Proceedings Article | 7 May 1997
KEYWORDS: Telepathology, Image compression, Image resolution, Image quality, Internet, Cameras, Computing systems, Scanners, Glasses, Telecommunications
In the telepathology, rendering devices significantly influence the perceived image quality. If the resolution and color depth are reduced beyond a certain point, however, it is not possible to obtain images which can be used in telepathology even in an ideal situation. With this in mind, we evaluated image quality, compression, size and rates of data exchange with several histological cases on several kinds of systems for our International Consortium for Internet Telepathology (ICIT) project. The ICIT network uses widely available nonpropriety hardware and software with the Internet as a means of communication.In this study, we discuss the effective image acquisition methods for telepathology. To evaluate microscopic images, various resolution size were used. The images were also evaluated at different JPEG compression ratio, including zero compression, and different format. To evaluate an entire glass slide image, a scanner in transparency mode and an NTSC camera were used. Every case showed similar results. For he microscopic image, although the high resolution images, such as 2k X 1.5k or higher, contain more diagnostic information than lower resolution images; sufficient data was retained in the latter that it does not appear to negatively effect diagnosis. The circumstance and condition for image acquisition, such as specimen thickness or dast of glass slide, are most influenced on the highest image resolution. Usually, we use 5-10 images/case for a telepathology conference. To see all images of a case at a glance before detailed observation, or to switch to the other images immediately, a lower resolution,such as 1k X 0.7k is useful. For the entire glass slide, the reviewer could select the desired area by scanner; however, selecting it by the NTSC camera, was not easy to do. On the monitor, the scanned image has almost the same information as the microscopic image captured by the NTSC camera with 2x objective lens. To ge ta high enough quality image, the important factors are correct usage of the microscope and the condition of glass slide, not only high performance equipment.Since we have been using the Internet as the communication medium, we selected 1024 X 774 and 640 X 480 with 1/7-1/15 compressed image for microscopic image and 2700 dpi scanned image for entire glass slide. For the static image telepathology, the most important image is the low power image such as the entire specimen. High resolution images such as 3k X 2k are also useful for different purpose such as publication.
