System and method for performing volume rendering using shadow calculation

• US 8,698,806 B2
• Filed: 11/09/2009
• Issued: 04/15/2014
• Est. Priority Date: 11/09/2009
• Status: Active Grant

• Current Assignee: Maxon Computer GmbH (Nemetschek SE)
• Original Assignee: Maxon Computer GmbH (Nemetschek SE)
• Inventors: Schneider, Harald, Kunert, Thomas
• Primary Examiner(s): Sajous, Wesner
• Assistant Examiner(s): Shin, Andrew
• Application Number:
  US12/614,466
• Publication Number:
  US 20110109631A1
• Time in Patent Office: 1,618 Days
• Field of Search: 345/419, 345/420, 345423-427, 345581-588, 345/619, 382/128, 382/131, 382/132, 382/154, 382/276, 382/277, 382/285, 382/305, 715/764, 715/781, 715/782, 715848-852, 463 30- 34, 600/300, 600/407, 600410-423, 600425-429, 600/436, 600437-461, 703/6, 703/11
• US Class Current: 345/426
• CPC Class Codes: G06T 15/08 Volume rendering
• CPC Class Codes: G06T 15/60 Shadow generation

Abstract

A method and a system are provided for performing volume rendering a 3D array of image data to produce images with an increased spatial information and thus increase the usefulness of the generated images.

Claims

1. A method for performing a volume rendering of a 3D array of image data using shadow calculation, the method comprising the steps of:

receiving the 3D array of image data;

determining a viewing direction and position of a light source;

depending on the position of the light source, automatically selecting a shadow-calculation method comprising ray casting or texture-based volume rendering;

determining a number of slices to use;

slicing the array of image data into the determined number of slices with the slices either perpendicular to the viewing direction, perpendicular to a bisector between the viewing direction and the direction of light from the source, or perpendicular to a bisector between the mirrored viewing direction and the light direction;

calculating shadows if the position of the light source moves or if the shadow-calculation method has been changed;

rendering the slices with ray casting or texture-based volume rendering and incorporating the shadows determined by the latest shadow calculation independent of the rendering method by which they were calculated; and

displaying the rendered data on a screen of a display device using ray casting and/or texture-based volume rendering.

2. The method defined in claim 1, further comprising the step of acquiring the 3D array of image data.

3. The method defined in claim 2 wherein the image data are acquired by one of the techniques including a computed tomographic (CT), helical CT, optical coherence tomography (OCT), spectral-domain optical coherence tomography (SD-OCT), x-ray, positron emission tomographic (PET), fluoroscopic, confocal microscopic, ultrasound, and magnetic resonance (MR) imaging technique.

4. The method defined in claim 1, further comprising the step, during rendering of the slices, of:

mapping the colors of a selected gradient to the grey scale values of the new images.

5. The method defined in claim 1, wherein the image data loaded for volume rendering are in different formats including DICOM, movies, image sequences.

6. The method defined in claim 1, wherein Boolean operations are used for modifying slices.

7. The method defined in claim 1, further comprising the step of:

dynamically adapting the number of the slices to reach a defined frame rate.

8. The method defined in claim 1, wherein there are multiple light sources whose positions are calculated.

9. The method defined in claim 1, wherein the rendered data is displayed as a real time monoscopic view, a real time stereoscopic view, a movie or a still image.

10. The method defined in claim 1, wherein the viewing direction, the position of the light source, and other parameters including colors and desired quality of the final presentation can be determined and adjusted by the user through a user interface.

11. The method defined in claim 1, further comprising the step of

subjecting the input 3D array of image data to filtering to enhance the quality of the presentation.

12. The method defined in claim 1, further comprising the step of subjecting the input 3D array of image data tracking to detect and reduce scanning errors including translation and rotation.

13. The method defined in claim 1, wherein certain parameters including the position of the light source and the viewing direction can be set by presets to allow for functions such as automated turntable animations.

14. A system for performing a volume rendering of a 3D array of image data using shadow calculation, the system comprising:

a memory device for storing a program;

at least one processor in communication with the memory device and operative with the program to;

receive the 3D array of image data;

determine a viewing direction and position of a light source;

depending on the a position of the light source, automatically select a shadow-calculation method comprising ray casting or texture-based volume rendering;

determine a number of slices to use;

slice the array of image data into the determined number of slices with the slices either perpendicular to the viewing direction, perpendicular to a bisector between the viewing direction and the light direction, or perpendicular to a bisector between the mirrored viewing direction and the light direction;

calculate shadows if the position of the light source moves or if the shadow-calculation method has been changed;

render the slices with ray casting or texture-based volume rendering and incorporating the shadows determined by the latest calculation independent of the rendering method by which they were calculated; and

a display in communication with the processor for displaying the rendered data in ray casting and/or texture-based volume rendering.

15. The system defined in claim 14, wherein the processor is a graphics-processing unit and/or a central-processing unit.

16. The system defined in claim 14, wherein the processor is further operative with program code to map the colors of a selected gradient to grey scale values of the new images during rendering of the slices.

17. The system defined in claim 14, wherein the processor is further operative with program code to acquire the 3D volume of image data.

18. The system defined in claim 17, wherein the image data are acquired by one of the methods including a computed tomographic (CT), helical CT, optical coherence tomography (OCT), spectral-domain optical coherence tomography (SD-OCT), x-ray, positron emission tomographic (PET), fluoroscopic, confocal microscopic, ultrasound, and magnetic resonance (MR) imaging technique.

19. The system defined in claim 14, wherein the image data loaded for volume rendering are in different formats including DICOM, Movies, Image sequences.

20. The system defined in claim 14 wherein Boolean operations are used for modifying slices.

21. The system defined in claim 14 wherein the number of the slices is adapted to reach a defined frame rate.

22. The system defined in claim 14, wherein there are multiple light sources whose positions are calculated.

23. The system defined in claim 14 wherein the rendered data is displayed as a real time monoscopic view, a real time stereoscopic view, a movie or a still image.

24. The system defined in claim 14 wherein the viewing direction, the position of the light source, and other parameters including colors and desired quality of the final presentation can be determined and adjusted by the user though a user interface.

25. The system defined in claim 14 wherein the processor is further operative with the program code to subject the input 3D array of image to data filtering to enhance the quality of the presentation.

26. The system defined in claim 14 wherein the processor is further operative with the program code to subject the input 3D array of image data to tracking to detect and reduce scanning errors including translation and rotation.

27. The system defined in claim 14 wherein certain parameters including the position of the light source and the viewing direction can be set by presets to allow for functions such as automated turntable animations.

28. A non-transitory computer readable medium having computer program logic recorded thereon for performing on a processor a volume rendering of a 3D array of image data using shadow calculation, the computer program logic comprising:

receiving the 3D array of image data;

determining a viewing direction and position of a light source;

depending on the position of the light source, automatically selecting a volume-rendering method comprising ray casting or texture-based volume rendering;

determining a number of slices to use;

slicing the array of image data into the determined number of slices with the slices either perpendicular to the viewing direction, perpendicular to the bisector between the viewing direction and the light direction, or perpendicular to the bisector between the mirrored viewing direction and the light direction;

calculating ray traced shadows with a position of a light source being used either fixed or movable;

rendering the slices with ray casting or texture-based volume rendering and incorporating the shadows determined by the latest shadow calculation independent of the rendering method by which they were calculated; and

displaying the rendered data on a screen with ray casting and/or texture-based volume rendering.

29. A computer-based system for performing a volume rendering of a 3D array of image data using shadow calculation, the system comprising:

means for receiving the 3D array of image data;

means for determining a viewing direction and position of a light source;

means for, depending on the position of the light source, automatically selecting a shadow-calculation method comprising ray casting or texture-based volume rendering;

means for determining a number of slices to use;

means for slicing the array of image data into the determined number of slices with the slices either perpendicular to the viewing direction, perpendicular to a bisector between the viewing direction and the direction of light from the source, or perpendicular to a bisector between the mirrored viewing direction and the light direction;

means for calculating shadows if the position of the light source moves or if the volume-rendering method has been changed;

means for rendering the slices with ray casting or texture-based volume rendering and incorporating the shadows determined by the latest shadow calculation independent of the rendering method by which they were calculated; and

means for displaying the rendered data on a screen of a display device with ray casting and/or texture-based volume rendering.