High resolution photonic chip integrated handheld miniature 3D non-destructive imaging system

Abstract

A 3D imaging system includes a photodetector module, a light-source module, a coupler, a reference arm, an objective lens, a sample path, and a controller. The light-source module is configured to provide at least one light beam. The coupler is optically coupled with the photodetector module and the light-source module, such that photodetector module, the light-source module, and the coupler are integrated into a combined chip on a PCB. The reference arm is optically coupled with the coupler. The sample path is optically coupled between the coupler and the objective lens. The controller is electrically coupled with the photodetector module and the sample path and includes a CNN model, in which the controller controls the sample path to perform an optical scan on a test object using the light beam and determines a location of a ROI of the test object via the CNN model.

Description

HIGH RESOLUTION PHOTONIC CHIP INTEGRATED HANDHELD MINIATURE 3D NON-DESTRUCTIVE IMAGING SYSTEMInventors: Kam Chiu LAU; Po Shan CHAN; Qi LANG; Fei YEUNG; Ka Shek LEETechnical Field:

[0001] The present invention generally relates to 3D non-destructive imaging technologies; and in particularly to an optical integrated chip or a photonic integrated circuit for 3D non-destructive imaging and an optical system using the same.Background:

[0002] Optical coherence tomography (OCT) is a 3D imaging technique commonly used by ophthalmologists, cardiologists, and oncologists. The micro-level depth resolution and centimeter depth range of OCT make it ideal for medical imaging of the retina and coronary arteries. Diseases such as diabetic retinopathy have become leading causes of blindness among the adult population, increasing the demand for routine eye screening. Early detection of retinal diseases through regular patient screening can be crucial in initiating treatment before potentially permanent vision loss occurs. OCT serves as an excellent screening tool for detecting retinal pathology, early disease, and monitoring treatment success.

[0003] Time-domain OCT (TD-OCT) performs a time-domain auto-correlation of reflected light with reference path light through a mechanical scan of the reference path length. A scanning element such as a microelectromechanical system (MEMS) scanner or galvanometer-based scanner placed in the sample arm allows acquisition of 2D cross-sections or 3D volumes.

[0004] Swept-Source OCT (SS-OCT) requires an expensive high-tuning-rate laser, which is considerably more costly than broadband LEDs. The high cost of current OCT systems is reflected in studies on patient-screening rates. Their availability may be limited outside of larger eye clinics, hospitals, and research laboratories.

[0005] Classical spectral-domain OCT (SD-OCT) systems require precision mechanical parts, increasing costs and necessitating an environment free from mechanical vibrations. Additionally, spectrometers in market-available SD-OCT systems rely on classical optical designs with bulk optical lenses precisely alignedwith diffraction gratings. This configuration results in large dimensions / volume, which is disadvantageous for detection.

[0006] Therefore, to meet the growing demands for routine eye screening, there is a need for streamlining OCT systems, which involves reducing their volume and enhancing ease of operation to accelerate scan times.Summary of Invention:

[0007] It is an objective of the present invention to provide systems and methods to address the aforementioned shortcomings and unmet needs in the state of the art.

[0008] In accordance with a first aspect of the present invention, a three-dimensions (3D) imaging system for handheld photonic chip integration is provided. The 3D imaging system includes a photodetector module, a light-source module, a coupler, a reference arm, a sample arm and a controller. The photodetector module is disposed at a print circuit board (PCB). The light-source module is disposed at the PCB and is configured to provide at least one light beam. The coupler is disposed at the PCB and is optically coupled with the photodetector module and the lightsource module, such that photodetector module, the light-source module, and the coupler are integrated into a combined chip on the PCB. The reference arm is optically coupled with the coupler. The sample arm is optically coupled with the coupler. The controller is electrically coupled with the photodetector module, the light source module and the sample arm and includes a convolutional neural network (CNN) model, in which the controller controls the sample arm to perform an optical scan on a test object using the light beam and determines a location of a region of interest (ROI) of the test object via the CNN model.

[0009] In accordance with a second aspect of the present invention, a method for 3D imaging using a 3D imaging system is provided. The method includes steps as follows: providing at least one light beam by a light-source module; splitting the light beam to first light-beam component and a second light-beam component by using a coupler; guiding the light beam to a reference arm and an optical path adjuster from the coupler, wherein the first light-beam component is guided to the reference arm and the second light-beam component is guided to the sample arm which further guides the second light-beam component to an objective lens; controlling, by a controller, the sample arm to perform a preliminary optical scan on a test object by the second light-beam component; determining, by the controller, alocation of a ROI of the test object via a CNN model according to the preliminary optical scan; and performing a focusing optical scan on the test object after the determining the location of the ROI of the test object.

[0010] In accordance with a third aspect of the present invention, a method for 3D imaging using an optical spectroscopy measurement is provided. The method includes steps as follows: operating the 3D imaging system as an optical spectroscopy measurement system for the optical spectroscopy measurement based on a reflection measurement for the ROI of the test object; receiving , by the photodetector module, a light signal along a light path / optical path. There are two beam shutters or variable attenuators in the light path / optical path. They can attenuate light in the reference arm to adjust the lighting intensity to match that of the sample arm. They can also block light in the reference arm. In the 3D imaging system, when the reference arm is blocked the light, an optical spectroscopy measurement system can be implemented, where spectroscopy is used for reflection measurements. The light reflected off a sample allows direct measurement of how the sample interacts with light, providing information for indirectly measuring other material properties.

[0011] The light reflected off the ROI of the test object for allowing direct measurement of how the ROI of the test object absorbs light by measuring the intensity of light as a beam of light passes through sample solution. The basic principle is that each compound absorbs or transmits light over a certain range of wavelength. The method further includes a step of analyzing specific features of the reflected light to determine the thickness and refractive index of the sample.

[0012] In the present disclosure, the components are integrated into an optical integrated chip, which can achieve favorable manufacturing accuracy and a compact size. For example, a 35-inch built-in touch screen for data preview and user interface is also integrated into the system. It can also be extended to a USB-C monitor. Accordingly, the system adopting the optical integrated chip can have a small volume, with an overall size including the handle of about 14 cm * 16 cm * 5 cm and a lightweight design of about 1.2 kg, as compared to conventional available products weighing 2.7 kg. The system is a fully integrated device, with a power consumption of 5.14 W, compared to conventional handheld OCT systems which consume more than 10 W. The system does not require an external power supply or PC; instead, a battery module is used and positioned in the handle grip. This makesit suitable for places where AC power is not available. USB power can be connected for extended battery life.Brief Description of Drawings:

[0013] Embodiments of the invention are described in more details hereinafter with reference to the drawings, in which:

[0014] FIG. 1 depicts a schematic diagram illustrating a 3D imaging system for handheld photonic chip integration according to an embodiment of the present disclosure ;

[0015] FIG. 2 depicts a schematic diagram illustrating a connection relationship among components of the 3D imaging system according to an embodiment of the present disclosure;

[0016] FIG. 3 shows a schematic diagram illustrating a configuration of the lightsource module 120 according to an embodiment of the present disclosure;

[0017] FIG. 4 depicts a simulation result of spot diagram according to one embodiment of the present invention;

[0018] FIG. 5 depicts a schematic diagram illustrating a testing or simulation according to an embodiment of the present disclosure;

[0019] FIG. 6 is the A-scan simulation result, in which X axis is the depth and Y axis is the backscatter intensity;

[0020] FIG. 7 is the B-scan simulation result, in which X axis is lateral coordinate and Y axis is the depth; and

[0021] FIG. 8 depicts a flowchart for the adaptive scanning procedure according to one embodiment of the present invention.Detailed Description of the Invention:

[0022] In the following description, systems and methods for three-dimensions (3D) imaging system for handheld photonic chip integration and the likes are set forth as preferred examples. It will be apparent to those skilled in the art that modifications, including additions and / or substitutions may be made without departing from the scope and spirit of the invention. Specific details may be omitted so as not to obscurethe invention; however, the disclosure is written to enable one skilled in the art to practice the teachings herein without undue experimentation.

[0023] In the present disclosure, the terms “electrically coupling” and “electrically coupled” encompass both wired electrical and optical connections (coupled / coupling) and wireless radio connections (coupled / coupling), facilitating the transfer or exchange of data or signals.

[0024] FIG. 1 depicts a schematic diagram illustrating a 3D imaging system 100 for handheld photonic chip integration according to an embodiment of the present disclosure. The 3D imaging system 100 refers to a various of elements arranged in a specific order, so as to achieve optical information processing. The 3D imaging system 100 can be, for example, an optical coherence tomography (OCT) system, an optical communication network, or a spectroscopy measurement system. The 3D imaging system 100 is configured to detect a sample or a test object OB. For example, the 3D imaging system 100 may serve as an optical spectroscopy measurement system for a detector of 3D imaging. In some embodiments, the test object OB can be retina of an eye, skin, otology, hair, nail health, or other suitable biological sample, and the present disclosure is not limited thereto. In some embodiments, the 3D imaging system 100 is applied to 3D imaging processing for different fields, for example, skin & otology, hair, nail health, odontology and other medical images sensing, detecting dental decay, industry inspection, 3D profiling, multilayer inspection, display and panels, drug coating, metrology of precision- machined parts, surface roughness detection, or non-destructive testing. As such, a high-resolution and low-cost photonic chip-integrated handheld miniature 3D nondestructive imaging system for sample detection is provided. However, the present disclosure is not limited thereto.

[0025] The 3D imaging system includes a print circuit board (PCB) 102, a controller 104, a photodetector module 110, a light-source module 120, a coupler 130, a reference arm 140, a sample arm 150, an objective lens 160, a housing 170, a battery module 180, and a monitor 182.

[0026] The housing 170 includes a component accommodation portion 172 and a handle grip portion 174 connected to each other. The PCB 102, the controller 104, the photodetector module 110, the light-source module 120, the coupler 130, the reference arm 140, and the sample arm 150 are enclosed by the component accommodation portion 172. The component accommodation portion 172 has aformer opening for placing the objective lens 160 and a back opening for placing the monitor 182. The handle grip portion 174 is physically separated than the PCB 102, the photodetector module 110, the light-source module 120, the coupler 130, the reference arm 140, the sample arm 150, and the monitor 182.

[0027] The controller 104, the photodetector module 110, the light-source module 120, and the coupler 130 are integrated into a combined chip on the PCB 102. The reference arm 140 and the sample arm 150 are optionally connected to or positioned on the PCB 102. The function and connection among these components are shown in FIG. 2 which depicts a schematic diagram illustrating a connection relationship among components of the 3D imaging system according to an embodiment of the present disclosure.

[0028] The photodetector module 110 features multiple accurate 14-bit ADCs with a total of 20 channels (or more than 20) and a sampling speed of 500MHz, providing exceptional sensitivity and accuracy. Operating in photoconductive mode, the onboard photodetector module 110 further enhances the system's sensitivity. Photodetector modules 110 may include components such as photodiodes, transimpedance amplifiers, analog-to-digital converters (ADCs), and signal processing units. For example, a photodetector module 110 includes multiple photodiodes for detecting light signals, transimpedance amplifiers to convert the photodiode currents into voltage signals, ADCs to digitize these voltage signals for processing, and signal processing units to analyze and interpret the digitized data.

[0029] The light-source module 120 may include light emitting diode (LED), super luminescent diode (SLD), or halogen lamp. Specifically, the light-source module 120 is selected to be a non-temperature-controlled, fiber-coupled SLD with low manufacturing cost. In one embodiment, the selected SLD size can be about 60 mm * 80 mm. The light-source module 120 is configured to provide at least one light beam LB (i.e., optical signal), in which the light beam LB is a broad band light beam. In some embodiments, a full width at half maximum (FWHM) of the light beam LB is in a range of about 1280 nm to about 1340 nm, and which peak wavelength thereof is about 1310 nm. In other embodiments, a FWHM of the light beam LB can be in a range of 820 nm to 880 nm (850 ±30 nm).

[0030] FIG. 3 shows a schematic diagram illustrating a configuration of the lightsource module 120 according to an embodiment of the present disclosure. In order to increase the axial (depth) resolution, two SLDs are combined to establish the OCTillumination source. The light-source module 120 includes a first SLD 124, a second SLD 126, a dichroic filter 127 optically between the first SLD 124 and the second SLD 126, a condenser lens 128 optically coupled with the dichroic filter 127. The 3D imaging system 100 further includes a single mode fiber 122 to receive at least one light beam propagated from the condenser lens 128 and to guide the light beam into the coupler 130. A first SLD light beam provided by the first SLD 124 partially passes the dichroic filter 127 and then enters the condenser lens 128, and a second SLD light beam provided the second SLD 126 is partially reflected by the dichroic filter 126 and then enters the condenser lens 128. In one embodiment, the first SLD light beam provided by the first SLD 124 and the second SLD light beam provided the second SLD 126 have different wavelength intervals. In this regard, the use of different wavelength intervals for the light beams emitted by the first SLD 124 and the second SLD 126 allows for spectral diversity in imaging, enhancing the system’s ability to capture a broader range of information about the sample. It also helps distinguish between different tissue types or materials based on their unique spectral signatures, contributing to higher-quality imaging results.

[0031] Referring is made back to FIG. 2. In some embodiments, the separate waveguide chips, the photodetector module 110, the light-source module 120, and the coupler 130 are integrated into a combined chip by chip-to-chip coupling techniques at the PCB 102. Different components can be interconnected using components capable of propagating light, such as waveguides or optical fibers, facilitating the transmission of light beams between the components for both reception and emission purposes. The light beams between the components for both reception and emission purposes can act as optical signals.

[0032] The reference arm 140 is optically coupled with the coupler 130 and establishes a reference light signal for comparison during OCT 3D imaging. This reference light helps measure the optical properties, such as time delay of light reflected from a sample (e.g., test object OB) or interference conditions, enabling high-resolution imaging used in medical diagnoses and material analysis. The reference arm 140 directs light back after reflection from a mirror. Specifically, the reference arm 140 includes a first collimator 142, a dispersion compensation unit 144, and a reference mirror 146. The first collimator 142 is optically coupled with the coupler 130 and is configured to convert a light beam passing therethrough intoparallel light. The dispersion compensation unit 144 is optically coupled between the first collimator 142 and the reference mirror 146. The dispersion compensation unit 144 is selected to account for the dispersion of the human eye and thus is configured to compensate for an optical path difference caused by dispersion. As such, a light beam transmitted from the coupler 130 is reflected at the reference mirror 146 and is propagated from the reference mirror 146 back to the coupler 130 and then to the photodetector module 110 for interference comparison.

[0033] The sample arm 150 is optically coupled between the coupler 130 and the objective lens 160, so as to guide a light beam from the coupler 130 to the objective lens 160. In this regard, when the light beam LV enters the coupler 130, the coupler 130 splits the light beam LB to first light-beam component LBC1 and a second lightbeam component LBC2. The first light-beam component LBC1 is guided to the reference arm 140; and the second light-beam component LBC2 is guided to the sample arm 150.

[0034] The optical path adjuster 150 includes a polarization controller 152 optically coupled with the coupler 130, a second collimator 154 coupled with the polarization controller 152, a scanning mirror module 156 coupled with the second collimator 154, and a tunable lens 158 optically coupled with the scanning mirror module 156.

[0035] Specifically, the polarization controller 152 in configured to adjusts the polarization state of the second light-beam component LBC2, enabling polarizationdependent measurements and control. The second collimator 154 is configured to align the second light-beam component LBC2 and ensures its collimation, optimizing its propagation through the system. The scanning mirror module 156 directs the second light-beam component LBC2to different locations, allowing for scanning and imaging capabilities. In one embodiment, the scanning mirror module 156 includes a reflection mirror and either a micro-electro-mechanical system (MEMS) or a galvo mirror scan system to fulfill the intended purpose as mentioned. The tunable lens 158 is configured to modify the focal length of the second lightbeam component LBC2, enabling dynamic control over the focus point and depth of field in imaging operation. In one embodiment, the tunable lens 158 is electrically coupled with the controller 104 and is triggered by the controller 104 to dynamically control an axial focus of the light-beam component LBC2 along an entire range of the test object OB. The tunable lens 158 is further optically coupled to the objective lens 160 for optical transmission.

[0036] By the above configuration, the second light-beam component LBC2 to be used for optically scanning the test object OB can have desired properties as follows. The second light-beam component LBC2 can get modulated to become a broadband light component / low coherence light component.

[0037] At the optical condition set as the waveband of light provided by the lightsource module 120 is about 1310±30 nm: the maximum image depth of the second light-beam component LBC2 provided by the 3D imaging system 100 for the test object OB is in a range from 5 mm to 6 mm; in one embodiment, the achievable1 A2maximum image depth is 5. 72mm, according to Zmax= - * where X is center 4 wavelength X, AX is total bandwidth, N is total channels of the photodetector module 044A2110. In one embodiment, according to AZ = ' , the 3D imaging system 100 hasdepth resolution in a range from 12 um to 13 um; for example, the achievable depth resolution is 12.58um. At the optical condition set as the waveband of light provided by the light-source module 120 is about 850±30 nm: the maximum image depth of the 3D imaging system achievable is 2.4mm; depth resolution is 5.3um. To emphasize the significance of these numbers, here are the performance of the 1st world’s hand-held OCT: scan depth is 2.5mm and depth resolution is 6um.

[0038] Moreover, lateral resolution which is also beam diameter on the object plane for the test object OB focused by the objective lens 160 is: 2w0= — =3.34um, where f is objective lens focal length and D is objective lens diameter. It is a high lateral resolution which is available to do skin detection.

[0039] FIG. 4 depicts a simulation result of spot diagram according to one embodiment of the present invention; and FIG. 5 depicts a schematic diagram illustrating a testing or simulation according to an embodiment of the present disclosure. In the testing / simulation, a testing sample includes two pieces of cover glasses with an air gap. The top cover glass 201 is with a thickness in a range of 0.19-0.22 mm, and the middle cover glasses 202 with the air-gap are with a thickness in a range of 0.13-0.16 mm. From the testing / simulation, the thickness of top cover glass 201 is about 0.21033mm and the thickness of the air-gap is about 0.15129mm.

[0040] In the simulation result of spot diagram, as shown in FIG. 4, GEO radius is the beam radius, and beam diameter on the sample is 1.67*2=3.34 um. The beam diameter is also referred to as lateral resolution. As compared with currentcommercial OCT instruments by all manufacturers, their stated lateral resolution is generally between 15 and 25 gm.

[0041] Regarding the system depth resolution measurement, it is to use the interference pattern to obtain time-domain depth signal through time-frequency conversion, and then obtain FWHM of the signal. FIG. 6 is the A-scan simulation result, in which X axis is the depth and Y axis is the backscatter intensity. FIG. 7 is the B-scan simulation result, in which X axis is lateral coordinate and Y axis is the depth.

[0042] Referring is made to FIG. 1 back. The objective lens 160 is positioned on an extending portion 176 of the housing 172. This extending portion 176 serves as an interchangeable attachment that can be connected to and detached from the component accommodation portion 172 of the housing 170 via the former opening. In one embodiment, in addition to the objective lens 160, a window lid and / or a cuvette holder can also be positioned on / at the extending portion 176 or mounted with the component accommodation portion 172. These attachments are also detachable.

[0043] The optical path from the coupler 130 to the test object OB can serve as a sample optical path. With the sample optical path, the second light-beam component LBC2 is to be reflected or scattered by the test object OB, and then the reflected or backscattered second light-beam component LBC2 will be received by the photodetector module 110 via the coupler 130 to form a depth reflectivity profile and is to be processed by the controller 104.

[0044] The controller 104 controller is electrically coupled with the photodetector module 110 and the sample path 150. The controller 104 includes a convolutional neural network (CNN) model for analyzing and can control the sample path 150 to perform an optical scan on the test object OB using the second light-beam component LBC2; then, the controller 104 can determine a location of a region of interest (ROI) of the test object OB via the CNN model.

[0045] In some embodiments, the controller 104 includes field programmable gate arrays (FPGA), a central processing unit (CPU) with one core or multiple cores, a microprocessor, or other programmable processing unit, digital signal processor (DSP), programmable controller, application specific integrated circuits (ASIC), programmable logic device (PLD), other similar devices, or combinations thereof.

[0046] In one embodiment, the controller 104 is integrated with ZYNQ architecture, combining / blending an ARM core for user applications and an FPGA for high-speed data processing, which is referred to as an electrical engineering (EE) design. This seamless integration ensures efficient data transmission and processing, enabling rapid execution of tasks and commands, data storage, and touchscreen control within the FPGA-based user space application running on embedded Linux. For example, data storage on peripherals such as SD cards, and driving a touchscreen in terms of UI display and touch screen control (e.g., via the monitor 182).

[0047] The absence of interruption in operation is a key advantage of the ZYNQ architecture, resulting from its unique shared RAM between the ARM and FPGA. This setup allows the FPGA to maintain high throughput while providing the ARM with real-time access to data as needed. The EE design acts as an important issue in ensuring the system’s overall performance and reliability, leveraging advanced technologies and methods for effective data transmission and processing. In the present invention, a cost-effective solution is presented for high-resolution nondestructive imaging applicable across various industries and applications.

[0048] Moreover, the system’s capabilities are particularly advantageous for OCT 3D imaging applications. By utilizing the FPGA as a function generator for generating control signals (e.g., Galvo signals for the sample path 150) for the two- axis Galvo scanning module in sample path 150, the system enables precise scanning along a ID path, targeting specific locations on a 2D plane, or conducting full 2D plane scanning. This advanced functionality, combined with powerful hardware and software components, allows the system to achieve high-resolution OCT 3D imaging.

[0049] The monitor 182 is electrically coupled with the PCB 102 and is configured to show a depth reflectivity profile (e.g., an image) provided by the photodetector module 110. In one embodiment, the monitor 182 has touchscreen for users operations. The battery module 180 is enclosed by the handle grip portion 174 of the housing 170 and is electrically coupled with the PCB 102. The battery module 180 can provide power to the whole 3D imaging system 100 via the PCB 102. For example, the monitor 182 is powered by the battery module 180 via the PCB 102. Also, the controller 104, the photodetector module 110, the light-source module 120 are powered by the battery module 180 via the PCB 102. As the battery module 180 can provide power to the whole 3D imaging system 100, there is noneed for any external power supply and therefore it is to completely realize a portable device.

[0050] The scanning operation of the 3D imaging system 100 is provided as follows. Firstly, a preparation stage is performed, including an initial process, a calibration process, an operation process, a scanning process.

[0051] The initial process begins with the installation of a front window lid onto the housing 170, followed by the user powering on the 3D imaging system 100. If the lid is not installed, a prompt message appears on the monitor 182, urging users to install the lid. Once the lid is installed, the self-calibration process for calibration automatically initiates.

[0052] To ensure an optimal signal-to-noise ratio, it is essential for the first lightbeam component LBC1 and the second light-beam component LBC2 (i.e., which are obtained by splitting the light beam LB from the light-source module 120 using the coupler 130) to possess similar intensities, enabling precise interference signal acquisition. This balance is achieved through the use of the shutter mode feature, allowing for independent acquisition of the spectrum of each light-beam component (i.e., LBC1 and LBC2). The intensity of the first light-beam component LBC1 is specifically recorded as the reference intensity baseline, facilitating accurate comparison and analysis of the obtained spectra. Additionally, in terms of the second light-beam component LBC2, together with galvo 2-axis zigzag scanning by the sample path 150, a center-aligned and optimized sample light path can be achieved.

[0053] Regarding the operational process, it begins with the controller 104 receiving a scanning request initiated by a user inputting instructions via the UI on the monitor 182. A galvo signal is then transmitted from the controller 104 to the sample pathl50, representing either a ID line scan, static point scan, or 2D area scan, and is prepared within the FPGA of the controller 104, utilizing the ARM core. The system status of peripherals, including the variable power light source, front window model, status of optical beam shutters, status of reference mirror, and status of the sample, is simultaneously checked within the FPGA of the controller 104 due to the hardware properties of the FPGA.

[0054] Thereafter, an adaptive scanning procedure involving CNN and U-net, implemented in the FPGA of the controller 104, utilizing the 2-axis Galvo scanning path of the sample path 150, is performed.

[0055] FIG. 8 depicts a flowchart for the adaptive scanning procedure according to one embodiment of the present invention. The adaptive scanning procedure includes steps S300, S310, and S320. The step S300 is controlling, by the controller 104, the sample path 150 to perform a preliminary optical scan on the test object OB by the second light-beam component LBC 2. The step S310 is determining, by the controller 104, a location of a region of interest (ROI) of the test object OB via a CNN model according to the preliminary optical scan. The step S 320 is performing a focusing optical scan on the test object OB after the determining the location of the ROI of the test object OB.

[0056] After step S300, the photodetector module 110 captures a first depth reflectivity profile from the reflected light beam of the test object OB, which may be presented as an image, such as an image of the human eye. Subsequently, during step S310, the controller 104 analyzes this first depth reflectivity profile, utilizing a CNN model, to determine the location of the region of interest (ROI) of the test object OB, such as the human retina. In step S320, with the ROI location determined, a focusing optical scan is conducted to concentrate on a specified small area within the ROI, such as the human retina, thereby enhancing scanning efficiency. For instance, while a preliminary optical scan covers a larger first area, the focusing optical scan targets a smaller second area within it. Consequently, after step S320, the photodetector module 110 captures a second depth reflectivity profile from the reflected light beam of the test object OB in this specified small area. The controller 104 then analyzes this second depth reflectivity profile, improving the efficiency as it is obtained from the smaller area.

[0057] The following will be illustrated with specific examples. First, a rough scan is conducted, assuming a scan area of 1000*1000 pixels, with the rough scan only measuring 100*100 pixels, which means a lower resolution of the same area. The processed data of each pixel (i.e., a total of 100*100=10000 pixels data) will be fed to a U-Net machine in the FPGA of the controller 104. Benefitting from the FPGA architecture, the instant result will indicate the location of the retina. Accordingly, this allows for a higher resolution scan in a specified small area, for example, 300*300 pixels. This approach can reduce the scanning time by approximately 90%. Following this, the collected data will be processed using the designated data processing method, transforming the entire scanning process from spatial domain data into 3D reconstructed data.

[0058] For more details, the output of the 20 channels of the photodetector module 110 is connected to current-feedback amplifier circuits, and then to the highspeed 10 GHz serial data interface of the FPGA, where the photo-detecting data is acquired and synchronized with a Galvo signal. In the 3D imaging system 100, scanning a 500 pixels * 512 pixels area 20 times per second requires a scan rate of 20*500*512 = 5.12 M scans / s. This confirms a scan speed of 5.12 M scans / s for the system of the present invention. As compared to conventional SD-OCT systems which achieve imaging speeds of 500K A-lines per second, the high scanning speed of the system of the present invention avoids distortion caused by external disturbances, such as breathing and heartbeat, when testing living samples. Without this synchronization, real-time 3D reconstruction or temporal 3D reconstruction would not be possible. A controllable light source of the light-source module 120 is also included in the desire design to allow the controller 104 to control optical power throughout the scanning process.

[0059] Moreover, during the adaptive scanning procedure, the monitor 182 can display a depth reflectivity profile captured by the photodetector module 102 from a reflection light beam of the test object OB, to show the results of the adaptive scanning procedure in-real time. In this regard, since the preliminary optical scan is made for finding the ROI of the test object OB, it is no need to show the result for it to users. Correspondingly, in one embodiment, a result of the preliminary optical scan is not permitted to be displayed on the monitor 182. The depth reflectivity profile which can reflect a result from the focusing optical scan will be shown on the monitor 182.

[0060] The functional units and modules of the apparatuses and methods in accordance with the embodiments disclosed herein may be implemented using computing devices, computer processors, or electronic circuitries including but not limited to application specific integrated circuits (ASIC), field programmable gate arrays (FPGA), microcontrollers, and other programmable logic devices configured or programmed according to the teachings of the present disclosure. Computer instructions or software codes running in the computing devices, computer processors, or programmable logic devices can readily be prepared by practitioners skilled in the software or electronic art based on the teachings of the present disclosure.

[0061] All or portions of the methods in accordance to the embodiments may be executed in one or more computing devices including server computers, personal computers, laptop computers, mobile computing devices such as smartphones and tablet computers.

[0062] The embodiments may include computer storage media, transient and non-transient memory devices having computer instructions or software codes stored therein, which can be used to program or configure the computing devices, computer processors, or electronic circuitries to perform any of the processes of the present invention. The storage media, transient and non-transient memory devices can include, but are not limited to, floppy disks, optical discs, Blu-ray Disc, DVD, CD-ROMs, and magneto-optical disks, ROMs, RAMs, flash memory devices, or any type of media or devices suitable for storing instructions, codes, and / or data.

[0063] Each of the functional units and modules in accordance with various embodiments also may be implemented in distributed computing environments and / or Cloud computing environments, wherein the whole or portions of machine instructions are executed in distributed fashion by one or more processing devices interconnected by a communication network, such as an intranet, Wide Area Network (WAN), Local Area Network (LAN), the Internet, and other forms of data transmission medium.

[0064] The foregoing description of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations will be apparent to the practitioner skilled in the art.

[0065] The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the invention for various embodiments and with various modifications that are suited to the particular use contemplated.

Claims

Claims:What is claimed is:

1. A three-dimensions (3D) imaging system for handheld photonic chip integration, comprising: a photodetector module disposed at a print circuit board (PCB); a light-source module disposed at the PCB and configured to provide at least one light beam; a coupler disposed at the PCB and optically coupled with the photodetector module and the light-source module, such that photodetector module, the lightsource module, and the coupler are integrated into a combined chip on the PCB; a reference arm optically coupled with the coupler; an objective lens; a sample path optically coupled between the coupler and the objective lens, so as to guide the light beam from the coupler to the objective lens; and a controller electrically coupled with the photodetector module and the sample path and comprising a convolutional neural network (CNN) model, wherein the controller controls the sample path to perform an optical scan on a test object using the light beam and determines a location of a region of interest (ROI) of the test object via the CNN model.

2. The 3D imaging system for handheld photonic chip integration of claim 1, wherein the light-source module comprises: a first super luminescent diode (SLD); a second SLD; a dichroic filter optically between the first SLD and the second SLD; a condenser lens optically coupled with the dichroic filter, wherein the 3D imaging system for handheld photonic chip integration further comprises a single mode fiber to receive the light beam propagated from the condenser lens and to guide the light beam into the coupler.

3. The 3D imaging system for handheld photonic chip integration of claim 2, wherein a first SLD light beam provided by the first SLD partially passes thedichroic filter and then enters the condenser lens, and wherein a second SLD light beam provided the second SLD is partially reflected by the dichroic filter and then enters the condenser lens.

4. The 3D imaging system for handheld photonic chip integration of claim 2, wherein a first SLD light beam provided by the first SLD and a second SLD light beam provided the second SLD have different wavelength intervals.

5. The 3D imaging system for handheld photonic chip integration of claim 1, wherein the reference arm comprises: a first collimator optically coupled with the coupler and configured to convert a light beam passing therethrough into parallel light; a reference mirror; and a dispersion compensation unit optically coupled between the first collimator and the reference mirror and configured to compensate for an optical path difference caused by dispersion, wherein a light beam from the coupler is reflected at the reference mirror and is propagated from the reference mirror to the coupler and then to the photodetector module for interference comparison.

6. The 3D imaging system for handheld photonic chip integration of claim 1, wherein the sample path further comprises a tunable lens electrically coupled with the controller and optically coupled with the objective lens, wherein the tunable lens is triggered by the controller to dynamically control an axial focus of the light beam along an entire range of the test object.

7. The 3D imaging system for handheld photonic chip integration of claim 1, wherein lateral resolution which is provided by the 3D imaging system on the test object and is focused by the objective lens is about 3.34um.

8. The 3D imaging system for handheld photonic chip integration of claim 1, further comprising: a housing enclosing the PCB, the photodetector module, the light-source module, the coupler, the reference arm, and the sample path, wherein the housing has a first opening for placing the objective lens.

9. The 3D imaging system for handheld photonic chip integration of claim 8, further comprising: a monitor electrically coupled with the PCB and configured to show a depth reflectivity profile provided by the photodetector module, wherein the housing has a second opening for placing the monitor.

10. The 3D imaging system for handheld photonic chip integration of claim 8, wherein the housing has a handle grip portion physically separated than the PCB, the photodetector module, the light-source module, the coupler, the reference arm, the sample path, and the monitor, and wherein the 3D imaging system further comprises a battery module enclosed by the handle grip portion of the housing and electrically coupled with the PCB.

11. The 3D imaging system for handheld photonic chip integration of claim 8, wherein the housing comprises a component accommodation portion for enclosing components and an extending portion that is connected to and detached from the component accommodation portion via the first opening, and wherein the objective lens extending portion is positioned at extending portion.

12. The 3D imaging system for handheld photonic chip integration of claim 1, wherein the controller applies an electrical engineering (EE) design to integrate ZYNQ architecture, combining an ARM core for user applications with an FPGA for high-speed data processing.

13. The 3D imaging system for handheld photonic chip integration of claim 12, wherein the photodetector module has an output of 20 channels connected to currentfeedback amplifier circuits, which are then connected to a high-speed 10 GHz serial data interface of the FPGA, allowing for acquisition of photo-detecting data synchronized with a Galvo signal via a scan rate 5.12 M scans / s.

14. A method for three-dimensions (3D) imaging using a 3D imaging system, comprising: providing at least one light beam by a light-source module;splitting the light beam to first light-beam component and a second lightbeam component by using a coupler; guiding the light beam to a reference arm and a sample path from the coupler, wherein the first light-beam component is guided to the reference arm and the second light-beam component is guided to the sample path which further guides the second light-beam component to an objective lens; controlling, by a controller, the sample path to perform a preliminary optical scan on a test object by the second light-beam component; determining, by the controller, a location of a region of interest (ROI) of the test object via a convolutional neural network (CNN) model according to the preliminary optical scan; and performing a focusing optical scan on the test object after the determining the location of the ROI of the test object.

15. The method for 3D imaging of claim 14, further comprising: analyzing a first depth reflectivity profile captured by a photodetector module from a reflection light beam of the test object, resulting from the preliminary optical scan, by the controller using the CNN model to indicate the location of the ROI of the test object.

16. The method for 3D imaging of claim 15, further comprising: analyzing a second depth reflectivity profile captured by the photodetector module from a reflection light beam of the test object, during the focusing optical scan.

17. The method for 3D imaging of claim 14, further comprising: displaying, by a monitor, a depth reflectivity profile captured by the photodetector module from a reflection light beam of the test object.

18. The method for 3D imaging of claim 14, wherein lateral resolution which is provided by the 3D imaging system on the test object and is focused by the objective lens is about 3.34um.

19. A method for 3D imaging using an optical spectroscopy measurement, comprising: operating the 3D imaging system of claim 1 as an optical spectroscopy measurement system for the optical spectroscopy measurement based on a reflection measurement for the ROI of the test object; receiving, by the photodetector module, a light signal along a light path / optical path, wherein there are two beam shutters or variable attenuators in the light path / optical path, which are able to attenuate light in a reference arm to adjust lighting intensity to match that of a sample arm, wherein the two beam shutters or variable attenuators are configured to block light in the reference arm, and wherein, when the reference arm blocks light, the optical spectroscopy measurement system is enabled to perform reflection measurements, and wherein light reflected off the test object allows direct measurement of how the test object interacts with light, providing information for indirectly measuring other material properties, wherein light reflected off the ROI of the test object for allowing direct measurement of how the ROI of the test object absorbs light by measuring intensity of the light as a beam of light passes through sample solution, using basic principle that each compound absorbs or transmits light over a certain range of wavelength; and analyzing specific features of the reflected light to determine the thickness and refractive index of the test object.

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