1,499 research outputs found
Results of precision processing (scene correction) of ERTS-1 images using digital image processing techniques
ERTS-1 MSS and RBV data recorded on computer compatible tapes have been analyzed and processed, and preliminary results have been obtained. No degradation of intensity (radiance) information occurred in implementing the geometric correction. The quality and resolution of the digitally processed images are very good, due primarily to the fact that the number of film generations and conversions is reduced to a minimum. Processing times of digitally processed images are about equivalent to the NDPF electro-optical processor
Thermal dosimetry for bladder hyperthermia treatment. An overview.
The urinary bladder is a fluid-filled organ. This makes, on the one hand, the internal surface of the bladder wall relatively easy to heat and ensures in most cases a relatively homogeneous temperature distribution; on the other hand the variable volume, organ motion, and moving fluid cause artefacts for most non-invasive thermometry methods, and require additional efforts in planning accurate thermal treatment of bladder cancer. We give an overview of the thermometry methods currently used and investigated for hyperthermia treatments of bladder cancer, and discuss their advantages and disadvantages within the context of the specific disease (muscle-invasive or non-muscle-invasive bladder cancer) and the heating technique used. The role of treatment simulation to determine the thermal dose delivered is also discussed. Generally speaking, invasive measurement methods are more accurate than non-invasive methods, but provide more limited spatial information; therefore, a combination of both is desirable, preferably supplemented by simulations. Current efforts at research and clinical centres continue to improve non-invasive thermometry methods and the reliability of treatment planning and control software. Due to the challenges in measuring temperature across the non-stationary bladder wall and surrounding tissues, more research is needed to increase our knowledge about the penetration depth and typical heating pattern of the various hyperthermia devices, in order to further improve treatments. The ability to better determine the delivered thermal dose will enable clinicians to investigate the optimal treatment parameters, and consequentially, to give better controlled, thus even more reliable and effective, thermal treatments
Merging panchromatic multispectral images for enhanced image analysis
This study evaluates several methods that enhance the spatial resolution of multispectral images using a finer resolution panchromatic image. The resultant hybrid, high resolution, multispectral data set has increased visible interpretation and improved classification accuracy, while preserving the radiometry of the original multispectral images. These methods can therefore be applied to create simulated high resolution multispectral data, as well as to enhance image analysis
The SUMER Data in the SOHO Archive
We have released an archive of all observational data of the VUV spectrometer
Solar Ultraviolet Measurements of Emitted Radiation (SUMER) on SOHO that has
been acquired until now. The operational phase started with 'first light'
observations on 27 January 1996 and will end in 2014. Future data will be added
to the archive when they become available. The archive consists of a set of raw
data (Level 0) and a set of data that are processed and calibrated to the best
knowledge we have today (Level 1). This communication describes step by step
the data acquisition and processing that has been applied in an automated
manner to build the archive. It summarizes the expertise and insights into the
scientific use of SUMER spectra that has accumulated over the years. It also
indicates possibilities for further enhancement of the data quality. With this
article we intend to convey our own understanding of the instrument performance
to the scientific community and to introduce the new, standard-FITS-format
database.Comment: 38 pages, 9 figures, accepted for publication by Solar Physic
LANDSAT-4 Scientific Characterization: Early Results Symposium
Radiometric calibration, geometric accuracy, spatial and spectral resolution, and image quality are examined for the thematic mapper and the multispectral band scanner on LANDSAT 4. Sensor performance is evaluated
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