Image processing method and image processing device

Abstract

A threshold value T which is a little larger than voxel values of a target tissue such as bloodstream is determined. Next, a virtual ray is projected, and voxel values on the virtual ray are obtained as an array A 1 (original array). Then, an array A 2 (replaced array) is generated by the voxel values of the array A 1 which are equal to or larger than the threshold value T are flipped-over at the threshold value T. Then, a part of the data on the array A 2 , e.g., flipped-over data corresponding to the center part of the calcified region is excluded. Next, a maximum value M 2 on the array A 2 is obtained, and a value M 1 on the array A 1 corresponding to the value M 2 is obtained. Then, the value M 1 is employed as a pixel value for the virtual ray.

1 . An image processing method by volume rendering, said image processing method comprising:
 selecting at least one point which is aligned on a virtual ray;   determining a degree of contribution of each value of the selected at least one point; and   determining a pixel value of an image by the volume rendering based on the determined degree of contribution and said each value of the selected at least one point.   
   
   
       2 . The image processing method according to  claim 1 , wherein at least one of the degree of contribution is zero. 
   
   
       3 . The image processing method according to  claim 1 , wherein the degree of contribution is determined based on data obtained by replacing original data on the virtual ray. 
   
   
       4 . The image processing method according to  claim 3 , wherein values of the replaced data are obtained by flipping values of the original data over at a threshold value. 
   
   
       5 . The image processing method according to  claim 1 , wherein the degree of contribution is determined further based on a gradient vector which is on a volume and corresponds to a position of the selected point, and a direction vector of the virtual ray. 
   
   
       6 . The image processing method according to  claim 1 , wherein the degree of contribution is determined further based on a change of voxel values on the virtual ray. 
   
   
       7 . The image processing method according to  claim 1 , further comprising:
 displaying a two-dimensional outline of a region included in a rendering object on the volume rendering image.   
   
   
       8 . The image processing method according to  claim 1 , further comprising:
 displaying excluding a region included in a rendering object on the volume rendering image.   
   
   
       9 . The image processing method according to  claim 1 , wherein the volume rendering image and an another image are displayed arranged in side by side, being overlapped with each other, or by showing a difference of the images. 
   
   
       10 . The image processing method according to  claim 1 , wherein the pixel value is determined only for a region which is designated by a user. 
   
   
       11 . The image processing method according to  claim 1 , wherein the pixel value is determined only for a window provided on a screen. 
   
   
       12 . The image processing method according to  claim 7 , wherein the outline is displayed while continuously changed. 
   
   
       13 . The image processing method according to  claims 1 , wherein the image processing is performed by parallel processing. 
   
   
       14 . The image processing method according to  claim 1 , wherein the image processing is performed by a GPU (graphics processing unit). 
   
   
       15 . The image processing method according to  claim 1 , wherein the image processing is performed by a GUI (graphical user interface) in which parameters are changeable. 
   
   
       16 . The image processing method according to  claim 1 , wherein the image processing is performed by MIP (Maximum Intensity Projection) method, MinIP (Minimum Intensity Projection) method, Raysum method, an average value method or ray casting method.