Apparatus and method of optical imaging for medical diagnosis

• US 8,334,900 B2
• Filed: 07/20/2009
• Issued: 12/18/2012
• Est. Priority Date: 07/21/2008
• Status: Active Grant

• Current Assignee: Hong Kong University of Science and Technology
• Original Assignee: Hong Kong University of Science and Technology
• Inventors: Qu, Jianan, Wu, Tao
• Primary Examiner(s): Backer, Firmin
• Assistant Examiner(s): Bui, Jonathan
• Application Number:
  US12/506,028
• Publication Number:
  US 20100149315A1
• Time in Patent Office: 1,247 Days
• Field of Search: 348/68, 382/128
• US Class Current: 348/68
• CPC Class Codes: A61B 1/00193 adapted for stereoscopic vision
• CPC Class Codes: A61B 1/00194 adapted for three-dimensional imaging
• CPC Class Codes: A61B 1/042 characterised by a proximal camera, e.g. a CCD camera
• CPC Class Codes: A61B 1/0605 for spatially modulated illumination
• CPC Class Codes: A61B 1/303 for the vagina, i.e. vaginoscopes
• CPC Class Codes: A61B 5/1076 for measuring dimensions inside body cavities, e.g. using catheters A61B3/1005 takes precedence
• CPC Class Codes: G06F 18/2135 based on approximation criteria, e.g. principal component analysis
• CPC Class Codes: G06V 10/145 Illumination specially adapted for pattern recognition, e.g. using gratings
• CPC Class Codes: G06V 10/7715 Feature extraction, e.g. by transforming the feature space, e.g. multi-dimensional scaling [MDS]; Mappings, e.g. subspace methods

Abstract

Described herein is a novel 3-D optical imaging system based on active stereo vision and motion tracking for to tracking the motion of patient and for registering the time-sequenced images of suspicious lesions recorded during endoscopic or colposcopic examinations. The system quantifies the acetic acid induced optical signals associated with early cancer development. The system includes at least one illuminating light source for generating light illuminating a portion of an object, at least one structured light source for projecting a structured light pattern on the portion of the object, at least one camera for imaging the portion of the object and the structured light pattern, and means for generating a quantitative measurement of an acetic acid-induced change of the portion of the object.

Claims

1. A system for providing optical imaging in a medical diagnosis, comprising:

at least one illuminating light source for generating light illuminating a portion of an object;

at least one structured light source for providing a projection channel and projecting a structured light-pattern on the portion of the object;

at least one camera for providing an imaging channel and imaging the portion of the object and the structured light pattern; and

a computer, configured to;

calculate by triangulation a three-dimensional topology of the portion of the object based on a correspondence established between the projection channel and the imaging channel;

perform three-dimensional motion tracking based on the calculated three-dimensional topology; and

generate a grade corresponding to a lesion of the object based on a multivariate analysis on temporal acetowhitening kinetics measurements performed on an area of the portion of the object corresponding to the lesion.

2. The system of claim 1, further comprising means for performing a diagnosis utilizing the grade.

3. The system of claim 1, further comprising means for removing a specular reflection of the light.

4. The system of claim 1, further comprising means for forming a cross-polarized reflection of the light for the at least one camera to generate at least one cross-polarized image of the portion of the object.

5. The system of claim 1, wherein the at least one camera generates a first and a second images of the portion of the object, the system further comprising means for registering the second image to the first image.

6. The system of claim 1, wherein the temporal acetowhitening kinetics measurements are indicative of at least one of a rapidity of an acetowhitening process, a duration of the acetowhitening process, an amplitude of acetowhitening signals associated with the acetowhitening process, a degree of the acetowhiteness process , a contrast of the acetowhitening process, a sharpness of a demarcation line between precancerous lesions and normal tissues, and a degree of the acetowhitening process when a change of a color of the portion of object reaches a maximum.

7. The system of claim 1, wherein the multivariate analysis includes at least one of a Principle Components Analysis (PCA) and a Support Vector Machine (SVM).

8. The system of claim 1, further including means for detecting the structured light pattern from images generated by the at least one camera.

9. The system of claim 1, wherein the at least one camera generates one or more images of the portion of the object, the system further comprising a frame grabber for capturing and storing the one or more images.

10. The system of claim 1, further comprising means for analyzing a motion of the object in three-dimensional space based on images generated by the at least one camera, wherein the motion of the object has at least one of six degrees of freedom and the six degrees of freedom include three degrees of translations and three degrees of rotations.

11. The system of claim 1, the at least one structured light source comprising:

a laser light source for generating a laser beam;

a holographic grating for diffracting the laser beam; and

one or more reflective surfaces for directing the diffracted laser beam.

12. The system of claim 11, wherein the at least one structured light source is synchronized with the camera.

13. The system of claim 11, wherein the structured light pattern includes one of a group of dots, a group of lines, a dot matrix, a plurality of stripes, and a grid pattern.

14. The system of claim 1, wherein the at least one illuminating light source includes one of a white-light source and a ring light-emitting diode (LED) illuminator.

15. The system of claim 1, further comprising:

a first linear polarizer for polarizing the light generated by the light source; and

a second linear polarizer for polarizing at least a portion of the light reflected from the object.

16. The system of claim 15, wherein the polarization of the first linear polarizer is perpendicular to the polarization of the second linear polarizer.

17. The system of claim 1, further comprising an electronic panel and programmable computer ports for automatically switching on and off the at least one illuminating light source and the at least one structured light source.

18. A method for providing optical imaging in medical diagnosis, comprising:

illuminating a portion of an object;

projecting, via a projection channel, a structured light pattern onto the portion of the object;

generating, via an imaging channel, a sequence of images of the illuminating portion of the object;

calculating by triangulation a three-dimensional topology of the portion of the object based on a correspondence established between the protection channel and the imaging channel;

performing three-dimensional motion tracking based on the calculated three-dimensional topology; and

generating a grade corresponding to a lesion of the object based on a multivariate analysis on temporal acetowhitening kinetics measurements performed on an area of the portion of the object corresponding to the lesion.

19. The method of claim 18, wherein the sequence of images includes one or more cross-polarized reflection images of the portion of the object.

20. The method of claim 18, the sequence of images include a first image and a second image, the method further comprising registering the second image to the first image.

21. One or more non-transitory computer readable media including computer codes for instructing one or more digital processor for providing optical imaging in a medical diagnosis, the computer codes including:

instructions for illuminating a portion of an object;

instructions for projecting, via a projection channel, a structured light pattern onto the portion of the object;

instructions for generating, via an imaging channel, a sequence of images of the illuminated portion of the object;

instructions for calculating by triangulation a three-dimensional topology of the portion of the object based on a correspondence established between the projection channel and the imaging channel;

instructions for performing three-dimensional motion tracking based on the calculated three-dimensional topology; and

instructions for generating a grade corresponding to a lesion of the object based on a multivariate analysis on temporal acetowhitening kinetics measurements performed on an area of the portion of the object corresponding to the lesion.

22. The one or more computer readable media of claim 21, the computer codes further comprising instructions for performing diagnosis of a precancerous lesion and a cancer on the portion of the object.

23. The one or more computer readable media of claim 21, the computer code further comprising instructions for registering the sequence of images to another image of the portion of the object.

24. The one or more computer readable media of claim 21, wherein the multivariate analysis includes at least one of a Principle Components Analysis (PCA) and a Support Vector Machine (SVM).

25. The one or more computer readable media of claim 21, the computer codes further including instructions for storing the sequence of images in a frame grabber.