METHOD FOR CORRECTION OF RELATIVE OBJECT-DETECTOR MOTION BETWEEN SUCCESSIVE VIEWS

• US 20070071357A1
• Filed: 11/10/2006
• Published: 03/29/2007
• Est. Priority Date: 04/19/2002
• Status: Active Grant

• Current Assignee: VisionGate, Inc.
• Original Assignee: VisionGate, Inc.
• Inventors: Nelson, Alan, Rahn, John
• Granted Patent: US 7,542,597 B2
• Time in Patent Office: Days
• US Class Current: 382/275
• CPC Class Codes: G01N 15/1433 using image recognition
• CPC Class Codes: G01N 15/1468 with spatial resolution of the texture or inner structure of the particle
• CPC Class Codes: G01N 15/147 the analysis being performed on a sample stream
• CPC Class Codes: G01N 2015/1006 for cytology
• CPC Class Codes: G01N 2015/1027 Determining speed or velocity of a particle
• CPC Class Codes: G01N 2021/0346 Capillary cells; Microcells
• CPC Class Codes: G01N 2021/1787 Tomographic, i.e. computerised reconstruction from projective measurements
• CPC Class Codes: G01N 21/05 Flow-through cuvettes G01N21/09 takes precedence; handling fluid samples G01N1/10
• CPC Class Codes: G01N 21/4795 spatially resolved investigating of object in scattering medium in vivo A61B
• CPC Class Codes: G01N 2201/0813 Arrangement of collimator tubes, glass or empty
• CPC Class Codes: G01N 2223/612 biological material
• CPC Class Codes: G02B 21/26 Stages; Adjusting means therefor
• CPC Class Codes: G02B 21/365 Control or image processing arrangements for digital or video microscopes G02B21/361, G02B21/362 take precedence
• CPC Class Codes: G06T 11/005 Specific pre-processing for tomographic reconstruction, e.g. calibration, source positioning, rebinning, scatter correction, retrospective gating
• CPC Class Codes: G06T 11/006 Inverse problem, transformation from projection-space into object-space, e.g. transform methods, back-projection, algebraic methods
• CPC Class Codes: G06T 2211/412 Dynamic
• CPC Class Codes: G06T 2211/421 Filtered back projection [FBP]

Abstract

An apparatus and method for correction of relative object-detector motion between successive views during optical tomographic imaging in three dimensions. An object of interest is illuminated to produce an image. A lateral offset correction value is determined for the image. An axial offset correction value is determined for the image. The lateral offset correction value and the axial offset correction value are applied to the image to produce a corrected file image.

Claims

1. Apparatus for correcting positioning and motion errors in an imaging system, comprising:

means for acquiring and electronically storing at least two consecutive views of an object, said at least two views including M rows and N colunns of image brightness data;

a first producing means for producing a first set of modified copies of each of said at least two consecutive views by applying an alteration of brightness level to pixels having brightness levels within a specified range;

a first cross-correlation means for performing a cross-correlation between said first set of modified copies with a reference pattern to produce a first cross-correlated array;

a first locating means for locating and evaluating a maximum of the first cross-correlated array, where a location of said maximum determines the value of a coefficient “

A”

;

a second producing means for producing a second set of modified copies of each of said at least two consecutive views by applying an alteration of brightness level to pixels having brightness levels within a specified range;

a second cross-correlation means for performing a second cross-correlation between two of said set of modified copies to produce a second cross-correlation array;

a second locating means for locating and evaluating a restricted maximum of the second cross-correlation array, said restriction being that the row or column on which said restricted maximum is located must be orthogonal to and intersect the row or column on which coefficient “

A”

is located, the location of said restricted maximum determining a coefficient “

B;

” and

a motion-corrected image means for producing a motion-corrected image by shifting at least one of said at least two consecutive views by values determined by coefficient “

A,” and

coefficient “

B.”

2. Apparatus according to claim 1, wherein the motion-corrected image means operates responsively to said values of said coefficients “

A” and

“

B”

for shifting one of the at least two consecutive views in two orthogonal directions relative to the other of the at least two consecutive views.

3. Apparatus according to claim 1, in which the first cross-correlating means includes a means for summing a selected one of the M rows and N columns to obtain a one-dimensional array, said summing being in a direction orthogonal to the direction of the shift whose magnitude is determined by said coefficient “

A.”

4. Apparatus according to claim 1 in which the reference pattern comprises an array of M rows and N columns of image brightness data in which all pixels can have only one of two possible brightness values.

5. Apparatus according to claim 1 wherein the reference pattern comprises an array of M rows and N colunums of image brightness data in which all pixels have the same brightness value, with the exception of two groups consisting of one or more rows or columns, said two groups having a brightness that is uniform, but different than the other pixels, and having a separation that corresponds to the separation of the opposing walls of said microcapillary tube, said opposing walls both appearing in the field of view of a succession of two or more images, said microcapillary tube containing an object of interest.

6. Apparatus according to claim 5 in which the object of interest comprises an object selected from the group consisting of a biological cell and a biological nucleus.

7. Apparatus according to claim 1 including means for finding a maximun value of a maximum correlation based on multiple thresholding.

8. Apparatus according to claim 5 including means for computing separation of at least one of two groups, rows and columns using at least one acquired image.

9. A method for three dimensional (3D) reconstruction of an object of interest, comprising the steps of:

(a) packing a set of objects of interest into a tube;

(b) illuminating at least one object of the set of objects of interest with at least one optical projection beam;

(c) translating the tube until the at least one object of interest is located within a region of the at least one optical projection beam;

(d) rotating the at least one object through a plurality of perspectives;

(e) generating an image at each perspective to produce a set of images; and

(f) correcting registration of the set of images of the at least one object of interest by determining a lateral offset correction value for each image, determining an axial offset correction value for each image, and applying the lateral offset correction value and the axial offset correction value to each image to produce a set of motion-corrected images.

10. The method of claim 9, wherein the at least one object comprises an object selected from the group consisting of a biological cell and a cell nucleus.

11. The method of claim 9, wherein the method of determining a lateral offset correction value for each image comprises the steps of:

(a) producing a modified copy of each of the set of images in which an alteration of brightness level is applied to pixels having brightness levels within a specified range;

(b) performing a cross-correlation between said modified copy of said view with a reference pattern to produce a cross-correlated array; and

(c) locating and evaluating a maximum of the cross-correlated array.

12. The method of claim 11, wherein the reference pattern is generated at a different perspective than that of the image from which said modified copy is produced.

13. The method of claim 11, wherein the reference pattern comprises a reference image generated at a different perspective than that of the image from which said modified copy is produced, where an alteration of brightness level is applied to pixels in the reference image having brightness levels within a specified range.

14. The method of claim 9, wherein the method of determining an axial offset correction value for each image comprises the steps of:

(a) producing a first set of modified copies of the set of images in which an alteration of brightness level is applied to pixels having brightness levels within a specified range;

(b) performing a first cross-correlation between the first set of modified copies and a reference pattern to produce a first cross-correlation array;

(c) locating and evaluating a maximum of the first cross-correlation array and performing a second cross-correlation between said first set of modified copies and said reference pattern to determine the value of a coefficient “

A”

;

(d) producing a second set of modified copies of the set of images in which an alteration of brightness level is applied to pixels having brightness levels within a specified range;

(e) performing a third cross-correlation between the second set of modified copies to produce a second cross-correlation array; and

(f) locating and evaluating the restricted maximum of the second cross-correlation array, said restriction being that the row or column on which said restricted maximum is located must be orthogonal to and intersect the row or column on which coefficient “

A”

is located, the location of said restricted maximum determining a coefficient “

B.”

15. The method of claim 14, wherein the reference pattern of image brightness data comprises a reference image generated from a different perspective than modified copies being correlated with the reference image.

16. The method of claim 14, wherein the reference pattern of image brightness data comprises a modified reference image, where an alteration of brightness level is applied to pixels in the reference pattern having brightness levels within a specified range to create the modified reference image.

17. The method of claim 14, wherein the reference pattern of image brightness data comprises a selected one of a modified and unmodified representation of a microcapillary tube.