this paper details an image intensifier enhancement program at Litton Electro-Optical systems (LEOS) and the U.S. Army Night Vision and electronic Sensors Directorate (NVESD) for the development of an unfilmed bulk co...
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ISBN:
(纸本)0819437735
this paper details an image intensifier enhancement program at Litton Electro-Optical systems (LEOS) and the U.S. Army Night Vision and electronic Sensors Directorate (NVESD) for the development of an unfilmed bulk conductive glass (BCG) Microchanel Plate (MCP) for use in any image intensifier (I-2) to enhance signal-to-noise, reliability, and lifetime. We will discuss the material characterization associated with this new class of MCP glass. then we will explore the outgassing and ion feedback properties of a BCG MCP in vacuum demountable: experiments. Electrical and optical measurements on BCG MCPs with standard Generation III configuration (9-13 micron channel pitch) will be discussed. test results will be presented for I-2 made with BCG MCPs. the goal of this program is to produce a high performance Generation iv or greater I-2 with a state-of-the art bulk conductive glass MCP in order to provide enhanced imaging capability for 21st century night vision systems.
In applications that demand high resolution images, it is often not feasible nor sometimes possible to acquire images of such high resolution by using current CCD camera with its inherent resolution. Instead, image pr...
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In applications that demand high resolution images, it is often not feasible nor sometimes possible to acquire images of such high resolution by using current CCD camera with its inherent resolution. Instead, imageprocessing methods may be used to construct a high resolution image from multiple, degraded, low resolution images. this paper presented a novel robust high resolution reconstruction method that consists of a high accuracy hierarchical registration, interpolation and postprocessing. this algorithm is found to be effective, robust and shows significant improvement over conventional interpolation algorithms. the success of this algorithm is demonstrated through various simulated and real images.
Standard CMOS technologies offer great flexibility in the design of image sensors, which is a big advantage especially for high framerate systems. For this application we have integrated an active pixel sensor with 25...
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Standard CMOS technologies offer great flexibility in the design of image sensors, which is a big advantage especially for high framerate systems. For this application we have integrated an active pixel sensor with 256 × 256 pixel using a standard 0.5μm CMOS technologie. With 16 analog outputs and a clockrate of 25-30 MHz per output, a continuous framerate of more than 5000 Hz is achieved. A global synchronous shutter is provided, but it required a more complex pixel circuit of five transistors and a special pixellayoutto get a good optical fill factor. the active area of the photodiode is 9 × 9 μm. these square diodes are arranged in a chess pattern, while the remaining space is used for the electronic circuit. Fill factor is nearly 50%. the sensor is embedded in a high-speed camera system with 16 ADCs, 256Mbyte dynamic RAM, FPGAs for high-speed real time imageprocessing, and a PC for user interface, data archive and network operation. Fixed pattern noise, which is always a problem of CMOS sensors, and the mismatching of the 16 analog channels is removed by a pixelwise gain-offset correction. After this, the chess pattern requires a reconstruction of all the 'missing' pixels, which can be done by a special edge sensitive algorithm. So a high quality 512 × 256 image with low remaining noise can be displayed. Sensor, architecture and processing are also suitable for color imaging.
texture plays an important part in many Content Based image Retrieval systems. this paper describes the results from a human study, which asked 30 volunteers to classify images from the Brodatz textures album. We use ...
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texture plays an important part in many Content Based image Retrieval systems. this paper describes the results from a human study, which asked 30 volunteers to classify images from the Brodatz textures album. We use these results to derive a subset which show good agreement among the different individuals. the results for this subset were used to evaluate the retrieval performance of a range of statistical, Fourier-based, and spatial/spatial filtering methods. However, no one computational method works well for all textures, unlike the human visual system. We show how each of the ten methods correlates with the rankings from the human studies the results typically match for only about 20%-25% of the images. Combining two techniques can improve the retrieval performance, as judged by human users. We also identify a further subset of the Brodatz images where no computer method correlates significantly with the composite human ranking. Of the 85 images selected by the human study, only 64 have any significant correlation with one or more of the computational methods in this paper. the excluded images, where human users agree with each other, but none of the methods we evaluated did, provide a further challenge to texture-based image retrieval techniques.
Visual telepresence systems which utilise virtual reality style helmet mounted displays have a number of limitations. the geometry of the camera positions and of the displays is fixed and is most suitable only for vie...
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Visual telepresence systems which utilise virtual reality style helmet mounted displays have a number of limitations. the geometry of the camera positions and of the displays is fixed and is most suitable only for viewing elements of a scene at a particular distance. In such a system, the operator's ability to gaze around without use of head movement is severely limited. A trade off must be made between a poor viewing resolution or a narrow width of viewing field. to address these limitations a prototype system where the geometry of the displays and cameras is dynamically controlled by the eye movement of the operator has been developed. this paper explores the reasons why it is necessary to actively adjust both the display system and the cameras and furthermore justifies the use of mechanical adjustment of the displays as an alternative to adjustment by electronic or imageprocessing methods. the electronic and mechanical design is described including optical arrangements and control algorithms. An assessment of the performance of the system against a fixed camera/display system when operators are assigned basic tasks involving depth and distance/size perception. the sensitivity to variations in transient performance of the display and camera vergence is also assessed.
Error diffusion dithering is a technique that is used to represent a grayscale image on a printer, a computer monitor or other bi-level displays. For a number of years it was believed that error diffusion algorithms c...
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Error diffusion dithering is a technique that is used to represent a grayscale image on a printer, a computer monitor or other bi-level displays. For a number of years it was believed that error diffusion algorithms can not be parallelized. On this paper we present a simple error-diffusion parallel algorithm that can be easily implemented on parallel computers that contain linear arrays of processing elements. It can also be implemented easily on specialized hardware. One of the advantages of our algorithm is its low implementation cost, its scalability, and its ability to benefit from standard fault-tolerance techniques.
Nonlinear diffusion processes and watershed algorithms have been well studied for gray-scale image segmentation. In this paper we extend the use of these techniques to color or multichannel images. First, we formulate...
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Nonlinear diffusion processes and watershed algorithms have been well studied for gray-scale image segmentation. In this paper we extend the use of these techniques to color or multichannel images. First, we formulate a general definition for a nonlinear diffusion process using the concept of an activity imagethat can be calculated for several image components. then, we explain how the final activity image, obtained as a result of the nonlinear diffusion process, is fed through a watershed algorithm, yielding the segmentation of the image. the qualitative performance of the algorithm is illustrated with results for both gray-scale and color photographic images. Finally, we discuss the segmentation results obtained using a few well-known color spaces and demonstrate that a color principal component analysis gives the best results. (C) 1999 spie and IS&t. [S1017-9909(99)00503-6].
We have developed a focused-procedure based upon a collection of imageprocessingalgorithmsthat serve to identify regions-of-interest, ROIs, over a digital image. the loci of these ROIs are quantitatively compared w...
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We have developed a focused-procedure based upon a collection of imageprocessingalgorithmsthat serve to identify regions-of-interest, ROIs, over a digital image. the loci of these ROIs are quantitatively compared with ROIs identified by human eye fixations or glimpses while subjects were looking atthe same digital images. the focused-procedure is applied to adjust and adaptthe compression ratio over a digital image: - high resolution and poor compression for ROIs; low resolution and strong compression for the major expanse of the entire image. In this way, an overall high compression ratio can be achieved, while atthe same time preserving, important visual information within particularly relevant regions of the image. We have bundled the focused-procedure with JPEG, so thatthe JPEG version allows the result of the compression to be formatted into a file compatible for standard JPEG decoding. thus, once the image has been compressed, it can be read without difficulty.
the classical approach in vision research - the derivation of basically linear filter models from experiments with simple artificial test stimuli - is currently undergoing a major revision. Instead of trying to keep t...
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the classical approach in vision research - the derivation of basically linear filter models from experiments with simple artificial test stimuli - is currently undergoing a major revision. Instead of trying to keep the dirty environment out of our clean labs we put it now right into the focus of scientific exploration. the new approach has a close relation to basic engineering strategies for electronicimageprocessing since its major concept is the exploitation of the statistical redundancies of the environment by appropriate neural transformations. the standard engineering methods are not sufficient, however. Even a basic biological feature like orientation selectivity requires the consideration of higher-order statistics, like cumulants or polyspectra. Furthermore, there exists an abundance of nonlinear phenomena in biological vision, for example the phase-invariance of complex cells, cortical gain control, or end-stopping, which make it necessary to consider unconventional modeling approaches like differential geometry or Volterra-Wiener systems. By use of such methods we cannot only gain a deeper understanding of the adaptation of the visual system to the complex natural environment, but we can also make the biological system an inspiring source for the design of novel strategies in electronicimageprocessing.
In an electronic color image capturing device using a single CCD or CMOS sensor, the color information is usually acquired into three sub-sampled color planes such as Red (R), Green (G) and Blue (B). Full resolution c...
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In an electronic color image capturing device using a single CCD or CMOS sensor, the color information is usually acquired into three sub-sampled color planes such as Red (R), Green (G) and Blue (B). Full resolution color is subsequently generated from this sub-sampled image using a suitable 'Color Interpolation' methodology. the color accuracy and appearance of the image is significantly affected by the color interpolation algorithm used to generate the full-resolution color image. In this paper, we present a new block matching based algorithm for color interpolation. the computational complexity of this algorithm is very low and hence suitable for real-time implementation in a portable image capture device e.g. a digital camera. the proposed algorithm produces the similar or better quality color images compared to most of the known color interpolation algorithms in the literature. We have presented results of comparison of the performance of the proposed algorithm with median interpolation and bilinear interpolation which are commonly used in practice.
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