Browse Prior Art Database

Generation Algorithm of Gray Degradation Table for ACR-NEMA Format Medical Image

IP.com Disclosure Number: IPCOM000115035D
Original Publication Date: 1995-Mar-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 58K

Publishing Venue

IBM

Related People

Takemura, T: AUTHOR

Abstract

Disclosed is a faster algorithm to generate gray degradation table used to convert ACR-NEMA format medical image to 8bits/pixel image, based on characteristics of the gray degradation table. In the table, entries which have identical values are repeated (power of 2) times, and appear every (power of 2) entries.

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Generation Algorithm of Gray Degradation Table for ACR-NEMA Format
Medical Image

      Disclosed is a faster algorithm to generate gray degradation
table used to convert ACR-NEMA format medical image to 8bits/pixel
image, based on characteristics of the gray degradation table.  In
the table, entries which have identical values are repeated (power of
2) times, and appear every (power of 2) entries.

      ACR-NEMA Format Medical Images, whose pixels are is represented
by 9 bits or hither, needs to be converted to the images in order to
be displayed on personal computer's display.

      This algorithm generates continuous entries which have the
identical value by coping the entry, and completes the table by
coping the sub-table.  To copes (2(i)) entries, only i times copy
instructions are required, and To copies (2(j)) tables, only j times
copy instructions are required.  The algorihm disclosed here uses
this characteristics to generate the table faster than the
conventional algorithm.

The Figure shows the representation of ACR-NEMA's pixel.

      Gray Degradation Table - Gray degradation table is a table
whose the i-th entry has a value of G(F(i)), when F is a projection
from input pixel values to real pixel values, and G is a projection
from real pixel values to output pixel values.

      In this table, entries from T(a * 2(n)) through T( (a+1) * 2(n)
- 1) have an identical value, when T(i) means the value of the i-th
entry of the table, and
n = High_Bit + 1 - Bits_Stored.

This means that continuous (2(n)) entr...