Systems and methods for hyperspectral imaging

• US 9,117,133 B2
• Filed: 02/12/2009
• Issued: 08/25/2015
• Est. Priority Date: 06/18/2008
• Status: Active Grant

• Current Assignee: Spectral Image, Inc.
• Original Assignee: Spectral Image, Inc.
• Inventors: Barnes, Michael, Pan, Zhihong, Zhang, Sizhong
• Primary Examiner(s): Le, Long V
• Assistant Examiner(s): IMPINK, BRADLEY GERALD
• Application Number:
  US12/370,557
• Publication Number:
  US 20090326383A1
• Time in Patent Office: 2,385 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• CPC Class Codes: A61B 5/0064 Body surface scanning
• CPC Class Codes: A61B 5/0075 by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy A61B5/0071 takes precedence
• CPC Class Codes: A61B 5/0077 Devices for viewing the surface of the body, e.g. camera, magnifying lens
• CPC Class Codes: A61B 5/417 the bone marrow
• CPC Class Codes: A61B 5/442 Evaluating skin mechanical properties, e.g. elasticity, hardness, texture, wrinkle assessment
• CPC Class Codes: A61B 5/444 Evaluating skin marks, e.g. mole, nevi, tumour, scar
• CPC Class Codes: A61B 5/445 Evaluating skin irritation or skin trauma, e.g. rash, eczema, wound, bed sore
• CPC Class Codes: A61B 5/7246 using correlation, e.g. template matching or determination of similarity
• CPC Class Codes: A61B 5/726 using Wavelet transforms
• CPC Class Codes: A61B 5/7267 involving training the classification device
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence
• CPC Class Codes: G06T 2207/30088 Skin; Dermal
• CPC Class Codes: G06T 2207/30096 Tumor; Lesion
• CPC Class Codes: G06T 7/0012 Biomedical image inspection
• CPC Class Codes: G06V 10/143 Sensing or illuminating at different wavelengths
• CPC Class Codes: G06V 2201/03 Recognition of patterns in medical or anatomical images
• CPC Class Codes: G16H 50/70 for mining of medical data, e.g. analysing previous cases of other patients
• CPC Class Codes: H04N 23/11 for generating image signals from visible and infrared light wavelengths
• CPC Class Codes: H04N 23/56 provided with illuminating means
• CPC Class Codes: H04N 23/71 : Circuitry for evaluating the brightness variation
• CPC Class Codes: H04N 23/75 : by influencing optical camera components
• CPC Class Codes: Y02A 90/10 : Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

Abstract

An apparatus for analyzing a subject including a hyperspectral image module is provided. It is used to identify a suspect region of a subject by using a hyperspectral sensor (for obtaining a hyperspectral image of the subject), a control computer including a processor unit (PU) and a computer readable memory (CRM) (for controlling and is in electronic communication with the sensor), a control software module including instructions stored in the CRM and executed by the PU (for controlling said at least one operating parameter of the sensor), a spectral calibrator module including instructions stored in the CRM and executed by the PU (for applying a wavelength dependent spectral calibration standard constructed for the sensor to a hyperspectral image), and a light source for illuminating the subject. An optional contact probe module is used to collect a signal of the suspect region for medical diagnosis.

Claims

1. An apparatus for analyzing a region of a subject, the apparatus comprising:

a hyperspectral sensor for obtaining a hyperspectral image of the region of said subject, the hyperspectral image comprising a plurality of measurements of reflected light from the region of the subject, wherein each respective measurement of reflected light in the plurality of measurements of reflected light is made at a respective wavelength in a plurality of wavelengths;

a control computer for controlling the hyperspectral sensor, wherein the control computer is in electronic communication with the hyperspectral sensor and wherein the control computer controls at least one operating parameter of the hyperspectral sensor, and wherein the control computer comprises a processor unit and a non-transitory computer readable memory;

a control software module, stored in the non-transitory computer readable memory and executed by the processor unit, the control software comprising instructions for controlling said at least one operating parameter of the hyperspectral sensor;

a spectral calibrator module, stored in the non-transitory computer readable memory and executed by the processor unit, the spectral calibrator module comprising instructions for;

calibrating the responsiveness of the hyperspectral sensor by;

collecting a hyperspectral image of a spectral calibration standard with the hyperspectral sensor, the spectral calibration standard having known reflectance at respective wavelengths of light in a plurality of wavelengths of light collected in the hyperspectral image of the spectral calibration standard; and

determining a plurality of correction factors by comparing measured reflections of light at each respective wavelength of light in the plurality of wavelengths of light collected in the hyperspectral image of the spectral calibration standard to corresponding expected reflections of light calculated based on the known reflectance of the spectral calibration standard at each respective wavelength of light in the plurality of wavelengths of light collected in the hyperspectral image of the spectral calibration standard, wherein each respective correction factor in the plurality of correction factors corresponds to a respective wavelength of light in the plurality of wavelengths of light collected in the hyperspectral image of the spectral calibration standard and is determined independently from the other correction factors in the plurality of correction factors,

correcting a first respective measurement of reflected light, having a first respective wavelength, in the hyperspectral image of the region of the subject with a first respective correction factor in the plurality of correction factors, the first correction factor corresponding to the first respective wavelength of reflected light, and

correcting a second respective measurement of reflected light, having a second respective wavelength, in the hyperspectral image of the region of the subject with a second respective correction factor in the plurality of correction factors, the second correction factor corresponding to the second respective wavelength of reflected light;

a spectral analyzer module, stored in the non-transitory computer readable memory and executed by the processor unit, the spectral analyzer module comprising instructions for;

normalizing the plurality of corrected measurements of reflected light from the region of the subject against the reflectance of the subject'"'"'s normal skin; and

a light source that illuminates the subject for the hyperspectral sensor.

2. The apparatus of claim 1, wherein the light source comprises a polarizer.

3. The apparatus of claim 2, wherein the hyperspectral sensor comprises a cross polarizer.

4. The apparatus of claim 1, wherein the hyperspectral sensor comprises a sensor head, and wherein the control software module comprises instructions for moving the sensor head through a range of distances relative to the subject, including a first distance that permits a wide field view of a portion of the region of the subject, and a second distance that permits a detailed view of the region of the subject.

5. The apparatus of claim 1, the apparatus further comprising:

a plurality of normalized signatures, each normalized signature in the plurality of normalized signatures corresponding to a characterized skin lesion; and

wherein the spectral analyzer module further comprises instructions for comparing a normalized spectrum acquired using the hyperspectral sensor to a normalized signature in the plurality of normalized signatures.

6. The apparatus of claim 5, wherein comparing the normalized spectrum acquired by the hyperspectral sensor to the normalized signature comprises determining a ratio of a respective normalized measurement of reflected light having a first wavelength in the normalized spectrum acquired by the hyperspectral sensor to a respective normalized value at the first wavelength in the normalized signature.

7. The apparatus of claim 5, wherein comparing the normalized spectrum acquired by the hyperspectral sensor to the normalized signature comprises determining a difference between a respective normalized measurement of reflected light having a first wavelength in the normalized spectrum acquired by the hyperspectral sensor and a respective normalized value at the first wavelength in the normalized signature.

8. The apparatus of claim 1, the apparatus further comprising:

a storage module, stored in the non-transitory computer readable memory, wherein the storage module comprises a plurality of spectra of the subject'"'"'s skin taken at different time points; and

wherein the spectral analyzer module further comprises instructions for comparing a spectrum acquired using the hyperspectral sensor to a spectra in the plurality of spectra of the subject'"'"'s skin taken at different time points.

9. The apparatus of claim 8, wherein the different time points span one or more contiguous years.

10. The apparatus of claim 8, wherein the spectral analyzer module further comprises instructions for analyzing the plurality of spectra to determine a time when a biological insult originated.

11. The apparatus of claim 10, wherein the biological insult is a lesion.

12. The apparatus of claim 1, the apparatus further comprising a sensor other than a hyperspectral sensor.

13. The apparatus of claim 12, wherein the other sensor is a digital camera, a LIDAR sensor, or a terahertz sensor.

14. The apparatus of claim 1, further comprising:

a contact probe module in electronic communication with the control computer, wherein the contact probe module is configured to measure the region of the subject, and wherein said contact probe module comprises a first probe head unit connected to a handle unit.

15. The apparatus of claim 14, wherein said contact probe module further comprises a connector unit connected to the handle unit.

16. The apparatus of claim 14, wherein said first probe head unit is configured to obtain a signal from the region of the subject, wherein said signal is an electrical, a magnetic, a thermal, a mechanical, a radiometric, a photometric, or an optical signal.

17. The apparatus of claim 14, wherein said first probe head unit is an electrical probe, a magnetic probe, a thermal probe, a mechanical probe, a radiometric probe, a photometric probe or an optical probe.

18. The apparatus of claim 1, wherein the light source provides an ultraviolet light.

19. The apparatus of claim 1, wherein the light source provides an infrared light.

20. The apparatus of claim 1, wherein the light source provides a visible light.

21. The apparatus of claim 1, wherein the region of said subject includes an epidermis of the subject.

22. The apparatus of claim 1, wherein the region of said subject includes a dermis of the subject.

23. The apparatus of claim 1, wherein normalizing the plurality of corrected measurements of reflected light from the region of the subject against the reflectance of the subject'"'"'s normal skin comprises determining a ratio of a respective measurement of reflected light having a first wavelength to a reflectance of the subject'"'"'s normal skin at the first wavelength.

24. The apparatus of claim 1, wherein normalizing the plurality of corrected measurements of reflected light from the region of the subject against the reflectance of the subject'"'"'s normal skin comprises determining a difference between a respective measurement of reflected light having a first wavelength and a reflectance of the subject'"'"'s normal skin at the first wavelength.

25. A method of diagnosing a skin cancer in a subject, the subject having a plurality of regions, the method comprising:

(A) providing the apparatus of claim 1;

(B) resolving light, using the hyperspectral sensor of the apparatus of claim 1, obtained from each region of the plurality of regions into a corresponding spectrum thereby obtaining a plurality of spectrums, each spectrum in the plurality of spectra corresponding to a region in the plurality of regions;

(C) correcting first and second respective measurements of reflected light in the plurality of spectra using the spectral calibrator module of the apparatus of claim 1, thereby forming a plurality of corrected spectrums;

(D) normalizing respective corrected measurements of reflected light against the reflectance of the subject'"'"'s normal skin, thereby forming a plurality of corrected normalized spectrums;

(E) obtaining, using a computer, based on a stored spectral signature corresponding to the skin cancer, a probability that a first spectrum in the plurality of corrected, normalized spectra includes indicia of the skin cancer being present in the region corresponding to the first corrected spectrum; and

(F) displaying to a user or outputting to a non-transitory computer readable memory an indicator representing a probable presence of the skin cancer in the corresponding region when the probability exceeds a pre-defined threshold.

26. The method of claim 25, further comprising:

(B0) obtaining, prior to said resolving step (B), the light from each region in the plurality of regions without regard to a visible characteristic of the plurality of regions.

27. A method of diagnosing a skin cancer of a subject using a contact probe module, the subject having a plurality of regions of skin of interest, the method comprising:

(A) providing the apparatus of claim 1;

(B) resolving light, using the hyperspectral sensor of the apparatus of claim 1, obtained from each region of skin in said plurality of regions of skin of the subject into a corresponding spectrum, thereby constructing a plurality of spectra;

(C) correcting first and second respective measurements of reflected light in the plurality of spectra using the spectral calibrator module of the apparatus of claim 1, thereby forming a plurality of corrected spectrums;

(D) normalizing respective corrected measurements of reflected light against the reflectance of the subject'"'"'s normal skin, thereby forming a plurality of corrected, normalized spectrums;

(E) identifying, using a computer, a first region of skin in said plurality of regions of skin by obtaining a first indication that a first spectrum in said plurality of corrected, normalized spectra that corresponds to the suspect region includes an indicia of said skin cancer being present in the suspect region;

(F) collecting, after said identifying (E), a measurement of said first region using said contact probe module thereby obtaining a second indication that said skin cancer is present in the first region, wherein said contact probe module is configured to obtain a signal from said first region; and

(G) outputting an indicator representing the presence of the skin cancer in the first region to a user, a user interface device, or a monitor;

or outputting an indicator representing the presence of the skin cancer in the first region in user readable form to a non-transitory computer readable memory or a local or remote computer system;

or displaying an indicator representing the presence of the skin cancer in the first region.

28. The method of claim 27, further comprising:

(B0) obtaining, prior to the resolving step (B), light from each region of skin in a plurality of regions of skin of interest.

29. The method of claim 27, wherein said signal is an electrical signal, a magnetic signal, a thermal signal, a mechanical signal, or an optical signal.