Tissue imaging

Abstract

The present disclosure relates to tissue imaging. The proposed concepts are directed to providing protocols, solutions, concepts, designs, methods and systems regarding imaging of tissue of a subject. In particular, polarized light is emitted to tissue of a subject, and light backscattered and / or transmitted by the tissue is detected by a filter that differs from the polarization of the emitted light. The detected light is used to generate an image of the tissue of the subject. In short, better depth penetration of tissue can be achieved by using polarized light. In addition, imaging the tissue using polarized light provides a comprehensive view of the structural characteristics of the tissue. This may be particularly beneficial for, for example, breast and / or teat tissue imaging in which calcification can be formed at depths that are difficult to image by usual optical methods.

Description

Technical Field

[0001] The present invention relates to the field of imaging tissue of a subject using light. Background Art

[0002] In recent years, the breast and nipple anatomy have become increasingly interesting due to their increased clinical relevance. In fact, this anatomy is associated with many pathologies, both large and small, mainly in the female population. Such pathologies range from blocked ducts in the nipple to tumor calcifications in the breast tissue. Currently, diagnostic techniques can access the internal breast through the nipple ducts, and surgeons can provide nipple-sparing mastectomies. However, there is a variation in the number of ducts present in the breast, and their spatial location is difficult to visualize. The best-known visualization techniques involve the use of ex vivo tissue, usually obtained via mastectomy.

[0003] In other words, the visualization pipeline as a whole is highly relevant for the diagnosis of various pathologies, but has proven challenging. In particular, in vivo visualization techniques suffer from serious deficiencies. In general, the development and changes of the characteristics of the nipple and breast tissue are important for the accurate and timely diagnosis of pathologies. However, deep tissue imaging of the breast is performed by radiographic techniques or (more recently) by ultrasound. Therefore, it is difficult to realize the benefits associated with regular and detailed imaging of the breast for early warning of suspected tumors.

[0004] Therefore, there is a need for a simple and cost-effective technique for observation and imaging. In particular, it would be particularly beneficial if such a technique could be integrated into current medical protocols for self-observation and reporting, especially at home.

[0005] US patent application number US2022 / 125280A1 describes a device including control circuitry for multi-mode imaging of a sample.

[0006] U.S. patent application number US2020 / 01383260A1 describes techniques for non-contact optical imaging involving acquiring multiple images.

[0007] Ji Qi et al., “Mueller Polarization Imaging for Surgical and Diagnostic Applications: A Review,” Journal of Biophotonics, Vol. 10, No. 8, August 1, 2017, pp. 950-982, describes the use of the Stokes-Mueller formula for polarized light. Summary of the invention

[0008] The invention is defined by the claims.

[0009] According to an example of one aspect of the present invention, there is provided a system for imaging tissue of a subject, comprising:

[0010] a light source configured to emit monochromatic light toward tissue of the subject;

[0011] a first polarizing filter configured to polarize light emitted by the light source and transmit the polarized light toward tissue of the subject;

[0012] a second polarization filter configured to filter light backscattered and / or transmitted by the tissue and to transmit the filtered light, wherein the filtered light is polarized differently than the emitted light;

[0013] a light sensor configured to detect the filtered light;

[0014] a controller configured to control the light source to emit a first light having a first wavelength and control the light sensor to detect a first filtered light corresponding to the first light; and

[0015] A processor is configured to process the first filtered light to generate an image of tissue of the subject.

[0016] By imaging the subject's tissue using polarized light, deeper imaging of the tissue is enabled, and the polarized light can penetrate deeper into the subject's tissue. Thus, the present invention provides a relatively simple and affordable (due to the absence of custom, complex and / or expensive components) way to image the subject's tissue. In fact, the system can be integrated into a personal care device to facilitate quick and simple imaging, thereby improving the potential frequency of imaging sessions and the accessibility of performing such imaging sessions away from medical supervision.

[0017] In other words, the polarization filter is first used to simply polarize the emitted light, and then (after reflection / backscattering of the light and / or transmission by the tissue) polarize the light differently. This enables deep (sub-surface) imaging of the tissue that can be used to roughly identify structures in the tissue. Subsequent analysis, parameter changes, and repeated measurements can be obtained to overcome potential spatial resolution issues.

[0018] In practice, complex and expensive optics are usually required to implement optical imaging for (bulk / below the surface) imaging of a subject. Such complex systems can be used to obtain high spatial resolution and high quality images, but require precise alignment, expensive optics, and cannot penetrate too deeply into tissue. The proposed invention overcomes these problems of ordinary optical systems, as well as post-processing and changes (learned by feedback) to improve image resolution and quality.

[0019] Additionally, different types of tissue interact differently with polarized light. That is, soft tissue may alter the polarization properties of polarized light in a different way than a tumor or calcification within the tissue. Therefore, by detecting backscattered and / or reflected light that passes through a polarization filter (having different polarization properties than the polarization filter used to polarize the emitted / generated light), the interaction of polarization produced by the tissue can be understood and used to identify structures in the tissue.

[0020] In some embodiments, the controller may also be configured to control the light source to emit a second light having a second wavelength different from the first wavelength, and control the light sensor to detect a second filtered light corresponding to the second light. In this case, the processor is further configured to process the first filtered light and the second filtered light to generate an image of the subject's tissue.

[0021] One means by which the spatial resolution and quality of an image of a subject's tissue can be improved is to acquire two images by light of different frequencies. This is known as spatial polarization difference imaging (SPDI), and essentially uses two different frequencies to illuminate the biological tissue, acquiring polarization images from the two frequencies. The final image can have an improved signal-to-noise ratio.

[0022] Specifically, the controller may be further configured to determine a second wavelength different from the first wavelength based on a predetermined sequence of wavelengths.

[0023] Each wavelength (and its relative differences) of light selected for emission / illumination of tissue will affect the resulting image quality. Therefore, the sequence of wavelengths can be followed to determine the optimal combination of wavelengths. Thus, an image with an improved signal-to-noise ratio can be obtained.

[0024] More particularly, the processor can be configured to process the first filtered light to generate a first intermediate image of the subject's tissue, process the second filtered light to generate a second intermediate image of the subject's tissue, and generate an image of the subject's tissue based on a difference between the first intermediate image and the second intermediate image.

[0025] In some embodiments, the processor is further configured to process the first filtered light to generate a Stokes vector representing polarization of the first filtered light, and analyze the Stokes vector using Mueller matrix decomposition to determine eigenvalues ​​describing characteristics of tissue of the subject.

[0026] Mueller matrix decomposition provides an effective tool for simply analyzing a representation of the polarization of the detected light - thereby providing information about the tissue properties of the tissue from which the light was backscattered and / or transmitted. This information can be used to determine the parameters of future imaging scans, or can be used to identify certain structures and / or pathologies.

[0027] In addition, the first polarization filter can be adapted to operate in multiple first polarization modes, wherein the polarization characteristics of the transmitted polarized light are different in each first polarization mode. Similarly, the second polarization filter can be adapted to operate in multiple second polarization modes, wherein the polarization characteristics of the filtered light are different in each second polarization mode.

[0028] Since the polarization characteristics of both polarization filters can be changed, the appropriate polarization for the particular tissue being imaged can be achieved. In addition, since the operating mode of the filters can be changed, multiple images of the same tissue with different polarizations can be obtained, and the overall horizontal resolution of the image of the tissue is improved.

[0029] In some embodiments, the light source may include a light emitter configured to emit light in the infrared, near infrared and / or visible light spectrum and a variable optical frequency filter configured to receive the emitted light and output monochromatic light to the subject's tissue. In this case, the controller may be configured to control the variable optical frequency filter to output monochromatic light having a first wavelength as the first light.

[0030] A light source suitable for implementing this embodiment of the invention can be implemented with relatively simple and inexpensive components (a light emitter (such as an LED) and an optical frequency filter). This also enables the selection of light of different wavelengths with one light source, thereby facilitating SPDI and improving the resulting image quality.

[0031] Additionally, in some embodiments, the processor may be further configured to process the first filtered light to determine an object detection value indicative of the presence of an object within the tissue of the subject.

[0032] This makes it possible to automatically detect objects without skilled personnel operating, thereby improving the usability of the system (especially for home use). In fact, once detected, the system can automatically focus on the area where the object is detected, ensuring that sufficient imaging is performed on this area.

[0033] More specifically, the control unit may be configured to, in response to the object detection value determined by the processor to satisfy the predetermined requirement: control the light source to emit multiple beams of light, each beam of light having a different wavelength, and control the light sensor to detect multiple beams of filtered light corresponding to the multiple beams of light having different wavelengths. In this case, the processor may also be configured to process the multiple beams of filtered light to generate a detailed image of the subject's tissue, the detailed image having a greater spatial resolution than the image of the subject's tissue.

[0034] By acquiring multiple images with different light wavelengths, the region of interest can benefit from improved imaging. As mentioned above, this improves the spatial resolution of the image and thus enables a better understanding of the (potential) objects in the tissue (i.e. tumors or calcifications).

[0035] Alternatively or additionally, in some embodiments, the control unit may be configured to, in response to the object detection value determined by the processor to meet the predetermined requirement: control the light source to emit multiple beams of light, each beam of light having different polarization characteristics, and control the light sensor to detect multiple beams of filtered light corresponding to the multiple beams of light having different polarization characteristics. In this case, the processor may also be configured to process the multiple beams of filtered light to generate a detailed image of the subject's tissue, the detailed image having a greater spatial resolution than the image of the subject's tissue.

[0036] Indeed, similar to the above, once detected, it may be beneficial to improve the horizontal resolution of the image associated with the detected object. This again improves the effectiveness of the system and the quality of the resulting imaging of the tissue.

[0037] In some embodiments, the system may further include an analysis unit configured to identify features present in an image of the subject's tissue and map the identified features to a model representing the subject's anatomical structure including the tissue to generate a subject-specific feature map.

[0038] Not only is it important to detect / image the tissue, but also it may be critical to analyze the tissue over time. In many cases, changes over time are more important for effective diagnosis and / or detection of pathology. Therefore, by automatically recording features and mapping the features to a model, the present invention can provide analysis over time.

[0039] In some cases, the analysis unit may also be configured to compare the subject-specific feature map with a previous subject-specific feature map representing a mapping of previously identified features of tissue of the subject; and identify changes in the subject's features based on a result of the comparison.

[0040] In a preferred embodiment, the tissue may be breast tissue of a subject and the system may be mounted on a breast pump device.

[0041] The subject's breast tissue is at risk for many different pathologies that may reside deep within the breast tissue. For example, the nipple duct may extend several millimeters below the surface and may be subject to blockage. Therefore, the system may be particularly beneficial for imaging breast tissue due to its ability to image deep below the tissue surface.

[0042] Furthermore, integration of the system into a breast pump may enable a simple and effective means of imaging a subject's breast tissue consistently and at home, in order to identify objects and potential pathology as early as possible (while avoiding the need for lengthy, invasive, preemptive testing / screening). Indeed, the proposed system is particularly suitable for mounting / integration with a breast pump due to the small and simple components required for implementation.

[0043] According to another example of an aspect of the present invention, there is provided a method for imaging tissue of a subject, comprising:

[0044] emitting a first light having a first wavelength toward tissue of the subject, wherein the first light is monochromatic;

[0045] filtering the first light so that the first light is polarized;

[0046] filtering light backscattered and / or transmitted by the tissue such that the backscattered and / or transmitted light is polarized, wherein the backscattered and / or transmitted light is polarized differently than the first light;

[0047] detecting polarized backscattered light and / or transmitted light; and

[0048] The detected light is processed to generate an image of the subject's tissue.

[0049] According to an additional example of another aspect of the present invention, there is provided a computer program product comprising computer program code means which, when executed on a computing device having a processing system, causes the processing system to perform all steps of a method for imaging tissue of a subject according to an embodiment of the present invention.

[0050] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] For a better understanding of the invention, and to more clearly show how the same may be put into practice, reference will now be made, by way of example only, to the accompanying drawings, in which:

[0052] Figure 1 A block diagram of a system for imaging tissue of a subject according to an embodiment of the present invention is presented;

[0053] Figure 2 A flow chart of a method for imaging tissue of a subject according to another embodiment of the present invention is presented;

[0054] Figure 3 A flow chart of a method for controlling a light source and a light sensor according to another aspect of the present invention is presented; and

[0055] Figure 4 is a simplified block diagram of a computer within which one or more components of an embodiment may be employed. DETAILED DESCRIPTION

[0056] The present invention will be described with reference to the accompanying drawings.

[0057] It should be understood that the detailed description and specific examples, although indicating exemplary embodiments of the apparatus, system and method, are for illustrative purposes only and are not intended to limit the scope of the invention. These and other features, aspects and advantages of the apparatus, system and method of the present invention will become better understood from the following description, the appended claims and the accompanying drawings. The fact that certain measures are cited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0058] It should be understood that the drawings are schematic and not drawn to scale. It should also be understood that the same reference numerals are used throughout the drawings to indicate the same or similar components.

[0059] The proposed concepts are intended to provide schemes, solutions, concepts, designs, methods and systems for imaging tissue of a subject. Specifically, polarized light is emitted to the tissue of the subject, and light backscattered and / or transmitted by the tissue is detected through a filter that is different from the polarization of the emitted light. The detected light is used to generate an image of the tissue of the subject. In short, better depth penetration of the tissue can be achieved by using polarized light. In addition, imaging the tissue using polarized light provides a comprehensive view of the structural properties of the tissue. This may be particularly beneficial for, for example, breast and / or nipple tissue imaging, where calcifications can form at depths that are difficult to image by conventional optical methods.

[0060] That is, by using polarized light rather than unpolarized light, an increase in optical depth penetration can be achieved. For example, depth penetration can be increased from 1mm to 2mm in typical optical methods to 6mm to 8mm when using polarized light. In fact, polarized measurements at depths of 10mm to 15mm can be achieved with a higher FWHM. This is particularly beneficial in breast tissue, where structures may form deep within the tissue and the nipple duct is often as deep as 5mm.

[0061] The present invention provides a tissue imaging method capable of monitoring changes in relevant anatomical structures. More specifically, the present invention may be particularly suitable for imaging breasts of various sizes (including nipple ducts and calcifications). The present invention can be implemented using readily available components, thereby enabling the present invention to be implemented at low cost.

[0062] In some cases, the present invention proposes to use polarization imaging through spectral polarization difference imaging (SPDI) and Mueller matrix imaging, which can be used to characterize bulk tissue. By combining SPDI with Mueller matrix imaging, the signal information content is increased even with an economical optical setup.

[0063] Furthermore, known problems associated with polarization imaging (e.g., the delivery of polarized light to tissue, and lower image quality) can be overcome simply by using the device longitudinally (i.e., many images acquired over time), which allows for an improvement in imaging quality in time. That is, a better S / N ratio can be obtained simply by repeating the measurements.

[0064] Currently, it is problematic to visualize all ducts in breast and / or nipple tissue in vivo. In fact, such visualization could prove to be very beneficial, as this tissue plays a very important role in the characterization of different conditions, such as ductal carcinoma in situ (DCIS) and duct-blocked mastitis.

[0065] Specifically, for DCIS, there is a pressing need to find imaging techniques that support standard mammographic techniques for diagnosis and characterization (especially given the cryptic nature of this tumor). In fact, even in mammograms, early detection of the tumor has proven difficult. In fact, there are no specific symptoms for DCIS, such as a bulge or breast pain. Most cases are diagnosed on a mammogram before any symptoms appear. DCIS most commonly shows up as new calcium deposits on a mammogram, but not always. Sometimes, distortion of breast tissue on a scan can be a sign of DCIS. DCIS accounts for approximately 20% of all breast tumors. Therefore, imaging methods that aid in the early detection of DCIS could prove invaluable.

[0066] Additionally, blocked milk ducts can occur in both women of childbearing age and women who are near menopause or after menopause. In the case of near menopause, duct ectasia may occur when one or more milk ducts beneath the nipple become enlarged. The walls of the ducts may thicken, and the ducts may fill with fluid. The milk ducts may become blocked or clogged with a thick, sticky substance. This condition usually does not cause symptoms, but some women may have nipple discharge, breast tenderness, or inflammation of the blocked ducts (periductal mastitis). In some cases, surgery is required to remove the affected milk ducts. It is important to be aware of the enlargement effect of this condition on the affected ducts in order to prevent subsequent adverse effects.

[0067] Of course, blocked ducts can also occur during breastfeeding. Milk ducts are tiny tubes that carry milk from glands (lobules) inside the breast to the nipple. Each nipple has about 15 to 25 tiny openings called pores, but only 6 or 7 of them open to release milk during breastfeeding. Sometimes the ducts become blocked with milk, which can cause areas of the breast to become red and sore. Some signs of blocked ducts may be a rim on the breast, a red and irritated rim, a tender or tender rim, or a feeling that the breasts are full even after breastfeeding. One way to address blocked ducts is to try using a breast pump. However, if the blockage is not resolved, it can worsen into postpartum mastitis (i.e., an inflammation of the breast).

[0068] Thus, some embodiments of the present invention provide an economical, effective and safe imaging technique for tissues (e.g., breast tissue) that are capable of detecting changes at sufficient depth. For example, imaging at depths greater than a few millimeters is beneficial for the diagnosis of the above-mentioned pathologies / conditions. That is, the present invention is intended to provide a means for easily associating physical changes in the structure of biological tissue in the imaged tissue with the above-mentioned pathological conditions. In some cases, the present invention may be implemented / included in a personal health device to enable simple (even at-home) detection of various conditions.

[0069] Focusing on the specific example of breast / nipple tissue imaging, the location of the blockage is often some distance behind the nipple, so the swelling can only be seen when imaging some distance behind the nipple. For this reason, a polarized imaging system may be beneficial. The use of polarization increases the effective depth of imaging by at least a factor of 2.

[0070] Therefore, the problem can be stated as how to image:

[0071] (i) Local changes to the entire nipple structure (milk ducts) of the breast in an efficient, simple and affordable manner. To achieve this, there is a need to detect blockages in the breast ducts during normal operation of a personal health device (primarily, but not exclusively, a breast pump). Signs of DCIS are monitored and detected by timely monitoring of the nipple duct environment, as well as signs of Paget's disease of the breast, which accounts for approximately 4% of all breast cancer cases and affects both female and male populations.

[0072] (ii) Global changes in tissue clusters within the breast in order to timely monitor their possible enlargement as a precursor signal for tumor-like development.

[0073] For local variations, in order to achieve this type of imaging, the details of the anatomical structures involved should be taken into account. For example, it is known that the diameter of the nipple ducts changes with the depth of the breast tissue. In fact, in order to detect a single duct, the system must be able to resolve structures that are 0.2mm to 0.8mm in diameter and 2mm to 5mm deep into the nipple tissue. This range is possible with polarization imaging.

[0074] Therefore, using this imaging capability, it is possible to obtain complete 3D imaging of the entire nipple.

[0075] For global changes, it would be beneficial to visualize changes in breast structure to identify any internal anatomical changes in the area of ​​interest. That is, monitoring temporal changes is useful for detecting possible abnormal physiological developments that could be precursors to calcifications or tumors that could be associated with breast cancer development.

[0076] In more detail, the monitoring of the temporal evolution of dense structures inside breast tissue with a diameter of about 4 mm to 20 mm (corresponding approximately to the T1 stage of breast tumor classification) is achievable by the present invention. This detection is within the capabilities of certain embodiments of the present invention, measured vertically from the corresponding skin surface inside the breast tissue, up to several centimeters. Similarly, for tumors with sizes in the T2 (2 cm to 5 cm) and T3 (>5 cm) stage range, embodiments of the present invention are able to find traces of structures at the same or greater (about 3 cm) depth.

[0077] More generally, the proposed invention exploits polarization due to the associated advantages in implementation, cost, and deep penetration in biological tissue. Electromagnetic waves (e.g., light) consist of coupled oscillating electric and magnetic fields that are always perpendicular to each other. The polarization of light refers to the direction of the electric field. In linear polarization, the field oscillates in a single direction. In circular or elliptical polarization, the electric field rotates at a constant rate in a plane as the wave propagates.

[0078] Imaging with polarized light is particularly suitable for the characterization / imaging of tissues required for the diagnosis of the various pathologies mentioned above, as it allows:

[0079] (i) Better deep penetration in biological tissues;

[0080] (ii) a comprehensive view of structural properties; and

[0081] (iii) Significantly wider collection angles compared to optical methods.

[0082] However, polarization-based imaging generally has limited resolution compared to optical, depth-defined methods. However, it should be noted that the resolution gap of optical depth-defined methods can be addressed by focusing on a limited volume of tissue to be imaged and / or using advanced computational methods to enhance the sensitivity of the polarization-determining method. Indeed, this may be of particular interest in applying the present invention to imaging of the milk ducts of the nipple (which may be relatively deep below the tissue surface, but of a smaller size).

[0083] Most bulk tissue polarimetry methods produce well-resolved lateral images but provide cumulative polarization properties over the depth direction of interrogation. Furthermore, bulk tissue polarimetry methods have the advantages of being less complex, less expensive, sensitive to larger sampling depths, and easier and faster to implement for large lateral fields of view than depth-resolved imaging modalities. All of these features fit well within the cost and simplicity of implementation requirements of any personal healthcare device.

[0084] The cumulative integration of polarization imaging methods allows for a deeper analysis of tissues, which is not a barrier in a personal healthcare setting, since the goal is to monitor and indicate suspected abnormal internal structures by comparing similar images at different times, rather than to precisely define the geometrical properties (size, volume, depth, etc.) of the identified changes in the tissue.

[0085] Furthermore, periodic use (ie, use over time) of the device for polarization imaging allows for an iterative reduction of the S / N ratio in the imaging measurements due to repetitive statistics.

[0086] Of course, various techniques can be used to improve polarized light-based tissue imaging. Specifically, Mueller matrix decomposition, a matrix method for manipulating the Stokes vector (representing the polarization of light), can be used. In summary, by collecting backscattered light and / or transmitted light, the interaction of polarized light with tissue can be analyzed to infer the composition and, therefore, the properties of the associated tissue.

[0087] In addition, spectral polarization difference imaging (SPDI) can be performed, using two different frequencies of light to illuminate biological tissue, acquiring polarization images from both of them. The final image is obtained from the subtraction of the two images acquired at different frequencies in order to improve the signal-to-noise ratio of the resulting image.

[0088] Thus, a specific implementation of the present invention may be embodied in a visible, near infrared and / or infrared (VISNIR) lighting and imaging device mounted on a personal healthcare device (e.g., a breast pump, a massage device), the lighting and imaging device comprising:

[0089] Lighting components (i.e., light sources), including:

[0090] (i) Broadband VISNIR light source (e.g., LED);

[0091] (ii) Programmable VISNIR optical frequency filter (monochromator, i.e. Fabry-Perot interferometer, etc.);

[0092] (iii) Programmable polarization filter (i.e. variable polarizer)

[0093] An imaging component (i.e., a light sensor) comprising:

[0094] (i) CMOS sensor without IR-NIR filter applied;

[0095] (ii) a lens for image focusing (i.e., a variable focal length lens, etc.);

[0096] (iii) Programmable polarization filter (i.e. variable polarizer)

[0097] Processor, including:

[0098] (i) Components for estimating / determining the presence of tissue (breast, nipple) in the field of view of the CMOS camera;

[0099] (ii) components used to implement SPDI;

[0100] (iii) Components for implementing Mueller matrix decomposition imaging.

[0101] A control module for achieving progressive multi-polarization and multi-frequency imaging of the imaged tissue and ultimately confirmed solid objects / calcifications.

[0102] In some cases, the control module may first implement a first (rough) estimate of VISNIR reflectance (using SPDI and the results of Mueller matrix decomposition) to assess the presence of objects inside tissue with a major axis greater than or equal to 2 mm to 4 mm (e.g., calcifications inside the breast).

[0103] The control module can then collect the results of SPDI and Mueller matrix decomposition at multiple frequencies and polarizations. This can ensure that details less than 2mm and / or better depth resolution of the identified objects are obtained.

[0104] The control module can also sample more images in areas where the probability of the object is high. For example, the sample of breast images can be increased in areas with a high incidence of tumors.

[0105] Subsequently, a 3D volume reconstruction can be generated from the 2D images acquired during the presence estimation process and a 3D mapping of the imaged structures to the tissue is performed. This can allow for longitudinal integration and analysis of the tissue.

[0106] Go to Figure 1 , depicts a simplified block diagram of a system for imaging tissue of a subject according to an embodiment of the present invention. The system includes a light source 110, a first polarizing filter 120, a second polarizing filter 130, a light sensor 140, a controller 150, and a processor 160. Optionally, the system also includes a first lens element 122 and a second lens element 132 and an analysis unit 170.

[0107] The system is configured to enable the generation of images of a (bulk) tissue of a subject. That is, the system can be used to generate images of a volume beneath the surface of a subject's skin, such as breast tissue, nipple tissue or muscle tissue.

[0108] As a specific example, the tissue may be breast and / or nipple tissue of a subject. Furthermore, in this case, the system may be mounted on a breast pump device. This means that imaging may be performed regularly without the need for separate equipment and time outside of a breast pumping scenario.

[0109] The light source 110 is configured to emit monochromatic light to the tissue of the subject. That is, the light source 110 is configured to illuminate the tissue of the subject with monochromatic light. In this case, the monochromatic light is light of a single wavelength or a narrow band of wavelengths.

[0110] For example, light source 110 may include a broadband light emitter (e.g., an LED) having an optical filter that allows only monochromatic light from the broadband light emitter. In some cases, the optical filter may be operated in multiple modes to pass monochromatic light of different wavelengths. Alternatively, light source 110 may simply include a light emitter configured to emit monochromatic light.

[0111] More particularly, the light source 110 may (optionally) include a light emitter 112 configured to emit light in the infrared, near-infrared and / or visible light spectrum and a variable optical frequency filter 114 configured to receive the emitted light and output monochromatic light to the subject's tissue.

[0112] In any case, light source 110 may emit light within the visible, infrared, and / or near infrared spectrum. Light emitted toward the tissue of the subject may simply mean that light source 110 provides light to appropriate optics for directing light from light source 110 toward the surface of the subject. Alternatively, light source 110 may be configured such that light (via first polarizing filter 120) is emitted directly toward the tissue.

[0113] To reiterate, it may be the case that the light source 110 can (selectively) emit different monochromatic lights. That is, the light source 110 can selectively emit light of different wavelengths. This enables multi-wavelength imaging for selective depth, and enables SPDI.

[0114] The light sensor 140 is configured to detect light backscattered (i.e., reflected) and / or transmitted by the subject's tissue (corresponding to emitted light). For example, the light sensor 140 may be a CMOS sensor or other camera system capable of detecting light (at least one of the visible, infrared, and near infrared spectra). In essence, the light sensor 140 may be any component capable of converting incident light into a signal describing the incident light for further analysis.

[0115] The light sensor 140 may be appropriately positioned to detect backscattered light and / or transmitted light. In some cases, it may be preferred that the light sensor 140 be positioned to detect only backscattered light, which facilitates a more compact system (i.e., does not require the sensor and light source to be positioned on opposite sides of the tissue). The light sensor 140 may include suitable optics for focusing / directing light toward a component for sensing light.

[0116] In addition to the light source 110 and the light sensor 140 , the system also includes a first polarization filter 120 and a second polarization filter 130 for implementing polarization-based imaging.

[0117] Specifically, the first polarizing filter 120 is configured to polarize / filter the light emitted by the light source 110 and transmit polarized light to the tissue of the subject. That is, the light from the light source 110 passes through the first polarizing filter 120 before illuminating the tissue. The first polarizing filter 120 polarizes the light in a first mode (e.g., horizontal, vertical, right circular, or left circular).

[0118] The second polarization filter is configured to polarize light after it is backscattered and / or transmitted by the subject's tissue, and transmit the resulting polarized light to the light sensor 140. In other words, the second polarization filter 130 is configured to filter / polarize light backscattered and / or transmitted by the tissue, and transmit the filtered light.

[0119] Importantly, the filtered light is polarized differently (eg, perpendicularly) than the emitted light. In other words, the first polarizing filter 120 and the second polarizing filter 130 polarize / filter light differently from each other.

[0120] The first polarizing filter 120 and the second polarizing filter 130 may be separate components. Alternatively, the first polarizing filter 120 and the second polarizing filter 130 may be different components of the same component. For example, the first polarizing filter 120 and the second polarizing filter 130 may be circular polarizers consisting of two independently polarizable annular concentric components forming a whole circle. The outer filter may overlap with the light source 110, while the inner filter overlaps with the light sensor 140. This may enable a more compact system.

[0121] Furthermore, the first polarization filter (and the second polarization filter) may be adapted to be operable in one or more (multiple) different polarization modes. In each polarization mode, the polarization filters may have a different polarization mode (i.e., they filter light differently). This enables multi-polarization imaging

[0122] In other words, the first polarization filter 120 is adapted to operate in a plurality of first polarization modes, wherein the polarization characteristics of the transmitted polarized light are different in each first polarization mode. In addition, the second polarization filter 130 is adapted to operate in a plurality of second polarization modes, wherein the polarization characteristics of the filtered light are different in each second polarization mode.

[0123] The system 100 may optionally include a first lens element 122 and / or a second lens element 132 for appropriately directing light that illuminates the tissue and light that is backscattered and / or transmitted by the tissue, respectively. The lens elements may simply be used to appropriately focus the light onto the appropriate components / tissues, or may be used to selectively direct light to or from the tissue.

[0124] Despite Figure 1 Although depicted as separate components, first lens element 122 and second lens element 132 may be implemented by a single component / device. Furthermore, first lens element 122 and second element may be provided in the optical path before or after the polarizing filter.

[0125] Therefore, the controller 150 is configured to control the operation of the above-mentioned components. Specifically, at the simplest, the controller 150 is configured to control the light source 110 to emit a first light having a first wavelength, and to control the light sensor 140 to detect a first filtered light corresponding to the first light. That is, the controller 150 causes the light source 110 to emit light to the tissue (via the first polarization filter 120), and causes the light sensor 140 to detect the emitted light (after being transmitted through the first polarization filter 120, backscattered light and / or transmitted by the tissue, and transmitted through the second polarization filter 130).

[0126] Subsequently, processor 160 is configured to process the first filtered light to generate an image of the subject's tissue. In other words, processor 160 processes / analyzes the signal describing the light detected by light sensor 140 in order to generate an image of (at least part of) the subject's tissue.

[0127] Of course, controller 150 may also cause light source 110 and light sensor 140 to perform the above multiple times. This may be performed on different portions of the subject's tissue, and the resulting light signals are used to generate a complete (or more complete) image of the subject's tissue.

[0128] More specifically, the controller 150 may also be configured to control the light source 110 to emit a second light having a second wavelength different from the first wavelength, and control the light sensor 140 to detect a second filtered light corresponding to the second light. That is, the tissue is illuminated with polarized light of two different wavelengths (or two narrow wavelength bands), and the light sensor 140 detects the light of the two different wavelengths.

[0129] Processor 160 is also configured to process the first filtered light and the second filtered light (or a signal descriptive of the first filtered light and the second filtered light) to generate an image of tissue of the subject.

[0130] To implement SDPI, processor 160 may be configured to process the first filtered light to generate a first intermediate image of the subject's tissue, process the second filtered light to generate a second intermediate image of the subject's tissue, and generate an image of the subject's tissue based on a difference between the first intermediate image and the second intermediate image. Thus, the signal-to-noise ratio of the image of the tissue may be improved.

[0131] The wavelength selected may depend on a predetermined sequence of wavelengths. That is, there may be certain wavelengths that may be used to illuminate the tissue. This may depend on the tissue / anatomy / structure of interest, including the depth and spatial resolution required. The controller 150 is configured to be based on a predetermined sequence of wavelengths (i.e., the controller 150 may consult a memory to determine the wavelengths).

[0132] Additionally or alternatively, the processor 160 can be configured to process the first filtered light to generate a Stokes vector representing the polarization of the first filtered light. The Stokes vector can then be analyzed / processed using a Mueller matrix decomposition to determine eigenvalues ​​describing characteristics of the subject's tissue. The eigenvalues ​​can describe the structure of the tissue and can be used in future selection of wavelength and / or polarization of light for imaging.

[0133] In addition, the processor 160 can be configured to process the first filtered light (i.e., a signal describing the first filtered light) to determine an object detection value indicating the presence of an object within the tissue of the subject. This can be implemented by an image processing algorithm configured to determine (irregular) objects in the image corresponding to the first filtered light.

[0134] Subsequently, and in response to the object detection value that satisfies the predetermined requirement determined by the processor 160, the controller 150 may control the light source 110 to emit a plurality of light beams, each light beam having a different wavelength, and control the light sensor 140 to detect a plurality of filtered light beams corresponding to the plurality of light beams having different wavelengths. That is, the controller 150 may control the light source 110 and the light sensor 140 to perform a wide scan of the tissue corresponding to the object.

[0135] Processor 160 can then process the multiple beams of filtered light to generate a detailed image of the subject's tissue having a greater spatial resolution than an image of the subject's tissue. That is, by imaging the tissue with multiple different wavelengths, an overall image having improved spatial resolution can be obtained than an image based on one wavelength of light.

[0136] Alternatively, or in addition to the above, in response to the object detection value determined by the processor 160 to meet the predetermined requirements, the control unit can be configured to control the light source 110 to emit multiple beams of light, each beam of light having different polarization characteristics. Of course, the control unit can also control the light sensor 140 to detect multiple beams of filtered light corresponding to the multiple beams of light with different polarization characteristics. This may require multiple polarizers or the ability to manipulate polarizers (using known methods (such as rotation), or by manipulating liquid crystals).

[0137] Similar to the above, processor 160 may also be configured to process the multiple beams of filtered light to generate a detailed image of the subject's tissue having a greater spatial resolution than the image of the subject's tissue.

[0138] It will be appreciated that a combination of the two approaches described above (multiple different wavelengths and multiple different polarizations of light for imaging tissue) may be employed to also generate improved images.

[0139] Finally, the system may also (optionally) include an analysis unit. The analysis unit is configured to identify features (e.g., structures, anatomical structures, calcifications, and tumors) present in an image of the subject's tissue. The analysis unit then maps the identified features to a model representing the subject's anatomical structure including the tissue to generate a subject-specific feature map. The model may be obtained from a memory or may be generated by the analysis unit.

[0140] In a complex example, the analysis unit may also be configured to compare the subject-specific feature map with a previous subject-specific feature map representing a mapping of previously identified features of the subject's tissue. Based on the results of the comparison, changes in the subject's features may be identified. For example, the growth rate of a tumor may be identified, or the release of a duct blockage may be noted.

[0141] Figure 2 A method for imaging tissue of a subject according to an embodiment of the invention is presented.

[0142] In step 210, a first light having a first wavelength is emitted toward the tissue of the subject. The first light is monochromatic light because it has one wavelength, or has a thin / narrow wavelength band. That is, the first light is used to illuminate the tissue of the subject.

[0143] In step 220, the first light is filtered so that the first light is polarized. This is performed before the first light is incident on the tissue of the subject. Thus, the monochromatic polarized light illuminates (and penetrates) the tissue of the subject.

[0144] In step 230, light backscattered and / or transmitted by the tissue is filtered such that the backscattered and / or transmitted light is polarized. The backscattered and / or transmitted light is polarized differently than the first light.

[0145] In other words, light is emitted, passes through a filter so as to have a first polarization, is reflected / backscattered and / or transmitted by tissue, and passes through another filter so as to have a second polarization (different from the first polarization).

[0146] In step 240, the polarized backscattered light and / or transmitted light is detected. This may include measuring the light and converting the light into a signal describing the polarized backscattered light and / or transmitted light.

[0147] Finally, the detected light is processed / analyzed to generate an image of the subject's tissue in step 250. Of course, some of the above steps may be repeated with light of different wavelengths and / or polarizations, and at different portions of the tissue.

[0148] A detailed description of the control implementation of the present invention will now be provided.

[0149] Specifically, the light sensor (e.g., camera) is provided with appropriate optics (such as a CMOS sensor) to image the subject's tissue under both visible, IR and / or NIR illumination. The light sensor can be any sensor currently used to detect light in such wavelength bands.

[0150] The optical sensor can capture images while the system is being operated (i.e., when the system is integrated into a personal care device, images can be captured in response to the device being used / operated). Whether the tissue / anatomical structure of interest is in the field of view of the image sensor can be determined by image processing or an AI module (e.g., nipple recognition, breast recognition, etc. through deep learning algorithms). Of course, while breast and nipple tissue are of particular interest, it should be understood that the proposed subsurface imaging techniques allow for imaging of any type of tissue in any anatomical part.

[0151] Once an anatomical structure is detected in the field of view of the light sensor, a progressive scanning protocol can be activated. The progressive scanning protocol can use information from the (relatively fast) SPDI to continuously increase the imaging depth (D) to improve the Mueller decomposition. In addition, the protocol can use the detailed optical properties obtained from the Mueller decomposition to improve the quality of the SPDI image. The improvement in the Mueller matrix decomposition is essentially due to taking into account the optical properties of the examined tissue; this knowledge essentially improves the possibility of Mueller matrix decomposition and returns a better signal-to-noise ratio distribution for the image. For SPDI, the detailed tissue information obtained from the results of Mueller matrix decomposition imaging of previous tissue layers at depth D enables the imaging method to increase its signal-to-noise ratio at depth D+1 because the polarization image details of the first of the two frequencies required for SPDI imaging are known and are more detailed than the simpler imaging used by the SPDI method alone.

[0152] Figure 3 This process is summarized, depicting the main stages of the imaging process with increasing depth.

[0153] For the SPDI image acquisition components shown, the VISNIR illumination component (i.e., light source) is first activated. This component, under the control of a common progressive multi-polarization and multi-frequency imaging sequence algorithm, begins to illuminate the subject's tissue with a series of frequencies (depending on the tissue to be imaged). In the case of the breast, the sequence algorithm can start from the higher parts of the NIR spectrum to achieve deeper tissue penetration (e.g., 800nm ​​and 1000nm are sequentially used to illuminate the subject). Of course, the light is also polarized in a given direction (e.g., horizontally, vertically) using a filter after the frequency selective filter / monochromator.

[0154] In a simple embodiment, the present invention uses only reflected / backscattered light, and the reflected light is therefore in turn collected by a polarizing filter that is polarized perpendicularly to the polarizing filter used to illuminate the subject; the collected light is then fed into the camera's optics to acquire an image. Alternatively, already transmitted light can also be collected, but this may require additional components and / or more complex optics.

[0155] The same procedure can be followed to acquire a second image at a second nearby frequency (e.g., 1000 nm if the previous image was acquired with 800 nm frequency illumination). The two initially acquired images are then subtracted to yield an SPDI image. In this image, the presence of semi-solid (e.g., calcifications, blocked ducts, etc.) structures is enhanced and becomes more visible by selecting the photons that bring the most information while eliminating the majority of backscattered photons that experience severe scattering inside the tissue or that are just backscattered from the tissue surface (i.e., skin).

[0156] In some cases, feedback from reflected / backscattered light can be automatically exploited to compensate for modifications in the optical signal delivered to the tissue (e.g., reflected light can indicate environmental changes, such as tilt, etc.). This process is repeated for several different polarizations to increase the horizontal resolution of the SPDI image. It should be noted that the opportunity to increase this resolution depends on the tissue being imaged. For example, this may be particularly useful for imaging smaller ducts inside the nipple.

[0157] Once the first SPDI imaging phase has been completed, the system switches to Mueller decomposition mode. The main change in this mode is the polarization filter, which allows a more complex range of polarizations and frequencies to be used to illuminate the tissue and read both the backscattered / reflected light filtering many polarization directions.

[0158] However, the optical properties derived during the SPDI phase are used in the Mueller analysis to speed up and ensure a robust decomposition (since knowledge of the properties of the tissue can be embedded in the decomposition algorithm). For example, for imaging the papillary ducts, the decomposition is mainly focused on the delayed component of the matrix, since it proves to be more suitable for imaging based on the spatial orientation of the tissue structure. In fact, the ducts form a structure similar to fiber bundles, which show a clear spatial orientation, making this particular decomposition very suitable for this imaging task.

[0159] The polarization change required for this imaging stage can be obtained by polarizing filters, including technologies such as liquid crystal (LC) or photoelastic modulators (PEM), by mechanically rotating linear polarizers, wire grid polarizers and quarter wave plates, or by diffraction using polarizing prisms, gratings or gradient index lenses.

[0160] The lateral resolution (Full Width at Half Maximum - FWHM of the point spread function of the incident beam of polarization-preserving photons in the tissue) is about 200 μm in the visible wavelength range and for typical tissue characteristics. This FWHM is well suited for imaging of papillary ducts at depths greater than 2 mm (which they typically reach or exceed).

[0161] The light source (i.e., a broadband LED) used in some embodiments of the present invention may output light in the spectrum from about 450 nm to 1200 nm. Thus, the range of subsequent approximate frequencies that the present invention may use to illuminate a subject is included within this range. Initially, the present invention may begin scanning with a difference of about 200 nm between the two frequencies. In the case of breast tissue, this enables an approximate resolution of about 5 mm (from a tissue depth of about 1.5 cm to 1 cm) for the depth and size of the most common calcifications in the breast. The ideal frequencies involved in the initial scan, as well as their spacing, vary for imaging different types of tissue given the size of the object that may be detected or the depth of interest.

[0162] Still, the sampling of the images of tissue can be guided by anisotropic spatial sampling dictated by the spatial distribution of the structures of interest. For example, it is known that tumors in breast tissue are more likely to develop in certain areas of the breast than in others. In practice, this means that the field of view of the camera is sampled according to known statistics.

[0163] The data thus acquired (SPDI and Mueller decomposition images, and the corresponding frequencies) can be saved and connected to a 3D model of the tissue of the subject that has been imaged. This enables the analysis of the temporal evolution of the imaged structures and ultimately the enrichment using frequencies with lower spacing to achieve better depth resolution. The task of the AI ​​module can be to analyze this acquired data both online and offline to detect possible anomalies.

[0164] In a specific example, when a breast is detected in the field of view of the camera, a 3D model of the anatomy of the breast can be obtained by the AI ​​module applied to the captured images. A 3D model can also be obtained for the nipple by the same AI module as in the breast, since in this case an image of the global anatomy is also acquired to trigger the polarization analysis. However, in this case, the model is further enriched by using the more detailed images acquired, since the limited size of the average nipple (0.6 cm high by 1.2 cm in diameter) allows a complete scan of the entire volume of the anatomy from side to side in subsequent acquisition sessions.

[0165] Figure 4 An example of a computer 1000 is illustrated in which one or more components of an embodiment may be employed. The various operations discussed above may utilize the functionality of the computer 1000. For example, one or more components of a system for obtaining input from a user to control an interface may be incorporated into any element, module, application, and / or component discussed herein. In this regard, it will be appreciated that the system functionality blocks may be run on a single computer, or may be distributed across several computers and locations (e.g., via an Internet connection).

[0166] Computer 1000 includes but is not limited to PC, workstation, laptop computer, PDA, handheld device, server, storage device, etc. In general, in terms of hardware architecture, computer 1000 may include one or more processors 1010, memory 1020 and one or more I / O devices 1030 that are communicatively coupled via a local interface (not shown). The local interface may be, for example but not limited to, one or more buses or other wired or wireless connections, as known in the art. The local interface may have additional elements, such as controllers, buffers (cache), drivers, repeaters and receivers, to enable communication. In addition, the local interface may include address, control and / or data connections to enable appropriate communication between the above components.

[0167] Processor 1010 is a hardware device for executing software that may be stored in memory 1020. Processor 1010 may be virtually any custom or commercially available processor, central processing unit (CPU), digital signal processor (DSP), or auxiliary processor among several processors associated with computer 1000, and processor 1010 may be a semiconductor-based microprocessor (in the form of a microchip) or a microprocessor.

[0168] The memory 1020 may include any one or a combination of volatile memory elements (e.g., random access memory (RAM), such as dynamic random access memory (DRAM), static random access memory (SRAM), etc.) and non-volatile memory elements (e.g., ROM, erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), magnetic tape, compact disk read-only memory (CD-ROM), magnetic disk, floppy disk, cassette, etc.). In addition, the memory 1020 may incorporate electronic, magnetic, optical and / or other types of storage media. It should be noted that the memory 1020 may have a distributed architecture in which various components are remote from each other but can be accessed by the processor 1010.

[0169] The software in the memory 1020 may include one or more separate programs, each of which includes an ordered list of executable instructions for implementing logical functions. According to an exemplary embodiment, the software in the memory 1020 includes a suitable operating system (O / S) 1050, a compiler 1060, a source code 1070, and one or more application programs 1080. As shown, the application program 1080 includes a plurality of functional components for implementing the features and operations of the exemplary embodiment. According to an exemplary embodiment, the application program 1080 of the computer 1000 may represent various application programs, computing units, logics, functional units, processes, operations, virtual entities, and / or modules, but the application program 1080 is not meant to be limiting.

[0170] The operating system 1050 controls the execution of other computer programs and provides scheduling, input-output control, file and data management, memory management, and communication control and related services. The inventors expect that the application program 1080 used to implement the exemplary embodiments can be applicable to all commercially available operating systems.

[0171] Application 1080 may be a source program, an executable program (object code), a script, or any other entity comprising a set of instructions to be executed. When a source program, the program is typically translated via a compiler (such as compiler 1060), an assembler, an interpreter, etc., which may or may not be included in memory 1020 to operate correctly in conjunction with O / S 1050. In addition, application 1080 may be written as an object-oriented programming language with data and method classes, or a procedural programming language with routines, subroutines, and / or functions, such as, but not limited to, C, C++, C#, Pascal, BASIC, API calls, HTML, XHTML, XML, ASP scripts, JavaScript, FORTRAN, COBOL, Perl, Java, ADA, .NET, functional programming, etc.

[0172] I / O devices 1030 may include input devices such as, but not limited to, a mouse, keyboard, scanner, microphone, camera, etc. In addition, I / O devices 1030 may also include output devices such as, but not limited to, a printer, display, etc. Finally, I / O devices 1030 may also include devices that transmit both input and output such as, but not limited to, a NIC or modulator / demodulator (for accessing remote devices, other files, devices, systems, or networks), a radio frequency (RF) or other transceiver, a telephone interface, a bridge, a router, etc. I / O devices 1030 also include components for communicating over various networks such as the Internet or an intranet.

[0173] If the computer 1000 is a PC, workstation, intelligent device, etc., the software in the memory 1020 may also include a basic input and output system (BIOS) (omitted for simplicity). The BIOS is a set of basic software routines that initialize and test the hardware at startup, start the O / S 1050, and support data transfer between hardware devices. The BIOS is stored in some type of read-only memory (such as ROM, PROM, EPROM, EEPROM, etc.) so that when the computer 800 is activated, the BIOS can be executed.

[0174] When the computer 1000 is in operation, the processor 1010 is configured to execute software stored in the memory 1020, transfer data to and from the memory 1020, and generally control the operation of the computer 1000 according to the software. The application programs 1080 and the O / S 1050 are read in whole or in part by the processor 1010, possibly buffered within the processor 1010, and then executed.

[0175] When the application 1080 is implemented in software, it should be noted that the application 1080 can be stored on virtually any computer-readable medium for use by or in conjunction with any computer-related system or method. In the context of this document, a computer-readable medium can be an electronic, magnetic, optical or other physical device or means that can contain or store a computer program for use by or in conjunction with a computer-related system or method.

[0176] Application 1080 may be embedded in any computer-readable medium for use by or in conjunction with an instruction execution system, device, or apparatus, such as a computer-based system, a system containing a processor, or other system that can obtain instructions from an instruction execution system, device, or apparatus and execute the instructions. In the context of this document, a "computer-readable medium" may be any device that can store, communicate, propagate, or transmit a program used by or in conjunction with an instruction execution system, device, or apparatus. A computer-readable medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, equipment, or propagation medium.

[0177] about Figure 2 and Figure 3 The method described and about Figure 1 The described systems may be implemented in hardware or software or a mixture of both (e.g., as firmware running on a hardware device). To the extent that the embodiments are partially or entirely implemented in software, the functional steps shown in the process flow diagrams may be performed by appropriately programmed physical computing devices, such as one or more central processing units (CPUs) or graphics processing units (GPUs). Each process and the individual component steps shown in its flow diagram may be performed by the same or different computing devices. According to an embodiment, a computer-readable storage medium stores a computer program including a computer program code that is configured to cause one or more physical computing devices to perform a method as described above when the program is run on one or more physical computing devices.

[0178] Storage media may include volatile and non-volatile computer memory, such as RAM, PROM, EPROM and EEPROM, optical disks (such as CD, DVD, BD), magnetic storage media (such as hard disks and tapes). The various storage media may be fixed within the computing device, or may be transportable so that one or more programs stored thereon may be loaded into a processor.

[0179] To the extent that the embodiments are partially or entirely implemented in hardware, Figure 1The blocks shown in the block diagrams may be separate physical components, or logical subdivisions of a single physical component, or may all be implemented in an integrated manner in one physical component. In implementation, the functionality of a block shown in the drawings may be divided between multiple components, or in implementation, the functionality of multiple blocks shown in the drawings may be combined in a single component. Hardware components suitable for embodiments of the present invention include, but are not limited to, conventional microprocessors, application specific integrated circuits (ASICs), and field programmable gate arrays (FPGAs). One or more blocks may be implemented as a combination of dedicated hardware to perform some functions and one or more programmed microprocessors and associated circuits to perform other functions.

[0180] By studying the drawings, the disclosure and the appended claims, other changes of the disclosed embodiments can be understood and implemented by those skilled in the art when practicing the claimed invention. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "one" or "an" does not exclude multiple. A single processor or other unit can implement the functions of several items listed in the claims. The fact that certain measures are recorded in mutually different dependent claims does not indicate that the combination of these measures cannot be used advantageously. If a computer program is discussed above, it can be stored / distributed on a suitable medium, such as an optical storage medium or solid-state medium supplied with or as part of other hardware, but can also be distributed in other forms, such as via the Internet or other wired or wireless telecommunications systems. If the term "suitable for" is used in a claim or specification, it should be noted that the term "suitable for" is intended to be equivalent to the term "configured to". Any figure mark in the claim should not be interpreted as limiting the scope.

[0181] The flow charts and block diagrams in the accompanying drawings illustrate the possible implementation architecture, functionality and operation of the system, method and computer program product according to various embodiments of the present invention. In this respect, each frame in the flow chart or block diagram can represent a module, fragment or part of an instruction, including one or more executable instructions for implementing a specified logical function. In some alternative implementations, the function annotated in the frame may not occur in the order annotated in the figure. For example, two frames shown in succession can actually be performed substantially simultaneously, or these frames can sometimes be performed in reverse order, depending on the functionality involved. It should also be noted that each frame in the block diagram and / or flow chart illustration and the combination of frames in the block diagram and / or flow chart illustration can be implemented by a system based on special-purpose hardware, which implements a specified function or action or performs a combination of special-purpose hardware and computer instructions.

Claims

1. A system (100) for imaging tissue of a subject, comprising: a light source (110) configured to emit monochromatic light toward the tissue of the subject; a first polarizing filter (120) configured to polarize light emitted by the light source and transmit polarized light toward the tissue of the subject; a second polarization filter (130) configured to filter light backscattered and / or transmitted by the tissue and to transmit the filtered light, wherein the filtered light is polarized differently than the emitted light; a light sensor (140) configured to detect the filtered light; A controller (150), the controller being configured to: Controlling the light source to emit first light having a first wavelength; controlling the light sensor to detect a first filtered light corresponding to the first light; controlling the light source to emit a second light having a second wavelength different from the first wavelength; and controlling the light sensor to detect a second filtered light corresponding to the second light; as well as A processor (160), the processor being configured to: processing the first filtered light to generate a first intermediate image of the tissue of the subject; processing the second filtered light to generate a second intermediate image of the tissue of the subject; and The processor is further configured to: An image of the tissue of the subject is generated based on a difference between the first intermediate image and the second intermediate image.

2. The system of claim 1, wherein the controller (150) is further configured to determine the second wavelength different from the first wavelength based on a predetermined sequence of wavelengths.

3. The system according to any one of claims 1 to 2, wherein the processor (160) is further configured to: processing the first filtered light to generate a Stokes vector representing polarization of the first filtered light; and The Stokes vectors are analyzed using Mueller matrix decomposition to determine eigenvalues ​​that describe properties of the tissue of the subject.

4. The system according to any one of claims 1 to 3, wherein the first polarization filter (120) is adapted to operate in a plurality of first polarization modes, wherein the polarization properties of the transmitted polarized light are different in each first polarization mode, and The second polarization filter (130) is adapted to operate in a plurality of second polarization modes, wherein the polarization characteristics of the filtered light are different in each second polarization mode.

5. The system according to any one of claims 1 to 4, wherein the light source (110) comprises: a light emitter (112) configured to emit light in the infrared, near infrared and / or visible light spectrum; as well as a variable optical frequency filter (114) configured to receive the emitted light and output monochromatic light to the tissue of the subject, and The controller (150) is configured to control the variable optical frequency filter to output monochromatic light having the first wavelength as the first light.

6. The system according to any one of claims 1 to 5, wherein the processor (160) is further configured to process the first filtered light to determine an object detection value indicative of the presence of an object within the tissue of the subject.

7. The system of claim 6, wherein the controller (150) is configured to, in response to the object detection value determined by the processor to satisfy a predetermined requirement: controlling the light source (110) to emit multiple beams of light, each beam of light having a different wavelength; and controlling the light sensor (140) to detect the plurality of filtered lights corresponding to the plurality of lights having different wavelengths, and The processor (160) is further configured to process the plurality of filtered beams of light to generate a detailed image of the tissue of the subject, the detailed image having a greater spatial resolution than the image of the tissue of the subject.

8. The system of claim 6 or 7, wherein the controller (150) is configured to, in response to the object detection value determined by the processor to satisfy a predetermined requirement: Controlling the light source (110) to emit multiple beams of light, each beam of light having a different polarization characteristic; and controlling the light sensor (140) to detect the plurality of filtered lights corresponding to the plurality of lights having different polarization characteristics, and The processor (160) is further configured to process the plurality of filtered beams of light to generate a detailed image of the tissue of the subject, the detailed image having a greater spatial resolution than the image of the tissue of the subject.

9. The system according to any one of claims 1 to 8, further comprising an analysis unit (170), the analysis unit being configured to: identifying features present in the image of the tissue of the subject; and The identified features are mapped to a model representing the anatomical structure of the subject including the tissue to generate a subject-specific feature map.

10. The system according to claim 9, wherein the analysis unit (170) is further configured to: comparing the subject-specific feature map to a previous subject-specific feature map representing a mapping of previously identified features of the tissue of the subject; and A change in a characteristic of the subject is identified based on the results of the comparing.

11. The system according to any one of claims 1 to 10, wherein the tissue is breast tissue of the subject, and wherein the system (100) is mounted on a breast pump device.

12. A method (200) for imaging tissue of a subject, comprising: emitting (210) first light having a first wavelength toward the tissue of the subject, wherein the first light is monochromatic; filtering (220) the first light so that the first light is polarized; filtering (230) light backscattered and / or transmitted by the tissue so that the backscattered and / or transmitted light is polarized, wherein the backscattered and / or transmitted light is polarized differently than the first light; detecting (240) the polarized backscattered light and / or the transmitted light; emitting (210) second light having a second wavelength toward the tissue of the subject, wherein the second light is monochromatic; filtering (220) the second light so that the first light is polarized; filtering (230) second light backscattered and / or transmitted by the tissue so that the backscattered and / or transmitted second light is polarized, wherein the backscattered and / or transmitted light is polarized differently than the second light; detecting (240) the polarized backscattered and / or transmitted second light; and processing the polarized backscattered and / or transmitted first light to generate a first intermediate image of the tissue of the subject; processing the polarized backscattered and / or transmitted second light to generate a second intermediate image of the tissue of the subject; and The method is characterized in that it also includes: An image of the tissue of the subject is generated based on a difference between the first intermediate image and the second intermediate image.

13. A computer program product comprising computer program code means for causing, when executed on a computing device having a processing system, the processing system to control a system according to claim 1 to carry out all the steps of a method according to claim 12.

Images