Browse Prior Art Database

Displaying Scanned Images On 3270/PC

IP.com Disclosure Number: IPCOM000100253D
Original Publication Date: 1990-Mar-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 84K

Publishing Venue

IBM

Related People

DiNicola, PD: AUTHOR [+3]

Abstract

Scanned images contain tremendous amounts of data that must be passed from the system memory to the All-Points-Addressable (APA) display buffers. This image data is much larger than what can be displayed on a display screen at one time, the size of the display screen being 720 pels wide by 350 pels high. Scanners commonly have resolutions of 200 pels per inch. Therefore, an 8-1/2-by-11-inch piece of paper would require a display 1700 pels wide by 2200 pels high to show an image at the resolution of the scanner. This resolution is roughly two times the width and six times the height of the display screen.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Displaying Scanned Images On 3270/PC

       Scanned images contain tremendous amounts of data that
must be passed from the system memory to the All-Points-Addressable
(APA) display buffers.  This image data is much larger than what can
be displayed on a display screen at one time, the size of the display
screen being 720 pels wide by 350 pels high.  Scanners commonly have
resolutions of 200 pels per inch.  Therefore, an 8-1/2-by-11-inch
piece of paper would require a display 1700 pels wide by 2200 pels
high to show an image at the resolution of the scanner.  This
resolution is roughly two times the width and six times the height of
the display screen.

      A simple software algorithm can be created to reduce the data
of the scanned image by approximately a factor of 2 to 720 pels wide
by 1050 pels high.  Still, this is three times larger than the
display height.  However, the image can now be viewed in three
separate buffer updates.  The data for the scanned image would need
to be stored in presentation space in system memory and the portion
of the image desired for viewing or scrolling would need to be loaded
in the APA display buffers and then reloaded if further scrolling
were required. Especially, if the scrolling required was at one scan
line resolution, also called smooth scrolling.  This would use a high
percentage of system cycles just updating the screen during
scrolling.  If other tasks were necessary while the screen was being
updated, the screen would jump and flash containing only pieces of
the new image and pieces of the old.  This would also require 94.5
bytes of system memory be available to store the scanned image.

      The described display memory provides the solutions to (1) the
heavy system requirements necessary for data movement during
scrolling, and (2) the storage for the three full pages of image
exists on the card relieving the large requirements for system
memory.

      A mechani...