomplished, under the control of a video signal processing unit. The electronic endoscope apparatus includes a light source for illuminating an interior portion of a biological body under medical examination; an image sensor for imaging the interior portion of the biological body by receiving light reflected therefrom to produce an image signal; a converter for converting the image signal into a corresponding video signal; and, a signal processing unit for detecting that variations in levels of the video signal are continued for a predetermined duration time to output a detection signal, and for turning off the light source in response to the detection signal.

Recent Developments In Large Area Scientific CCD Image Sensors

Abstract: The design and performance of a 1024x1024 pixel charge-coupled device (CCD) imager are described. This device is fabricated utilizing a 3-phase, three-level polysilicon gate process. The chip is thinned and is employed in the back-illumination mode. Detailed measurements including imagery, read noise, full well capacity, charge transfer efficiency, linearity, dark current, spectral response, residual image, and charge collection efficiency are reported.

Image density control method for an image forming apparatus

Abstract: A method applicable to an image forming apparatus which is implemented by an electrophotographic procedure for maintaining that the density of images to be produced by the apparatus is adequate at all times. When the density of a toner image of a reference image or a predetermined pattern sensed by the image density sensor lies in a predetermined adequate range, a sensing level associated with the toner density sensor responsive to the toner density of a developer is not changed. When the density of the toner image does not lie in the adequate range, it is determined that at least the sensing level of the toner density sensing being used at that time has to be changed. Then, whether or not the sensed density of the toner image of the reference image exists in a range in which the image density is controllable is determined. If the sensed density lies in the controllable range, the sensing level of the density sensor being used at that time is suitably changed in response to the sensed density of the toner image. If otherwise, i.e., when the image density sensor is in a fault, toner density control is continued without changing the sensing level of the toner image sensor being used.