Systems and methods of subtraction angiography utilizing motion prediction
A system and method for calculating a pixel-shift vector that predicts the motion in dynamic image data and can be used to shift reference image data in order to generate a subtracted image with reduced motion artifacts. The pixel-shift vector is calculated based on displacement vectors that have been calculated based on past motion in the dynamic image data. One embodiment determines a virtual pixel-shift vector as a function of stored pixel-shift vectors that were previously determined as a function of a previously captured live frame. The virtual pixel-shift vector is a prediction of the location of the current live frame before the current live frame is captured. The mask frame is adjusted as a function of this virtual pixel-shift vector. The current live frame is then subtracted from the mask frame adjusted as a function of the virtual pixel-shift vector. The adjusted mask frame and the live frame will then overlap and the subtracted image will have reduced artifacts.
1. A method, comprising:
accessing reference image data;
accessing first dynamic image data;
determining first pixel-shift vector data indicating a shift amount and shift direction, as a function of the reference image data and the first dynamic image data;
accessing second dynamic image data;
determining second pixel-shift vector data indicating a shift amount and shift direction, as a function of the reference image data and the second dynamic image data;
determining third pixel-shift vector data as a function exclusively of the first pixel-shift vector data and the second pixel-shift vector data;
adjusting the reference image data as a function of the third pixel-shift vector data;
accessing third dynamic image data;
subtracting the adjusted reference image data from the third dynamic image data; and
generating resultant image data as a function of the subtracting step.
2. The method according to claim 1 , further comprising:
determining third pixel-shift vector data by interpolation between first pixel-shift vector data and the second pixel-shift vector data and
storing the resultant image data.
3. The method according to claim 1 , further comprising:
displaying the resultant image data.
4. The method according to claim 1 , further comprising:
determining the first pixel-shift vector data at a predetermined frame rate of the first dynamic image data.
5. The method according to claim 1 , further comprising:
adjusting the reference image data as a function of the second pixel shift vector data when the second pixel-shift vector data is known at the time the third dynamic image data is accessed.
6. The method according to claim 1 ,
wherein the reference image data is a first frame of data; and
wherein the first dynamic image data is a subsequent frame of data.
7. The method according to claim 1 , wherein the reference image data is a mask frame.
8. A method, comprising:
accessing reference image data;
accessing first and second dynamic image data;
determining first pixel-shift vector data indicating a shift amount and shift direction, as a function of the reference image data and the first dynamic image data;
determining second pixel-shift vector data indicating a shift amount and shift direction, as a function of the reference image data and the second dynamic image data;
determining third pixel-shift vector data by interpolation between first pixel-shift vector data and the second pixel-shift vector data; and
adjusting the reference image data as a function of the third pixel-shift vector data.
9. The method according to claim 8 , further comprising:
calculating said third pixel-shift vector data as a function exclusively of the first and second pixel-shift vector data;
accessing second dynamic image data;
subtracting the adjusted reference image data from the second dynamic image data; and
generating resultant image data as a function of the subtracting step.
10. The method according to claim 9 , further comprising:
determining the first pixel-shift vector data at a predetermined frame rate of dynamic image data; and
determining the second pixel-shift vector data at a predetermined frame rate of dynamic image data.
11. A method, comprising:
accessing a reference frame;
accessing dynamic frame data;
calculating first pixel-shift vector data indicating a shift amount and shift direction, as a function of the reference frame and the dynamic frame data;
calculating second pixel-shift vector data indicating a shift amount and shift direction, as a function of the reference frame and the dynamic frame data;
calculating virtual pixel-shift vector data as a function exclusively of the first and second pixel-shift vector data;
shifting the reference frame as a function of the virtual pixel-shift vector data;
accessing second dynamic frame data;
subtracting the second dynamic frame data from the shifted reference frame; and
generating resultant image data as a function of the subtracting step.
12. The method according to claim 11 , further comprising:
determining virtual pixel-shift vector data by interpolation between first pixel-shift vector data and the second pixel-shift vector data and
storing the pixel-shift vector data.
13. The method according to claim 12 , wherein the pixel-shift vector data is stored in an array.
14. The method according to claim 11 , further comprising:
determining the first pixel-shift vector data at a predetermined frame rate of dynamic image data.
15. The method according to claim 11 , further comprising:
storing the resultant image data.
16. The method according to claim 11 , further comprising:
displaying the resultant image data.
17. An apparatus implemented using at least one processor, comprising:
means for accessing reference image data;
means for accessing first dynamic image data;
means for determining first pixel-shift vector data indicating a shift amount and shift direction, as a function of the reference image data and the first dynamic image data;
means for accessing second dynamic image data;
means for determining second pixel-shift vector data indicating a shift amount and shift direction, as a function of the reference image data and the second dynamic image data;
means for determining third pixel-shift vector data as a function exclusively of the first pixel-shift vector data and the second pixel-shift vector data;
means for adjusting the reference image data as a function of the third pixel-shift vector data;
means for accessing third dynamic image data;
means for subtracting the adjusted reference image data from the third dynamic image data; and
means for generating resultant image data as a function of the subtracting step.
18. The apparatus according to claim 17 , further comprising:
means for storing the resultant image data.
19. The apparatus according to claim 17 , further comprising:
means for determining the first pixel-shift vector data at a predetermined frame rate of the first dynamic image data.
20. The apparatus according to claim 17 , further comprising:
means for adjusting the reference image data as a function of the second pixel shift vector data when the second pixel-shift vector data is known at the time the third dynamic image data is accessed.
21. The apparatus according to claim 17 ,
wherein the reference image data is a first frame of data; and
wherein the first dynamic image data is a subsequent frame of data.
22. The apparatus according to claim 17 ,
wherein the reference image data is a mask frame.
23. An apparatus implemented using at least one processor, comprising:
means for accessing reference image data;
means for accessing first and second dynamic image data;
means for determining first pixel-shift vector data indicating a shift amount and shift direction, as a function of the reference image data and the first dynamic image data;
means for determining second pixel-shift vector data indicating a shift amount and shift direction, as a function of the reference image data and the second dynamic image data;
means for determining third pixel-shift vector data by interpolation between the first pixel-shift vector data and the second pixel-shift vector data; and
means for adjusting the reference image data as a function of the third pixel-shift vector data.
24. An apparatus implemented using at least one processor, comprising:
means for accessing a reference frame;
means for accessing dynamic frame data;
means for calculating first pixel-shift vector data indicating a shift amount and shift direction, as a function of the reference frame and the dynamic frame data;
means for calculating second pixel-shift vector data indicating a shift amount and shift direction, as a function of the reference frame and the dynamic frame data;
means for calculating virtual pixel-shift vector data as a function exclusively of the first and second pixel-shift vector data;
means for shifting the reference frame as a function of the virtual pixel-shift vector data;
means for accessing second dynamic frame data;
means for subtracting the second dynamic frame data from the shifted reference frame; and
means for generating resultant image data as a function of the subtracting step.
25. A system, comprising:
at least one processor; and
at least one memory, coupled to the at least one processor, storing program code adapted to cause the at least one processor to
access reference image data;
access first dynamic image data;
determine first pixel-shift vector data indicating a shift amount and shift direction, as a function of the reference image data and the first dynamic image data;
access second dynamic image data;
determine second pixel-shift vector data indicating a shift amount and shift direction, as a function of the reference image data and the second dynamic image data;
determine third pixel-shift vector data as a function exclusively of the first pixel-shift vector data and the second pixel-shift vector data;
adjust the reference image data as a function of the third pixel-shift vector data;
access third dynamic image data;
subtract the adjusted reference image data from the third dynamic image data; and
generate resultant image data as a function of the subtracting step.
26. A system, comprising:
at least one processor; and
at least one memory, coupled to the at least one processor, storing program code adapted to cause the at least one processor to:
access a reference frame;
access dynamic frame data;
calculate first pixel-shift vector data indicating a shift amount and shift direction, as a function of the reference frame and the dynamic frame data;
calculate second pixel-shift vector data indicating a shift amount and shift direction, as a function of reference image data and the second dynamic image data;
calculate virtual pixel-shift vector data as a function exclusively of the first and second pixel-shift vector data;
shift the reference frame as a function of the virtual pixel-shift vector data;
access second dynamic frame data;
subtract the second dynamic frame data from the shifted reference frame; and
generate resultant image data as a function of the subtracting step.