<title>Image capture and printing system for digitally generated medical-diagnostic images</title>

Abstract

The printing of digitally generated images from medical diagnostic equipment has typically been done on analog systems after D to A conversion. Newer digital printing systems do not generally yield optimum results since they re-sample the incoming video signal according to their own internal pixel matrix. This leads to a loss of contrast and resolution plus the introduction of aliasing artifacts into the image. Using the method of synchronous sampling of the incoming video signal an almost perfect digitization of the original image can be achieved. Starting with the known display pixel matrix the pixel display clock can be regenerated by a precision phase locked frequency synthesizer. Quantizing levels are duplicated through calibration of the system. Sampling phase error is adjusted out such that each pixel is sampled at its center. Comparison with non-synchronous techniques and multi-generation performance of this system will be demonstrated. The images are then transferred digitally on disk for storage and later printing by a CRT based slow scan camera system. Image parameter files saved with the image allow the camera to generate a gamma correction look-up table for printing. The film image will then precisely and consistently match the CRT image viewed by the system operator. The system is capable of digitizing and printing up to 10242 images with the same high quality as the original displayed image.