Claims:We claim:

1. An apparatus for adaptive illumination, comprising:
one or more light sources to emit light beam of multiple wavelengths;
a time division multiplexing module to produce time multiplexed beams from the emitted light beams;
a light beams combiner to produce a collimated light beam from the time multiplexed beams; and
a processor, to operate a spatial light modulator configured in the apparatus to produce a spatial pattern of a subject, with adaptive intensity when the collimated light beam is modulated by the spatial light modulator to adaptively illuminate the subject.

2. The apparatus as claimed in claim 1, wherein the collimated light beams are directed onto the spatial light modulator by a polarizing beam splitter.

3. The apparatus as claimed in claim 1, wherein the spatial pattern is produced based on one or more parameters received by the processor.

4. The apparatus as claimed in claim 2, wherein the spatial light modulator is one of, a Liquid Crystals on Silicon (LCoS) and a Digital Micro-mirror Device (DMD).

5. A method for adaptive illumination, comprising:
emitting light beam of multiple wavelengths;
producing a time multiplexed beams from the emitted light beam;
producing, a collimated light beam from the time multiplexed beams; and
operating a spatial light modulator, by a processor, to produce spatial pattern of a subject, having adaptive intensity, wherein the collimated light beam is modulated by the spatial light modulator to adaptively illuminate the subject.

6. The method as claimed in claim 5, wherein the single collimated light beam is directed onto the spatial light modulator by a polarizing beam splitter.

7. The apparatus as claimed in claim 1, wherein the spatial pattern is produced based on one or more parameters received by the processor.

8. The method as claimed in claim 7, wherein the spatial light modulation is achieved by using one of, a Liquid Crystals on Silicon (LCoS) and a Digital Micro-mirror Device (DMD).
, Description:TECHNICAL FIELD

The present disclosure is related, in general, to an apparatus for illumination a subject. More particularly, but not exclusively, the disclosure discloses an apparatus and a method for adaptive illumination of the subject using spatial pattern of the subject.

BACKGROUND

Modern medical imaging instruments such as fundus cameras, microscopes, etc. serve as diagnostic tools for public screening to reduce the time and effort to diagnose different symptoms of a disease. The success rate of these tools depends on the quality of acquired images in the intended regions. Bad image quality can significantly reduce the specificity and the sensitivity parameters related to the instrument, which in turn yields wrong decisions.

Images acquired from digital fundus/microscopes, have oversaturation and under saturation regions, which are caused due to overexposure and underexposure due to uncontrolled illumination. This improper and poor illumination will produce bad quality image. The over exposed areas of images or very darkness in images may cause the identification of information difficult. Same has been observed in fluorescence based imaging modalities, especially photo bleaching.

Structured light illumination has been implemented in the medical imaging instruments by using projectors for highlighting the specific features in the subject. There are commercial multispectral imaging devices for spectral selective imaging and for contrast enhancement. High Dynamic Range (HDR) imaging methods are available using multiple exposures using light sources with varied wavelength and associated controllers. All the techniques mentioned above are intended for a specific purpose. Also, these techniques do not account for the spatial intensity and spectral variations in the subject. They can only control the intensity and wavelength over the whole surface of the subject, thus they lose localized intricate details. Above techniques do not allow for flexibility of changing the intensity, wavelength and relative exposure parameters on the field at pixel level.

Figure 1 illustrates apparatus for illuminating subject 108 for capturing its image as a typical prior art. For example the subject 108 may be retina of an eye. This apparatus comprises an imaging module 102 and an illumination module 110. The illumination module 110 comprises a white flash LED light source 118 to emit light beam of light rays with a predefined wavelength and Infrared (IR) Light Emitting Diode (LED) source116 used for continuously monitoring the retina 108 through a hot mirror 112 to pass reflected rays of pre-configured wavelengths onto a polarizer 114 through collimating lens apparatus 120, further made to incident on the retina 108. The retina is then imaged for analysis by an imaging module 102. However, this technique does not account for the either variations in intensity spatially or variations in spectral contents in the retina of the eye 108. This technique can control intensity and wavelength globally over the whole surface of the retina 108, thus losing localized intricate details. The reflected ray from the retina 108 is projected onto an image sensor 220 through appropriate collimating lens 219 and the image is captured. But captured image may result in oversaturated bright region and dark region, both making the salient features of the image not traceable or not noticeable, which play dominant role diagnosis.

SUMMARY

The above mentioned one or more shortcomings in the prior art are overcome by an apparatus for adaptively illuminated sources such that a subject is made to illuminate adequately for avoiding over and under saturation a method thereof as claimed and additional advantages are provided in the present disclosure.

Further, some 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.

An embodiment of the present disclosure presents an apparatus for adaptively illuminating a subject, the apparatus comprising, one or more light sources to emit light beam of multiple wavelengths, an associated time multiplexing module to produce a time multiplexed beam from all the emitted light beams, a light beam combiner to produce a collimated light beam from the time multiplexed beams and a processor to operate a spatial light modulator configured in the apparatus produce a spatial pattern of a subject, with adaptive intensity when the collimated light beam is modulated by the spatial light modulator to adaptively illuminate the subject. In an embodiment, the present invention discloses a method for adaptively illuminating a subject comprising, emitting light beams of multiple wavelengths, where light beam of each wave length from corresponding light emitting diode is switched on and switched off time multiplexed fashion, producing a collimated light beam from the time multiplexed beams and producing spatial pattern of a subject, with adaptive intensity when the collimated light beam is modulated by the spatial light modulator to adaptively illuminate the subject.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The novel features and characteristics of the disclosure are set forth in the appended claims. The disclosure itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals represent like elements and in which:

Figure 1 shows a conventional apparatus for illuminating a subject;

Figure 2 illustrates an apparatus for adaptive illumination in accordance with some embodiments of the present disclosure;

Figure 3 illustrates the apparatus set-up of Figure 2, with an RGB flash LED as the light source and a switching module in accordance with some embodiments of the present disclosure;

Figure 4 illustrates the apparatus set-up of Figure 3, along with light beams combiner in accordance with some embodiments of the present disclosure;

Figure 5 illustrates the set-up of Figure 4, with a dichroic cube mirror replacing the light beams combiner in accordance with some embodiments of the present disclosure;
Figure 6 shows an Infrared view and a spatial pattern of retina of an eye in accordance with some embodiments of the present disclosure;
Figure 7 shows a graph, time multiplexed switching of incident light rays on the retina of the eye and the retina pattern location that are illuminated in accordance with some embodiments of the present disclosure; and

Figure 8 illustrates a method flow chart for adaptive illumination in accordance with some embodiments of the present disclosure.

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 apparatus.

In an embodiment of the present disclosure, an apparatus for adaptive illumination is presented. The apparatus comprises of one or more light sources to emit light beams of multiple wavelengths. These light beams are spatially modulated to illuminate a subject. In an embodiment, the light sources can be but not limited to a white flash LED, multi spectral light, hyper spectral light, RGB light etc. The detailed description is illustrated as follows.
Figure 2 shows an apparatus for adaptive illumination, wherein the apparatus comprises an illumination module 200 and an imaging module 216. The illumination module 200 comprises a white flash LED 208 to emit light beam of pre-configured wavelengths, an Infrared (IR) Light Emitting Diode (LED) 212 to continuously monitor the subject 218, a hot mirror 210 to allow preconfigured wavelengths to pass through it and reflect rest of the incident wavelengths. The illumination module 200 further comprises a polarizing beam splitter 202 and a spatial light modulator 204. The polarizing beam splitter 202 directs the light beam from the light source 208 onto a spatial light modulator 204. The spatial light modulator 204 is operated by a processor or a computing system 206 that essentially configure the illumination module 200. The processor 206 operates the spatial light modulator 204 to produce spatial pattern based on the parametric information that is assessed by the live Infrared image of the subject 218. Further, the subject 218 is imaged for analysis using one or more wavelengths light beams. The above said required parameters may be, for example, overexposure, rightly exposed and under exposed regions are speedily computed by the processor 206 using the live Infrared image fed as input. Here, the intensity of the spatial pattern is modulated by the spatial light modulator 204. Also, the spatial light modulator 204 modulates the spatial intensity of the light beam such that, the preconfigured wavelength’s are intensity modulated based on the location to be incident on the subject 218.The resulting light beam from the spatial light modulator 204 pass through a series of lens apparatus 214 and thereby illuminates spatial locations of the subject 218, thus resulting in adaptive illumination.

In an embodiment, the spatial light modulator 204may be one of, but is not limited to, Liquid Crystal on Silicon (LCoS) or Digital Micro-mirror Device (DMD). In an exemplary embodiment, the present disclosure may be implemented using an LCoS. The LCoS is communicatively connected to the processor 206. The processor operates the LCoS to produce spatial modulated light beam that is projected on the subject 218 through the polariser beam splitter 202, collimating lens 214 and second beam splitter 222. In an embodiment, the processor 206 receives one or more parameters for producing the spatial pattern as pre-configured by the user. Based on these one or more parameters, the processor 206 configures the LCoS to produce a spatial pattern of the subject 218.The LCoS spatially modulates the intensity of the light beam to produce an intensity modulated light beam, by absorbing predefined amount of the light and reflecting the rest of the incident light. Also, LCoS helps in controlling the intensity of the light beam at pixel level, thus increasing the accuracy of intensity modulation. The intensity modulated light beam is spatially modulated to illuminate predefined regions of the subject 218.

In an embodiment, the one or more parameters input to the illumination unit 200 may be pre-configured by the user. Also, the one or more parameters may be input to the illumination unit 200 from one or more systems associated with the illumination unit 200.

Figure 3 of the present disclosure illustrates an apparatus as shown in Figure 2, further comprising a time multiplexing module 304 and a RGB flash LED 302 that can flash only red, green blue light beams, separately replacing the white flash LED 208. The RGB flash LED 302 emits a beam of light comprising three wavelengths corresponding to Red light beam, Green light beam and Blue light beam. The light emitted is controlled by the time multiplexing module 304 to produce time multiplexed beams of all red, green and blue light with a pre-configurable time durations. Here, the time sequence of the wavelengths’ propagation of the light beam is selectively time multiplexed based on the one or more parameters as specified by the user. The one or more parameters may comprise specific locations of the subject 218, the adaptive intensity with which the light beam should incident a particular location of the subject 218, etc. In an embodiment, a user may include a person, a person using a device such as those included in this disclosure, or such a device itself. The time multiplexed light beam exiting the time multiplexing module 304 is then incident on the polarizer beam splitter 202. The polarizer beam splitter 202 directs the time multiplexed beam onto the LCoS 204.The LCoS 204 modulates the intensity of the time multiplexed wavelength of light beam and produces an intensity modulated beam. This intensity modulated beam further propagates through the series of lens apparatus 214 to project on the subject 218. The LCoS 204 is controlled by a processor 206 configured in the illumination apparatus explicitly, based on one or more parameters received from the live infrared image. The time multiplexed beam is used for spatial modulation by the spatial light modulator 204 such that areas of the subject 218 pre-configured by the user are illuminated by pre-configured wavelengths.

In an embodiment, the LCoS 204 modulates the intensity of each of the wavelengths of the time multiplexed wavelengths of beam individually and results in an intensity modulated beam. The intensity modulated beam comprises multiple wavelengths, where each of the wavelengths propagates with a time delay between every other wavelength and has an intensity variations adopted by live infrared image of the subject 218.

The LCoS 204 is programmed to impose the spatial modulation in synchronous with time multiplexed beam to attain spatial pattern in accordance with parametric attributes of subject 218 that ultimately results in an adequate illumination required for imaging the same. The intensity modulated beam is used to generate modulated spatial pattern by the LCoS 204. The spatial pattern is produced by the LCoS 204 based on the one or more parameters obtained using processor 206 using the received live infrared image from image sensor for the subject 218. The one or more parameters may comprise specific areas of the subject, the intensity with which the light beam should incident a particular area of the subject, etc. In an embodiment, a user may include a person, a person using a device such as those included in this disclosure, or such a device itself.

As illustrated in figure 4, one or more light sources may be configured, such that each of the one or more light sources 404 emits multi spectral light beams. Hence, a beam combining technique is equipped to produce a single collimated light beam from the multiple beams. In an example embodiment, a light guide combiner 402 may be used as a light beam collimator to produce a single collimated light beam from emitted multiple beams. The one or more light sources 404 emitting light beams are selectively time multiplexed usingtime multiplexing module 304, thereby producing time multiplexed beams of various wavelengths. This time multiplexed beams are then collimated into a single collimated beam by the light guide combiner 402. The light guide combiner 402 employs total internal reflection principle to combine multiple light beams of various wavelengths into a single collimated light beam of time multiplexed wavelengths. Further, the single collimated light beam is passed through a polarizing beam splitter 202 which directs the single collimated beam onto the LCoS 204. The LCoS 204 modulates the intensity of the single collimated beam to produce an intensity modulated beam. Furthermore, the processor 206 operates the LCoS 204 to produce a spatial pattern from the single collimated light beam by employing attributes of live infrared image. Also, the one or more parameters for modulating the light beams are provided by the processor 206 to the LCoS204.

In another example embodiment, the light beam collimator may be one of but not limited to, a dichroic mirror and prisms and gratings (not shown in diagrams). Figure 5 shows a dichroic cube mirror 502 along with other embodiments of the present disclosure. The dichroic mirror produces a single collimated light beam from emerging light beams from one or more light sources 404 having varied wavelengths. The single collimated light beam obtained is then passed through a polarizing beam splitter 202, which directs the single collimated light beam onto an LCoS mirror 204. The LCoS mirror 204 spatially modulates the intensity of the single collimated light beam to produce an intensity modulated beam. The processor 206 receives one or more parameters from the captured live infrared image of the subject 218 for modulating light beam adaptively and producing spatial patterns. Using these one or more parameters, the processor 206 instructs the LCoS 204 to modulate the time multiplexed light beam and produce a spatial pattern accordingly. The resulting beam is intensity modulated and may be termed as intensity modulated beam. The intensity modulated beam then illuminates spatial locations of the subject 218 adequately to obtain the image for intended analysis. This kind of illumination leads to an adaptive illumination since it depends on the required performance tuning of intended output based on the attributes of image obtained by live infrared monitoring.

Figure 6 shows a simulated image of the subject 218. In an aspect of the present disclosure, the subject may be retina of a human eye. The present disclosure uses an Infrared LED source 212 and employs camera sensor 220 that is capable of monitoring and capturing image of the subject218 and provide a live view 602. The Infrared live view 602 is utilized to refine the attributes that are needed for generating spatial pattern in LCoS in accordance with some embodiments of the illumination module 200 .In Figure 6, 604 illustrate a sample spatial pattern on LCoS204. Based on this spatial pattern 604, the time multiplexing of wavelengths of the multiple light beams and thereby intensity of the beams is modulated. The intensity modulated beam is made to project on the retina surface of the human eye 218 through optical path comprising of lens apparatus 214 and polarising beam splitters(202 and 222). Every part of the retina gets illuminated differently due to the intensity modulated beam. This phenomenon is illustrated in Figure 7, which shows that a certain location of the retina is illuminated in a particular fashion when a pre-configured wavelength of adaptive intensity is incident on that that particular location of the retina. As illustrated in the figure, 702 shows that when beam of light having a wavelength ?1 with adaptiveintensityi1is incident on the retina of the human eye 218 at time t1, location 1 of the retina reacts to the incident light beam and is imaged by the imaging module216. Likewise, 704 illustrates that when a wavelength corresponding to ?2 with adaptive intensity i2 is incident on the retina 218 at time t2, location 2 of the retina reacts to the incident light beam and is imaged by the imaging module216. Similarly, location 3 of the retina reacts to the incident light beam when a wavelength corresponding to ?3 with adaptive intensity i3is projected on the retina 218 at time t3. Figure 7, 708 represents final image obtained after imaging the retina of the human eye 218. The final image represents the different reactions of the retina 218 at each of the locations based on the wavelengths and intensity of impact at these locations.

Figure 8 shows a flowchart illustrating a method for illuminating a subject for imaging 800, in accordance with some embodiments of the present disclosure.

The order in which the method 800 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.

At step 802, light beams having multiple wavelengths are emitted by one or more light sources 404. The one or more light sources 404 may emit light beams of a single predefined wavelength or multiple wavelengths.

At step 804, time multiplexed light beams are produced from the emitted light source. The time multiplexing module 304 selectively switches the time multiplexed sequence of the beam of light beam having various wavelengths’ of the light beam within the exposure period of an imaging module216.

At 806, a collimated light beam is produced from the time multiplexed beams. The time multiplexed light beams from step 804 are collimated to a single light beam employing light beam combiners. In an exemplary embodiment, the present disclosure illustrates collimating multiple beams using one of but not limited to, a light guide combiner 402, a dichroic cube mirror 502 and prisms and gratings. The single collimated light beam is passed through polarizing beam splitters 202 which direct the light beam onto a spatial modulator 204.
At step 808, a spatial pattern of predefined intensity of a subject 218is produced. A processor 206 configured in the illumination apparatus receives one or more parameters from the infrared image captured using camera 220. The one or more parameters define the spatial pattern to be produced. Based on these one or more parameters, the processor 206 configures the spatial light modulator 204 to produce a spatial pattern.

In an exemplary embodiment, the spatial modulator may be a Liquid Crystal on Silicon (LCoS). The LCoS 204spatially modulates the intensity of the light beam by absorbing adaptively defined amount of the light and reflecting the rest of the incident light. Also, the LCoS 204 helps in controlling the intensity of the light beam at pixel level, thus increasing the accuracy of intensity modulation. The intensity modulated light beam comprises multiple wavelengths where each of the wavelengths’ spatial intensities is adaptively defined and is modulated by the LCoS 204 based on the spatial pattern. The spatial pattern is produced by the LCoS 204 upon receiving instructions by the processor 206 as configured in the illumination module 200. The spatial pattern of the subject 218 is produced upon receiving an Infrared live view image of the subject 218. Based on the Infrared live view image, one or more parameters are input to the processor 206 by a user. Based on these one or more parameters, the processor 206 instructs the LCoS 204 to produce an appropriate spatial pattern for the subject 218. This spatial pattern further helps in time multiplexing the light beam having various wavelengths of the light and modulating the spatial intensities of each of the wavelengths of the light beam.

Advantages of the embodiment of the present disclosure are illustrated herein.

In an embodiment, the present disclosure illustrates an apparatus for illuminating a subject for imaging. The illumination apparatus helps in achieving highest signal to noise ratio and preserves intricate details while acquiring the image.

In an embodiment, the present disclosure illustrates illuminating a subject with appropriate illumination parameters like intensity, wavelength in order to obtain the best contrast, feature visibility enhancement.

In an embodiment, the present disclosure illustrates development of illumination of a subject using light beam combiner and spatial light modulator such as LCoS and DMD with live image processing to decide the adequate possible illumination.

In an embodiment, the present disclosure illustrates controlling spatial intensity, exposure and wavelength simultaneously. The present invention is not limited to retinal imaging but can be applied to fluorescence imaging where photo-bleaching can be eliminated.

In an embodiment, the present disclosure illustrates how specific areas of a subject can be illuminated with varied intensity. When light beam is modulated to produce the spatial pattern, specific areas of the subject can be illuminated. Further, different areas of the subject can be illuminated with different wavelength and intensity. This spatial control of light beam helps in analysis the subject.

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.

The illustrated operations of Figure 8 show certain events occurring in a certain order. In alternative embodiments, certain operations may be performed in a different order, modified or removed. Moreover, steps may be added to the above described logic and still conform to the described embodiments. Further, operations described herein may occur sequentially or certain operations may be processed in parallel. Yet further, operations may be performed by a single processing unit or by distributed processing units.

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 disclosure of the embodiments of the invention is 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

Referral Numerals Description
102 Imaging Module (prior art)
104 Polarizing beam splitter (prior art)
106 Image Sensor (existing system)
108 Subject (existing system)
110 Illumination Module (existing system)
112 Hot Mirror (existing system)
114 Polarizer (existing system)
116 Infrared LED Camera(existing system)
118 White Flash LED (existing system)
120 Lens Apparatus (existing system)
200 Illumination unit
202 Polarizer Beam Splitter
204 Spatial Light Modulator
206 Processor or computing system
208 White Flash LED
210 Hot Mirror
212 Infrared LED source
214 Lens Apparatus
216 Imaging Module
218 Retina of a human eye
220 Image Sensor
222 Polarizing Beam Splitter
302 RGB Flash LED
304 Time division multiplexing Module
402 Light Guide Combiner
404 One or more Light Sources
502 Dichroic Mirror
602 Infrared Live View
604 Spatial Pattern on LCoS Mirror device
702 Subject response for wavelength 1
704 Subject response for wavelength 2
706 Subject response for wavelength 3
708 Consolidated image for all wavelength