Showing papers on "Digital camera published in 1993"

The trustworthy digital camera: restoring credibility to the photographic image

Abstract: The trustworthy digital camera is an application of existing technology toward the solution of an evermore-troubling social problem, the eroding credibility of the photographic image. Although it will always be possible to lie with a photograph (using such time-honored techniques as false perspective and misleading captions), this proposed device will prevent the explosion of very capable personal computers from driving up the incidence of doctored photographs being passed off as truth. A solution to this problem comes from the proposed digital signature standard (DSS), which incorporates modern cryptographic techniques to authenticate electronic mail messages. >

Event recording system with digital line camera

Abstract: A system for recording and displaying a time-sequential scene on a computer comprising a digital camera, an image timer, and a main control computer. The digital camera transmits a sequence of digital image frames to the timer representative of the image of a body passing a plane in space. Each frame represents a line of the body, thus forming a fractional part of the scene. Once the frame reaches the image timer, it is digitally marked with a time reference and buffered into a block of information. The main control computer stores blocks of information from the image timer for a variety of processing and features available to the user. A compression system compresses a sequence of digital image frames for storage into a selected memory, preferably a virtual memory subsystem, or hard-disc drive.

An adressable 256 X 256 photodiode image sensor array with an 8-bit digital output

Abstract: We have constructed an addressable 256 × 256 photodiode sensor array together with an 8-bit ADC (analog-to-digital converter) on the same chip. Such a digital camera is easy to connect to a computer where also the flexibility of the computer can be used to control the camera output. The sensor has been constructed in two versions. The first version was implemented with a 256-column parallel-bit-slice image processor on the same die in a commercial project and the second as a separate addressable digital image sensor. The sensor was functionally fabricated using 1.6 µm design rules in a 1.2 µm CMOS process where it required a total area of 96 mm2.

Still picture recording digital camera which outputs a dynamic picture when incident light is limited and outputs a still picture when incident light is interrupted

Abstract: A still picture recording digital camera including a light quantity limiter for interrupting incident light to the camera; an image pickup unit including a pixel for converting the incident light to an electric pixel signal and outputting the pixel signal as a digital image signal; a signal processor for generating a digital image signal having a predetermined format; a recording unit for recording the digital image signal output from the image pickup unit or the signal processor; the light quantity limiter limiting the incident light quantity to a predetermined quantity and then interrupting the incident light; the image pickup unit outputting a dynamic picture digital image signal when the light quantity limiter is limiting the incident light quantity, and outputting a still picture image signal after the light quantity limiter has interrupted the incident light; and the signal processor performing different signal processing operations when the signal processor has received a digital image signal for a dynamic picture and a digital image signal for a still picture.

An Intelligent Linear Image Sensor

Abstract: A 256-pixel intelligent linear image sensor with 256 on-chip 8-bit A/D converters, control logic and microprocessor interface is presented. The frame rate of this complete single-chip digital camera is software-selectable up to 8.000 frames/s. Area-of-interest extraction and asynchronous acquisition of a frame on demand are provided. Fabricated in a 2 ?m standard CMOS process, the sensor is fully functional and requires a total area of 19 mm2. Operation in direct connection with the parallel port of a personal computer is demonstrated.

Phototriangulation using ccd camera in close-range environment

Abstract: The steady decrease in cost of a digital camera and frame grabber, together with higher resolution will result in more photogrammetric applications using such a camera. This is because of the advantages of speed and automation in image acquisition and measurement. In this paper, a standard frame-transfer charged-coupled device (CCD) camera was used to acquire close-range digital images for phototriangulation. Its accuracy in determining three-dimensional coordinates of premarked targets was compared with values derived from the conventional surveying method of triangulation. Two image-processing techniques, image correlation and moment preservation, were utilized to measure premarked targets interactively on a computer monitor.

Digital camera for recording color images

Abstract: A method of operation for a digital color camera permits the rapid accumulation of three basic color images that can be combined into a full-color reproduction. The scene to be captured is focused through a blue filter onto the active array of a conventional frame transfer CCD. The data representing the received image is condensed, by summing or bining, to reduce the number of pixels representing the image, and is transferred to the storage array of the CCD where it occupies one-half of the available storage area. The first exposure of the active array is terminated by a filter/shutter mechanism that also serves to replace the blue filter with a red one. The scene is then focused on the active array through the red filter and the exposure again terminated by the filter/shutter assembly. The data representing this image are then summed or bined to reduce the number of pixels representing the image and the data is transferred to the unoccupied one-half of the storage array. The scene is then focused through a green filter onto the active array and the exposure is terminated by an opaque section of the filter/shutter mechanism. The data representing this image is not summed or bined, and the active area of the CCD serves as a storage area for the image. After the data in the storage area has been transferred to the digitizing and processing circuits, the data in the active area is transferred with full resolution to the now empty storage area. Advantage is taken of certain characteristics of the human eye that permit resolution to be sacrificed in certain color segments while retaining overall acceptable image quality.

Performance evaluation of a 12-bit, 8Mpel/s digital camera

Abstract: A new generation, large frame (1317 X 1035 pel) digital camera, based on the MicroImager 1400 (MI1400), has been developed. The new MicroImager 1400-12 (MI1400- 12) uses improved noise reduction circuits to allow for 12 bit digitization up to 8 Mpel/s. Methods of correlated double sampling were investigated and a clamp-and-sample design was chosen. The MicroImager is a full frame device with a 100% fill factor. Integration time, readout frequency and pixel additive mode (binning) are under computer control. The camera outputs digital, RS-422 compatible data to the host frame memory through a 50-pin high density connector. The system is compatible with various (E)ISA and VME based imaging boards. The applications are quantitative digital microscopy in brightfield and fluorescence and in numerous industrial and medical camera applications. A number of comparative performance measurements were defined and carried out including spatial resolution (impulse response), photometric response (linearity), sensitivity, dynamic range, signal-to-noise ratio and other noise parameters. The MI1400-12 has a slightly improved impulse response. When used with primary image plane optics, the MicroImager shows a 6% improvement in the spatial resolution over standard C-mount compensation optics. In further comparisons the linearity of the MI1400-12's response holds to a coefficient of regression larger than 0.999 and has a four-fold increase in sensitivity over the MI1400. A dynamic range of 61 dB was measured for single frames corresponding to an 8 dB increase. For a 30 frame average, 77 dB was achieved. Circuit noise parameters (random noise at dark levels) improved by a factor of 3 to 4.

Steam bubble collapse velocity measurements with a particle image velocimetry technique using fluorescent tracers

Abstract: Particle image velocimetry (PIV) is a flow visualization method that can produce qualitative and quantitative full-field maps for fluid flow parameters (such as velocity and shear stress) over an extended area. The use of digital cameras for data acquisition to study high-speed fluid flows is usually limited by the camera frame acquisition rate. The velocity of the fluid under study must be limited to ensure that particles suspended in the flow field remain in the camera's focal plane in successive images. The use of digital cameras for data acquisition is desirable to simplify and expedite the data analysis. A method is presented in this paper that will measure changes in the flow field that occur at the relatively fast framing rate of 100 to 320 its per frame. However, to achieve this high framing rate, the laser will be operated in a double-pulse mode with one camera exposed twice. The directional ambiguity presented by the double exposure can be resolved by capturing a single exposure of the second pulse with a second digital camera. The study of collapsing steam bubbles also presents the problem of distinguishing between the light reflected by the liquid-gas interface and the light refracted by themore » surrounding tracer particles. This problem was resolved through the use of fluorescent seeds and appropriate filters. The fitter blocked most of the green light reflected by the bubbles and passed the red light emitted by the fluorescent seeds.« less

Digital camera adaptor for handy computer and handy computer

Abstract: PURPOSE: To provide a digital camera adaptor for a handy computer by which picture information is directly and simply fetched by the handy computer suitable for carrying, low in cost and small in size and the movel handy computer with the digital camera adaptor mounted thereon. CONSTITUTION: The digital camera adaptor B for handy computer is a device in which image pickup unit whose major components are a lens and an image pickup element adopting a charge-coupled device is contained in a case 10 having a mechanical mount structure with respect to the handy computer main body A and the outer side of the case 10 is provided with an adaptor side bus coupling terminal 14 connectable to a bus coupling terminal 7 for peripheral equipment connection for the handy computer main body A and the digital camera adaptor B is mounted on the handy computer. COPYRIGHT: (C)1995,JPO

Ccd digital camera system

Abstract: PURPOSE:To accelerate the read of image data by utilizing an image memory provided at a display device in the digital camera system constituted for compressing picked-up image data, recording them in a recording medium and mounting the display device which can display images. CONSTITUTION:This system is composed of a CCD digital camera CA in a system for compressing the image data outputted from a CCD image pickup element 1 and recording them in a memory card 10 and a display device DP attachable and detachable to this camera for storing the picked-up images in an image memory 21 and displaying these images later. At the camera CA, the reading time of image data is shortened by detecting the state of mounting the display device, switching the input / output of a compression/extension part 7, temporarily storing the image data from the CCD image pickup element into the image memory 21 and compressing these image data.

Fast-frame-rate 512 x 512 CCD digital camera system

Abstract: This paper details the performance and shows images obtained from a 512 X 512 CCD camera capable of recording 400 digitized frames per second. A brief description of the data acquisition hardware and image analysis software is also included.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Fill flash with flash triggering at the shutter period midway point

Abstract: A camera system and method for operation of fill flash photography, combining natural and flash light, which centres the times of natural light and flash light images. Synchronization is achieved by centring the time a flash is triggered midway between the opening front curtain and closing rear curtain of the shutter. In a particular preferred embodiment, a digital camera is coupled to a computer forming a system which stores images for image processing. The system includes a means for determining a period during which the shutter of the camera system will be opened and a means to determine a middle period in the the open shutter period. Preferably, the flash is fired at the midway point of the shutter period. This midway point in time is used to trigger the flash so it is substantially centred in time within the shutter period.