Method for optical resolution measurement of optical devices

Abstract

Embodiments herein provide a method of determining an optical device modulation transfer function (MTF). The method described herein includes projecting a baseline image of a pattern from a light engine to a detector. The baseline image is analyzed to determine a baseline function. A baseline fast Fourier transform (FFT) or a baseline MTF of the baseline function is taken. The method further includes projecting an image of the pattern from the light engine to one or more optical devices. The pattern is outcoupled from the one or more optical devices to the detector. The image is analyzed to determine a function. A function FFT or a function MTF is taken corresponding to the image. An optical device MTF of the one or more optical devices is determined by comparing the baseline FFT to the function FFT determined by analyzing the image, or by comparing the baseline MTF to the function MTF determined by analyzing the image.

Description

Technical Field

[0001] The embodiments disclosed herein generally relate to optical devices. More specifically, the embodiments described herein provide a method for determining the modulation transfer function (MTF) of an optical device. Background Technology

[0002] Virtual reality is generally considered to be a computer-generated simulated environment in which the user has a tangible physical presence. Virtual reality experiences can be generated in 3D and viewed using head-mounted displays (HMDs), such as glasses or other wearable display devices with near-eye display panels as lenses, to display virtual reality environments that replace the real environment.

[0003] However, augmented reality experiences allow users to still see their surroundings through the display lenses of glasses or other HMD devices, and also see images of virtual objects generated for display and appearing as part of the environment. Augmented reality can include any type of input, such as audio and haptic input, as well as virtual images, graphics, and videos that enhance or augment the user's experience of the environment. As an emerging technology, augmented reality faces many challenges and design limitations.

[0004] One such challenge is determining the optical resolution of an optical device to ensure compliance with image quality standards. Current measurement systems for optical devices generally have low sampling rates and low throughput across large fields of view, and cannot adequately compensate for defects in image quality caused by the camera and image projector within the measurement system. Additionally, the measurement system may be bulky and susceptible to defects associated with the image projector. Therefore, it is desirable to have a system and method for measuring optical resolution that will not be affected by defects associated with the image projector or camera, and will have improved throughput. Accordingly, what is needed in the art is a method for determining the MTF of an optical device. Summary of the Invention

[0005] In one embodiment, a method is provided. The method includes projecting a baseline image of a pattern. The baseline image is projected from an optical engine of a measurement system. The measurement system includes a stage disposed below the optical engine. The stage is operable to mount one or more optical devices thereon. The optical engine, disposed above the stage, projects the baseline image onto the one or more optical devices. The measurement system further includes a detector oriented toward the stage. The method further includes capturing the baseline image. The baseline image is captured by the detector. The method further includes analyzing the baseline image to locate a first plurality of points on the baseline image. The first plurality of points are converted into a baseline function. The method further includes obtaining a baseline fast Fourier transform (FFT) of the baseline function and mounting the one or more optical devices on the stage. The method further includes projecting an image of the pattern from the optical engine onto the one or more optical devices and capturing the image. The image is captured by the detector. The method further includes analyzing the image to locate a second plurality of points on the image. The second plurality of points are converted into a function. The method further includes obtaining a function FFT corresponding to the image, and determining the optical device modulation transfer function (MTF) of the one or more optical devices by comparing the baseline FFT with the function FFT corresponding to the image.

[0006] In another embodiment, a method is provided. The method includes projecting a baseline image of a pattern. The baseline image is projected from an optical engine of a measurement system. The measurement system includes a stage disposed below the optical engine. The stage is operable to mount one or more optical devices thereon. The optical engine, disposed above the stage, projects the baseline image onto the one or more optical devices. The measurement system further includes a detector oriented toward the stage. The method further includes obtaining a baseline Fast Fourier Transform (FFT) corresponding to the baseline image and projecting the image of the pattern onto the one or more optical devices. The image is projected from the optical engine onto the one or more optical devices. The method further includes capturing the image. The image is captured by the detector. The method further includes obtaining a functional FFT corresponding to the image and determining the optical device modulation transfer function (MTF) of the one or more optical devices by comparing the baseline FFT with the functional FFT corresponding to the image.

[0007] In yet another embodiment, a method is provided. The method includes projecting a baseline image of a pattern from an optical engine onto a detector of a measurement system. The method further includes capturing and analyzing the baseline image by the detector to determine a baseline Fast Fourier Transform (FFT). The method further includes projecting an image of the pattern from the optical engine onto one or more optical devices. The image is projected onto the detector via the one or more optical devices. The method further includes capturing and analyzing the image by the detector. The method further includes determining the optical device modulation transfer function (MTF) of the one or more optical devices. Attached Figure Description

[0008] To gain a more detailed understanding of the features of this disclosure described above, a more specific description of the disclosure, which has been briefly outlined above, can be obtained by referring to the embodiments (partially illustrated in the accompanying drawings). However, it should be noted that the drawings are merely illustrative of embodiments and should not be considered as limiting its scope, and other equally effective embodiments are permissible.

[0009] Figure 1A This is a front perspective view of the substrate according to the embodiments described herein.

[0010] Figure 1B This is a frontal perspective view of the optical device according to the embodiments described herein.

[0011] Figure 2 This is a schematic cross-sectional view of the measurement system according to the embodiments described herein.

[0012] Figure 3 This is a flowchart of a method for determining the modulation transfer function (MTF) of an optical device according to the embodiments described herein.

[0013] Figure 4 This is a schematic diagram of the system during the method of determining the modulation transfer function (MTF) of an optical device.

[0014] To facilitate understanding, the same reference numerals have been used as much as possible to refer to common elements in the figures. It is conceivable that elements and features of one embodiment may be beneficially incorporated into other embodiments without further description. Detailed Implementation

[0015] The embodiments disclosed herein generally relate to optical devices. More specifically, the embodiments described herein provide a method for determining the modulation transfer function (MTF) of an optical device. The method includes projecting a baseline image of a pattern. The baseline image is projected from an optical engine of a measurement system. The measurement system includes a stage disposed below the optical engine. The stage is operable to mount one or more optical devices thereon. The optical engine, disposed above the stage, projects the baseline image onto the one or more optical devices. The measurement system further includes a detector oriented toward the stage. The method further includes capturing the baseline image. The baseline image is captured by the detector. The method further includes analyzing the baseline image to locate a first plurality of points on the baseline image. The first plurality of points are converted into a baseline function. The method further includes obtaining a baseline FFT or baseline MTF of the baseline function, and mounting the one or more optical devices on the stage. The method further includes projecting an image of the pattern from the optical engine onto the one or more optical devices and capturing the image. The image is captured by the detector. The method further includes analyzing the image to locate a second plurality of points on the image. The second plurality of points are converted into a function. The method further includes obtaining a function FFT or function MTF corresponding to the image, and determining the optical device MTF of the one or more optical devices by comparing the baseline FFT with the function FFT, or by comparing the baseline MTF with the function MTF.

[0016] Figure 1A This is a front perspective view of a substrate 101 according to an embodiment described herein. The substrate includes a plurality of optical devices 100 disposed on a surface 103 of the substrate 101. The optical devices 100 are waveguide combiners for virtual reality, augmented reality, or mixed reality. In some embodiments that can be combined with other embodiments described herein, the optical devices 100 are flat optical devices, such as metasurfaces.

[0017] The substrate 101 can be any substrate used in the art, and can be opaque or transparent to a selected laser wavelength depending on the application of the substrate 101. Additionally, the substrate 101 can have different shapes, thicknesses, and diameters. For example, the substrate 101 can have a diameter of about 150 mm to about 300 mm. The substrate 101 can have a circular, rectangular, or square shape. The substrate 101 can have a thickness between about 300 μm and about 1 mm. Although only nine optical devices 100 are shown on the substrate 101, any number of optical devices 100 can be provided on the surface 103.

[0018] Figure 1BThis is a front perspective view of the optical device 100. It will be understood that the optical device 100 described herein is an illustrative optical device and other optical devices or modifications thereof may be used to achieve aspects of this disclosure. The optical device 100 includes a plurality of optical device structures 102 disposed on a surface 103 of a substrate 101. The optical device structures 102 may be nanostructures having submicron dimensions (e.g., nanometer-sized dimensions). Regions of the optical device structures 102 correspond to one or more gratings 104, such as a first grating 104a, a second grating 104b, and a third grating 104c. In some embodiments that can be combined with other embodiments described herein, the optical device 100 includes at least a first grating 104a corresponding to an input coupling grating and a third grating 104c corresponding to an output coupling grating. In some embodiments that can be combined with other embodiments described herein, the optical device 100 also includes a second grating 104b corresponding to an intermediate grating. The optical device structures 102 may be angled or binary. The optical device structure 102 may have other shapes, including (but not limited to) circles, triangles, ellipses, regular polygons, irregular polygons, and / or irregular cross-sections.

[0019] In operation, the first grating 104a receives an incident light beam (virtual image) of a certain intensity from the light source. The incident light beam is split by the optical device structure 102 into T1 beams with the full intensity of the incident light beam to guide the virtual image to an intermediate grating (if used) or a third grating 104c. In some embodiments that can be combined with other embodiments described herein, the T1 beams undergo total internal reflection (TIR) ​​through the optical device 100 until they contact the optical device structure 102 of the intermediate grating. The optical device structure 102 of the intermediate grating diffracts these T1 beams into T-1 beams, which undergo TIR through the optical device 100 to the optical device structure 102 of the third grating 104c. The optical device structure 102 of the third grating 104c outcouples these T-1 beams to the user's eye to modulate the field of view of the virtual image generated from the light source from the user's point of view and further increase the user's viewing angle of the virtual image. In other embodiments (which can be combined with other embodiments described herein), the T1 beams pass through the optical device 100 and undergo TIR until these T1 beams contact the optical device structure 102 of the third grating 104c and are outcoupled to modulate the field of view of the virtual image generated from the light source.

[0020] To ensure that the optical device 100 meets image quality standards, the optical device MTF of the optical device 100 is obtained. In some embodiments, the optical device MTF provides image quality information regarding image resolution and image contrast. Embodiments of the measurement system 200 described herein provide the ability to obtain the optical device MTF with increased throughput and better quality control. Additionally, embodiments of the measurement system 200 described herein provide the ability to obtain the optical device MTF so that the measured optical device MTF is not strongly affected by defects in the image projector and / or camera (such as distortion and astigmatism). The embodiments described herein allow for image quality separation between the optical device 100 and the measurement system 200, which may include defects attributable only to the camera or projector. MTF is a metric used to determine the ability of the optical device 100 to convert the contrast of an object into an image at a specific resolution.

[0021] Figure 2 This is a schematic cross-sectional view of a measurement system 200 according to an embodiment described herein. The measurement system 200 includes a body 201 having a first opening 203 and a second opening 205 to allow a stage 207 to move through it. The stage 207 is operable to move within the body 201 of the measurement system 200 in the X, Y, and Z directions. The stage 207 includes a bracket 209 operable to hold an optical device 100 (as shown herein) or one or more substrates 101.

[0022] The measurement system 200 is operable to project images, enabling the determination of the MTF of the optical device 100. The stage 207 and bracket 209 may be transparent, so that the MTF obtained using the measurement system 200 is not affected by the translucency of the stage 207 or bracket 209. The measurement system 200 communicates with a controller 220, which is operable to control the operation of the measurement system 200 and method 300 described herein.

[0023] Controller 220 is coupled to measurement system 200. Controller 220 includes a processor 252, memory 254, and support circuitry 256, all coupled to each other. Controller 220 is electrically coupled to measurement system 200 via wire 258. Processor 252 may be any form of general-purpose microprocessor or general-purpose central processing unit (CPU), each of which can be used in industrial settings such as programmable logic controllers (PLCs), supervisory control and data acquisition (SCADA) systems, general-purpose graphics processing units (GPUs), or other suitable industrial controllers. Memory 254 is non-transitory and may be one or more readily available memories, such as random access memory (RAM), read-only memory (ROM), or any other form of digital storage, whether local or remote. Memory 254 contains instructions that, when executed by processor 252, facilitate the execution of method 300. The instructions in memory 254 are in the form of a program product, such as a program that implements the methods of this disclosure. The program code of the program product may conform to any of several different programming languages. Exemplary computer-readable storage media include (but are not limited to): (i) non-writable storage media (e.g., read-only memory devices within a computer, such as CD-ROM discs readable by a CD-ROM drive, flash memory, ROM chips, or any type of solid-state non-volatile semiconductor memory) that permanently store information thereon; and (ii) writable storage media (e.g., floppy disks or hard disk drives within a disk drive or any type of solid-state random access semiconductor memory) that store changeable information thereon. Such computer-readable storage media are examples of this disclosure when they carry computer-readable instructions that direct the functionality of the methods described herein.

[0024] The measurement system 200 includes an upper portion 204 oriented toward the top side 222 of the optical device 100 and a lower portion oriented toward the bottom side of the optical device 100. The upper portion 204 of the measurement system 200 includes a alignment camera 208, a light engine 210, and a reflection detector 212. The alignment camera 208 is operable to determine the position of the stage 207 and the optical device 100. The light engine 210 is operable to illuminate a first grating 104a. In some embodiments that can be combined with other embodiments described herein, the light engine 210 projects an image of a pattern onto the first grating 104a. The reflection detector 212 detects an out-coupled beam projected from the top side of the optical device 100 from a third grating 104c. The lower portion 206 of the first subsystem 202 includes a barcode reader 214 and a transmission detector 216. The barcode reader 214 is operable to read codes of these optical devices, such as a Quick Response (QR) code or barcode of the optical device 100. The code read by reader 214 may include instructions for obtaining the optical device MTF of various optical devices 100. Transmission detector 216 detects the out-coupled beam projected from the third grating 104c through the bottom side of optical device 100.

[0025] The method 300 described herein includes illuminating a first grating 104a of an optical device 100 by a light engine 210, wherein the incident coupled light undergoes a transflection infrared (TIR) ​​until its outgoing coupled (e.g., reflected or transmitted) becomes an image captured by a transmission detector 216. These images may correspond to the red, green, and blue channels from the light engine 210. These images are processed as described in method 300 to capture the MTF of the optical device 100.

[0026] Figure 3 This is a flowchart of method 300 for determining the MTF of an optical device. Figure 4 This is a schematic diagram of the measurement system 200 during the method for determining the MTF of an optical device. For ease of explanation, reference will be made to... Figure 4 The method 300 is described using the measurement system 200 shown herein. The method 300 is operable on other measurement systems not described herein.

[0027] Measurement system 200 includes a light engine 210 and a transmission detector 216. In some embodiments that can be combined with other embodiments described herein, measurement system 200 also includes a reflection detector 212 (displayed in the image). Figure 2(In the image). The light engine 210 includes a light source 402, a reticle 404, and a first lens 406. The light engine 210 may further include at least one of a quarter-wave plate or a linear polarizer. In some embodiments that may be combined with other embodiments described herein, the light source 402 is configured to project red, green, and blue light. The reticle 404 may be a display. The transmission detector 316 includes a second lens 408 and a camera 410.

[0028] In operation 301, a baseline image is projected by the light engine 210 of the measurement system 200 in the absence of the optical device 100. This baseline image is projected after the light source 402 projects red, green, or blue light through the tracing plate 404 to form a pattern. The baseline image has this pattern. In some embodiments that can be combined with other embodiments described, the light engine 210 is a high-resolution image projector having a field of view (FOV) of about 10 degrees to about 120 degrees. The FOV of the light engine 210 is fixed or adjustable. The pattern is determined by the tracing plate 404. The tracing plate 404 may have one of a checkerboard pattern, a line-pair pattern, or a dot matrix pattern. In some embodiments that can be combined with other embodiments described, the tracing plate 404 is a high-resolution patterned mask. The pattern of the tracing plate 404 may be formed via electron beam, ion beam, or photolithography. In other embodiments (which can be combined with other embodiments described), the light engine 210 is one of an LCOS, CLP, micro-LED, or OLED microdisplay.

[0029] In operation 302, the baseline image is captured. This baseline image can be captured by a transmission detector 216. The baseline image has a pattern formed by caliper patches 404. In some embodiments that can be combined with other embodiments described herein, the transmission detector 216 includes a camera 410. The camera 410 is a high-resolution camera. The camera 410 has a field of view (FOV) of approximately 10 degrees to approximately 120 degrees. The FOV of the camera 410 is fixed or adjustable. The camera 410 can be a CCD or CMOS sensor. The camera 410 has an FOV sampling rate of approximately 1 degree per measurement.

[0030] In operation 303, the baseline image is analyzed. In some embodiments that can be combined with other embodiments described herein, the baseline image is analyzed to locate multiple points on the baseline image. Each of these multiple points may correspond to a different field of view (FOV) across the baseline image. For example, each of these multiple points may correspond to the edges of adjacent squares in a checkerboard pattern. The multiple points are converted into a baseline function determined according to the formed pattern. For example, the baseline function may be a point spread function, a line spread function, or an edge spread function.

[0031] In operation 304, the baseline FFT or baseline MTF corresponding to the baseline function of the baseline image is obtained. To correctly obtain the baseline FFT or baseline MTF, it is necessary to minimize the light intensity variation across the baseline image. The light intensity variation across the baseline image can be reduced by adjusting the exposure time of the baseline image. The exposure time can be adjusted for each of the multiple points of the baseline function.

[0032] In operation 305, such as Figure 4 As shown, an image is projected by the light engine 210 of the measurement system 200 when the optical device 100 is present. This image is projected after the light source 402 projects red, green, or blue light through the gradation patch 404 to form a pattern. The image includes this pattern. The pattern is projected onto the first grating 104a and undergoes TIR through the optical device 100 until the pattern couples out from the third grating 104c. In some embodiments that can be combined with other embodiments described herein, the optical device 100 may include a waveguide combiner based on a surface relief grating, a waveguide combiner based on a volume hologram, a bird bath waveguide combiner, a partial mirror array combiner, or an optically-free combiner. The pattern is determined by the gradation patch 404. The gradation patch 404 may have one of a checkerboard pattern, a line-pair pattern, or a dot matrix pattern. In some embodiments that can be combined with other embodiments described, the gradation patch 404 is a high-resolution patterned mask.

[0033] At operation 306, an image of the optical device 100 is captured. This image can be captured by the transmission detector 216. The image is coupled outward from the third grating 104c on the bottom side of the optical device 100 toward the transmission detector 216. The image has the pattern defined by the grating 404. In some embodiments that can be combined with other embodiments described herein, the transmission detector 216 includes a camera 410. In some embodiments that can be combined with other embodiments described herein, the reflection detector 212 can capture an image of the pattern. For example, when the image is coupled outward from the top side of the optical device 100, the reflection detector 212 can partially or completely capture the image.

[0034] In operation 307, the image is analyzed. In some embodiments that can be combined with other embodiments described herein, the image is analyzed to locate multiple points. Each of these multiple points may correspond to a different field of view (FOV) across the image. For example, each of these multiple points may correspond to the edges of adjacent squares in a checkerboard pattern. The multiple points are converted into a function determined by the pattern. For example, the function may be a point spread function, a line spread function, or an edge spread function. In some embodiments that can be combined with other embodiments described herein, the function corresponds to the baseline function. For example, when the baseline function is a point spread function, this function will also be a point spread function.

[0035] In operation 308, the function FFT or function MTF corresponding to the image is obtained. To correctly obtain the function FFT or function MTF, it is necessary to minimize the light intensity variation across the image. The light intensity variation across the image can be reduced by adjusting the exposure time of the image. The exposure time can be adjusted for each of multiple points of the function.

[0036] In operation 309, the optical device MTF is obtained. The optical device MTF is obtained by dividing the function FFT corresponding to the image by the baseline FFT, or by dividing the function MTF by the baseline MTF. The optical device MTF obtained by method 300 is less susceptible to defects in the optical engine 210. For example, astigmatism or distortion appearing in the optical engine 210 is filtered out by obtaining the baseline FFT or baseline MTF separately from the function FFT or function MTF corresponding to the image, thus isolating and compensating for the defects. In some embodiments that can be combined with other embodiments described herein, the MTF of the complete FOV of the optical device 100 is obtained using an image capture of the optical device.

[0037] In summary, this paper describes a method for determining the MTF of an optical device. The method described herein includes projecting a baseline image of a pattern from an optical engine onto a detector. The baseline image is analyzed to determine a baseline function. A baseline FFT or baseline MTF of the baseline function is obtained. The method further includes projecting an image of the pattern from the optical engine onto one or more optical devices. The pattern is coupled from the one or more optical devices to the detector. The image is analyzed to determine a function. A function FFT or function MTF is obtained corresponding to the image. The optical device MTF is determined by comparing the baseline FFT with the function FFT or by comparing the baseline MTF with the function MTF. The method described herein provides optical device MTF measurements without being affected by potential defects in the optical engine. Additionally, due to the high-resolution image projectors and high-resolution cameras each having a FOV of approximately 10 degrees to approximately 120 degrees, the method provided herein acquires complete, dense FOV MTF data for the optical device in a single image (e.g., processing all FOV angles in parallel in a single shot), thus improving throughput for optical device manufacturing and quality control. Overall, the method presented in this paper allows for compensation of image quality defects caused by the image projector and camera by enabling the isolation of the optical device's MTF (Mean Transmission Factor). In this way, quality degradation can be avoided and higher throughput can be achieved.

[0038] Although the foregoing describes an embodiment of this disclosure, other and additional embodiments of this disclosure may be devised without departing from the basic scope of this disclosure, the scope of which is defined by the appended claims.

Claims

1. A method for determining the modulation transfer function of an optical device, comprising: A baseline image of a projected pattern, the baseline image being projected from the light engine of a measurement system, the measurement system having: A stage, the stage being disposed below the optical engine, the stage being operable to mount one or more optical devices thereon, wherein the optical engine, disposed above the stage, projects the baseline image onto the one or more optical devices; and Detector, the detector being oriented to face the stage; The baseline image is captured by the detector; The baseline image is analyzed to locate a first plurality of points on the baseline image, and the first plurality of points are converted into a baseline function; Obtain the baseline fast Fourier transform of the baseline function; The one or more optical devices are mounted on the stage; A pattern image of the pattern is projected from the light engine onto the one or more optical devices; The pattern image is captured by the detector; The pattern image is analyzed to locate a second plurality of points on the pattern image, and the second plurality of points are converted into functions; Obtain the Fast Fourier Transform of the function corresponding to the pattern image; and The optical device modulation transfer function of the one or more optical devices is determined by comparing the baseline fast Fourier transform with the function fast Fourier transform corresponding to the pattern image.

2. The method of claim 1, further comprising adjusting the exposure time of the baseline image when capturing the baseline image.

3. The method of claim 1, further comprising adjusting the exposure time of the pattern image when capturing the pattern image.

4. The method of claim 1, wherein the baseline function and the function determined by analyzing the pattern image are one of a point spread function, a line spread function, or an edge spread function.

5. The method of claim 1, wherein the step of determining the modulation transfer function of the optical device comprises dividing the fast Fourier transform of the function corresponding to the pattern image by the baseline fast Fourier transform.

6. The method of claim 1, further comprising capturing the pattern image by a reflection detector, the reflection detector being oriented toward the stage.

7. The method of claim 1, wherein the light engine is a high-resolution image projector having a field of view of 10 to 120 degrees.

8. The method of claim 1, wherein one or more of the first plurality of points and the second plurality of points represent the edges of adjacent quadrilaterals in a chessboard pattern.

9. A method for determining the modulation transfer function of an optical device, comprising: A baseline image of a projected pattern, the baseline image being projected from the light engine of a measurement system, the measurement system having: A stage, disposed below the optical engine, operable to mount one or more optical devices thereon, wherein the optical engine, disposed above the stage, projects the baseline image onto the one or more optical devices; and Detector, the detector being oriented to face the stage; The baseline image is captured by the detector; Obtain the baseline fast Fourier transform corresponding to the baseline image; The pattern image of the pattern is projected onto one or more optical devices, and the pattern image is projected from the light engine onto one or more optical devices; The pattern image is captured by the detector; Obtain the Fast Fourier Transform of the function corresponding to the pattern image; and The optical device modulation transfer function of the one or more optical devices is determined by comparing the baseline fast Fourier transform with the function fast Fourier transform corresponding to the pattern image.

10. The method of claim 9, further comprising adjusting the exposure time of the baseline image when capturing the baseline image.

11. The method of claim 9, wherein the light engine is a high-resolution image projector having a field of view of 10 to 120 degrees.

12. The method of claim 9, further comprising: The baseline image is analyzed to locate a first plurality of points on the baseline image, the first plurality of points being converted into a baseline function; and The pattern image is analyzed to locate a second plurality of points on the pattern image, and these second plurality of points are converted into functions. One or more of the first plurality of points and the second plurality of points represent the edges of adjacent quadrilaterals in the chessboard pattern.

13. The method of claim 9, further comprising capturing the pattern image by a reflection detector oriented toward the stage.

14. The method of claim 9, wherein the step of determining the optical device modulation transfer function of the one or more optical devices comprises dividing the fast Fourier transform of the function corresponding to the pattern image by the baseline fast Fourier transform.

15. A method for determining the modulation transfer function of an optical device, comprising: The baseline image of the pattern is projected from the light engine onto the detector of the measurement system; The baseline image is captured by the detector; Analyzing the baseline image, wherein the step of analyzing the baseline image includes determining the baseline fast Fourier transform or the baseline modulation transfer function; The pattern image of the pattern is projected from the light engine onto one or more optical devices, and the pattern image is projected onto the detector through the one or more optical devices; The pattern image is captured by the detector; Analyzing the pattern image, wherein the steps of analyzing the pattern image include determining a functional modulation transfer function or a function fast Fourier transform corresponding to the pattern image; and Determining the optical device modulation transfer function of the one or more optical devices, wherein the step of determining the optical device modulation transfer function includes: Divide the function modulation transfer function by the baseline modulation transfer function; or Divide the function's Fast Fourier Transform by the baseline Fast Fourier Transform.

16. The method of claim 15, further comprising adjusting the exposure time of the baseline image when capturing the baseline image.

17. The method of claim 15, wherein the light engine is a high-resolution image projector having a field of view of 10 to 120 degrees.

18. The method of claim 15, further comprising a stage disposed below the optical engine, and capturing the pattern image by means of a reflection detector oriented toward the stage.

Images