Method for carving volume data based on image
View Patent ↗Provided is an image-based volume data carving method for rapidly carving a specific area of dimensional volume data based on images. The method includes the steps of: generating a mask image to be carved from an input image; dividing a viewing transform matrix of the mask image into a shear transform matrix and a warp transform matrix, and calculating a scale factor from the shear transform matrix; modifying the mask image to be parallel to an axis of the volume data; shearing a volume slice in such a manner that the volume data can be parallel to viewing rays passing through a volume, and scaling the size of the volume slice; and carving part of the volume slice through an operation between the mask image and each volume slice.
1. A computer-readable medium that stores executable instructions to carve volume data based on an image, the instructions for causing a machine to perform the steps of:
a) generating a mask image to be carved from an input image;
b) dividing a viewing transform matrix of the mask image into a shear transform matrix and a warp transform matrix, and calculating a scale factor from the shear transform matrix, wherein a transform matrix M scale is acquired from the shear transform matrix in consideration of characteristics of the shear transform matrix when a camera projection method is a near-to-far projection wherein the scale transform matrix is acquired by dividing the shear transform matrix S perspective into a pure shear transform matrix M shear and a scale transform matrix M scale in consideration of characteristics of the shear transform matrix based on matrix relationship shown in an equation which is expressed as:
S
Perspective
=
M
Scale
·
M
Shear
=
(
1
0
-
e
o
,
w
e
o
,
x
0
0
1
-
e
o
,
y
e
o
,
z
0
0
0
1
0
0
0
-
e
o
,
w
e
o
,
z
1
)
where e o,x , e o,y , e o,z , and e o,w denotes x, y, z and w coordinates in an eye on coordinate system for an object, respectively;
c) modifying the mask image to be parallel to an axis of the volume data based on the viewing transform matrix;
d) shearing a volume slice in such a manner that the volume data can be parallel to viewing rays passing through a volume by using the mask image, and scaling the size of the volume slice by using the scale factor; and
e) carving part of the volume slice through an operation between the mask image modified in the step c) and each volume slice sheared/scaled in the step d).
2. The computer-readable medium as recited in claim 1 , wherein in the scale factor calculating procedure of the step b) finds the scale transform matrix M scale is acquired from the shear transform matrix in consideration of characteristics of the shear transform matrix when a camera projection method is a near-to-far projection.