Browse Prior Art Database

Command Structure for a Low Cost (Primitive) Film Scanner

IP.com Disclosure Number: IPCOM000110535D
Original Publication Date: 1992-Dec-01
Included in the Prior Art Database: 2005-Mar-25
Document File: 9 page(s) / 386K

Publishing Venue

IBM

Related People

Edgar, AD: AUTHOR [+2]

Abstract

Disclosed is a command set that could be used to control a primitive film scanner where virtually all of the control functions are implemented in the attached host computer (e.g., PS/2* or Workstation).

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 16% of the total text.

Command Structure for a Low Cost (Primitive) Film Scanner

       Disclosed is a command set that could be used to control
a primitive film scanner where virtually all of the control functions
are implemented in the attached host computer (e.g., PS/2* or
Workstation).

      Current film scanners are either very expensive with associated
high image quality and flexibility or low cost with associated low
image quality and lack of flexibility.  The command structure
described in this article allows a low-cost device to be controlled,
without additional hardware beyond the controlling PC, without
limiting the flexibility associated with high-quality image results.
There are two major factors in enabling a low-cost, high-quality film
scanner:
1.) The removal of all but the essential (i.e., that which must be
implemented in hardware), control functions from the hardware and
implementing them in PC software.
2.) Implementation of precision compensating algorithms within the PC
software which, in turn, allows less precise lower cost hardware.
This article describes a scheme for accomplishing the former.

      Today most still-image capture is done either by a relatively
expensive video camera focused on the item to be captured, in turn
connected to some sort of capture adapter installed in a PC or
Workstation, or through the use of an expensive scanner working on
either film or a print, itself often attached to a special adapter.
Some of the newest scanners are quite inexpensive but do not offer
much flexibility and make many compromises to quality to achieve
their low price.  All of these represent expensive or compromised
solutions and essentially preclude high quality image capture from
many people who will likely soon want to do this within the confines
of their own workspace.

      To build a scanner meeting the objectives it is necessary to
carefully control that device from a series of low-cost computer/
operating system platforms.  A command structure to accomplish these
objectives is described below:
Scanner Command Interface

      The following is a functional description of the commands that
can be issued to the scanner hardware from the attached computer's
program (e.g., PS/2).  In addition the data sent from the scanner
hardware to the computer's software is also functionally described.
It should be noted that the scanner hardware does not initiate any
communication with the host but merely responds to commands from the
host.  Detail formats that are shown are meant to clarify the
disclosure and could be modified to accommodate hardware processing
logic as needed.  The commands are divided into several categories
based on the scanner subsystem that they control.  In the following
descriptions the commands are shown as 32-bit words with S
representing the sign bit, x representing  a currently unused bit
containing an undetermined value (reserved for future expansion) and
N & L representing the numeric port...