A dual-lens two-dimensional code reading system based on a trilobal phase mask

Abstract

The application relates to the technical field of image processing, in particular to a double-lens two-dimensional code reading system based on a three-leaf phase mask, which comprises a first imaging module and a second imaging module; a composite three-leaf phase mask is located in front of the second imaging module to perform wavefront coding modulation on light rays entering the second imaging module; and an image processing module identifies a first target image or identifies a second target image after decoding. In view of the problem that the two-dimensional code imaging recognition system in the prior art has a slow recognition speed, a double-lens imaging system with different working ranges is introduced, and a composite three-leaf phase mask is introduced to perform wavefront modulation, so that the working range of the second imaging module is expanded, the working range of the system is effectively expanded without introducing a further mechanical zoom structure, full-range high-precision imaging from a near distance of 300 mm to a far distance of 2.4 m is realized, and the complex and changeable two-dimensional code reading requirements in the industrial automation field can be met.

Description

Technical Field

[0001] This invention relates to the field of image processing technology, and specifically to a dual-lens QR code reading system based on a trilobal phase mask. Background Technology

[0002] QR code recognition technology, as one of the core technologies in the field of automatic identification and data acquisition, has been widely applied in many fields such as industrial automation, smart logistics, smart manufacturing, retail settlement, and public safety. Its principle typically involves using an image sensor to capture images of areas marked with QR codes, performing binarization processing on the images, extracting the corresponding positioning markers and encoding areas, and then decoding to obtain the corresponding information. In practical applications, QR codes may appear at different distances. For example, on an assembly line, the QR code on a workpiece may move continuously from near (e.g., 300 mm) to far (e.g., 2.4 meters); in a warehouse environment, operators need to read barcodes at different heights and distances on shelves. Therefore, barcode reading devices must have the ability to cover a wide working distance range to cope with complex and ever-changing reading needs.

[0003] For example, patent application CN202010266805.6 discloses a QR code recognition method, device, electronic device, and storage medium. The QR code recognition method includes: acquiring an image to be recognized, the image containing a QR code; when the number of location detection markers for the QR code in the image to be recognized is a first number, increasing the number of location detection markers from the first number to a second number; controlling a camera to perform zoom processing based on the location detection markers to obtain an intermediate image; and performing QR code recognition on the intermediate image to obtain the QR code recognition result. The provided QR code recognition method, device, electronic device, and storage medium solve the problem of low success rate of QR code recognition in long-distance environments in the prior art.

[0004] However, in actual implementation, the inventors found that such technical solutions are usually limited by the optical characteristics of the lens itself. Without a mechanical focusing structure, the depth of field range can usually only be maintained in a relatively narrow range, making it difficult to achieve good recognition accuracy. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, a dual-lens QR code reading system based on a trilobal phase mask is provided.

[0006] The specific technical solution is as follows: A dual-lens QR code reading system based on a trilobal phase mask includes: A first imaging module is used to acquire an image of a first target within a first working range; The second imaging module is used to acquire the image of the second target within the second working range; A composite trefoil phase mask is located in front of the second imaging module to perform wavefront coding modulation on the light incident on the second imaging module. An image processing module, which is connected to the first imaging module and the second imaging module respectively; The image processing module either identifies the first target image or identifies the second target image after decoding.

[0007] On the other hand, the image processing module includes: A ranging module, which determines the actual distance of the target object relative to the first imaging module and the second imaging module; The selection module is connected to the ranging module; The selection module selects either the first target image or the second target image as the recognition image based on the actual distance and the pre-calibrated depth range. The identification module is connected to the selection module; The recognition module recognizes the image, obtains the recognition result, and outputs it. When the second target image is used as the recognition image, the recognition module first decodes it and then performs recognition.

[0008] On the other hand, the dual-lens QR code reading system also includes an infrared ranging device; The ranging module is connected to the infrared ranging device and determines the actual distance based on the measurement results of the infrared ranging device.

[0009] On the other hand, the infrared ranging device acquires and generates infrared depth images; The ranging module estimates the position of the first target image to generate a target mask, and then segments the infrared depth image based on the target mask to determine the actual distance.

[0010] On the other hand, the total phase distribution of the composite lobed phase mask includes a lobed phase main encoding term and an auxiliary compensation term; The combined phase distribution of the trefoil-shaped phase main encoding term and the auxiliary compensation term includes:

[0011] In the formula, Normalized polar coordinates for the pupil The main coding intensity is the trilobal phase. The direction angle of the main coding item. This is an auxiliary compensation coefficient.

[0012] On the other hand, the integrated phase distribution is applied to an aspherical substrate; The aspherical substrate is used to provide basic optical power and aberration correction.

[0013] On the other hand, the selection module includes: An actual distance acquisition module acquires the actual distance and adds it to the distance sequence; Hysteresis detection module, which is connected to the actual distance acquisition module; The hysteresis judgment module determines whether the actual distance changes within the boundary interval based on the distance sequence and generates a boundary judgment result. A first determining module, which is connected to the hysteresis determination module; When the boundary judgment result is negative, the first determining module selects either the first target image or the second target image as the recognition image according to the depth range. The second determining module is connected to the hysteresis judgment module; When the boundary judgment result is yes, the second determining module determines the closest working interval according to the distance sequence, and then selects the first target image or the second target image as the recognition image based on the closest working interval.

[0014] On the other hand, the recognition module decodes the second target image according to the frequency domain Wiener filtering method.

[0015] On the other hand, the first working range is between 300mm and 1m, and the second working range is between 1m and 2.4m.

[0016] The above technical solution has the following advantages or beneficial effects: To address the issue of slow recognition speed in existing QR code imaging and recognition systems, a dual-lens imaging system with different working ranges is introduced. By incorporating a composite trilobal phase mask for wavefront modulation, the working range of the second imaging module is expanded. This effectively extends the system's working range without introducing further mechanical zoom structures, achieving high-precision imaging across the entire range from a close distance of 300mm to a distant distance of 2.4m, thus meeting the complex and varied QR code reading needs in the field of industrial automation. Attached Figure Description

[0017] Embodiments of the invention will be described more fully with reference to the accompanying drawings. However, the drawings are for illustration and explanation only and do not constitute a limitation on the scope of the invention.

[0018] Figure 1 This is an overall schematic diagram of an embodiment of the present invention; Figure 2 This is a schematic diagram of the image processing module in an embodiment of the present invention; Figure 3 This is a schematic diagram of the decoded image in an embodiment of the present invention; Figure 4 This is a schematic diagram of the infrared ranging device in an embodiment of the present invention; Figure 5 This is a schematic diagram of the selected module in an embodiment of the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0021] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0022] This invention includes: A dual-lens QR code reading system based on a trilobal phase mask, such as Figure 1 As shown, it includes: First imaging module 1, the first imaging module 1 is used to acquire the first target image within the first working range; The second imaging module 2 is used to acquire images of the second target within the second working range; A composite trilobal phase mask 3 is located in front of the second imaging module to perform wavefront coding modulation on the light incident on the second imaging module. Image processing module 4 is connected to the first imaging module 1 and the second imaging module 2 respectively; Image processing module 4 identifies the first target image or identifies the second target image after decoding.

[0023] Specifically, to address the issue of slow recognition speed in existing QR code imaging and recognition systems, a dual-lens imaging system with different working ranges is introduced. By introducing a composite trilobal phase mask for wavefront modulation, the working range of the second imaging module is expanded. Without introducing further mechanical zoom structures, the system's working range is effectively extended, achieving high-precision imaging across the entire range from a close distance of 300mm to a far distance of 2.4m, which can meet the complex and ever-changing QR code reading needs in the field of industrial automation.

[0024] In actual implementation, the aforementioned dual-lens QR code reading system is manifested as a QR code reading system configured with specific computer programs.

[0025] The first imaging module 1 is a combination of a first optical lens and an image sensor corresponding to the first working range, and the second imaging module 2 is a combination of a second optical lens and an image sensor corresponding to the second working range.

[0026] The composite trilobal phase mask 3 is located in front of the second imaging module to perform wavefront-coded modulation on the light incident on the second imaging module. The composite trilobal phase mask 3 is a wavefront modulation element loaded with a composite trilobal phase-coded image. In actual optical path design, it is loaded in the optical path of the second optical lens or in front of the front lens, mainly located in front of the aperture of the second optical lens.

[0027] The wavefront modulation element is mainly an aspherical optical element. As needed, an aspherical surface can be added to the composite trilobal phase-coded image to provide basic focusing function and aberration correction, as well as auxiliary correction terms to eliminate residual aberrations or dispersion.

[0028] The image processing module 4 is a computer device, such as an embedded processing device, which is connected to the first imaging module 1 and the second imaging module 2 via cables, including power cables and signal cables. The image processing module 4 has a corresponding storage medium storing corresponding computer instructions, enabling it to control the first imaging module 1 to acquire a first target image and the second imaging module 2 to acquire a second target image when executing these instructions, and to perform recognition on the first target image or decode and recognize the second target image. In one embodiment, this image processing module is implemented based on a computing device using an ARM platform.

[0029] In actual data collection, taking an industrial barcode scanning scenario as an example, QR code labels are placed on corresponding goods or workpieces. Since the volume of the goods is inherently uncertain, the QR code labels may be located at different distances. In this case, a longer collection range can be achieved by pre-determining the working range of the first and second optical lenses and collecting data simultaneously.

[0030] For example, taking a first optical lens for close-range acquisition and a second optical lens for long-range acquisition as an example, the focal length of the first optical lens can be selected between 8mm and 12mm, such as 10mm, and is designed to cover a close-range working range of 300mm to 1m as the first working range. This lens has a large field of view, which is suitable for reading large QR codes at close range or reading multiple QR codes simultaneously.

[0031] The focal length of the second optical lens can be selected between 20mm and 30mm, such as 25mm. Considering the issue of shallower depth of field with longer focal lengths, a composite trilobal phase mask 3 is added in conjunction with the decoding program in the image processing module 4 to achieve a secondary working range of 1m to 2.4m. This lens has a high magnification, ensuring the ability to resolve small QR code modules at long distances.

[0032] The image sensor uses a high-resolution CMOS or CCD sensor. In this embodiment, it is an 8-megapixel CMOS sensor with a pixel size of 2.0μm.

[0033] When the target object enters the area, the image processing module 4 controls the first imaging module 1 to acquire the first target image and controls the second imaging module 2 to acquire the second target image. Then, the actual distance of the target object is estimated to determine which lens's working range the target object is in. Subsequently, the first target image is selected for recognition or the second target image is decoded and then recognized to obtain the scanning result.

[0034] When the system operates in long-range mode, image processing module 4 uses a deconvolution algorithm to digitally decode and restore the acquired trefoil-coded image, obtaining a clear image for QR code recognition. For images acquired in short-range mode, recognition is performed directly. Image processing module 4 performs QR code localization, binarization, error correction, and recognition on the clear image, ultimately outputting the reading result.

[0035] To achieve the aforementioned extended working range effect, in this embodiment, the total phase distribution of the composite lobed phase mask includes at least a lobed phase main encoding term and an auxiliary compensation term; The combined phase distribution of the trefoil-shaped phase main coding term and auxiliary compensation term includes:

[0036] In the formula, Normalized polar coordinates for the pupil The main coding intensity is the trilobal phase. The direction angle of the main coding item. This is an auxiliary compensation coefficient.

[0037] Specifically, in order to load the trefoil phase coding pattern, this embodiment adds a composite trefoil phase mask containing the trefoil phase main coding term and auxiliary compensation term.

[0038] Among them, the trefoil phase main encoding term is used to form a stable and decodeable trefoil point spread function, and the auxiliary compensation term is used to adjust the energy distribution of the point spread function, compensate for the residual aberration of the second optical lens, or improve the stability of subsequent decoding and restoration.

[0039] In rectangular coordinate form, the trefoil-shaped phase master coding term can be equivalently represented as: Alternatively, a Zernike third-order ±3rd-order trefoil phase term equivalent to its rotation; auxiliary compensation terms can be radial fourth-order terms, fourth-order spherical aberration compensation terms, or corresponding terms in the extended polynomial. The above phase terms can be synthesized into a single continuous freeform surface, rather than necessarily using multiple discrete phase plates.

[0040] parameter and The optimal parameters can be determined through optical design software. During optimization, the stability of the dot spread function of the second optical lens within a working distance range of 1m to 2.4m, the recoverability of the QR code module edges, and the success rate of reading after recovery are used as evaluation indicators, while also considering the ability to preserve high-frequency information and processing feasibility. Typically, a trilobal phase main coding term is used as the primary modulation term, with auxiliary compensation terms used as weak compensation terms to avoid excessively strong compensation terms leading to overly complex dot spread functions or instability in subsequent deconvolution.

[0041] In one embodiment, the composite phase distribution is applied onto an aspherical substrate; Aspherical substrates are used to provide basic optical power and aberration correction.

[0042] Specifically, in actual production, the aforementioned comprehensive phase distribution can also be applied to an aspherical substrate, resulting in the actual total phase distribution. It consists of three terms: aspherical base phase, trefoil phase main coding term, and auxiliary compensation term.

[0043] The surface shape of the phase modulation surface is described using the extended polynomial or freeform surface form commonly used in optical design. The total phase distribution is... At that time, the corresponding physical vector height can be calculated based on the material's refractive index, approximately satisfying the following condition. , in λ represents the refractive index of the substrate material at wavelength λ. A monolithic composite trilobal phase mask can be formed by superimposing a trilobal main phase encoding term and an auxiliary compensation term within the same surface profile.

[0044] The phase modulation effect of this surface shape on the incident light wave originates from the optical path difference: as the light passes through different coordinate positions, the corresponding phase delay occurs due to local thickness differences. This causes the point spread function of the optical system to exhibit a stable, predictable, and trefoil-shaped coding pattern when defocused, rather than the rapid diffusion of traditional systems. The substrate material is selected from low-birefringence optical glass suitable for precision molding, which has the characteristics of good refractive index uniformity, high thermal stability, and strong weather resistance, and can meet the long-term reliability requirements of harsh environments such as automotive and security applications.

[0045] In actual production, to improve production efficiency, a precision glass molding process can be used. In the mold manufacturing stage, a mold surface complementary to the target surface is directly machined on an ultra-precision machine tool using single-point diamond turning. After turning, the surface roughness reaches the nanometer level, and the surface residual is controlled within the process requirements. A wear-resistant layer is deposited on the mold surface to extend its service life. In the molding stage, the glass preform is heated above its softening point under nitrogen protection, and then the mold is closed and held under appropriate pressure to ensure that the glass material fully replicates the mold surface structure. It is then slowly annealed and cooled to release internal stress. The molded phase modulation element is coated with a broadband antireflection film on both sides to ensure high transmittance over a wide spectral range.

[0046] Surface profile inspection employs a non-contact coordinate measuring machine (CMM) to perform grid scanning on the full-aperture surface profile. The measured profile is then compared with the design value, requiring that the full-aperture surface profile residual and surface roughness be controlled within the design tolerance range. During integrated assembly, since the phase modulation surface and lens substrate are integrally formed, no additional alignment process is required, effectively avoiding the eccentricity error caused by the assembly of discrete components and ensuring the coincidence of the phase modulation center with the optical axis. This integrated manufacturing strategy, while reducing the overall system length and mass production costs, provides a stable and consistent wavefront encoding foundation for the optical system.

[0047] In one embodiment, such as Figure 2 As shown, the image processing module 4 includes: The ranging module 41 determines the actual distance of the target object relative to the first imaging module and the second imaging module. Select module 42, and connect module 42 to distance measuring module 41; The selection module selects either the first target image or the second target image as the recognition image based on the actual distance and the pre-calibrated depth range. Identification module 43, identification module 43 is connected to selection module 42; The recognition module 43 recognizes the image, obtains the recognition result, and outputs it. When the second target image is used as the recognition image, the recognition module first decodes it and then performs recognition.

[0048] Specifically, in order to achieve a more accurate recognition effect, in this embodiment, a ranging module 41 and a selection module 42 are introduced into the software of the image processing module 4.

[0049] The ranging module 41 determines the actual distance of the target object relative to the first imaging module and the second imaging module by connecting to an external sensor or by performing visual estimation. Subsequently, the selection module 42 selects either the first target image or the second target image as the recognition image for subsequent identification based on the actual distance and a pre-calibrated depth range, and assigns a source marker to the recognition image. The source marker is used by the recognition module 43 to determine whether decoding is required before recognition.

[0050] The identification module 43 pre-stores a point spread function corresponding to the composite trilobal phase mask. This point spread function can be obtained through theoretical calculation, optical simulation, or actual calibration. A decoding and restoration algorithm is constructed based on this point spread function, which can be based on frequency domain or spatial domain features.

[0051] In a typical embodiment, frequency-domain Wiener filtering is used for decoding. Frequency-domain Wiener filtering is a linear estimation method for the original image under the minimum mean square error criterion. Let the frequency domain representation of the acquired trefoil-shaped coded image be... The composite trilobal phase mask encoding PSF is Its Fourier transform, i.e., optical transfer function, is Then, the Wiener filter formula in its practical form can be used for restoration: , in for The complex conjugate, is the regularization constant.

[0052] In practical engineering, the value of K can be determined based on the system signal-to-noise ratio, sensor noise level, or experimental calibration results. Since the composite trefoil phase mask provides a relatively stable trefoil-coded feature for the point spread function over a long range, the image processing unit can use the corresponding composite coded PSF for decoding and restoration. To reduce computational load and improve reading speed, the image processing unit can also first obtain the QR code ROI region through QR code positioning graphics or candidate region detection, perform trefoil phase mask coded PSF decoding and restoration only on this ROI region, and then perform QR code recognition.

[0053] The above algorithm corresponds to the optical encoding characteristics described in this application: the optical end provides a stable encoding PSF with trilobal features through a composite trilobal phase mask, and the algorithm performs digital decoding and restoration based on this PSF, forming a complete "composite trilobal phase mask optical encoding-digital decoding" QR code reading scheme. This effectively solves the problem of inconsistent image quality at different object distances with traditional lenses. In traditional lens imaging, when the lens is focused at 1000mm, the QR code image at an object distance of 1000mm is the clearest; however, when the object distance deviates to 500mm or 2000mm, due to depth-of-field limitations, the image gradually becomes blurry, making it difficult to maintain stable and clear image quality across the entire distance range.

[0054] In contrast, by employing a composite trilobal phase mask, a composite trilobal phase mask is introduced into the optical path of the second optical lens to encode and modulate the incident light wave. For example... Figure 3 As shown in the "Encoded Image," regardless of the object distance of 500mm, 1000mm, or 2000mm, the blurred image obtained by the system exhibits an approximately stable trilobal coding feature, meaning the point spread function is insensitive to defocusing and maintains recoverability. Subsequently, the image processing unit decodes and restores the encoded image based on a preset composite trilobal phase mask coded point spread function, thus recovering a clear QR code image, as shown below. Figure 3 The image is shown in the "Decoded Image" section.

[0055] Therefore, the composite trilobal phase mask wavefront coding technology enables a fixed-focus telephoto lens to obtain coded images that can be decoded and restored within a full range of distances from 1m to 2.4m. Combined with digital image restoration algorithms, clear imaging is achieved, thus enabling seamless and efficient reading from close to far distances without any mechanical focusing.

[0056] The following methods can be used to select the appropriate lens during the measurement process.

[0057] In one embodiment, such as Figure 4 As shown, the dual-lens QR code reading system also includes an infrared ranging device 41A; The ranging module 41 is connected to the infrared ranging device 41A, and determines the actual distance based on the measurement results of the infrared ranging device 41A.

[0058] Specifically, in this embodiment, the ranging module 41 uses an external infrared ranging device 41A to measure distance. The infrared ranging device 41A is arranged in parallel with the first imaging module 1 and the second imaging module 2 and has the same direction. It emits infrared rays to the target object and directly measures the distance based on the time-of-flight method to obtain the measurement reading as the actual distance.

[0059] In another embodiment, the infrared ranging device 41A acquires and generates an infrared depth image; The ranging module 41 estimates the position of the first target image to generate a target mask, and then segments the infrared depth image based on the target mask to determine the actual distance.

[0060] Specifically, for some smaller products / workpieces, where the data acquisition may not be directly aligned with the infrared beam, depth maps can be used for estimation.

[0061] Specifically, in this embodiment, the infrared ranging device 41A is mainly based on a monocular or binocular infrared camera. It is used to capture infrared images and perform visual estimation based on a pre-calibrated intrinsic parameter matrix to convert them into corresponding depth maps. At the same time, the ranging module 41 performs position estimation on the first target image to generate a target mask. Then, based on a pre-calibrated extrinsic parameter matrix, the target mask is transferred to the infrared depth image. The corresponding depth measurement value in the infrared depth image is selected according to the mask segmentation range, and the actual distance is obtained by means of average statistics.

[0062] In another embodiment, the ranging module 41 directly relies on the first target image and the second target image to perform asymmetric binocular estimation to obtain the actual distance.

[0063] Specifically, corresponding intrinsic and extrinsic parameters are pre-calibrated for the first imaging module 1 and the second imaging module 2. When acquiring the first and second target images, although the images located outside the working distance or not yet decoded have lower clarity, making it difficult to accurately identify the encoded regions in the QR code, they can still be used to detect target objects in the images. Here, the OpenCV algorithm is used to coarsely extract the target to form bounding boxes. Based on the center of the bounding boxes and the pre-calibrated extrinsic parameters, the bounding boxes in the second target image are transferred to the first target image. Subsequently, asymmetric binocular estimation is performed on the target objects corresponding to the bounding boxes using the intrinsic parameter matrix to obtain the actual distance.

[0064] In one embodiment, such as Figure 5 As shown, the selection module 42 includes: Actual distance acquisition module 421 acquires the actual distance and adds it to the distance sequence; Hysteresis detection module 422, which is connected to actual distance acquisition module 421; Hysteresis detection module 422 determines whether the actual distance changes within the boundary interval based on the distance sequence and generates a boundary detection result; First determination module 423, first determination module 423 is connected to hysteresis judgment module 422; When the boundary judgment result is negative, the first determining module 423 selects either the first target image or the second target image as the recognition image according to the depth range; The second determination module 424 is connected to the hysteresis judgment module 423; When the boundary judgment result is yes, the second determining module 424 determines the closest working interval according to the distance sequence, and then selects the first target image or the second target image as the recognition image based on the closest working interval.

[0065] Specifically, to achieve better recognition results, a hysteresis judgment mechanism is introduced in the selection module 42 in this embodiment. Specifically, during the actual acquisition process, the first acquisition module 1 and the second acquisition module 2 are controlled to continuously acquire aligned video streams, and the actual distance is acquired using the same timestamp alignment method.

[0066] The distance sequence is maintained based on the continuously collected actual distances, and the hysteresis judgment module 422 determines whether the actual distance changes within the boundary interval based on the distance sequence and generates the boundary judgment result.

[0067] The judgment process includes extracting the corresponding distance window value from the end of the distance sequence through a preset window length, determining whether the target position is moving through standard deviation statistics, and if so, further judging whether the actual distance falls exactly in the boundary interval between the pre-calibrated first working range and the second working range.

[0068] Subsequently, based on the judgment result, identification is performed using either the first determination module or the second determination module. When the boundary judgment result is negative, the first target image or the second target image is directly selected as the identification image according to the depth range. If the result is positive, the closest working interval is determined statistically according to the distance sequence, and then the first target image or the second target image is selected as the identification image based on the closest working interval. Alternatively, the first target image and the second target image are identified simultaneously, and the identification result with the higher confidence level is output.

[0069] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present invention should be included within the protection scope of the present invention.

Claims

1. A dual-lens QR code reading system based on a trilobal phase mask, characterized in that, include: A first imaging module is used to acquire an image of a first target within a first working range; The second imaging module is used to acquire the image of the second target within the second working range; A composite trefoil phase mask is located in front of the second imaging module to perform wavefront coding modulation on the light incident on the second imaging module. An image processing module, which is connected to the first imaging module and the second imaging module respectively; The image processing module either identifies the first target image or identifies the second target image after decoding.

2. The dual-lens QR code reading system according to claim 1, characterized in that, The image processing module includes: A ranging module, which determines the actual distance of the target object relative to the first imaging module and the second imaging module; The selection module is connected to the ranging module; The selection module selects either the first target image or the second target image as the recognition image based on the actual distance and the pre-calibrated depth range. The identification module is connected to the selection module; The recognition module recognizes the image, obtains the recognition result, and outputs it. When the second target image is used as the recognition image, the recognition module first decodes it and then performs recognition.

3. The dual-lens QR code reading system according to claim 2, characterized in that, The dual-lens QR code reading system also includes an infrared ranging device; The ranging module is connected to the infrared ranging device and determines the actual distance based on the measurement results of the infrared ranging device.

4. The dual-lens QR code reading system according to claim 3, characterized in that, The infrared ranging device acquires and generates infrared depth images; The ranging module estimates the position of the first target image to generate a target mask, and then segments the infrared depth image based on the target mask to determine the actual distance.

5. The dual-lens QR code reading system according to claim 1, characterized in that, The total phase distribution of the composite lobed phase mask includes a lobed phase main encoding term and an auxiliary compensation term; The combined phase distribution of the trefoil-shaped phase main encoding term and the auxiliary compensation term includes: ； In the formula, Normalized polar coordinates for the pupil The main coding intensity of the trilobal phase is... The direction angle of the main coding item. This is an auxiliary compensation coefficient.

6. The dual-lens QR code reading system according to claim 5, characterized in that, The composite phase distribution is applied onto an aspherical substrate; The aspherical substrate is used to provide basic optical power and aberration correction.

7. The dual-lens QR code reading system according to claim 2, characterized in that, The selection module includes: An actual distance acquisition module acquires the actual distance and adds it to the distance sequence; Hysteresis detection module, which is connected to the actual distance acquisition module; The hysteresis judgment module determines whether the actual distance changes within the boundary interval based on the distance sequence and generates a boundary judgment result. A first determining module, which is connected to the hysteresis determination module; When the boundary judgment result is negative, the first determining module selects either the first target image or the second target image as the recognition image according to the depth range. The second determining module is connected to the hysteresis judgment module; When the boundary judgment result is yes, the second determining module determines the closest working interval according to the distance sequence, and then selects the first target image or the second target image as the recognition image based on the closest working interval.

8. The dual-lens QR code reading system according to claim 2, characterized in that, The recognition module decodes the second target image using the frequency domain Wiener filtering method.

9. The dual-lens QR code reading system according to claim 1, characterized in that, The first working range is between 300mm and 1m, and the second working range is between 1m and 2.4m.

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