Image acquisition device, optical recognition method and optical recognition system

Abstract

An optical recognition method, applicable to an optical recognition device, includes a control device, a spatial light modulator, and a light sensor. The method comprises: using the optical recognition device to acquire a corresponding first image from a physical environment; identifying at least one high-brightness pixel in the first image; controlling the spatial light modulator to generate a second image based on the position of the at least one high-brightness pixel, wherein the resolution of the second image is greater than that of the first image; and identifying a pattern of at least one retroreflector in the physical environment based on the second image. The present invention also relates to an image acquisition device and an optical recognition system.

Description

Technical Field

[0001] The present disclosure relates to an image acquisition device, an optical recognition method, and an optical recognition system, and more particularly to an image acquisition device, an optical recognition method, and an optical recognition system for a single-pixel camera. Background Art

[0002] In current optical recognition applications, optical cameras are often used to photograph objects to be located in a physical environment, and the position or other information of the objects to be located is determined by identifying a two-dimensional barcode attached to the surface of the objects in the photographed photos.

[0003] However, the above approach has several drawbacks. For example, the 2D barcode may be in the shadow and cannot be clearly identified, or the captured photo may contain other sensitive information, resulting in the risk of confidential information being leaked. Summary of the Invention

[0004] The present disclosure provides an image acquisition device, which includes a lens, a spatial light modulator, a light sensor, and a control device. The lens includes a first lens for receiving a plurality of reflected light rays from a physical environment, and the physical environment includes at least one retroreflector. The spatial light modulator is used to receive the reflected light rays from the first lens and selectively transmit the reflected light rays to the second lens. The light sensor is used to receive the reflected light rays from the second lens to generate a sensing result. The control device is coupled to the spatial light modulator and the light sensor, and is used to: generate a first image corresponding to the physical environment according to the sensing result of the light sensor; identify a plurality of high-brightness pixels in the first image; control the spatial light modulator to generate a second image according to the position of the high-brightness pixels, and the resolution of the second image is greater than the resolution of the first image; and identify the pattern of at least one retroreflector based on the second image.

[0005] This disclosure provides an optical recognition method applicable to an optical recognition device. The optical recognition device includes a control device, a spatial light modulator, and a light sensor. The optical recognition method includes the following steps: using the optical recognition device to acquire a corresponding first image from a physical environment; identifying at least one high-brightness pixel in the first image; controlling the spatial light modulator to generate a second image based on the position of the at least one high-brightness pixel, wherein the resolution of the second image is greater than the resolution of the first image; and identifying the pattern of at least one retroreflector in the physical environment based on the second image.

[0006] The present disclosure provides an optical recognition system, which is located in a physical environment and includes a first image acquisition device and a second image acquisition device. The first image acquisition device is used to generate a first light having a first frequency. The second image acquisition device is used to generate a second light having a second frequency, and the first frequency is different from the second frequency. When the physical environment generates at least one reflected light, the first image acquisition device and the second image acquisition device are used to perform the following operations based on the portion of the at least one reflected light corresponding to the first light and the portion corresponding to the second light, respectively: generate a first image corresponding to the physical environment; identify at least one high-brightness pixel in the first image; generate a second image based on the position of the at least one high-brightness pixel, wherein the resolution of the second image is greater than the resolution of the first image; and identify the pattern of at least one retroreflector in the physical environment based on the second image.

[0007] One of the advantages of the above-mentioned optical recognition device and optical recognition method is that they can remove other sensitive information that may be contained in the photo, thereby achieving the technical effect of de-identification.

[0008] One of the advantages of the above-mentioned optical recognition device and optical recognition method is that they can improve the problem that a two-dimensional barcode cannot be clearly recognized in a shadow. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 Schematic diagram of an optical recognition device according to some embodiments of the present disclosure.

[0010] Figure 2A and Figure 2B FIG. 1 is a schematic diagram of a spatial light modulator according to some embodiments of the present disclosure.

[0011] Figure 3 1 and 2 are front and side views of an image acquisition device according to some embodiments of the present disclosure.

[0012] Figure 4 Schematic diagram of the operation of an image acquisition device according to some embodiments of the present disclosure.

[0013] Figures 5A to 5C Schematic diagram of a retroreflector according to some embodiments of the present disclosure.

[0014] Figure 6 The figure is an operational flow chart of an optical recognition method according to some embodiments of the present disclosure.

[0015] Figures 7A to 7C Based on Figure 6 FIG. 1 is a schematic diagram illustrating the operation of the optical recognition method according to an embodiment of the present invention.

[0016] Description of reference numerals:

[0017] 100: Optical recognition device

[0018] 110: First lens

[0019] 120: Spatial Light Modulator

[0020] 130: Second lens

[0021] 140: Light sensor

[0022] 150: Control device

[0023] 101: Field of View

[0024] 102: Flat Image

[0025] 151: Analog-to-digital converter

[0026] 152: Signal Processor

[0027] 153: Memory

[0028] 154: Reconstruction Unit

[0029] PX: Display pixels

[0030] 200: Area

[0031] 300,300-1,300-2: Image acquisition device

[0032] 310: Lens

[0033] 311: Light Emitting Diode

[0034] 312: Lens

[0035] RF, RF1, RF2, RF3: Retroreflectors

[0036] Freq1, Freq2: frequency

[0037] 600: Optical recognition method

[0038] S601~S603:Process

[0039] 701, 702, 703: Plane images DETAILED DESCRIPTION

[0040] The following is a detailed description of embodiments with accompanying drawings. However, the specific embodiments described are only used to explain the present invention and are not used to limit the present invention. The description of the structural operations is not used to limit the order of their execution. Any structure formed by re-combining the elements to produce a device with equal technical effects is within the scope of the disclosure of the present invention.

[0041] The terms used throughout the specification and claims generally have their ordinary meanings in the art, in the context of this disclosure, and in the specific context, unless otherwise noted. Certain terms used to describe the present disclosure are discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art regarding the description of the present disclosure.

[0042] Figure 1 FIG. 1 is a schematic diagram of an optical recognition device 100 according to some embodiments of the present disclosure. Figure 1 As shown, the optical recognition device 100 includes a first lens 110 , a spatial light modulator 120 , a second lens 130 , a light sensor 140 , and a control device 150 .

[0043] In operation, the optical recognition device 100 can capture a two-dimensional planar image 102 corresponding to the field of view 101 from the physical environment through the first lens 110 and the spatial light modulator 120. Specifically, the first lens 110 can receive a plurality of reflected light rays from the physical environment and transmit the received reflected light rays to the spatial light modulator 120. Under the control of the control device 150, the spatial light modulator 120 can selectively transmit the reflected light rays received by the first lens 110 toward the second lens 130, so that the reflected light rays can be focused by the second lens 130 onto the optical sensor 140. Finally, the control device 150 creates a two-dimensional planar image 102 of the physical environment corresponding to the field of view 101 based on the sensing results of the optical sensor 140.

[0044] In some embodiments, the spatial light modulator 120 may be implemented by a digital micromirror device (DMD), and the optical recognition device 100 may be a single pixel camera.

[0045] Figure 2A and Figure 2B FIG. 1 is a schematic diagram of a spatial light modulator 120 according to some embodiments of the present disclosure. Figure 2A and 2B As shown, the spatial light modulator 120 includes a reflective array composed of a plurality of micromirrors, and the tilt angle of each of the micromirrors can be controlled by the control device 150 so that the reflected light irradiated on the micromirrors propagates to the second lens 130 or does not propagate to the second lens 130.

[0046] Each micromirror corresponds to a display pixel PX of the plane image 102. For ease of explanation, Figure 2A and 2BThe reflective array of the spatial light modulator 120 includes only 16 micromirrors, but this disclosure is not limited to this. For example, the reflective array of the spatial light modulator 120 may include 1024×768 micromirrors. If the control device 150 controls each micromirror of the spatial light modulator 120 to rotate in the direction of the second lens 130, the reflected light impinging on the micromirrors can be detected by the light sensor 140. At this point, all micromirrors in the reflective array can be considered to be in the on state, and all micromirrors can be used to transmit reflected light to the light sensor 140, so that the brightness of the planar image 102 is maximized.

[0047] On the other hand, Figure 2B As shown, the control device 150 can also control some of the micromirrors of the spatial light modulator 120 to rotate in directions other than the direction of the second lens 130, so that the reflected light irradiated on these micromirrors cannot be detected by the light sensor 140. In this case, the micromirrors rotated in the aforementioned other directions can be considered to be in an off state (indicated by the mesh bottom) and will not transmit reflected light to the light sensor 140. In this embodiment, turning on only a portion of the micromirrors is equivalent to capturing only a portion of the field of view 101 (corresponding to the area 200 marked by the dotted box in the planar image 102). By equivalently reducing the captured area, the amount of calculation can be reduced, thereby reducing the difficulty of the control device 150 in reconstructing the planar image 102.

[0048] In summary, the control device 150 can selectively filter the reflected light in a specific area by controlling the tilt angle of the micromirrors of the spatial light modulator 120 (hereinafter referred to as the reflection pattern of the spatial light modulator 120 ).

[0049] Please refer to Figure 1 In some embodiments, the control device 150 includes an analog-to-digital converter 151, a signal processor 152, a memory 153, and a reconstruction unit 154. Structurally, the analog-to-digital converter 151 is electrically connected to the light sensor 140 and the signal processor 152, while the signal processor 152 is electrically connected to the memory 153, the reconstruction unit 154, and the spatial light modulator 120.

[0050] In operation, the analog-to-digital converter 151 samples the light intensity detected by the light sensor 140 and transmits the sampling result to the memory 153 and the reconstruction unit 154 via the signal processor 152. In some embodiments, the signal processor 152 includes an amplification circuit and a filtering circuit for processing the sampling result.

[0051] For example, the control device 150 can control the spatial light modulator 120 to randomly change the reflection pattern M times within one second. When the spatial light modulator 120 presents a first reflection pattern, the light sensor 140 detects the corresponding first light intensity. When the spatial light modulator 120 presents a second reflection pattern, the light sensor 140 detects the corresponding second light intensity, and so on. When the spatial light modulator 120 presents an Mth reflection pattern, the light sensor 140 detects the corresponding Mth light intensity. At this time, the analog-to-digital converter 151 sequentially samples the M light intensities corresponding to the M reflection patterns to generate M sampling results. The M sampling results are processed by the signal processor 152 and stored in the memory 153, or transmitted to the reconstruction unit 154, so that the reconstruction unit 154 generates a corresponding planar image 102 based on the M reflection patterns of the spatial light modulator 120.

[0052] Figure 3 1 and 2 are front and side views of an image acquisition device 300 according to some embodiments of the present disclosure. Figure 3 As shown, the lens 310 of the image acquisition device 300 includes a plurality of light emitting diodes 311 and a lens 312. The light emitting diodes 311 are disposed around the lens 312. In one embodiment, the light emitting diodes 311 are used to illuminate at least one retroreflector in the physical environment with light of a predetermined frequency, such as Figure 4 For convenience of description, this disclosure uses the term "retroreflector RF" to refer to any one of the retroreflectors RF1, RF2, and RF3.

[0053] Generally speaking, the retro-reflector RF has the physical property of reflecting light in the direction of incidence while minimizing scattering. In other words, the intensity of light reflected by the retro-reflector RF is significantly higher than the intensity of other reflected light in the physical environment, making the brightness of the retro-reflector RF in the planar image 102 significantly higher than other objects in the physical environment.

[0054] In some embodiments, the optical recognition device 100 can be disposed inside the image acquisition device 300, so that the lens 312 of the image acquisition device 300 can be Figure 1 The image acquisition device 300 further includes a spatial light modulator 120, a second lens 130, a light sensor 140, and a control device 150. It is worth noting that in order to simplify the drawings, other components of the image acquisition device 300 are not shown. Figure 3 Among.

[0055] Figure 4FIG2 is a schematic diagram of the operation of multiple image acquisition devices 300-1 and 300-2 according to some embodiments of the present disclosure, wherein both the image acquisition devices 300-1 and 300-2 can be implemented by the image acquisition device 300, that is, the image acquisition devices 300-1 and 300-2 can each include an optical recognition device 100. Figure 4 As shown, the viewing angles of image capture devices 300-1 and 300-2 form a field of view 101. The physical environment within field of view 101 includes a plurality of retroreflectors RF1, RF2, and RF3, and image capture devices 300-1 and 300-2 are respectively configured to illuminate retroreflectors RF1, RF2, and RF3 within field of view 101 with light of different frequencies. In some embodiments, the light is generated by light emitting diodes 311 on image capture devices 300-1 and 300-2.

[0056] More specifically, image acquisition device 300-1 illuminates retroreflectors RF1 and RF2 with light 410 having a frequency Freq1, while image acquisition device 300-2 illuminates retroreflectors RF2 and RF3 with light 420 having a frequency Freq2. In other words, retroreflector RF1 generates reflected light with a frequency Freq1, retroreflector RF2 generates reflected light with frequencies Freq1 and Freq2, and retroreflector RF3 generates reflected light with a frequency Freq2. In some embodiments, the center frequency of signal processor 152 of image acquisition device 300-1 is set to the same as frequency Freq1. Through bandpass filtering, image acquisition device 300-1 can receive reflected light with frequency Freq1 from retroreflectors RF1 and RF2 while effectively filtering out reflected light with frequency Freq2 from retroreflector RF2 to reduce interference. Similarly, if the center frequency of the signal processor 152 of the image acquisition device 300-2 is set to be the same as the frequency Freq2, through bandpass filtering, the image acquisition device 300-2 can receive the reflected light with frequency Freq2 from the retroreflectors RF2 and RF3, and effectively filter out the reflected light with frequency Freq1 from the retroreflector RF2 to reduce interference.

[0057] In some embodiments, the retro-reflectors RF, RF1, RF2, and RF3 include two-dimensional barcodes (QR codes) printed on special materials.

[0058] Figures 5A to 5C FIG. 1 is a schematic diagram of a retroreflector RF according to some embodiments of the present disclosure. Figure 5AAs shown, the pattern of the two-dimensional barcode of the retro-reflector RF can be designed to include a high-grayscale (e.g., white) rectangular frame, a low-grayscale (e.g., black) rectangular frame, and a plurality of rectangular areas. These rectangular areas are surrounded by low-grayscale rectangular frames, which are in turn surrounded by high-grayscale rectangular frames. These rectangular areas can be high-grayscale, low-grayscale, or partially high-grayscale and partially low-grayscale.

[0059] In some embodiments, the two-dimensional barcode of the retro-reflector RF includes a position detection pattern or an alignment pattern. Therefore, the two-dimensional barcode of the retro-reflector RF can still be identified as the same two-dimensional barcode under different observation angles (for example, rotated 90 degrees, 180 degrees, and 270 degrees). For example, Figure 5B and Figure 5C As shown, Figure 5B The two-dimensional bar code and Figure 5C The two-dimensional barcodes can be regarded as the same two-dimensional barcode, so that the image acquisition device 300 can Figure 5B and Figure 5C The two-dimensional bar code determines the position information of the retro-reflector RF.

[0060] Figure 6 FIG. 6 is a flowchart illustrating an optical recognition method 600 according to some embodiments of the present disclosure. Figures 7A to 7C Based on Figure 6 The operation diagram of the optical recognition method 600 shown in the embodiment of FIG. Figure 7A 、 Figure 7B 、 Figure 7C To illustrate Figure 6 's operating procedures, but is not limited thereto.

[0061] In process S601 , the optical recognition device 100 is used to obtain a corresponding image 701 from the physical environment. For example, under the control of the control device 150 , the first lens 110 and the spatial light modulator 120 capture the physical environment within the entire field of view 101 to generate the image 701 .

[0062] In some embodiments, image 701 may be Figure 1 A two-dimensional plane image 102 is created by the optical recognition device 100.

[0063] In process S602, the optical recognition device 100 is used to recognize at least one high-brightness pixel in the image 701, and the spatial light modulator 120 is controlled to generate an image 702 according to the position of the high-brightness pixel in the image 701, and the resolution of the image 702 is greater than the resolution of the image 701. For example, the image 701 includes high-brightness pixels corresponding to three different retroreflectors RF1, RF2, and RF3. At this time, in order to recognize the two-dimensional barcode of the retroreflector RF3, the optical recognition device 100 can increase the resolution and control the spatial light modulator 120 to only turn on the micromirrors around the high-brightness pixels corresponding to the retroreflector RF3, so as to only capture the retroreflector RF3 and its surrounding area to generate the following image: Figure 7B Planar image 702 is shown.

[0064] In some embodiments, increasing the resolution may reduce the signal-to-noise ratio of the light sensor 140. In this case, the control device 150 can control the spatial light modulator 120 to reduce the frequency of switching the reflective patterns to extend the exposure time of each reflective pattern, thereby compensating for (improving) the signal-to-noise ratio of the light sensor 140.

[0065] In process S603, the optical recognition device 100 may recognize a pattern on at least one retroreflector in the physical environment based on the image 702. For example, the optical recognition device 100 may recognize multiple rectangular frames and multiple rectangular areas on the retroreflector RF3 based on the planar image 702 to identify a two-dimensional barcode on the retroreflector RF3.

[0066] In some embodiments, the optical recognition device 100 may first generate an image 703 with a better signal-to-noise ratio based on the positions of the multiple rectangular frames and multiple rectangular areas in the image 702. The optical recognition device 100 may then identify the two-dimensional barcode of the retro-reflector RF3 based on the brightness (grayscale) of each of the multiple rectangular areas in the image 703.

[0067] In summary, the optical recognition device 100 can first perform a panoramic image with a short exposure time at low resolution in process S601 to quickly identify the high-brightness pixel areas of the planar image 701. Then, in process S602, a local image with a long exposure time at high resolution is performed to clearly identify the 2D barcode on the retro-reflector RF in process S603. By increasing the resolution but reducing the imaging area, the difficulty of image reconstruction can be reduced while still clearly identifying the 2D barcode on the retro-reflector RF.

[0068] Although the present disclosure has been disclosed in the form of an embodiment as described above, it is not intended to limit the present disclosure. Anyone with ordinary knowledge in the art can make various changes and modifications without departing from the concept and scope of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on what is defined in the claims.

Claims

1. An image acquisition device, comprising: A lens, comprising a first lens, configured to receive a plurality of reflected light rays from a physical environment, wherein the physical environment comprises at least one retroreflector; a spatial light modulator for receiving the plurality of reflected light rays from the first lens and selectively transmitting the plurality of reflected light rays to a second lens; a light sensor for receiving the plurality of reflected light rays from the second lens to generate a sensing result; as well as A control device is coupled to the spatial light modulator and the light sensor and is used to: generating a first image corresponding to the physical environment according to the sensing result; Identifying at least one high-brightness pixel in the first image; controlling the spatial light modulator to generate a second image according to the position of the at least one high-brightness pixel, wherein the resolution of the second image is greater than the resolution of the first image; and A pattern of the at least one retro-reflector is identified based on the second image.

2. The image acquisition device as claimed in claim 1, wherein the lens further comprises: A plurality of light emitting diodes are used to illuminate the physical environment with light of a preset frequency so that the physical environment generates the plurality of reflected light rays.

3. The image acquisition device as claimed in claim 2, wherein the spatial light modulator comprises: a plurality of reflective micromirrors; When the control device controls the spatial light modulator to generate the second image according to the position of the at least one high-brightness pixel, the control device reduces the frequency of the spatial light modulator switching the tilt angles of the plurality of reflective micromirrors.

4. The image acquisition device of claim 1 , wherein when the control device recognizes the pattern of the at least one retro-reflector based on the second image, the control device is configured to execute: identifying a plurality of rectangular regions in the pattern; and A two-dimensional barcode in the pattern is identified according to the grayscale of each of the plurality of rectangular areas.

5. An optical recognition method, applicable to an optical recognition device, wherein the optical recognition device includes a control device, a spatial light modulator, and a light sensor, and the optical recognition method comprises: Using the optical recognition device to acquire a corresponding first image from a physical environment; Identifying at least one high-brightness pixel in the first image; controlling the spatial light modulator to generate a second image according to the position of the at least one high-brightness pixel, wherein the resolution of the second image is greater than the resolution of the first image; and A pattern of at least one retro-reflector in the physical environment is identified based on the second image.

6. The optical recognition method according to claim 5, wherein the optical recognition device acquires the corresponding first image from the physical environment comprising: receiving a plurality of reflected light rays from the physical environment, wherein the plurality of reflected light rays are generated by a plurality of light emitting diodes irradiating the physical environment with light rays of a predetermined frequency; using a first lens to transmit the plurality of reflected light rays to the spatial light modulator; and The spatial light modulator is utilized to selectively transmit the plurality of reflected lights to the light sensor.

7. The optical recognition method of claim 6 , wherein the spatial light modulator comprises a plurality of reflective micromirrors, and controlling the spatial light modulator to generate the second image according to the position of the at least one high-brightness pixel comprises: The frequency of switching the tilt angles of the plurality of reflective micromirrors by the spatial light modulator is reduced.

8. The optical recognition method of claim 5 , wherein recognizing the pattern of the at least one retro-reflector in the physical environment based on the second image comprises: identifying a plurality of rectangular regions in the pattern; and A two-dimensional barcode in the pattern is identified according to the grayscales of the plurality of rectangular areas.

9. An optical recognition system located in a physical environment, comprising: a first image capturing device for generating a first light with a first frequency; and a second image capturing device for generating a second light having a second frequency, wherein the first frequency is different from the second frequency; When the physical environment generates at least one reflected light, the first image capturing device and the second image capturing device are respectively configured to perform the following operations based on a portion of the at least one reflected light corresponding to the first light and a portion of the at least one reflected light corresponding to the second light: generating a first image corresponding to the physical environment; Identifying at least one high-brightness pixel in the first image; generating a second image according to the position of the at least one high-brightness pixel, wherein the resolution of the second image is greater than the resolution of the first image; and A pattern of at least one retro-reflector in the physical environment is identified based on the second image.

10. The optical recognition system according to claim 9, wherein: A center frequency of a signal processor of the first image acquisition device is the same as the first frequency to filter out the portion of the at least one reflected light corresponding to the first light, and a center frequency of a signal processor of the second image acquisition device is the same as the second frequency to filter out the portion of the at least one reflected light corresponding to the second light.

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