Browse Prior Art Database

Algorithm for Detecting Center of Object by Image Processing

IP.com Disclosure Number: IPCOM000100427D
Original Publication Date: 1990-Apr-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 71K

Publishing Venue

IBM

Related People

Saitoh, F: AUTHOR

Abstract

An algorithm is described which detects the center of an object represented in a gray scale image. It can detect the center even if the image does not have good contrast.

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This is the abbreviated version, containing approximately 77% of the total text.

Algorithm for Detecting Center of Object by Image Processing

       An algorithm is described which detects the center of an
object represented in a gray scale image.  It can detect the center
even if the image does not have good contrast.

      Referring to Fig. 1, a two-dimensional gray scale image 1 can
be considered a three-dimensional body if the brightness or gray
level of each picture element of the image 1 is plotted along the Z
axis, as shown in Fig. 2. The three-dimensional body will have a
height corresponding to the difference between gray levels of the
background 2 and the brightest picture element with the gray levels
defining contour lines.  Thus, the body can be considered to comprise
a set of volume units addressable by X, Y and Z coordinates, as shown
in Fig. 3(A).

      In processing, in the first step, picture elements of the image
1 which have the brightest gray level are first determined, and X and
Y addresses of the picture elements are detected.  Then, the image 1
is modified such that the gray level of the detected picture elements
is reduced by one.  This corresponds to removing the volume units of
the greatest Z coordinate value from the set, as shown in Fig. 3(B).

      In the second step, picture elements of the modified image 1
which now have the brightest gray level are selected, and X and Y
addresses of the selected picture elements are detected.  The image 1
is modified again such that the gray level of the picture e...