1. An image interpretation aiding method comprising the steps of:
generating first projection images of a first region in a first three-dimensional image representing a subject by projecting, onto a plane perpendicular to a first observation direction to the subject in the first three-dimensional image, pixels in the first region specified by a first cross section perpendicular to the first observation direction and a first thickness equal to a first pitch, which is a thickness from the first cross section in the first observation direction, while moving a position of the first cross section in the first observation direction by the first pitch;
generating second projection images of a second region in a second three-dimensional image representing the subject obtained at a time different from the first three-dimensional image by projecting, onto a plane perpendicular to a second observation direction to the subject in the second three-dimensional image, pixels in the second region specified by a second cross section perpendicular to the second observation direction and a second thickness equal to a second pitch, which is a thickness from the second cross section in the second observation direction, while moving a position of the second cross section in the second observation direction by the second pitch;
carrying out alignment processing for aligning the subject in each of combinations of the first projection images and the second projection images corresponding to each other; and
generating a superposed subtraction image based on a difference between all the first projection images and all the second projection images having been subjected to the alignment processing.
2. The image interpretation aiding method according to claim 1, the step of generating the superposed subtraction image comprising the steps of:
generating subtraction images from a difference in each of the combinations of the first projection images and the second projection images having been subjected to the alignment processing; and
generating the superposed subtraction image by superposing the subtraction images.
3. The image interpretation aiding method according to claim 1, the step of generating the superposed subtraction image comprising the steps of:
generating a first superposed projection image by superposing the first projection images having been subjected to the alignment processing;
generating a second superposed projection image by superposing the second projection images having been subjected to the alignment processing; and
generating the superposed subtraction image by finding a difference between the first superposed projection image and the second superposed projection image.
4. The image interpretation aiding method according to claim 1,
the first three-dimensional image and the second three-dimensional image respectively comprising cross sectional images representing slice regions generated by sequentially slicing the subject according to slice thicknesses predetermined respectively for the first three-dimensional image and the second three-dimensional image,
the first thickness being larger than the predetermined slice thickness for the first three-dimensional image, and
the second thickness being larger than the predetermined slice thickness for the second three-dimensional image.
5. The image interpretation aiding method according to claim 1, wherein the alignment processing comprises the steps of:
observation direction alignment processing for determining the combinations of the first projection images and the second projection images corresponding to each other by respectively selecting the second projection images having the highest correlation of pixel values with the respective first projection images; and
two-dimensional alignment processing comprising global matching, local matching, and warping,
the global matching being overall linear alignment processing for detecting an overall amount of rotation andor translation between the two projection images comprising each of the combinations,
the local matching being local non-linear alignment processing for detecting shift vectors between corresponding local areas in the two projection images and for determining shift vectors between each pair of corresponding pixels in the two projection images based on the shift vectors between the local areas, and
the warping being processing for nonlinearly transforming one of the two projection images to the other one of the two projection images based on the shift vectors between the pixels.
6. The image interpretation aiding method according to claim 1, further comprising the steps of:
setting a three-dimensional volume of interest in the first three-dimensional image;
calculating magnitude of displacement and rotation of the volume in the case where pixel values of the volume show the highest correlation with pixel values of a corresponding volume in the second three-dimensional image while translating and rotating the volume in the second three-dimensional image; and
carrying out overall alignment between the two three-dimensional images by translating and rotating pixels in one of the two three-dimensional images based on the magnitude of displacement and rotation, wherein
the steps of generating the first projection images and the second projection images are carried out after the overall alignment.
7. An image interpretation aiding apparatus comprising:
first cross section specification means for specifying a first cross section perpendicular to a first observation direction to a subject in a first three-dimensional image representing the subject;
first thickness specification means for specifying a first thickness from the first cross section in the first observation direction;
first projection image generation means for generating first projection images of a first region in the first three-dimensional image by projecting, onto a plane perpendicular to the first observation direction, pixels in the first region specified by the first cross section and the first thickness while moving a position of the first cross section in the first observation direction by a pitch equal to the first thickness;
second cross section specification means for specifying a second cross section perpendicular to a second observation direction to the same subject in a second three-dimensional image representing the subject and obtained at a time different from the first three-dimensional image;
second thickness specification means for specifying a second thickness from the second cross section in the second observation direction;
second projection image generation means for generating second projection images of a second region in the second three-dimensional image by projecting, onto a plane perpendicular to the second observation direction, pixels in the second region specified by the second cross section and the second thickness while moving a position of the second cross section in the second observation direction by a pitch equal to the second thickness;
alignment processing means for carrying out alignment processing on the subject in each of combinations of the first projection images and the second projection images corresponding to each other; and
superposed subtraction image generation means for generating a superposed subtraction image based on a difference between all the first projection images and all the second projection images having been subjected to the alignment processing.
8. The image interpretation aiding apparatus according to claim 7, wherein the superposed subtraction image generation means generates:
subtraction images based on a difference in each of the combinations of the first projection images and the corresponding second projection images having been subjected to the alignment processing, and
the superposed subtraction image by superposing the subtraction images.
9. The image interpretation aiding apparatus according to claim 7, wherein the superposed subtraction image generation means generates:
a first superposed projection image by superposing the first projection images having been subjected to the alignment processing,
a second superposed projection image by superposing the second projection images having been subjected to the alignment processing, and
the superposed subtraction image by finding a difference between the first superposed projection image and the second superposed projection image.
10. The image interpretation aiding apparatus according to claim 7,
the first three-dimensional image and the second three-dimensional image respectively comprising cross sectional images representing slice regions generated by sequentially slicing the subject according to slice thicknesses predetermined respectively for the first three-dimensional image and the second three-dimensional image, wherein
the first thickness specification means and the second thickness specification means respectively examine values specified respectively as the first thickness and the second thickness and respectively display a warning message in the case where the value specified as the first thickness is not larger than the predetermined slice thickness for the first three-dimensional image and in the case where the value specified as the second thickness is not larger than the predetermined slice thickness for the second three-dimensional image.
11. The image interpretation aiding apparatus according to claim 7,
the first three-dimensional image and the second three-dimensional image respectively comprising cross sectional images representing slice regions generated by sequentially slicing the subject according to slice thicknesses predetermined respectively for the first three-dimensional image and the second three-dimensional image, wherein
the first thickness specification means and the second thickness specification means respectively display the predetermined slice thickness for the first three-dimensional image and the predetermined slice thickness for the second three-dimensional image in advance for prompting specification of values larger than the displayed slice thicknesses.
12. The image interpretation aiding apparatus according to claim 7, wherein the second cross section specification means specifies a cross section corresponding to the first cross section in the second three-dimensional image as the second cross section, and
the second thickness specification means specifies a value that is the same as the first thickness as the second thickness.
13. The image interpretation aiding apparatus according to claim 7, wherein the alignment processing means comprises:
an observation direction alignment processing unit for determining the combinations of the first projection images and the second projection images corresponding to each other by respectively selecting the second projection images having the highest correlation of pixel values with the respective first projection images; and
a two-dimensional alignment processing unit for carrying out global matching, local matching, and warping,
the global matching being overall linear alignment processing for detecting an overall amount of rotation andor translation between the two projection images comprising each of the combinations,
the local matching being local non-linear alignment processing for detecting shift vectors between corresponding local areas in the two projection images and for determining shift vectors between each pair of corresponding pixels in the two projection images based on the shift vectors between the local areas, and
the warping being a process for nonlinearly transforming one of the two projection images to the other one of the two projection images based on the shift vectors between the pixels.
14. The image interpretation aiding apparatus according to claim 7, the image interpretation aiding apparatus further comprising:
means for setting a three-dimensional volume of interest in the first thee-dimensional image,
for calculating magnitude of displacement and rotation of the volume in the case where pixel values of the volume show the highest correlation with pixel values of a corresponding volume in the second three-dimensional image while translating and rotating the volume in the second three-dimensional image, and
for carrying out overall alignment between the two three-dimensional images by translating and rotating the pixels in one of the two three-dimensional images based on the magnitude of displacement and rotation, wherein
the first cross section specification means and the second cross section specification means respectively specify the first cross section and the second cross section after the overall alignment.
15. A computer-readable recording medium storing an image interpretation aiding program for causing a computer to function as:
first cross section specification means for specifying a first cross section perpendicular to a first observation direction to a subject in a first three-dimensional image representing the subject;
first thickness specification means for specifying a first thickness from the first cross section in the first observation direction;
first projection image generation means for generating first projection images of a first region in the first three-dimensional image by projecting, onto a plane perpendicular to the first observation direction, pixels in the first region specified by the first cross section and the first thickness while moving a position of the first cross section in the first observation direction by a pitch equal to the first thickness;
second cross section specification means for specifying a second cross section perpendicular to a second observation direction to the same subject in a second three- dimensional image representing the subject and obtained at a time different from the first three-dimensional image;
second thickness specification means for specifying a second thickness from the second cross section in the second observation direction;
second projection image generation means for generating second projection images of a second region in the second three-dimensional image by projecting, onto a plane perpendicular to the second observation direction, pixels in the second region specified by the second cross section and the second thickness while moving a position of the second cross section in the second observation direction by a pitch equal to the second thickness;
alignment processing means for carrying out alignment processing on the subject in each of combinations of the first projection images and the second projection images corresponding to each other; and
superposed subtraction image generation means for generating a superposed subtraction image based on a difference between all the first projection images and the second projection images having been subjected to the alignment processing.
16. A computer-readable recording medium storing the image interpretation aiding program of claim 15, the image interpretation aiding program causing the computer to cause the superposed subtraction image generation means to generate:
subtraction images based on a difference in each of the combinations of the first projection images and the corresponding second projection images having been subjected to the alignment processing, and
the superposed subtraction image by superposing the subtraction images.
17. A computer-readable recording medium storing the image interpretation aiding program of claim 15, the image interpretation aiding program causing the computer to cause the superposed subtraction image generation means to generate:
a first superposed projection image by superposing the first projection images having been subjected to the alignment processing,
a second superposed projection image by superposing the second projection images having been subjected to the alignment processing, and
the superposed subtraction image by finding a difference between the first superposed projection image and the second superposed projection image.
18. A computer-readable recording medium storing the image interpretation aiding program of claim 15,
the first three-dimensional image and the second three-dimensional image respectively comprising cross sectional images representing slice regions generated by sequentially slicing the subject according to slice thicknesses predetermined respectively for the first three-dimensional image and the second three-dimensional image, and the image interpretation aiding program causing the computer to cause
the first thickness specification means and the second thickness specification means to respectively examine values specified as the first thickness and the second thickness and to respectively display a warning message in the case where the value specified as the first thickness is not larger than the predetermined slice thickness for the first three-dimensional image and in the case where the value specified as the second thickness is not larger than the predetermined slice thickness for the second three-dimensional image.
19. A computer-readable recording medium storing the image interpretation aiding program of claim 15,
the first three-dimensional image and the second three-dimensional image respectively comprising cross sectional images representing slice regions generated by sequentially slicing the subject according to slice thicknesses predetermined respectively for the first three-dimensional image and the second three-dimensional image, and the image interpretation aiding program causing the computer to cause
the first thickness specification means and the second thickness specification means to respectively display the predetermined slice thickness for the first three-dimensional image and the predetermined slice thickness for the second three-dimensional image in advance for prompting specification of values larger than the displayed slice thicknesses.
20. A computer-readable recording medium storing the image interpretation aiding program of claim 15, wherein the image interpretation aiding program causes the computer to cause:
the second cross section specification means to specify a cross section corresponding to the first cross section in the second three-dimensional image as the second cross section, and
the second thickness specification means to specify a value that is the same as the first thickness as the second thickness.
21. A computer-readable recording medium storing the image interpretation aiding program of claim 15, wherein the image interpretation aiding program causes the computer to cause the alignment processing means to function as:
an observation direction alignment processing unit for determining the combinations of the first projection images and the second projection images corresponding to each other by respectively selecting the second projection images having the highest correlation of pixel values with the respective first projection images; and
a two-dimensional alignment processing unit for carrying out global matching, local matching, and warping,
the global matching being overall linear alignment processing for detecting an overall amount of rotation andor translation between the two projection images comprising each of the combinations,
the local matching being local non-linear alignment processing for detecting shift vectors between corresponding local areas in the two projection images and for determining shift vectors between each pair of corresponding pixels in the two projection images based on the shift vectors between the local areas, and
the warping being a process for nonlinearly transforming one of the two projection images to the other one of the two projection images based on the shift vectors between the pixels.
22. A computer-readable recording medium storing the image interpretation aiding program of claim 15, the image interpretation aiding program further causing the computer to further function as:
means for setting a three-dimensional volume of interest in the first three-dimensional image,
for calculating magnitude of displacement and rotation of the volume in the case where pixel values of the volume show the highest correlation with pixel values of a corresponding volume in the second three-dimensional image while translating and rotating the volume in the second three-dimensional image, and
for carrying out overall alignment between the two three-dimensional images by translating and rotating the pixels in one of the two three-dimensional images based on the magnitude of displacement and rotation, wherein
the first cross section specification means and the second cross section specification means specify the first cross section and the second cross section after the overall alignment.
23. The image interpretation aiding method according to claim 1, wherein said superposed subtraction image is the same size as the first and second projection images, and
the first projection images, the second projection images, and the superposed subtraction image are digital image data.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for forming a hitch receiver which comprises:
placing a tubular blank into a first device, wherein said tubular blank includes a continuous opening throughout a length of said tubular blank, further wherein said first device comprises a first die having a longitudinal aperture disposed therein and a first punch wherein said first punch is sized to fit within said first die, further wherein said first die comprises a first inner mandrel sized to fit within at least a portion of said continuous opening throughout said length of said tubular blank and a first exterior forming wall of said first die wherein said first exterior forming wall comprises a first head forming portion connected to a first transition forming portion connected to a first body forming portion;
extruding said tubular blank into said first device, wherein said tubular blank is extruded into said first die using said first punch such that said tubular blank is extruded into a volume between said first inner mandrel and said first exterior forming wall;
removing said first punch from said first die;
removing said tubular blank from said first device;
placing said tubular blank into a second device wherein said second device comprises a second die having a longitudinal aperture disposed therein and a second punch wherein said second punch is sized to fit within said second die, further wherein said second die comprises a second inner mandrel sized to fit within at least a portion of said continuous opening throughout said length of said tubular blank and a second exterior forming wall, wherein said second exterior forming wall comprises a second head forming portion connected to a second transition forming portion connected to a second body forming portion; and
extruding said tubular blank into said second device to from said hitch receiver, wherein said tubular blank is extruded into said second die using said second punch such that said tubular blank is extruded into a volume between said second inner mandrel and said second exterior forming wall.
2. The method of claim 1 wherein said tubular blank has a generally rectangular cross-section.
3. The method of claim 1 wherein said tubular blank is extruded through said first device at ambient temperature.
4. The method of claim 1 wherein said tubular blank is extruded through said second device at ambient temperature.
5. The method of claim 1 which further comprises
creating a second opening through said tubular blank such that said second opening is generally perpendicular to said continuous opening throughout said length of said tubular blank, wherein said second device further comprises a side punch and said second opening is created using said side punch within said second device.
6. The method of claim 5 wherein said step of creating of said second opening occurs simultaneously with said step of extruding of said tubular blank into said second device.
7. The method of claim 5 wherein said step of creating of said second opening occurs prior to said step of extruding of said tubular blank into said second device.
8. The method of claim 5 wherein said step of creating of said second opening occurs after said step of extruding of said tubular blank into said second device.
9. The method of claim 1 wherein said second punch comprises a head punch portion connected to a reservoir portion connected to a shaft portion and further wherein said reservoir portion of said second punch is concave.
10. The hitch receiver created by the method of claim 1.
11. A method for forming a hitch receiver which comprises:
placing a tubular blank into a first device, wherein said tubular blank includes a continuous opening throughout a length of said tubular blank, further wherein said first device comprises a first die having a longitudinal aperture disposed therein and a first punch wherein said first punch is sized to fit within said first die, further wherein said first die comprises a first inner mandrel sized to fit within at least a portion of said continuous opening throughout said length of said tubular blank and a first exterior forming wall of said die wherein said first exterior forming wall comprises a first head forming portion connected to a first transition forming portion connected to a first body forming portion;
extruding said tubular blank into said first device, wherein said tubular blank is extruded into said first die using said first punch such that said tubular blank is extruded into a volume between said first inner mandrel and said first exterior forming wall;
removing said first punch from said first die;
removing said tubular blank from said first device;
placing said tubular blank into a second device wherein said second device comprises a second die having a longitudinal aperture disposed therein, a second punch, and a side punch, wherein said second punch is sized to fit within said second die, further wherein said second die comprises a second inner mandrel sized to fit within at least a portion of said continuous opening throughout said length of said tubular blank and a second exterior forming wall of said second die, wherein said second exterior forming wall comprises a second head forming portion connected to a second transition forming portion connected to a second body forming portion, and further wherein said second punch comprises a head punch portion connected to a reservoir portion connected to a shaft portion, and further wherein said reservoir portion of said second punch is concave;
extruding said tubular blank into said second device to from said hitch receiver, wherein said tubular blank is extruded into said second die using said second punch such that said tubular blank is extruded into a volume between said second inner mandrel and said second exterior forming wall; and
creating said second opening through a tubular blank such that said second opening is generally perpendicular to said continuous opening throughout said length of said tubular blank, wherein said second opening is created using said side punch within said second device.
12. The method of claim 11 wherein said tubular blank has a generally rectangular cross-section.
13. The method of claim 11 wherein said tubular blank is extruded through said first device at ambient temperature.
14. The method of claim 11 wherein said tubular blank is extruded through said second device at ambient temperature.
15. The method of claim 11 wherein said step of creating of said second opening occurs simultaneously with said step of extruding of said tubular blank into said second device.
16. The method of claim 11 wherein said step of creating of said second opening occurs prior to said step of extruding of said tubular blank into said second device.
17. The method of claim 11 wherein said step of creating of said second opening occurs after said step of extruding of said tubular blank into said second device.
18. The hitch receiver created by the method of claim 11.
19. A method for forming a hitch receiver which comprises placing a tubular blank into a device, wherein said tubular blank includes a continuous opening throughout the length of said tubular blank, further wherein said device comprises a die having a longitudinal aperture disposed therein and a punch wherein said punch is sized to fit within said die, further wherein said die comprises an inner mandrel sized to fit within at least a portion of said continuous opening throughout said length of said tubular blank and an exterior forming wall of said die wherein said exterior forming wall defines a head portion connected to a transition portion connected to a body portion, wherein said tubular blank is extruded into said die using said punch such that said tubular blank is extruded into a volume between said inner mandrel and said exterior forming wall to form said hitch receiver, and further wherein said die and said punch are configured such that the edges of the portion of said tubular blank formed by said head portion of said exterior forming wall of said die are dull-edged.
20. The method of claim 19 wherein said tubular blank has a generally rectangular cross-section.
21. The method of claim 19 wherein said tubular blank is extruded through said device at ambient temperature.
22. The method of claim 19 which further comprises creating a second opening through said tubular blank such that said second opening is generally perpendicular to said continuous opening throughout said length of said tubular blank, wherein said device further comprises a side punch and said second opening is created using said side punch within said device.
23. The method of claim 19 wherein said creating of said second opening occurs simultaneously with said extruding of said tubular blank into said device.
24. The method of claim 19 wherein said creating of said second opening occurs prior to said extruding of said tubular blank into said device.
25. The method of claim 19 wherein said creating of said second opening occurs after said extruding of said tubular blank into said device.
26. The hitch receiver created by the method of claim 19.