Traitement en cours

Veuillez attendre...

Paramétrages

Paramétrages

Aller à Demande

1. WO2013130587 - PROCÉDÉ ET APPAREIL DE CORRECTION DE PHASE PROLONGÉE EN IMAGERIE PAR RÉSONANCE MAGNÉTIQUE ASSERVIE EN PHASE

Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

[ EN ]

CLAIMS

1. A computerized method for generating a phase corrected magnetic resonance image or images comprising:

(a) acquiring a magnetic resonance image or images containing background or error phase information;

(b) calculating two vector images A and B using the acquired image or images so that a vector orientation by one of the two vector images at a pixel is substantially determined by the background or error phase at the pixel, and the vector orientation at the pixel by the other vector image is substantially different from that determined by the background or error phase at the pixel;

(c) applying a sequenced region growing phase correction algorithm to the vector images A and B to construct a new vector image V, wherein the algorithm comprises:

(i) selecting an initial seed pixel or pixels and assigning either A or B of the initial seed pixel or pixels as a value of V for the initial seed pixel or pixels;

(ii) selecting a secondary seed pixel and selecting either A or B of the secondary seed pixel as a value of V for the secondary seed pixel based on whether A or B of the secondary seed pixel has a smaller angular difference with an estimated V for the secondary seed pixel;

(iii) determining for the secondary seed pixel a local quality metric for each of the nearest neighbor pixels of the secondary seed pixel for which V has not been determined and assigning a priority to each of the nearest neighbor pixels using the local quality metric in order to determine the sequence by which each of the nearest neighbor pixels is to be selected as a further seed pixel;

(iv) repeating the steps of (ii) and (iii) to complete the sequenced region growing with respect to further seed pixels and to construct the vector image V so that a vector orientation of V at each pixel is substantially determined by the background or error phase at the pixel;

(d) generating the phase corrected magnetic resonance image or images from the acquired magnetic resonance image or images using the vector image V; and

(e) displaying or archiving the phase corrected magnetic resonance image or images.

2. The method of claim 1, further comprising correcting vector images A and B with a global linear error phase correction in one or more dimensions prior to performing the sequenced region growing.

3. The method of claim 1, further comprising applying a low-pass filter to vector image V before generating the phase corrected magnetic resonance image or images.

4. The method of claim 1 , wherein amplitudes of the vector images A and B at a pixel are weighted by a signal amplitude at the pixel.

5. The method of claim 1, wherein an initial seed pixel or pixels are selected from a high-quality region, wherein high-quality comprises a predetermined signal-to-noise ratio or a predetermined local orientational coherence for the vector images A or B.

6. The method of claim 1, wherein an initial seed pixel or pixels and the value of V at the initial seed pixel or pixels are selected based on an orientational coherence of either A or B at the initial seed pixel or pixels with V at a spatially or temporally neighboring pixel or pixels of a spatially or temporally neighboring image for which V is already known or has been determined.

7. The method of claim 1, wherein an initial seed pixel or pixels are placed onto a high priority pixel stack or stacks among a series of pixel stacks that are initially empty and which facilitate a sequencing of the sequenced region growing.

8. The method of claim 1, wherein a pixel is selected as a secondary seed pixel if it has not been processed previously as a seed pixel and it is on a pixel stack that has a highest priority among pixel stacks that contain at least one pixel that has not been processed as a seed pixel.

9. The method of claim 1, wherein the local quality metric of a pixel is calculated as the smaller of two orientational differences between A and B of the pixel with an estimated V for the pixel.

10. The method of claim 9, wherein the estimated V for a pixel is a first order estimation that includes an average and a linear expansion of V for pixels that are located within a neighboring region of the pixel and for which Fhas been previously determined.

11. The method of claim 9, wherein the estimated V for a pixel is a zeroth order estimation calculated as an average of V for pixels located within a neighboring region of the pixel and for which V has been previously determined.

12. The method of claim 11, wherein a size of the neighboring region is either fixed or adaptively adjusted based on a local quality metric for the pixel.

13. The method of claim 11 , wherein a size of the neighboring region is either fixed or adaptively adjusted based on a local quality metric for the pixel.

14. The method of claim 1, wherein the maximum possible range of 0 - π for the angular difference between any two vectors is used to gauge and bin the local quality metric and to place a pixel onto a pixel stack.

15. The method of claim 14, wherein the pixel stack covering a subrange of 0 - π for the quality metric is assigned a priority, and wherein a pixel stack of a higher priority is for receiving pixels with a smaller quality metric and a pixel stack of a lower priority is for receiving pixels with a larger quality metric.

16. The method of claim 15, wherein the priority of a pixel stack from which a pixel is selected as a seed pixel is recorded for the sequenced region growing as a quality metric index to reflect an integrity of the sequenced region growing.

17. The method of claim 16, wherein the quality metric index is used to segment an image into different segments of possible inconsistent region growing and then to combine the different segments into an overall consistent region growing to form a final vector image V.

18. The method of claim 1, wherein a value of the vector A for an initial seed pixel is assigned as VA, and a sequenced region growing is performed to construct a vector image VA, and wherein a value of the vector B for the same initial seed pixel is assigned as VB, and another sequenced region growing is performed to construct a vector image VB.

19. The method of claim 18, wherein either vector image VA or vector image VB is set to be a final vector image V, depending on whether vector image VA or vector image VB has a greater overall orientational smoothness.

20. The method of claim 1, wherein the sequenced region growing is performed in two spatial dimensions.

21. The method of claim 1, wherein the sequenced region growing is performed in three spatial dimensions.

22. The method of claim 1, wherein the sequenced region growing is performed by including the temporal dimension for a series of dynamically acquired images.

23. The method of claim 1 wherein acquiring a magnetic resonance image or images comprises acquiring two-point Dixon water and fat images, wherein a first image S1 is acquired at a first echo time TE1 and a second image S2 is acquired at a second echo time TE2.

24. The method of claim 23, wherein acquiring two-point Dixon water and fat images comprises using dual-echo bipolar readout gradients.

25. The method of claim 23, wherein acquiring two-point Dixon water and fat images comprises using dual-echo unipolar readout gradients.

26. The method of claim 23, wherein acquiring two-point Dixon water and fat images comprises using triple-echo readout gradients.

27. The method of claim 23, wherein acquiring two-point Dixon water and fat images comprises using interleaved single echo readout gradients.

28. The method of claim 23, wherein selection of TE1 and TE2 is flexible except to avoid a small orientational difference between vector image A and vector image B.

29. The method of claim 23, wherein the images S1 and S2 are expressed according to the following equations:



where W and F are amplitudes for water and fat respectively, P1 is a phase factor of image S1, P is an additional phase factor of image S2 relative to image S1 and is determined by a background or error phase, and the method further comprises determining by an image based pre-calibration an amplitude attenuation factor (δ1, δ2) and phase (θ1, θ2) as a function of two echo times (TE1, TE2) for the fat signal.

30. The method of claim 29, wherein pre-calibration of (δ1, δ2) is performed in part by determining an echo time dependence of a signal amplitude of a known fat-only image region, and pre-calibration of (θ1, θ2) is performed in part by determining an echo time dependence of a phase discontinuity between a known fat-only image region and a neighboring known water-only region.

31. The method of claim 29, wherein pre-calibration is performed for a given pulse sequence, a scan protocol, or a field strength.

32. The method of claim 23, wherein the images S1 and S2 are used to generate two vector images A and B as expressed according to the following equations:



where QA and QB are the two mathematically possible solutions of the following quadratic equation of Q, which is defined as (i.e., the water fraction for a given pixel):


j

where M1 and M2 are the square of the amplitudes of the images S1 and S2, respectively (i.e., M1 = ⃒S12 and M2 = |S2 |2).

33. The method of claim 32, wherein the vector images are further normalized and weighted by a signal amplitude, such as:



where again, M1 = ⃒S12 and M2 = ⃒S22 .

34. The method of claim 33, wherein sequenced region growing is used to construct image V from the two vector images A and B.

35. The method of claim 34, wherein the vector image V is used to phase correct and remove the phase factor P from the image S2, the phase corrected S2 is combined with S1 to solve for WP1 and FP1, and then to generate a water-only image and a fat-only image according to the following equations:



where Real{ ... } is to take the real component of its complex argument, * is to take the complex conjugate of its argument, and
and
represent low-pass filtering of WP1 and FPi, respectively.

36. The method of claim 1 wherein acquiring a magnetic resonance image or images comprises acquiring a single-point Dixon water and fat image wherein a flexible echo time TE is used and the acquired magnetic resonance image is expressed as: S = (W + Fe)P, where θ is dependent on TE and the dependence is determined with an image-based pre-calibration, and P (≡ e ) is a phase factor for the image S.

37. The method of claim 36, wherein the vector image A is set to S and the vector image B is set to Se-iθ .

38. The method of claim 37, wherein a sequenced region growing is used to construct a vector image V from the two vector images A and B, the vector image V is used to phase correct or remove P from S to form S', and a water-only image and a fat-only image are generated according to:



where Real{ ... } and Imag{ ... } are to take the real and imaginary components of their component, respectively.

39. The method of claim 1, wherein acquiring a magnetic resonance image or images comprises acquiring a single-point silicone specific image wherein an echo time TE when water and fat signals are substantially in-phase is used, and the acquired magnetic resonance image is expressed according to the following equation:


where Θ is determined with an image-based pre-calibration for the echo time TE as a phase discontinuity of a known silicone-only image region and a neighboring known water or fat only image region, and P (≡ e) is a phase factor for the image S.

40. The method of claim 39, wherein vector image A is set to S and vector image B is set to Se-iθ .

41. The method of claim 40, wherein a sequenced region growing is used to construct a vector image V from the two vector images A and B, the vector image V is used to phase correct or remove P from S to form S', and a silicone-only image and a silicone-suppressed image are generated according to:



where Real{ ... } and Imag{ ... } are to take the real and imaginary components of their component, respectively.

42. The method of claim 1, wherein acquiring a magnetic resonance image or images comprises acquiring an inversion recovery image at an inversion recovery time TI and the image is expressed according to the following equation:


where I is a signal magnitude and θ is a measured signal phase that comprises a background or error phase and an intrinsic signal phase.

43. The method of claim 42, wherein vector image A is set to S and vector image B is set to -S .

44. The method of claim 43, wherein a sequenced region growing is used to construct a vector image V from the two vector images A and B, the vector image V is used to phase correct the image S , and the phase corrected image S is displayed and archived as a phase sensitive inversion recovery image.

45. A system for generating a phase corrected magnetic resonance image or images comprising:

(A) a magnetic resonance imaging controller;

(B) a processor coupled to the controller and configured to execute phase correction instructions applicable to a magnetic resonance image or images, wherein the instructions comprise:

(a) calculating two vector images A and B associated with an acquired image or images so that a vector orientation by one of the two vector images at a pixel is substantially determined by a background or error phase at the pixel, and the vector orientation at the pixel by the other vector image is substantially different from that determined by the background or error phase at the pixel;

(b) applying a sequenced region growing phase correction algorithm to the vector images A and B to construct a new vector image V, wherein the sequenced region growing phase correction algorithm comprises:

(i) selecting an initial seed pixel or pixels and assigning either A or B of the initial seed pixel or pixels as a value of V for the initial seed pixel or pixels;

(ii) selecting a secondary seed pixel and selecting either A or B of the secondary seed pixel as a value of V for the secondary seed pixel based on whether A or B of the secondary seed pixel has a smaller angular difference with an estimated V for the secondary seed pixel;

(iii) determining for the secondary seed pixel a local quality metric for each of the nearest neighbor pixels of the secondary seed pixel for which V has not been determined and assigning a priority to each of the nearest neighbor pixels using the local quality metric in order to determine the sequence by which each of the nearest neighbor pixels is to be selected as a further seed pixel;

(iv) repeating the steps of (ii) and (iii) to complete the sequenced region growing with respect to further seed pixels and to construct the vector image V so that a vector orientation of V at each pixel is substantially determined by the background or error phase at the pixel;

(c) generating a phase corrected magnetic resonance image or images from the acquired magnetic resonance image or images using the vector image V; and

(d) displaying or archiving the phase corrected magnetic resonance image or images; and

(C) an output or storage device configured to display or store the phase corrected magnetic resonance image or images.

The system of claim 45, wherein the processor is further configured to execute correction instructions reflecting the method of claim 2.

47. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 3.

48. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 4.

49. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 5.

50. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 6.

51. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 7.

52. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 8.

53. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 9.

54. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 10.

55. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 11.

56. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 12.

57. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 13.

58. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 14.

59. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 15.

60. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 16.

61. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 17.

62. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 18.

63. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 19.

64. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 20.

65. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 21.

66. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 22.

67. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 23.

68. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 24.

69. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 25.

70. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 26.

71. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 27.

72. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 28.

73. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 29.

74. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 30.

75. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 31.

76. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 32.

77. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 33.

78. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 34.

79. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 35.

80. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 36.

81. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 37.

82. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 39.

83. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 40.

84. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 41.

85. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 42.

86. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 43.

87. The system of claim 46, wherein the processor is further configured to execute phase correction instructions reflecting the method of claim 44.

88. A non-transitory computer readable storage medium with an executable program stored thereon, wherein the program instructs a microprocessor to perform steps comprising:

(a) loading into memory a magnetic resonance image or images;

(b) calculating two vector images A and B associated with the loaded image or images so that a vector orientation by one of the two vector images at a pixel is substantially determined by a background or error phase at the pixel, and the vector orientation at the pixel by the other vector image is substantially different from that determined by the background or error phase at the pixel;

(c) applying a sequenced region growing phase correction algorithm to the vector images A and B to construct a new vector image V, wherein the sequenced region growing phase correction algorithm comprises:

(i) selecting an initial seed pixel or pixels and assigning either A or B of the initial seed pixel or pixels as a value of V for the initial seed pixel or pixels;

(ii) selecting a secondary seed pixel and selecting either A or B of the secondary seed pixel as a value of V for the secondary seed pixel based on whether A or B of the secondary seed pixel has a smaller angular difference with an estimated V for the secondary seed pixel;

(iii) determining for the secondary seed pixel a local quality metric for each of the nearest neighbor pixels of the secondary seed pixel for which V has not been determined and assigning a priority to each of the nearest neighbor pixels using the local quality metric to determine the sequence by which each of the nearest neighbor pixels is to be selected as a further seed pixel;

(iv) repeating the steps of (ii) and (iii) to complete the sequenced region growing with respect to further seed pixels and to construct the vector image V so that a vector orientation of V at each pixel is substantially determined by the background or error phase at the pixel;

(d) generating the phase corrected magnetic resonance image or images from the acquired magnetic resonance image or images using the vector image V; and

(e) displaying or archiving the phase corrected magnetic resonance image or images.

89. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 2.

90. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 3.

91. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 4.

92. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 5.

93. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 6.

94. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 7.

95. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 8.

96. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 9.

97. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 10.

98. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 11.

99. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 12.

100. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 13.

101. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 14.

102. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 15.

103. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 16.

104. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 17.

105. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 18.

106. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 19.

107. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 20.

108. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 21.

109. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 22.

110. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 23.

111. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 24.

112. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 25.

113. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 26.

114. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 27.

115. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 28.

116. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 29.

117. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 30.

118. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 31.

119. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 32.

120. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 33.

121. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 34.

122. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 35.

123. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 36.

124. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 37.

125. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 39.

126. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 40.

127. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 41.

128. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 42.

129. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 43.

130. The non-transitory computer readable storage medium of claim 88, with an executable program stored thereon, wherein the program further instructs a microprocessor to perform steps reflecting the method of claim 44.