Biomedical subjects

Y Ishimitsu

Publications and source records attributed to Y Ishimitsu.

3 recordsLinked to original sources

PubMed1988

Picture archiving and communication systems (PACS) for radiological images: state of the art.

Implementation of a Picture Archiving and Communication System (PACS) is a system integration task and requires the knowledge of multidisciplinary fields. This paper reviews current PACS development with emphasis on radiological images. The following topics are covered: methods of image acquisition, image compression, storage, display, communication, and image database structure. Methods of implementation of PACS in a clinical environment as well as current operational PACS in hospitals are reviewed. A survey of private industry participating in PACS research and development are also given.

Hospital Information Systems↗

PubMedDate not supplied

Radiological laser film scanner sampling artifact.

Artifacts seen on laser digitized radiographs are analyzed and mathematically explained based on the concept of image contrast. Our investigation considered the following determinants: (a) laser spot size, (b) signal processing components, (c) image characteristics, and (d) observer performance. A functional relationship between the sampling interval, laser spot size, and the contrast of the artifact seen on the digitized image is derived. This relationship is verified experimentally using a variable spot size laser source and sampling at interval of 175.0 microns. The problem of digitizing artifact seen on film images obtained with anti-scatter grids is discussed.

Analog-Digital Conversion↗

PubMedDate not supplied

Light photon equalization and its application to X-ray film digitization.

The principle of light photon equalization (LPE) is to modulate the light source during X-ray film digitization so that the dynamic range of the transmitted light into a photo-detector can be precisely controlled to obtain improved signal-to-noise ratio (SNR). The modulation of the light source is derived from a smoothed image of the original digitized image. The final output digital image is reconstructed by convoluting the modulation function with the resultant LPE image. The LPE was implemented in a laser film digitizer as a prototype. The results shows that, although the dynamic range of X-ray films is about 10(4):1, the range of the transmission light into a photo detector was reduced to 10(2):1 with this technique. Also the SNR improved by a maximum factor of five in the lung area of a digitized chest radiograph.

Algorithms↗