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Showing papers on "Image resolution published in 1998"


Journal ArticleDOI
TL;DR: In this article, a micro-resolution particle image velocimetry (micro-PIV) system was developed to measure instantaneous and ensemble-averaged flow fields in micron-scale fluidic devices.
Abstract: A micron-resolution particle image velocimetry (micro-PIV) system has been developed to measure instantaneous and ensemble-averaged flow fields in micron-scale fluidic devices. The system utilizes an epifluorescent microscope, 100–300 nm diameter seed particles, and an intensified CCD camera to record high-resolution particle-image fields. Velocity vector fields can be measured with spatial resolutions down to 6.9×6.9×1.5 μm. The vector fields are analyzed using a double-frame cross-correlation algorithm. In this technique, the spatial resolution and the accuracy of the velocity measurements is limited by the diffraction limit of the recording optics, noise in the particle image field, and the interaction of the fluid with the finite-sized seed particles. The stochastic influence of Brownian motion plays a significant role in the accuracy of instantaneous velocity measurements. The micro-PIV technique is applied to measure velocities in a Hele–Shaw flow around a 30 μm (major diameter) elliptical cylinder, with a bulk velocity of approximately 50 μm s-1.

1,187 citations


Patent
29 Apr 1998
TL;DR: In this article, the spatial resolution of a multispectral digital image is enhanced in a process of the type wherein a higher spatial resolution panchromatic image is merged with a plurality of lower spatial resolution spectral band images.
Abstract: The spatial resolution of a multispectral digital image is enhanced in a process of the type wherein a higher spatial resolution panchromatic image is merged with a plurality of lower spatial resolution spectral band images. A lower spatial resolution panchromatic image is simulated and a Gram-Schmidt transformation is performed on the simulated lower spatial resolution panchromatic image and the plurality of lower spatial resolution spectral band images. The simulated lower spatial resolution panchromatic image is employed as the first band in the Gram-Schmidt transformation. The statistics of the higher spatial resolution panchromatic image are adjusted to match the statistics of the first transform band resulting from the Gram-Schmidt transformation and the higher spatial resolution panchromatic image (with adjusted statistics) is substituted for the first transform band resulting from the Gram-Schmidt transformation to produce a new set of transform bands. Finally, the inverse Gram-Schmidt transformation is performed on the new set of transform bands to produce the enhanced spatial resolution multispectral digital image.

740 citations


Journal ArticleDOI
TL;DR: In this article, an x-ray detector based on a transparent, i.e., nonscattering, luminescent screen has been developed for phase contrast imaging and microtomography.
Abstract: Microimaging techniques with synchrotron radiation demand fast, on-line x-ray detectors with a spatial resolution in the micrometer or submicrometer range. For this task an x-ray detector based on a transparent, i.e., nonscattering, luminescent screen has been developed. Its performance is described experimentally and theoretically. The detector consists of an Y3Al5O12:Ce screen, microscope optics, and a low-noise CCD camera, operated at x-ray energies between 10 and 50 keV. Good image quality is achieved if the depth of focus of the optical system is matched to the x-ray absorption length or thickness of the scintillator. A spatial resolution of 0.8 µm fwhm (1000 line pairs/mm with 10% contrast) was measured by recording the interferogram of a boron fiber. First applications in phase contrast imaging and microtomography are shown.

379 citations


Journal ArticleDOI
TL;DR: An adaptive filtering approach in Radon space based on the local statistical properties of the CT projections, which is effective in reducing or eliminating quantum noise induced artifacts in CT.
Abstract: The quality of a computed tomography (CT) image is often degraded by streaking artifacts resulting from excessive x-ray quantum noise. Often, a patient has to be rescanned at a higher technique or at a larger slice thickness in order to obtain an acceptable image for diagnosis. This results in a higher dose to the patient, a degraded cross plane resolution, or a reduced patient throughput. In this paper, we propose an adaptive filtering approach in Radon space based on the local statistical properties of the CT projections. We first model the noise characteristics of a projection sample undergoing important preprocessing steps. A filter is then designed such that its parameters are dynamically adjusted to adapt to the local noise characteristics. Because of the adaptive nature of the filter, a proper balance between streak artifact suppression and spatial resolution preservation is achieved. Phantom and clinical studies have been conducted to evaluate the robustness of our approach. Results demonstrate that the adaptive filtering approach is effective in reducing or eliminating quantum noise induced artifacts in CT. At the same time, the impact on the spatial resolution is kept at a low level.

353 citations


Journal ArticleDOI
TL;DR: The noise characteristics show that the proposed algorithm efficiently utilizes the data collected with optimized sampling scan, and enables the algorithm to achieve acceptable image quality and spatial resolution at a scanning speed that is about three times faster than that for single-slice CT.
Abstract: Efforts are being made to develop a new type of CT system that can scan volumes over a large range within a short time with thin slice images. One of the most promising approaches is the combination of helical scanning with multi-slice CT, which involves several detector arrays stacked in the z direction. However, the algorithm for image reconstruction remains one of the biggest problems in multi-slice CT. Two helical interpolation methods for single-slice CT, 360LI and 180LI, were used as starting points and extended to multi-slice CT. The extended methods, however, had a serious image quality problem due to the following three reasons: (1) excessively close slice positions of the complementary and direct data, resulting in a larger sampling interval; (2) the existence of several discontinuous changeovers in pairs of data samples for interpolation; and (3) the existence of cone angles. Therefore we have proposed a new algorithm to overcome the problem. It consists of the following three parts: (1) optimized sampling scan; (2) filter interpolation; and (3) fan-beam reconstruction. Optimized sampling scan refers to a special type of multi-slice helical scan developed to shift the slice position of complementary data and to acquire data with a much smaller sampling interval in the z direction. Filter interpolation refers to a filtering process performed in the z direction using several data. The normal fan-beam reconstruction technique is used. The section sensitivity profile (SSP) and image quality for four-array multi-slice CT were investigated by computer simulations. Combinations of three types of optimized sampling scan and various filter widths were used. The algorithm enables us to achieve acceptable image quality and spatial resolution at a scanning speed that is about three times faster than that for single-slice CT. The noise characteristics show that the proposed algorithm efficiently utilizes the data collected with optimized sampling scan. The new algorithm allows suitable combinations of scan and filter parameters to be selected to meet the purpose of each examination.

341 citations


Patent
18 May 1998
TL;DR: In this article, the digital images are indexed in accordance with a plurality of recorded parameters including time, date and geographic location data (altitude and longitude), as well as image data such as lens focal length, auto focus distance, shutter speed, exposure duration, aperture setting, frame number, image quality, flash status and light meter readings.
Abstract: System and methods for querying digital image archives containing digital photographs and/or videos (collectively, “digital images”). The digital images are indexed in accordance with a plurality of recorded parameters including time, date and geographic location data (altitude and longitude), as well as image data such as lens focal length, auto focus distance, shutter speed, exposure duration, aperture setting, frame number, image quality, flash status and light meter readings, which are used for searching a database consisting of the digital images. These images are preferably generated by an image capturing system which is capable of measuring and recording a plurality of parameters with each captured digital image. The image retrieval system allows a querying user to search the image archive by formulating one or more of a plurality of query types which are based on the recorded parameters, and then retrieve and display those images having the specified parameters.

340 citations


Patent
02 Jun 1998
TL;DR: In this paper, a method and system for accelerating a user interface on a display of an image capture unit is described, which includes a low resolution image, medium resolution image and high resolution image.
Abstract: A method and system for accelerating a user interface on a display of an image capture unit is disclosed. The first aspect of the invention comprises a method and system for providing a low resolution image (606), medium resolution image (608) and high resolution image (604) within each image file (346) and allowing the medium resolution image to be viewed on the display. The second aspect of the invention comprises a method for providing a low resolution image within each file that is associated with a high resolution image within each image file, allowing the low resolution image to be viewed on the display and causing the related high resolution image to be displayed on top of the low resolution image dependent upon the quality of the low resolution image. The method and system also includes allowing for navigation between low resolution images based upon user interaction.

317 citations


Journal ArticleDOI
TL;DR: The use of the focus as a virtual element is examined, and the virtual source has been shown to exhibit the same behavior as an actual transducer element in response to synthetic aperture processing techniques.
Abstract: A new imaging technique has been proposed that combines conventional B-mode and synthetic aperture imaging techniques to overcome the limited depth of field for a highly focused transducer. The new technique improves lateral resolution beyond the focus of the transducer by considering the focus a virtual element and applying synthetic aperture focusing techniques. In this paper, the use of the focus as a virtual element is examined, considering the issues that are of concern when imaging with an array of actual elements: the tradeoff between lateral resolution and sidelobe level, the tradeoff between system complexity (channel count/amount of computation) and the appearance of grating lobes, and the issue of signal to noise ratio (SNR) of the processed image. To examine these issues, pulse-echo RF signals were collected for a tungsten wire in degassed water, monofilament nylon wires in a tissue-mimicking phantom, and cyst targets in the phantom. Results show apodization lowers the sidelobes, but only at the expense of lateral resolution, as is the case for classical synthetic aperture imaging. Grating lobes are not significant until spatial sampling is more than one wavelength, when the beam is not steered. Resolution comparable to the resolution at the transducer focus can be achieved beyond the focal region while obtaining an acceptable SNR. Specifically, for a 15-MHz focused transducer, the 6-dB beamwidth at the focus is 157 /spl mu/m, and with synthetic aperture processing the 6-dB beamwidths at 3, 5, and 7 mm beyond the focus are 189 /spl mu/m, 184 /spl mu/m, and 215 /spl mu/m, respectively. The image SNR is 38.6 dB when the wire is at the focus, and it is 32.8 dB, 35.3 dB, and 38.1 dB after synthetic aperture processing when the wire is 3, 5, and 7 mm beyond the focus, respectively. With these experiments, the virtual source has been shown to exhibit the same behavior as an actual transducer element in response to synthetic aperture processing techniques.

313 citations


Journal ArticleDOI
TL;DR: A new image compression technique called DjVu is presented that enables fast transmission of document images over low-speed connections, while faithfully reproducing the visual aspect of the document, including color, fonts, pictures, and paper texture.

312 citations


01 Jan 1998
TL;DR: The current state of the art of super-resolution restoration of video sequences is reviewed and promising directions for future research are identified.
Abstract: Recent years have seen growing interest in the problem of super-resolution restoration of video sequences. Whereas in the traditional single image restoration problem only a single input image is available for processing, the task of reconstructing super-resolution images from multiple undersampled and degraded images can take advantage of the additional spatiotemporal data available in the image sequence. In particular, camera and scene motion lead to frames in the source video sequence containing similar, but not identical information. The additional information available in these frames make possible reconstruction of visually superior frames at higher resolution than that of the original data. In this paper we review the current state of the art and identify promising directions for future research. The authors are with the Laboratory for Image and Signal Analysis (LISA), University of Notre Dame, Notre Dame, IN 46556. E-mail: rls@nd.edu .

269 citations


Journal ArticleDOI
TL;DR: The experimental results show that the proposed watermarking technique results in an almost invisible difference between the watermarked image and the original image, and is robust to common image processing operations and JPEG lossy compression.
Abstract: In this paper, a multiresolution-based technique for embedding digital "watermarks" into images is proposed. The watermarking technique has been proposed as a method by hiding secret information in the images so as to discourage unauthorized copying or attesting the origin of the images. In our method, we take advantage of multiresolution signal decomposition. Both the watermark and the host image are composed of multiresolution representations with different structures and then the decomposed watermarks of different resolution are embedded into the corresponding resolution of the decomposed images. In case of image quality degradation, the low-resolution rendition of the watermark will still be preserved within the corresponding low-resolution components of the image. The experimental results show that the proposed watermarking technique results in an almost invisible difference between the watermarked image and the original image, and is robust to common image processing operations and JPEG lossy compression.

Proceedings ArticleDOI
23 Jun 1998
TL;DR: M mosaicing for a sequence of images acquired by a camera rotating about its centre is described, in the automation and estimation of image registration: images.
Abstract: We describe mosaicing for a sequence of images acquired by a camera rotating about its centre. The novel contributions are in two areas. First, in the automation and estimation of image registration: images

Patent
13 Nov 1998
TL;DR: In this paper, an optoelectronic camera comprises an objective system formed by a number of optical active structures (L), particularly refractive structures in the form of microlenses or lenslets provided in an array.
Abstract: An optoelectronic camera comprises an objective system formed by a number of optical active structures (L), particularly refractive structures in the form of microlenses or lenslets provided in an array. A detector device (D) is assigned to the lens array and comprises detectors (Dn) formed by sensor elements (E) which define pixels in the optical image. Each detector (Dn) defines a sample of the optical image and optimally all samples are used to generate a digital image. The optoelectronic camera may be realized as a colour image camera, particularly for recording images in an RGB system. In a method for digital electronic formatting of an image recorded with the optoelectronic camera, zoom and pan functions are implemented in the camera.

Proceedings ArticleDOI
24 Jul 1998
TL;DR: This work develops and discusses multiple-center-of-projection images, and explains their advantages over conventional range images for image-based rendering, including greater flexibility during image acquisition and improved image reconstruction due to greater connectivity information.
Abstract: In image-based rendering, images acquired from a scene are used to represent the scene itself. A number of reference images are required to fully represent even the simplest scene. This leads to a number of problems during image acquisition and subsequent reconstruction. We present the multiple-center-of-projection image, a single image acquired from multiple locations, which solves many of the problems of working with multiple range images. This work develops and discusses multiple-center-ofprojection images, and explains their advantages over conventional range images for image-based rendering. The contributions include greater flexibility during image acquisition and improved image reconstruction due to greater connectivity information. We discuss the acquisition and rendering of multiple-center-of-projection datasets, and the associated sampling issues. We also discuss the unique epipolar and correspondence properties of this class of image. CR Categories: I.3.3 [Computer Graphics]: Picture/Image Generation – Digitizing and scanning, Viewing algorithms; I.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism; I.4.10 [Image Processing]: Scene Analysis

Journal ArticleDOI
TL;DR: An optical flow technique based on the use of dynamic programming has been applied to Particle Image Velocimetry thus yielding a significant increase in the accuracy and spatial resolution of the velocity field as discussed by the authors.
Abstract: An optical Flow technique based on the use of Dynamic Programming has been applied to Particle Image Velocimetry thus yielding a significant increase in the accuracy and spatial resolution of the velocity field. Results are presented for calibrated synthetic sequences of images and for sequences of real images taken for a thermally driven flow of water with a freezing front. The accuracy remains better than 0.5 pixel/frame for tested two-image sequences and 0.2 pixel/frame for four-image sequences, even with a 10% added noise level and allowing 10% of particles of appear or disappear. A velocity vector is obtained for every pixel of the image.

Journal ArticleDOI
TL;DR: In this article, a novel ion counting method for improving the spatial resolution and detection sensitivity of two-dimensional product imaging in molecular beam experiments is presented, which makes use of real-time digital image processing to retrieve, threshold, and determine the local maximum of each ion hitting a microchannel plate assembly.
Abstract: A novel ion-counting method for significantly improving the spatial resolution and detection sensitivity of two-dimensional product imaging in molecular beam experiments is presented. The method makes use of real-time digital image processing to retrieve, threshold, and determine the local maximum of each ion hitting a microchannel plate assembly. The current version can process data at rates up to 3.07 Mbyte/s, and methods for accelerating this rate are proposed.

Journal ArticleDOI
TL;DR: In this article, a wide acceptance angle first-order reflectron lens has been incorporated into a three-dimensional atom probe (3DAP) to provide improved mass resolution, which is capable of resolving isotopes in the mass spectrum, with resolutions better than m/Δm=500 full width at half maximum and 250 full width in 10% maximum.
Abstract: A wide acceptance angle first-order reflectron lens has been incorporated into a three-dimensional atom probe (3DAP) to provide improved mass resolution. This new 3DAP instrument is capable of resolving isotopes in the mass spectrum, with resolutions better than m/Δm=500 full width at half maximum and 250 full width at 10% maximum. However, use of a reflectron for energy compensation within an imaging system means that improvements in mass resolution result in degradation of the spatial resolution. This article addresses the detailed design of the energy compensated 3DAP, and the minimization and compensation of chromatic aberrations in the imaging performance of the instrument. Some applications of the new instrument are included to illustrate its capabilities in the atomic-scale analysis of engineering alloys.

Journal ArticleDOI
TL;DR: This work proposes a straightforward method to restore motion-blurred images given only the blurred image itself, and identifies the point-spread function (PSF) of the blur and uses it to restore the blur image.
Abstract: We deal with the problem of restoration of images blurred by relative motion between the camera and the object of interest. This problem is common when the imaging system is in moving vehicles or held by human hands, and in robot vision. For correct restoration of the degraded image, it is useful to know the point-spread function (PSF) of the blurring system. We propose a straightforward method to restore motion-blurred images given only the blurred image itself. The method first identifies the PSF of the blur and then uses it to restore the blurred image. The blur identification here is based on the concept that image characteristics along the direction of motion are affected mostly by the blur and are different from the characteristics in other directions. By filtering the blurred image, we emphasize the PSF correlation properties at the expense of those of the original image. Experimental results for image restoration are presented for both synthetic and real motion blur.

Patent
Ping Wah Wong1
30 Apr 1998
TL;DR: The watermark insertion procedure computes a hash function and then combines the output of the hashed function of a modified image block, a key and various image parameters with a block of the watermark bitmap, resulting in a combined image block as discussed by the authors.
Abstract: The present invention provides an invisible digital watermarking technique that can serve the two purposes of ownership verification and authentication, that can detect changes in pixel values as well as image size, and that may be used in public key or alternatively, secret key watermarking systems. The watermark insertion procedure computes a hash function and then combines the output of the hashed function of a modified image block, a key and various image parameters with a block of the watermark bitmap, resulting in a combined image block. As a final step to create a watermarked image block, the combined image block is inserted into the LSB of the modified image. The watermark extraction procedure takes the watermarked image block and creates two different image blocks: a first image block with the LSB's of the watermarked image block set to zero, and a second image block with the LSB's of the watermarked image block extracted. The watermark extraction procedure uses the hash function to calculate a digest of values, resulting in a hashed output. The hashed output is combined with the second image block, preferably using an exclusive OR function. The result of the combined hashed output with the second image block is a block of the extracted watermark.

Journal ArticleDOI
TL;DR: Limits need to be overcome before these devices can be used clinically, including developing larger flat-panel light sensors, the elimination of "noisy" pixels with high dark signal, and improvements in the uniform sensitivity of the sensors.
Abstract: We have measured the linearity, spatial resolution (MTF), noise (NPS), and signal-to-noise characteristics (DQE) of an electronic portal imaging device(EPID) based on an amorphous silicon flat-panel array. The array has a 128×128 -pixel matrix and each pixel is 0.75×0.75 mm 2 in dimension so the array covers an area of 96×96 mm 2 . The array acts like a large area light sensor and records the optical signals generated in a metal plate/phosphor screen x-ray detector when the detector is irradiated by a megavoltage x-ray beam. In addition, approximately 0.5% of the total signal is generated by nonoptical processes. The noise measurements show that the device is quantum noise limited with the noise power generated by the x-ray quanta being up to 100 times greater than the noise added by the external readout electronics and flat-panel light sensor itself. However, the flat-panel light sensor does reduce the spatial resolution (compared to a perfect optical sensor with infinitesimal pixel size) because of its moderate pixel size and because optical spread can occur in the transparent glues used to attach the phosphor screen to the flat-panel light sensor. The response of the sensor is very linear and does not suffer from the glare phenomenon associated with TV camera-based EPIDs—characteristics which suggest that the amorphous siliconEPID will be well suited to transit dosimetry. Nevertheless, some limitations need to be overcome before these devices can be used clinically. These include developing larger flat-panel light sensors, the elimination of “noisy” pixels with high dark signal, and improvements in the uniform sensitivity of the sensors. This last requirement is only needed for transit dosimetry applications where it would greatly simplify calibration of the device. In addition, an image acquisition scheme must be developed to eliminate artifacts created by the pulsed x-ray beam generated by linear accelerators. Despite these limitations, our studies suggest that the amorphous siliconEPIDs are very well suited to portal imaging.

Patent
25 Mar 1998
TL;DR: In this article, the authors present a system for sight labeling, which includes an image acquiring section for taking images, a position information acquisition section for recording a camera position while the images are being taken, a camera descriptive information acquiring section, a map information management section for managing map information, determining a view space inside map information space based on the acquired position, camera angle, focal distance and image size, and capturing constructions present inside the view space.
Abstract: The device and system for sight labeling according to the present invention comprises an image acquiring section for taking images, a position information acquiring section for recording a camera position while the images are being taken, a camera descriptive information acquiring section for acquiring the camera angle, focal distance and image size while the image are being taken, a map information management section for managing map information, determining a view space inside map information space based on the acquired position, camera angle, focal distance and image size, and capturing constructions present inside the view space, a label information preparation section for preparing label information including the names or descriptive information of constructions and transfer positions, a labeling information output section for overlaying the names or descriptive information from the map information at positions in the images corresponding to position information in the prepared label information, and a control section for controlling each of the sections described above.

Journal ArticleDOI
TL;DR: The Backus-Gilbert inversion (BGI) technique and the scatterometer image-reconstruction (SIR) algorithm are investigated as possible methods for creating enhanced resolution images from SSM/I data.
Abstract: One of the limitations in using Special Sensor Microwave/Imager (SSM/I) data for land and vegetation studies is the relatively low-spatial resolution. To ameliorate this limitation, resolution-enhancement algorithms can be applied to the data. In this paper, the Backus-Gilbert inversion (BGI) technique and the scatterometer image-reconstruction (SIR) algorithm are investigated as possible methods for creating enhanced resolution images from SSM/I data. The two algorithms are compared via both the simulation and the actual SSM/I data. The algorithms offer similar resolution enhancement, though SIR requires significantly less computation. Sample results over two land regions of South America are presented.

Journal ArticleDOI
TL;DR: In this article, the authors focus on the analysis of profile view images with reference to the fine details of the contrasts both in the metal particles and in the outer support layers, and prove that complex contrasts which very often appear in the images can be interpreted on the grounds of the structural features of the catalysts and on the recording conditions in the microscope.

Journal ArticleDOI
TL;DR: A similar image quality to the current single-slice MVCT scanner is achieved with the advantage of providing tens of tomographic slices for a single gantry rotation.

Patent
11 Sep 1998
TL;DR: In this paper, a method and system for removal of flash artifacts from a digital image containing pixels therein, including using a database of reference flash-corrupted images for identifying corrupted pixels within the digital image that have been corrupted by a flash, and modifying the color values of each corrupted pixel of the image, to correct the corrupted pixel color values.
Abstract: A method and system for removal of flash artifacts from a digital image containing pixels therein, including using a database of reference flash-corrupted images for identifying corrupted pixels within the digital image that have been corrupted by a flash, and modifying the color values of each corrupted pixel of the digital image, to correct the corrupted pixel color values.

Journal ArticleDOI
TL;DR: In this article, a 6 mm section of a sandstone core sample was obtained prior and subsequent to flooding to residual oil and brine phases were observable within the imaged rock matrix.

Patent
21 Jul 1998
TL;DR: In this article, a spatial light modulator can store pixel data in a plurality of small circuits coupled to pixel mirrors and simultaneously drive these pixel mirrors a frame at a time, which can convert binary images to grey-scale images and separate red, green and blue images into color images.
Abstract: A device such as a display device or a spatial light modulator can store pixel data in a plurality of small circuits coupled to pixel mirrors and simultaneously drive these pixel mirrors a frame at a time. This device is particularly beneficial for implementing improved image quality techniques which can convert binary images to grey-scale images and/or separate red, green and blue images into color images and displaying those images using the natural process of integration which occurs when a person views images at sufficiently high rates.

Journal ArticleDOI
08 Nov 1998
TL;DR: An opto-electronic motion tracking system based upon commercially available technology that is capable of very accurate real-time measurements of the position and orientation of the patient's bead that could potentially be used to provide motion correction of list-mode emission data on an event-by-event basis.
Abstract: Head motion during PET scanning is widely regarded as a source of image degradation and resolution loss. Recent improvements in the spatial resolution of state-of-the-art tomographs may be compromised by patient motion during scanning, as these high resolution data will be increasingly susceptible to smaller movements of the head. The authors have developed an opto-electronic motion tracking system based on commercially-available technology that is capable of very accurate real-time measurements of the position and orientation of the patient's head. These positions are transformed to the reference frame of the PET scanner, and could potentially be used to provide motion correction of list-mode emission data on an event-by-event basis.

Proceedings ArticleDOI
TL;DR: In this article, an add-on imaging spectrograph is described, which provides a unique combination of high quality image in a small, rugged, industrial, easy-to-use component.
Abstract: Imaging spectrometry has mainly been a research tool, employing laboratory spectrographs and scientific cameras. This paper describes an add-on imaging spectrograph that provides a unique combination of high quality image in a small, rugged, industrial, easy-to-use component. The spectrograph is based on a prism/grating/prism (PGP) dispersing element which provides straight optical axis, astigmatism free image and polarization independent throughput. A volume holographic transmission grating is used for high efficiency (up to 70%). The tubular optomechanical construction of the spectrograph is stable and small, D30 x L110 mm with F/2.8 numerical aperture and 2/3 inch image size. Equipped with C-mounts, the spectrograph plugs between lens and area camera, converting the camera to a spectral line imaging system. The spectrograph allows the utilization of rapidly developing monochrome camera techniques, like high speed digital cameras, smart cameras and CMOS sensors, in color and spectral analytical applications. It is the first component available for upgrading existing industrial monochrome vision systems with color/spectral capability without the need to change the basic platform hardware and software. The spectrograph brings the accuracy of spectral colorimetry to industrial vision and overcomes the complex calibration that is needed when an RGB color camera is applied to colorimetric applications. Other applications include NIR imaging (up to 2500 nm), spectral microscopy, multichannel fiberoptics spectrometry and remote sensing.

Proceedings ArticleDOI
TL;DR: A high resolution near IR camera (CONICA) for the firs VLT unit is under development, which will provide diffraction limited spatial resolution being combined with the adaptive optics system NAOS.
Abstract: A high resolution near IR camera (CONICA) for the firs VLT unit is under development, which will provide diffraction limited spatial resolution being combined with the adaptive optics system NAOS. CONICA serves as a multi-mode instrument for the wavelength region between 1.0 and 5.0 micrometers , offering broad band, narrow band or Fabry Perot direct imaging capabilities, polarimetric modes using Wollaston prism or wire grid analyzers and long slit spectroscopy up to a spectral resolution of about 1000 per two pixel. We presented a first concept of CONICA in 1995. In the mean time, large parts of the instrument have been manufactured, the cryostat and the adapter have been finished and first cryogenic test have been performed. This paper describes the actual design and status of development of CONICA focusing on those aspects which have not been described in detail before or the design of which have been changed in the mean time.