Image processing apparatus and method

• US 5,680,471 A
• Filed: 07/27/1994
• Issued: 10/21/1997
• Est. Priority Date: 07/27/1993
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Nakayama, Hiroshi, Kanebako, Toyomitsu
• Primary Examiner(s): Couso, Jose L.
• Assistant Examiner(s): Do, Anh Hong
• Application Number:
  US08/281,037
• Time in Patent Office: 1,182 Days
• Field of Search: 382/128, 382/132, 382/173, 382/190, 128/661.08, 128/661.1, 128/774, 128/653.2, 364/413.23
• US Class Current: 382/128
• CPC Class Codes: A61B 6/4225 using image intensifiers
• CPC Class Codes: A61B 6/503 for diagnosis of the heart
• CPC Class Codes: G06T 2207/10121 Fluoroscopy
• CPC Class Codes: G06T 2207/30048 Heart; Cardiac
• CPC Class Codes: G06T 7/0012 Biomedical image inspection
• CPC Class Codes: G06T 7/12 Edge-based segmentation
• CPC Class Codes: G06T 7/194 involving foreground-background segmentation
• CPC Class Codes: G06T 7/60 Analysis of geometric attributes

Abstract

An image processor acquires an image including a desired portion of an object to be examined. An image memory temporarily stores the acquired image, and an outline is extracted from an area of interest from the desired portion of the object. The outline is extracted by dividing the image stored in the image memory into plural areas using parallel lines, and a threshold value is set for each of the plural divided areas. Points having values exceeding the threshold values are connected.

Claims

1. An image processing apparatus comprising:

image acquiring means for acquiring an image including a desired portion of an object to be examined;

image memory means for temporarily storing the acquired image; and

outline extracting means for extracting an area of interest from a desired portion of the object wherein

said outline extracting means includes

long axis setting means for setting a long axis in a first direction of the image,

first profile generating means for drawing a plurality of lines on the image in a second direction perpendicular to the long axis so as to divide the image stored in said image memory means into a plurality of areas, and generating a plurality of first profile data for the respective perpendicular lines,

density setting means for searching a background area outside the area of interest and an inner area inside the area of interest on the basis of the first profile data, and obtaining densities of the background area and the Inner area,

threshold value determining means for determining a threshold value for each of the plurality of divided areas on the basis of a weighted mean of the densities of the background area and the inner area, and

outline setting means for determining an outline point constituting a boundary between the outside and inside of the area of interest by using the threshold values determined for the respective first profile data, and connecting the outline points.

2. An apparatus according to claim 1, wherein said first profile generating means includes

position detecting means for detecting a maximum density position in the first profile data between the predetermined position on the outside and the long axis, in a direction from the predetermined position on the outside to the long axis, and

background area density replacing means for replacing the maximum density position detected by said position detecting means with a background area density.

3. An apparatus according to claim 2, wherein said background density replacing means includes

determination means for determining whether the maximum density position is between an outline point set by the immediately preceding first profile data and the predetermined position on the outside, and

means for replacing the background density with a density of the maximum density position on the basis of the determination result obtained by said determination means.

4. An apparatus according to claim 2, wherein said background density replacing means includes

determination means for determining whether the maximum density position is between an outline point set by the immediately preceding first profile data and the predetermined position on the outside, and

starting point changing means for changing the search starting point to the maximum density position on the basis of the determination result obtained by said determination means.

5. An apparatus according to claim 1, wherein said density setting means includes means for setting an average of a sum of currently read background densities of the first profile data and previously read background densities of the first profile data.

6. An apparatus according to claim 5, wherein said first profile generating means includes means for generating first profile data proportional in number to a length of the long axis.

7. An apparatus according to claim 1, wherein said first profile generating means includes means for generating first profile data proportional in number to a length of the long axis.

8. An apparatus according to claim 1, wherein

said threshold value determining means includes

means for setting first and second threshold values for left and right sides of the first profile data with respect to the long axis, and

said outline setting means includes means for detecting the outline points on the basis of the first and second threshold values on the left and right sides of the long axis.

9. An apparatus according to claim 1, wherein said outline extracting means further include means for searching a background area on the first profile data.

10. An apparatus according to claim 1, wherein said first profile generating means includes

means for drawing the plurality of perpendicular lines at substantially equal intervals, and

search starting point setting means for setting a representative point of the background area as a search starting point at a predetermined position spaced apart by a predetermined distance from an outline point obtained from the immediately preceding first profile data.

11. An apparatus according to claim 10, wherein said search starting point determining means includes means for setting a point spaced apart outward from the outline point by a distance proportional to a length of the long axis as a search starting point.

12. An image processing method comprising:

the first step of acquiring an image including a desired portion of an object to be examined;

the second step of temporarily storing the acquired image; and

the third step of extracting an area of interest from the desired portion of the object,

wherein the third step includes the substeps of

setting a long axis in a first direction of the image to divide the image stored in said image memory means into a plurality of areas,

drawing a plurality of perpendicular lines on the image in a second direction perpendicular to the long axis, and generating a plurality of first profile data for the respective perpendicular lines

searching a background area outside the area of interest and an inner area inside the area of interest on the basis of each of the first profile data, and obtaining densities of the background area and the inner area,

determining a threshold value for each of the plurality of divided areas on the basis of an average of a sum of the densities of the background area and the inner area, and determining outline points constituting a boundary between the outside and inside of the area of interest by using the threshold values determined for the respective first profile data, and connecting outline points.