Patent Publication Number: US-2018028059-A1

Title: An apparatus for multi-mode imaging of eye

Description:
TECHNICAL FIELD 
     The present subject matter is related, in general to ophthalmic apparatus and more particularly, but not exclusively to an apparatus integrated with multiple modalities for imaging eye. 
     BACKGROUND 
     The visual capacity of human eye is dependent on health of various tissue layers of the eye such as cornea, lens and retina. Damage to nerve fibers and blood vessels of the retina can progressively modify the tissue structure and lead to poor vision or blindness. Therefore, there is a requirement for affordable, low-power screening devices, for early detection of various eye ailments. Early symptoms of many eye ailments can be visualized as abnormal changes in the retinal or corneal structure. At present, diagnosis requires use of a variety of image forming models and acquisition techniques (‘modalities’), each with its own physical apparatus and associated with embedded software. For example, the modalities may be a Frequency Domain-Optical Coherence Tomography (FD-OCT) imaging, a hyper/multi-spectral imaging and a Red Green Blue/infrared (RGB/IR) imaging. 
     At present, it is typical for each such modality to be handled by a separate apparatus. Each apparatus has its own requirements of filters, mirrors, light emitters, detectors, and so on, along optical path followed by optical signals. If multiple modalities are merged in a single apparatus, the elements needed for each modality can block the optical path for another. Moreover, each imaging technology produces an image with a different field of view, resolution, and size for the features of interest. Apart from this difficulty, the cost of the multiple items of specialized apparatus makes the diagnostic process less affordable. Moreover, the system is often bulky and not portable. 
     In particular, the existing technique provides separate equipment for OCT imaging, hyper-spectral imaging, multi-spectral and RGB/IR imaging. However, a single imaging device is often insufficient to enable a preliminary diagnosis or confirmation of symptoms related to a particular ophthalmic or systemic ailment. As a result, multiple devices are required. This leads to a great amount of waiting for a patient between the successive eye tests and inefficiency in clinical scheduling as the patient has to wait at each equipment for observation. Further, these factors make it problematic to deploy such non-portable apparatus in public health screening camps, both logistically and in the financial risk of damage. 
     SUMMARY 
     One or more shortcomings of the prior art are overcome and additional advantages are provided through the present disclosure. Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure. 
     Accordingly, the present disclosure relates to an apparatus for multi-mode imaging of an eye. The apparatus comprises a first source component, a second source component, a coupler, a polarizing mirror, a first digital micro mirror device, a second digital micro mirror device, a combining component and a detection unit. The first source component generates an illumination light. The second source component generates a white light. The coupler is configured to receive the illumination light from the first source component and split the illumination light into a first light and a second light. The coupler projects the first light onto a reflecting mirror and the second light onto the eye. The coupler receives the first light reflected from the reflecting mirror and the second light reflected from the eye and combines the reflected first light and the reflected second light to form an interference pattern. The polarizing mirror receives the white light from the second source component and projects the white light onto the eye through a focusing lens. The first digital micro mirror device, comprising one or more first mirrors, receives the white light reflected from the eye through the polarizing mirror and scatters the reflected white light. The combining component performs at least one of receiving the interference pattern from the coupler when a first mode is active or receiving the reflected white light from the first digital micro mirror device when a second mode is active. The detection unit comprises a diffraction grating, a second digital micro mirror device, a photo detector and a digitizer. The diffraction grating receives at least one of the interference pattern or the white light from the combining component and diffracts at least one of the interference pattern and the white light into one or more spectral components. The second digital micro mirror device comprising one or more second mirrors receives each of the one or more spectral components from the diffraction grating and scatters each of the one or more spectral components. The photo detector is configured to receive each of the scattered one or more spectral components and convert each of the scattered one or more spectral components into an analog signal. The digitizer converts the analog signal into a digital signal, wherein the digital signal is processed by a computing device associated with the apparatus used for multi-mode imaging of the eye. 
     Further, the present disclosure relates to a method for multi-mode imaging of an eye using an apparatus. The method comprises receiving, by a combining component, at least one of an interference pattern from a coupler when a first mode is active or a reflected white light scattered from a first digital micro mirror device, comprising one or more first mirrors, when a second mode is active. The method further comprises projecting, by the combining component, at least one of the interference pattern or the white light onto a diffraction grating for diffracting into one or more spectral components. Upon receiving at least one of the interference pattern or the white light, the diffraction grating diffracts each of the one or more spectral components onto a second digital micro mirror device wherein the second digital micro mirror device comprises one or more second mirrors. The second digital micro mirror device scatters each of the one or more spectral components. The method further comprises projecting, by the second digital micro mirror device, each of the one or more scattered spectral components onto a photo detector. The photo detector converts each of the one or more scattered spectral components into an analog signal. The digitizer converts the analog signal into a digital signal for multi-mode imaging of the eye. 
     The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate exemplary embodiments and, together with the description, serve to explain the disclosed principles. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system and/or methods in accordance with embodiments of the present subject matter are now described, by way of example only, and with reference to the accompanying figures, in which: 
         FIG. 1  shows a block diagram illustrating an apparatus for performing FD-OCT imaging of the eye in accordance with some embodiments of the present disclosure; 
         FIG. 2  shows a block diagram illustrating an apparatus for performing hyper spectral/multispectral/RGB/IR imaging of the eye in accordance with some embodiments of the present disclosure; 
         FIG. 3  shows a block diagram illustrating an apparatus for multi-mode imaging of the eye in accordance with some embodiments of the present disclosure; 
         FIG. 4  shows a block diagram illustrating an apparatus for multi-mode imaging of the eye using a plane mirror in accordance with some embodiments of the present disclosure; and 
         FIG. 5  illustrates a flowchart showing method for performing multi-mode imaging of eye in accordance with some embodiments of the present disclosure. 
     
    
    
     It should be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of illustrative systems embodying the principles of the present subject matter. Similarly, it will be appreciated that any flow charts, flow diagrams, state transition diagrams, pseudo code, and the like represent various processes which may be substantially represented in computer readable medium and executed by a computer or processor, whether or not such computer or processor is explicitly shown. 
     DETAILED DESCRIPTION 
     In the present document, the word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment or implementation of the present subject matter described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments. 
     While the disclosure is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the drawings and will be described in detail below. It should be understood, however that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the spirit and the scope of the disclosure. 
     The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, device or method that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or device or method. In other words, one or more elements in a system or apparatus proceeded by “comprises . . . a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or method. 
     In the following detailed description of the embodiments of the disclosure, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration specific embodiments in which the disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the present disclosure. The following description is, therefore, not to be taken in a limiting sense. 
       FIG. 1 a    shows a block diagram illustrating an apparatus for performing FD-OCT imaging of the eye in accordance with some embodiments of the present disclosure. 
     In FD-OCT imaging mode, the apparatus captures a cross-section or 3-dimensional image of a shallow region of the eye. For eye imaging, this image provides information of detailed structure in multiple layers of the cornea, lens or retina, with great diagnostic value in detecting lesions or other abnormalities in eye. The FD-OCT imaging mode is basically used for telemedicine based screening and management of Age-related Macular Degeneration (AMD) and other retinal diseases. In an embodiment, the apparatus with FD-OCT imaging mode assesses the microscopic structure of intra-retinal layers and choroidal vessel system. 
     As shown in  FIG. 1 a   , the apparatus comprises a first source component  103 , a reference unit  105 , a sample unit  107  and a detection unit  109 . The apparatus is associated with a computing device  101 . The computing device  101  comprises a processor, a memory and a display as shown in  FIG. 1 b   . The first source component  103  comprises a diode  113  and a coupler  117 . The reference unit  105  comprises a first collimating lens  118  and a reflecting mirror  119 . The sample unit  107  comprises a second collimating lens  121 , a first galvano-mirror  123 , a second galvano-mirror  125 , a first focussing lens  127  and a target  131 . The detection unit  107  comprises a third collimating lens  137 , a diffraction grating  139 , a second digital micro mirror device  141 , a second focusing lens  143 , a photo detector  145 , a digitizer  147  and a second digital micro mirror controller  149 . 
     In an embodiment, the computing device  101  provides an illumination generation signal  111  to the diode  113  for generating an illumination light. The diode  113  generates an illumination light. As an example, wavelength of the generated illumination light is 840 nm. The wavelength of the generated illumination light may vary based on band range of the illumination light. The illumination light is guided onto the coupler  117  through an optical fibre  115 . Upon receiving the illumination light, the coupler  117  splits the illumination light into a first light and a second light. In an embodiment, wavelength of the first light and the second light are equal. The coupler  117  projects the first light onto the reflecting mirror  119  through the first collimating lens  118  and projects the second light onto the second collimating lens  121  for collimating the second light. The reflecting mirror  119  reflects the first light back to the coupler  117  through the collimating lens  118 . The second collimating lens  121  guides the second light onto the first galvano-mirror  123 . As an example, a polygon mirror may be used in the apparatus instead of galvano-mirror. The first galvano-mirror  123  deflects the second light and the deflected second light is directed towards the second galvano-mirror  125 . In an embodiment, the first galvano mirror  123  and the second galvano mirror  125  can be combined and a 2D Micro Electro Mechanical Systems (MEMS) mirror may be used which functions as an x-y scanner. The second galvano-mirror  125  deflects the second light onto a first focussing lens  127 . The first galvano-mirror  123  and the second galvano-mirror  125  are controlled by the computing device  101  though the controlling signals  133 . In an embodiment, the movement of the first focussing lens  127  is controlled by the computing device  101 . In another embodiment, the movement of the first focussing lens  127  can be set manually. The first focussing lens  127  projects the second light onto the target  131 . As an example, the target may be cornea of the eye or retina of the eye. The second light reflected from the eye is projected towards the coupler  117  through the first focusing lens  127 , the second galvano-mirror  125 , the first galvano-mirror  123  and the second collimating lens  121 . The coupler  117  combines the reflected first light and the reflected second light to form an interference pattern. The coupler  117  guides the interference pattern towards the detection unit  109 . The coupler  117  projects the interference pattern onto the third collimator lens  137  through a unidirectional fibre  135 . The third collimating lens  137  projects the interference pattern onto the diffraction grating  139 . The diffraction grating  139  is configured to disperse and diffract the light into components which travel in distinct directions. The components are dependent on their wavelength and spacing between lines on the diffraction grating  139 . The diffraction grating  139  may be either reflective or refractive type. The diffraction grating  139  diffracts the interference pattern into one or more spectral components. The one or more spectral components are received by the second digital micro mirror device  141 . The second digital micro mirror device  141  comprises of one or more second mirrors. The activation or deactivation or orientation of each of the one or more second mirrors is controlled by the second digital micro mirror controller  149  connected to the computing device  101 . The second digital micro mirror controller  149  generates a mirror controlling signal  151  at one or more time intervals based on which the one or more second mirrors are activated. In an embodiment, the one or more second mirrors may be placed in a way that the mirrors face towards the photo detector  145  or face away from the photo detector  145 . 
     The one or more second mirrors in the second digital micro mirror device  141  scatter each of the one or more spectral components. The second focussing lens  143  is placed between the second digital micro mirror device  141  and the photo detector  145 . The second digital micro mirror device  141  projects each of the scattered one or more spectral components through the second focussing lens  143  on the photo detector  145 . Upon receiving the scattered spectral components, the photo detector  145  converts the optical signal i.e the scattered spectral components into an analog signal. The photo detector  145  is connected to a digitizer  147 . The digitizer  147  receives the analog signal from the photo detector  145  and digitizes the analog signal. The digital signal corresponds to number of pixels in the image of the eye. The digital signal is used to assess the microscopic structure of intra-retinal layers and inter-corneal layers of the eye. In an embodiment, the digital signal is used to reconstruct the OCT image by the computing device  101  and the reconstructed image is displayed on the display of the computing device  101 . 
       FIG. 2  shows a block diagram illustrating the apparatus for performing hyper spectral/multispectral/RGB/IR imaging of the eye in accordance with some embodiments of the present disclosure. 
     In hyper spectral/multispectral/RGB/IR imaging mode, the apparatus identifies retinal blood vessels, the optic disc, oxygen saturation levels, and pathological indicators of various eye ailments, such as macular pigments, drusen, etc. Also, RGB imaging helps to locate the optic disc, macula, posterior pole, retinal blood vessels, drusen, pigmentation, etc. 
     The apparatus comprises a second source component  201 , a sample unit  203  and a detection unit  109 . The apparatus is connected to the computing device  101 . The second source component  201  comprises an IR light source  205 , a white light source  207  and a hot mirror  209 . The IR light source  205  produces an IR light  213  and the white light source  207  produces a white light  211 . The white light  211  and the IR light  213  are mixed by the hot mirror  209 . The sample unit  203  comprises a first digital micro mirror device  223 , a fourth collimating lens  221 , a polarizing mirror  215 , an optical element  217 , the first focusing lens  127  and the target  131 . The detection unit  109  comprises the diffraction grating  139 , lens  227 , lens  229 , the second digital micro mirror device  141 , the focusing lens  143 , the photo detector  145 , the digitizer  147 , the first digital micro mirror controller  225  and the second digital micro mirror controller  149 . 
     In an embodiment, the hot mirror  209  reflects the IR light  213  and directs the white light  211  to the polarizing mirror  215 . The polarizing mirror  215  projects the white light  211  onto the eye  131  through the optical element  217  and the first focusing lens  127 . The optical element  217  is placed in between the polarizing mirror  215  and the first focusing lens  127 . The eye  131  reflects the white light  211  and the reflected white light  211  is projected on the first digital micro mirror device  223  through the collimating lens  221 . The first digital micro mirror device  223  comprises of one or more first mirrors. The activation/deactivation of the one or more first mirrors is controlled by the first digital micro mirror controller  225  connected to the computing device  101 . The first digital micro mirror device  223  reflects the white light and the reflected white light is projected onto the diffraction grating  139  through the relay lens  227 . The diffraction grating  139  scatters the white light into one or more spectral components. The one or more spectral components correspond to components of a hyper spectral image. Each of the one or more spectral components is projected onto a second digital micro mirror device  141  through relay lens  229 . The second digital micro mirror device  141  comprises of one or more second mirrors. The activation/deactivation/orientation of each of the one or more second mirrors are controlled by the second digital micro mirror controller  149  connected to the computing device  101 . The one or more second mirrors of the second digital micro mirror device  141  are used as a reflection based pixel wise light projector which scatters the spectral components and the scattered spectral components are projected onto the photo detector  145  through the second focusing lens  143 . The photo detector  145  converts the scattered spectral components/optical signals into an analog signal. The analog signal is passed to the digitizer  147 . The digitizer  147  converts the analog signal into a digital signal. The digital signal is processed by the computing device  101  for hyper spectral/multispectral/RGB/IR imaging of the eye. The digital signal is used by the computing device  101  for reconstructing the hyper spectral/multispectral/RGB/IR image. The reconstructed hyper spectral/multispectral/RGB/IR image is displayed on display of the computing device  101  for analyzing. 
       FIG. 3  shows a block diagram illustrating an apparatus for multi-mode imaging of the eye in accordance with some embodiments of the present disclosure. 
     In an embodiment, the apparatus is configured for multi-mode imaging of the eye. The multiple modes are RGB color retina or cornea image capturing mode, frequency domain (FD) optical coherence tomography (OCT) mode and 3-dimensional hyper spectral/3-dimensional multi-spectral mode. A user may select any of the above modes according to which the apparatus is implemented. 
     In an embodiment, the OCT mode is a first mode and the RGB color retina or cornea image capturing mode and 3-dimensional hyper spectral/3-dimensional multi-spectral mode is a second mode. 
     In an embodiment, the apparatus as shown in  FIG. 3  is configured to perform multi-mode imaging of the eye without obstructing optical paths of each mode. 
     The apparatus comprises the first source component  103 , the second source component  201 , the reference unit  105 , the sample unit  301 , a combining component  303  and the detection unit  109 . The apparatus is connected to the computing device  101 . The first source component  103  comprises the diode  113  and the coupler  117 . The second source component  201  comprises the IR light source  205 , the white light source  207  and the hot mirror  209 . The reference unit  105  comprises the first collimating lens  118  and the reflecting mirror  119 . The sample unit  301  comprises the first galvano-mirror  123 , the second galvano-mirror  125 , the second collimating lens  121 , the first optical element  217 , the first focusing lens  127 , the polarizing mirror  215 , a fourth collimating lens  221  and the first digital micro mirror device  223 . The detection unit  109  comprises the diffraction grating  139 , the third collimating lens  137 , the second digital micro mirror device  141 , the second focusing lens  143 , the photo detector  145 , the digitizer  147 , the first digital micro mirror controller  225  and the second digital micro mirror controller  149 . 
     The first source component  103  is configured to generate the illumination light and the second source component  201  is configured to generate the white light. In an embodiment, when the first mode is activated, the apparatus functions as illustrated in  FIG. 1 . 
     The computing device  101  provides an illumination generation signal  111  to the diode  113  for generating the illumination light. The diode  113  generates the illumination light. As an example, wavelength of the generated illumination light is 840 nm. As an example, the wavelength of the generated illumination light may vary based on band range of the illumination light. The illumination light is guided onto the coupler  117  through an optical fibre  115 . Upon receiving the illumination light, the coupler  117  splits the illumination light into a first light and a second light. The wavelength of the first light and the second light are equal. The coupler  117  projects the first light onto the reflecting mirror  119  through the first collimating lens  118  and projects the second light onto the second collimating lens  121  and then to the first galvano-mirror  123 . The second light deflected from the first galvano-mirror  123  is projected onto the second galvano-mirror  125 . In an embodiment, the first galvano mirror  123  and the second galvano mirror  125  can be combined and a 2D MEMS mirror may be used which functions as an x-y scanner. The second light deflected from the second galvano-mirror  125  is projected onto the first optical element  217 . The first galvano-mirror  123  and the second galvano-mirror  125  are controlled by the computing device  101  through a controlling signal  133 . The first optical element  217  is used to block the optical path for the second mode i.e when the first mode is active the first optical element  217  blocks the optical path from the second source component  201 . The first optical element  217  projects the second light onto the eye  131  through the first focussing lens  127 . The reflected first light from the eye  131  is received by the coupler  117  through the first focusing lens  127 , the first optical element  217 , the second galvano-mirror  125  and the first galvano-mirror  123 . 
     The reflecting mirror  119  reflects the first light onto the coupler  117 . The coupler  117  receives the reflected first light and the reflected second light. The coupler  117  combines the reflected first light and the reflected second light to form the interference pattern. The coupler projects interference pattern onto the combining component  303 . 
     In an embodiment, when the second mode is activated, the apparatus functions as illustrated in  FIG. 2 . 
     The second source component  201  comprises the white light source  207  and the IR light source  205 . The white light source  207  generates the white light  211  and the IR light source  205  generates the IR light  213 . The white light  211  and the IR light  213  are mixed by the hot mirror  209 . The hot mirror  209  reflects the IR light  213  and directs the white light  211  onto the polarizing mirror  215 . The polarizing mirror  215  directs the white light  211  onto the eye  131  through the first focusing lens  127 . The polarizing mirror  215  receives the reflected white light from the eye  131  and projects onto the first digital micro mirror device  223  through the fourth collimator lens  221 . The first digital micro mirror device  223  comprises of one or more first mirrors. The activation/deactivation or orientation of the one or more first mirrors are controlled by the first digital micro mirror controller  225 . The first digital micro mirror controller  225  is connected to the computing device  101 . The computing device  101  provides a signal to the first digital micro mirror controller  225  based on which the first digital micro mirror controller  225  controls the activation/deactivation of the one or more first mirrors. The first digital micro mirror device  223  scatters the reflected white light and provides the reflected white light to the combining component  303  through the optical fibre  305 . 
     The combining component  303  projects the interference pattern onto the diffraction grating  139  through the third collimator lens  137  when the first mode is active and projects the reflected white light onto the diffraction grating  139  through the third collimator lens  137  when the second mode is active. The diffraction grating  139  diffracts the interference pattern into one or more spectral components during the first mode. The diffraction grating  139  diffracts the reflected white light into one or more spectral components during the second mode. The second digital micro mirror device  141  receives each of the one or more spectral components from the diffraction grating  139 . The second digital micro mirror device  141  comprises of one or more second mirrors. The activation/deactivation or orientation of the one or more second mirrors is controlled by the second digital micro mirror controller  149 . The second digital micro mirror controller  149  is connected to the computing device  101 . The spectral components reflected from each of the one or more second mirror corresponds to each pixel of the image. In an embodiment, the second digital micro mirror device  141  is used as a reflection based pixel wise light projector which scatters the spectral components. The second digital micro mirror device  141  scatters each of the one or more spectral components and the scattered each of the one or more spectral components is provided to the photo detector  145  through the second focusing lens  143 . The photo detector  145  converts the optical signal into analog signal. The digitizer  147  receives the analog signal and converts into digital signal. The digital signal is processed by the computing device  101  for multi-mode imaging of the eye. 
       FIG. 4  shows a block diagram illustrating an apparatus for multi-mode imaging of the eye using a plane mirror  401  in accordance with some embodiments of the present disclosure. 
     In one implementation, the apparatus shown in  FIG. 4  is an alternative embodiment of the apparatus illustrated in  FIG. 3 . The apparatus illustrated in  FIG. 3  uses two digital micro mirror devices namely the first digital micro mirror device  223  and the second digital micro mirror device  141 . The first digital micro mirror device  223  is configured to receive reflected white light from the eye and to provide the reflected white light to the combining component  303 . The second digital micro mirror device  141  is configured to receive each of the one or more spectral components and scatter each of the one or more spectral components. The apparatus as shown in  FIG. 4  uses a plane mirror when the second mode is active for receiving the reflected white light from the eye. The first digital micro mirror device  223  is removed from the apparatus illustrated in  FIG. 4 . The plane mirror  401  receives the reflected white light from the eye through the relay compound lens  403  and  405  and projects the reflected white light onto the second digital micro mirror device  141 . The apparatus as shown in  FIG. 4  does not use the combining component as illustrated in  FIG. 3  as the plane mirror  401  receives the reflected white light and projects directly onto the second digital micro mirror device  141 . The functions of the apparatus as shown in  FIG. 4  when the first mode is active are as illustrated in  FIG. 1 . The functions of the apparatus as shown in  FIG. 4  when the second mode is active are as illustrated in  FIG. 2 . 
       FIG. 5  illustrates a flowchart showing method for performing multi-mode imaging of eye in accordance with some embodiments of the present disclosure. 
     As illustrated in  FIG. 5 , the method  500  comprises one or more blocks for performing multi-mode imaging of eye using an apparatus as illustrated in  FIG. 3 . The method may be described in the general context of computer executable instructions. Generally, computer executable instructions can include routines, programs, objects, components, data structures, procedures, modules, and functions, which perform particular functions or implement particular abstract data types. 
     The order in which the method  500  is described is not intended to be construed as a limitation, and any number of the described method blocks can be combined in any order to implement the method. Additionally, individual blocks may be deleted from the methods without departing from the spirit and scope of the subject matter described herein. Furthermore, the method can be implemented in any suitable hardware, software, firmware, or combination thereof. 
     When a user selects the first mode, the apparatus is implemented to perform the OCT imaging modality. When the user selects the second mode, the apparatus is implemented to perform RGB color retina or cornea image capturing mode and 3-dimensional hyper spectral/3-dimensional multi-spectral mode is a second mode. The apparatus comprises the first source component  103 , the second source component  201 , the reference unit  105 , the sample unit  301 , a combining component  301  and the detection unit  109 . The apparatus is connected to the computing device  101 . The first source component  103  comprises the diode  113  and the coupler  117 . The second source component  201  comprises the IR light source  205 , the white light source  207  and the hot mirror  209 . The reference unit  105  comprises the first collimating lens  118  and the reflecting mirror  119 . The sample unit  105  comprises the first galvano-mirror  123 , the second galvano-mirror  123 , the first optical element  217 , the first focusing lens  127 , the polarizing mirror  215  and the first digital micro mirror device  223 . The detection unit  109  comprises the diffraction grating  139 , the third collimating lens  137 , the second digital micro mirror device  141 , the second focusing lens  143 , the second digital micro mirror device  141 , the photo detector  145 , the digitizer  147 , the first digital micro mirror controller  225  and the second digital micro mirror controller  149 . 
     The first source component  103  is configured to generate the illumination light and the second source component is configured to generate the white light. 
     The computing device  101  provides a signal  111  to the diode  113  for generating the illumination light. The diode  113  generates the illumination light. The illumination light is guided onto the coupler  117  through the optical fibre  115 . Upon receiving the illumination light, the coupler  117  splits the illumination light into a first light and a second light. The wavelength of the first light and the second light are equal. The coupler  117  projects the first light onto the reflecting mirror  119  through the first collimating lens  118  and projects the second light onto the first galvano-mirror  123 . The second light deflected from the first galvano-mirror  123  is projected onto the second galvano-mirror  125 . The second light deflected from the second galvano mirror  125  is projected onto the first optical element  217 . The first optical element  217  projects the second light onto the eye  131  through the first focussing lens  127 . The reflected second light from the eye is received by the coupler  117  through the first focusing lens  127 , the first optical element  217 , the second galvano-mirror  125  and the first galvano-mirror  123 . 
     The reflecting mirror  119  reflects the first light onto the coupler  117 . The coupler  117  receives the reflected first light and the reflected second light. The coupler  117  combines the reflected first light and the reflected second light to form the interference pattern. The coupler  117  projects the interference pattern to the combining component  303 . 
     The second source component  201  comprises the white light source  207  and the IR light source  205 . The white light source  207  generates the white light  211  and the IR light source  205  generates the IR light  213 . The white light  211  and the IR light  213  are mixed by the hot mirror  209 . The hot mirror  209  reflects the IR light  213  and directs the white light  211  onto the polarizing mirror  215 . The polarizing mirror  215  directs the white light  211  onto the eye  131  through the first focusing lens  127 . The polarizing mirror  215  receives the reflected white light from the eye  131  and projects onto the first digital micro mirror device  223  through the fourth collimator lens  221 . The first digital micro mirror device  223  scatters the reflected white light and provides the reflected white light to the combining component  303  through the optical fibre  305 . 
     At block  501 , the combining component  303  receives at least one of the interference patterns from the coupler  117  when the first mode is active and the reflected white light from the first digital micro mirror device  223  when the second mode is active. 
     At block  503 , the combining component  303  projects the interference pattern on to the diffraction grating  139  through the third collimator lens  137  when the first mode is active and projects the reflected white light onto the diffraction grating  139  through the third collimator lens  137  when the second mode is active. The diffraction grating  139  diffracts the interference pattern or the reflected white light into one or more spectral components. 
     At block  505 , the diffraction grating  139  projects the one or more spectral components to the second digital micro mirror device  141 . The second digital micro mirror device  141  scatters each of the one or more spectral components. 
     At block  507 , the second digital micro mirror device  141  projects each of the scattered one or more spectral components to the photo detector  145  through the second focusing lens  143 . 
     At block  509 , the photo detector  145  converts the optical signal into analog signal. 
     At block  511 , the digitiser  147  receives the analog signal and converts into digital signal. 
     At block  513 , the computing unit  101  receives the digital signal and processes the digital signal for multi-mode imaging of the eye. 
     Advantages of the Embodiment of the Present Disclosure are Illustrated Herein 
     In an embodiment, the present disclosure provides a single apparatus for FD-OCT imaging, 3-Dmulti spectral imaging, RGB/IR imaging and 3-D hyper spectral imaging. 
     In an embodiment, the optical elements used for each image capturing mode does not reduce the quality of the image captured by another mode. 
     In an embodiment, the present disclosure provides a single cost-effective, affordable and portable apparatus for performing multiple modalities. 
     In an embodiment, there is no need for a patient to be moved from one apparatus to another apparatus while being diagnosed. 
     In an embodiment, the present disclosure provides a method for capturing the images and displaying on the display screen instead of ophthalmoscope based detection by clinician&#39;s eye which cannot perceive ultrasound or infrared radiations. 
     The terms “an embodiment”, “embodiment”, “embodiments”, “the embodiment”, “the embodiments”, “one or more embodiments”, “some embodiments”, and “one embodiment” mean “one or more (but not all) embodiments of the invention(s)” unless expressly specified otherwise. 
     The terms “including”, “comprising”, “having” and variations thereof mean “including but not limited to”, unless expressly specified otherwise. 
     The enumerated listing of items does not imply that any or all of the items are mutually exclusive, unless expressly specified otherwise. 
     The terms “a”, “an” and “the” mean “one or more”, unless expressly specified otherwise. 
     A description of an embodiment with several components in communication with each other does not imply that all such components are required. On the contrary a variety of optional components are described to illustrate the wide variety of possible embodiments of the invention. 
     When a single device or article is described herein, it will be readily apparent that more than one device/article (whether or not they cooperate) may be used in place of a single device/article. Similarly, where more than one device or article is described herein (whether or not they cooperate), it will be readily apparent that a single device/article may be used in place of the more than one device or article or a different number of devices/articles may be used instead of the shown number of devices or programs. The functionality and/or the features of a device may be alternatively embodied by one or more other devices which are not explicitly described as having such functionality/features. Thus, other embodiments of the invention need not include the device itself. 
     Finally, the language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the invention be limited not by this detailed description, but rather by any claims that issue on an application based here on. Accordingly, the embodiments of the present invention are intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims. 
     While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims. 
     
       
         
           
               
            
               
                   
               
               
                 Referral Numerals: 
               
            
           
           
               
               
            
               
                 Reference Number 
                 Description 
               
               
                   
               
               
                 101 
                 Computing device 
               
               
                 103 
                 First source component 
               
               
                 105 
                 Reference unit 
               
               
                 107 
                 Sample unit 
               
               
                 109 
                 Detection unit 
               
               
                 111 
                 Illumination Generation signal 
               
               
                 113 
                 diode 
               
               
                 115 
                 Optical fibre 
               
               
                 117 
                 coupler 
               
               
                 118 
                 First collimator lens 
               
               
                 119 
                 Reflecting mirror 
               
               
                 121 
                 Second collimator lens 
               
               
                 123 
                 First galvano-mirror 
               
               
                 125 
                 Second galvano-mirror 
               
               
                 127 
                 First focusing lens 
               
               
                 131 
                 Target/eye 
               
               
                 133 
                 Controlling signal 
               
               
                 135 
                 Unidirectional fibre 
               
               
                 137 
                 Third collimator lens 
               
               
                 139 
                 Diffraction grating 
               
               
                 141 
                 Second digital micro mirror device 
               
               
                 143 
                 Second focusing lens 
               
               
                 145 
                 Photo detector 
               
               
                 147 
                 digitizer 
               
               
                 149 
                 Second digital micro mirror controller 
               
               
                 151 
                 Mirror controlling signal 
               
               
                 201 
                 Second source component 
               
               
                 203 
                 Sample unit 
               
               
                 205 
                 IR light source 
               
               
                 207 
                 White light source 
               
               
                 209 
                 Hot mirror 
               
               
                 211 
                 White light 
               
               
                 213 
                 IR light 
               
               
                 215 
                 Polarizing mirror 
               
               
                 217 
                 First optical element 
               
               
                 221 
                 Fourth collimator lens 
               
               
                 223 
                 Second digital micro mirror device 
               
               
                 225 
                 Second digital micro mirror controller 
               
               
                 301 
                 Sample unit 
               
               
                 303 
                 Combining component 
               
               
                 305 
                 Optical fibre 
               
               
                 401 
                 Plane mirror 
               
               
                 403, 405 
                 Relay Compound lens