Non-uniformly corrected rectangular camera and its electronic rearview mirror system cms

Abstract

The application discloses a non-uniformly corrected rectangular camera and an electronic rearview mirror system CMS thereof. The non-uniformly corrected rectangular camera comprises a first lens, a second lens and a third lens arranged in sequence from an object side to an image side; wherein the first lens is a convex-concave lens composite lens, a convex part surface of the first lens close to the object side is a free surface, and the surface is centered on a convex lens axial direction, different surface shapes are set at different positions of the free surface according to ISO_FDIS_16505-Calculation of Magnification Factor data, and a first lens surface has a non-uniform magnification factor. The application solves the distortion problem from the lens segment, so that the pixel information is all reserved.

Description

Technical Field

[0001] This invention relates to the field of optics and lenses, and more specifically to a non-uniformly corrected rectangular camera and its electronic rearview mirror system (CMS). Background Technology

[0002] Typically, the optical lenses in a camera system are circular lenses, composed of both convex and concave lenses. However, a problem exists: a single lens cannot achieve different magnifications or multiple focal lengths on its surface. Meanwhile, many chips and devices are integrated into a single system to achieve high-speed computing and data processing capabilities. Field-programmable gate arrays (FPGAs) can load different external configuration files to implement different functions, offering extremely high flexibility. Information acquired from an external CMOS image sensor is transmitted and processed by the SoC FPGA's processing module.

[0003] Currently, most distortion correction methods involve inputting the image into a CDC (Distortion Center for Diagnostics) and then using software algorithms to select, enlarge, or reduce pixels at different locations within the image. This inevitably leads to some loss of image information. This invention solves the distortion problem at the lens level, ensuring that all pixel information is preserved. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention designs a convex-concave composite lens capable of achieving multiple magnifications, thereby enabling preliminary correction of the image entering the lens and achieving the lowest possible distortion rate. Furthermore, compared to ordinary circular lenses, this invention uses a rectangular lens, which better fits the rear CDC (Central Damping Device).

[0005] The objective of this invention is achieved by at least one of the following technical solutions.

[0006] A non-uniformly corrected rectangular camera includes a first lens, a second lens, and a third lens arranged sequentially from the object side to the image side;

[0007] Among them, the first lens is a convex-concave lens composite lens. The convex part of the first lens near the object side is a freeform surface. With the convex lens axis as the center, its surface can be set with different surface shapes at different positions according to ISO_FDIS_16505-Calculation of Magnification Factor data, so that the surface of the first lens has uneven magnification.

[0008] The second lens is a double-convex lens;

[0009] The third lens is a convex-concave lens compound lens, consisting of a base and a biconvex lens.

[0010] Furthermore, the first, second, and third lenses are all rectangular lenses, which fit the rear CDC better than ordinary circular lenses.

[0011] Furthermore, the first lens includes a first rectangular lens and a second rectangular lens that are in direct or indirect contact from the object side to the image side through a non-optical means;

[0012] The first rectangular lens and the second rectangular lens are placed adjacent to each other along the optical axis. The first rectangular lens provides the equivalent function of a convex lens and has both positive and negative refractive power. Specifically, the angle between the diagonal axis and the two axes of symmetry of the rectangle is equivalent to a convex mirror. The second rectangular lens has negative refractive power.

[0013] The convex surface of the first rectangular lens faces the object side, and the concave surface of the second rectangular lens faces the image side.

[0014] Furthermore, in the first lens, the area between the upper and lower 15° angles of the two central axes parallel to the horizontal and vertical axes of the first lens is a plane lens with curvature tending to infinity, which does not magnify the image. The other areas are convex lenses that have a magnifying effect.

[0015] Furthermore, at the four corners of the first rectangular lens, the curvature of the convex lens surface and the focal length are changed by altering the curvature of the diagonal lines, thereby correcting image distortion, as detailed below:

[0016] The first rectangular lens is divided into eight regions by eight dividing lines from the center point of the lens to the edge of the lens, namely two central axis lines of symmetry passing through the center point of the lens and two diagonal lines. Each region corresponds to a different curvature, resulting in different magnification.

[0017] For the cross-sectional shape of each diagonal of the first rectangular lens, when the diameter D of the first rectangular lens is set to 2.5mm to 5mm, the width W of the groove in the radial direction from the optical axis of the first rectangular lens toward the outer periphery of the lens is set to 0.05um or more and 5um or less, and the depth d of the groove is set to 0.05um or more and 2.5um or less.

[0018] In the convex surface of the first rectangular lens, the radius of curvature of the line connecting the center point of the lens to the four corners is controlled within 200mm to correct the image distortion at the four corners of the first rectangular lens.

[0019] Furthermore, ordinary lenses can cause barrel distortion due to uneven magnification after forming an image. Therefore, according to ISO standard data, the lens curvature is increased in areas with insufficient magnification to improve the magnification, thereby ensuring that the magnification is equal in all areas of the image and eliminating distortion.

[0020] For the center point of the convex surface of the first rectangular lens and one of the connecting lines of the four corners, the angle between the connecting lines on both sides of the two lens regions formed by the connecting line and the two adjacent connecting lines is 60°. When the angle between the object image and the center line of the lens is 65°, the left and right sides of the pincushion distortion pattern are magnified to repair the distortion.

[0021] The angle between the connecting lines on both sides of the other lens area is 120°, which is used to amplify the distortion depressions on the upper and lower sides.

[0022] Furthermore, the second lens is a double-sided convex lens, with both the object-side and image-side surfaces being convex lenses, and both sides being spherical mirrors.

[0023] Furthermore, the object-side surface of the third lens is a convex lens, and the image-side surface is a planar base.

[0024] Furthermore, the thickness of the first lens is between 0.6 and 0.9 mm, the thickness of the second lens is between 0.5 and 0.84 mm, and the thickness of the third lens is between 0.86 and 1.54 mm.

[0025] The distance between the first lens and the second lens should be set between 0.245 and 0.433 mm, depending on the thickness of the first lens and the second lens.

[0026] The distance between the second lens and the third lens should be set between 0.125 and 0.455 mm, depending on the thickness of the second and third lenses.

[0027] The equivalent lens formed by the combination of the first, second, and third lenses has a magnification that increases linearly from the center of the image towards the four corners along the four diagonals where the initial image is formed, i.e., when the object and the lens are at the same level. The magnification is y = kx, where k is determined by the focal length (thickness of the equivalent lens) and the distance between the equivalent lenses. y and x represent the magnification and the distance between the object and the equivalent lens, respectively. When the distance between the object and the equivalent lens is a standard distance of 20 meters, the magnification increases from 0.34 to 0.863.

[0028] The electronic rearview mirror system (CMS) of a non-uniformly corrected rectangular camera includes an image sensor, an ARM subsystem, and an FPGA subsystem. The ARM subsystem and the FPGA subsystem are connected via a bus. The ARM subsystem includes an ARM microprocessor, and the FPGA subsystem includes an FPGA processor.

[0029] The FPGA processor connects to the image sensor to perform image acquisition and preprocessing, and converts the image into video image data which is then input into the ARM microprocessor. The ARM microprocessor receives the video image data and passes it to the FPGA processor for accelerated processing.

[0030] Compared with the prior art, the advantages of this invention are:

[0031] This invention achieves preliminary correction of the image entering the lens by adjusting the mirror at different positions, thereby achieving the lowest possible distortion rate. At the same time, compared with ordinary circular lenses, this invention uses rectangular lenses, which fit the rear CDC better.

[0032] Currently, most distortion correction methods involve inputting the image into a CDC (Distortion Center for Diagnostics) and then using software algorithms to select, enlarge, or reduce pixels at different locations within the image. This inevitably leads to some loss of image information. This invention solves the distortion problem at the lens level, ensuring that all pixel information is preserved. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the electronic rearview mirror system (CMS) structure of a rectangular camera with non-uniform correction in an embodiment of the present invention;

[0034] Figure 2 This is a side view of the viewing angle range of the electronic rearview mirror in an embodiment of the present invention;

[0035] Figure 3 This is a top view of the viewing angle range of the electronic rearview mirror in an embodiment of the present invention;

[0036] Figure 4 This is a flowchart illustrating the workflow of the electronic rearview mirror system (CMS) for a rectangular camera with non-uniform correction in an embodiment of the present invention.

[0037] Figure 5 This is a structural diagram of a rectangular camera with non-uniform correction in an embodiment of the present invention;

[0038] Figure 6 This is a schematic diagram of the first lens structure in a rectangular camera with non-uniform correction in an embodiment of the present invention;

[0039] Figure 7 This is a schematic diagram of the first lens structure in a non-uniformly corrected rectangular camera according to an embodiment of the present invention.

[0040] Figure 8a and Figure 8b These are schematic diagrams showing the effects of non-uniformly corrected rectangular camera structure before and after correction in embodiments of the present invention. Specific Implementation

[0041] To make the objectives, technical solutions, and advantages of the present invention clearer, the specific implementation of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0042] Example 1:

[0043] Non-uniformly corrected rectangular cameras, such as Figure 5 As shown, it includes a first lens 10, a second lens 20, and a third lens 30 arranged sequentially from the object side to the image side;

[0044] Among them, the first lens 10 is a convex-concave lens composite lens. The convex part of the first lens near the object side is a freeform surface. With the convex lens axis as the center, its surface can be set with different surface shapes at different positions according to ISO_FDIS_16505-Calculation of Magnification Factor data, so that the surface of the first lens 10 has uneven magnification.

[0045] The second lens 20 is a double-sided convex lens;

[0046] The third lens 30 is a convex-concave lens composite lens, including a base 302 and a biconvex lens 301.

[0047] In this embodiment, the first lens 10, the second lens 20, and the third lens 30 are all rectangular lenses, which fit the rear CDC better than ordinary circular lenses.

[0048] Furthermore, the first lens 10 includes a first rectangular lens 101 and a second rectangular lens 102 that are in direct or indirect contact from the object side to the image side in a non-optical manner;

[0049] The first rectangular lens 101 and the second rectangular lens 102 are placed adjacent to each other along the optical axis. The first rectangular lens 101 provides the equivalent function of a convex lens and has both positive and negative refractive power. Specifically, the angle region between the diagonal axis and the two axes of symmetry of the rectangle is equivalent to a convex mirror. The second rectangular lens 102 has negative refractive power.

[0050] The convex surface of the first rectangular lens 101 faces the object side, and the concave surface of the second rectangular lens 102 faces the image side.

[0051] In this embodiment, the reflectivity of the object side and the image side of the first lens 10 are 1.503 and 9.6523, respectively.

[0052] like Figure 8aAs shown, in the first lens 10, the area between the upper and lower 15° angles of the two central axes parallel to the horizontal and vertical axes of the first lens 10 is a plane lens with curvature tending to infinity, which does not magnify the image. The other areas are convex lenses with magnification.

[0053] Furthermore, at the four corners of the first rectangular lens 101, the curvature of the convex lens surface and the focal length are changed by altering the curvature of the diagonal lines, thereby achieving the correction of image distortion, as detailed below:

[0054] The first rectangular lens 101 is divided into eight regions by eight dividing lines from the center point of the lens to the edge of the lens, namely two central axis lines of symmetry passing through the center point of the lens and two diagonals. Each region corresponds to a different curvature, resulting in different magnifications. The eight dividing lines include the first dividing line 1011, the second dividing line 1012, the third dividing line 1013, the fourth dividing line 1014, the fifth dividing line 1015, the sixth dividing line 1016, the seventh dividing line 1017, and the eighth dividing line 1018.

[0055] For the cross-sectional shape of each diagonal of the first rectangular lens 101, when the diameter D of the first rectangular lens 101 is set to 2.5mm to 5mm, the width W of the groove in the radial direction from the optical axis of the first rectangular lens 101 toward the outer periphery of the lens is set to 0.05um or more and 5um or less, and the depth d of the groove is set to 0.05um or more and 2.5um or less.

[0056] In the convex surface of the first rectangular lens 101, the radius of curvature of the line connecting the center point of the lens to the four corners is controlled within 200mm, so as to correct the image distortion at the four corners of the first rectangular lens 101.

[0057] Furthermore, ordinary lenses can cause barrel distortion due to uneven magnification after forming an image. Therefore, according to ISO standard data, the lens curvature is increased in areas with insufficient magnification to improve the magnification, thereby ensuring that the magnification is equal in all areas of the image and eliminating distortion.

[0058] For one of the connecting lines 1016 between the center point of the convex surface of the first rectangular lens 101 and the four corners, the angle between the connecting lines on both sides of a lens region formed by the connecting line 1016 and the two adjacent connecting lines is 60°, and the angle between the object image and the lens centerline is 65°.

[0059] In this embodiment, when the object distance is 20 meters, the magnification is 0.4252, which is higher than the 0.3109 in the middle area of ​​the lens, so that the left and right sides of the pincushion distortion pattern are magnified to repair the distortion;

[0060] The angle between the connecting lines on both sides of the other lens area is 120°;

[0061] In this embodiment, when the angle between the object image and the center line of the lens is 65° and the object distance is 20 meters, the magnification is 0.3316. When the object distance is within 0.5 meters, the magnification is 0.5293, which is used to magnify the distortion depressions on the upper and lower sides.

[0062] Furthermore, the second lens 20 is a double-sided convex lens, with both the object side and the image side being convex lenses, and both sides being spherical mirrors.

[0063] Furthermore, the object side of the third lens 30 is a convex lens 301, and the image side is a planar base 302.

[0064] Furthermore, the thickness of the first lens 10 is between 0.6 and 0.9 mm, the thickness of the second lens 20 is between 0.5 and 0.84 mm, and the thickness of the third lens 30 is between 0.86 and 1.54 mm.

[0065] In this embodiment, the thickness of the first lens 10 is 0.7 mm, the thickness of the second lens 20 is 0.7 mm, and the thickness of the third lens 30 is 1 mm.

[0066] The distance between the first lens 10 and the second lens 20 should be set between 0.245 and 0.433 mm, depending on the thickness of the first lens 10 and the second lens 20.

[0067] The distance between the second lens 20 and the third lens 30 should be set between 0.125 and 0.455 mm, depending on the thickness of the second lens 20 and the third lens 30.

[0068] The overall effect of the equivalent lens formed by the combination of the first lens 10, the second lens 20, and the third lens 30 is as follows: Figure 8a As shown by the dashed arrows, along the four diagonals that form the initial image, the magnification increases linearly from the center of the image towards the four corners, following the direction of the arrows as shown in the figure. y = kx, where k is determined by the focal length (thickness of the equivalent lens) and the distance between the equivalent lens. y and x represent the magnification and the distance between the object and the equivalent lens, respectively. When the distance between the object and the equivalent lens is a standard distance of 20 meters, the magnification increases from 0.34 to 0.863.

[0069] Figure 8a and Figure 8b These are schematic diagrams of a rectangular camera structure before and after non-uniform correction.

[0070] Example 2:

[0071] In this embodiment, the thickness of the first lens 10 is 0.8 mm, the thickness of the second lens 20 is 0.8 mm, and the thickness of the third lens 30 is 1.2 mm.

[0072] Example 3:

[0073] The electronic rearview mirror system (CMS) of a non-uniformly corrected rectangular camera includes an image sensor, an ARM subsystem, and an FPGA subsystem. The ARM subsystem and the FPGA subsystem are connected via a bus. The ARM subsystem includes an ARM microprocessor, and the FPGA subsystem includes an FPGA processor.

[0074] The FPGA processor connects to the image sensor to perform image acquisition and preprocessing, and converts the image into video image data which is then input into the ARM microprocessor. The ARM microprocessor receives the video image data and passes it to the FPGA processor for accelerated processing.

[0075] The field of view of electronic rearview mirrors is as follows Figure 2 and Figure 3 As shown. The flowchart of the image information acquisition program is as follows. Figure 4 As shown, the system first determines whether image acquisition has started, i.e., whether there is data input. If not, the process ends. If there is data input, the system reads the data transmitted by the CMS, the SoC FPGA preprocesses the data, and the ARM chip reads the data from the external storage for further preprocessing.

[0076] FPGAs enable parallel computing and offer rich I / O ports for development configuration, providing strong development flexibility. They can serve as coprocessors for platforms, providing acceleration support. FPGA chips handle tasks such as image acquisition, caching, image resolution adjustment, and image algorithm acceleration. This invention separates heavy algorithmic tasks such as real-time video processing from the CPU, enabling it to handle heavy computing tasks and save resources; it also compensates for the shortcomings of ARM in terms of computing power.

[0077] QSYS is used to accelerate image processing. The CMOS image sensor module transmits real-time image data to the FPGA chip via the HDMI 2.0 interface. The HDMI video signal is shared with the LCD interface. LCD_DATA[4:0] is connected to D[23:19] of the AD9889B, LCD_DATA[10:5] is connected to D[15:10] of the AD9889B, and LCD_DATA[15:11] is connected to D[7:3] of the AD9889B. An HDMI transmitter chip is used to convert the RGB signal to a TMDS signal. The hardware platform uses the AD9889B chip from Anorlog Devices. It operates at 1.8V. The AD9889B chip is connected to the HDMI interface through a CM2030 port protection circuit to prevent electrical damage to the chip caused by static electricity.

[0078] The ARM main module is designed to receive video image data using its rich interface features, pass the data to the FPGA for accelerated processing, control the production line operation, and provide a human-machine interface.

[0079] An ARM processor is used to receive image data generated on-site. Because the data storage capacity of the FPGA and ARM is limited, two external data memories (RAM1 and RAM2) are connected respectively.

[0080] The FPGA serves as the video data acquisition and preprocessing module for the ARM processor. The interface between the CMOS image sensor and the FPGA utilizes the FPGA's GPIO pins; by reconfiguring these pins, communication with the ARM processor is possible. To compensate for the FPGA's limited internal RAM, image information can be transmitted to external RAM for storage via the interface circuit. This system uses the XC6SLX150-2FGG484C FPGA development board, designing an interface to interface with it, making it an independent module within the system.

[0081] The AM335x series integrates two MACs with a maximum clock speed of 720MHz. The AM3359ZCZ packaged chip from this product series was selected as the ARM processor in this system.

[0082] The AM3359 supports three types of SDRAM: mDDR (LPDDR), DDR2, and DDR3. When DDR2 is selected, the AM3359 connects to DDR2 via its EMIF interface. There is only one EMIF interface, supporting a maximum address space of 1GB (0x8000000O-0xBFFFFFFF) and supporting 8-bit / 16-bit data widths. The ARM processor connects to an external display via a CAN bus interface. The CAN transceiver interface chip 82C250 connects to the physical bus via its two outputs, CANH and CANL, ensuring that the issues encountered in RS-485 networks—such as multiple nodes simultaneously sending data to the bus, causing a short circuit and damaging some nodes—are avoided. Furthermore, the CAN nodes have an automatic output shutdown function in case of severe errors, preventing other nodes from being affected and preventing bus lockup due to a single node problem.

[0083] For power supply, the TPS65217c is used as the power module for DC power supply, USB power supply, and backup power supply. The AC power supply can receive 5V DC power converted from AC power. When the development board is connected to a PC via USB, it receives 5V power from the PC. The two BAT pins can receive backup power (battery) power. BAT_SENSE is used to sense the backup power supply and is directly connected to it. TS is used to sense the backup power supply temperature. Since this hardware platform does not have a battery slot, the relevant pins are connected to the expansion port. When using the above power supply methods, SYS outputs a 5V system voltage, powering VIN_DCDC1, VIN_DCDC2, and VIN_DCDC3 to drive the three DC-DC converters. A 10uF capacitor is connected externally to the pins for filtering.

Claims

1. A rectangular camera with non-uniform correction, characterized in that, It includes a first lens, a second lens, and a third lens arranged sequentially from the object side to the image side; Among them, the first lens is a convex-concave lens composite lens. The convex part of the first lens near the object side is a freeform surface. With the convex lens axis as the center, its surface is set with different surface shapes at different positions according to ISO_FDIS_16505-Calculation of Magnification Factor data, so that the surface of the first lens has uneven magnification. The second lens is a double-convex lens; The third lens is a convex-concave lens composite lens, consisting of a base and a biconvex lens; The first lens includes a first rectangular lens and a second rectangular lens that are in direct or indirect contact with each other from the object side to the image side through non-optical means. The first rectangular lens and the second rectangular lens are placed adjacent to each other along the optical axis. The first rectangular lens provides the equivalent function of a convex lens and has both positive and negative refractive power. Specifically, the angle between the diagonal axis and the two axes of symmetry of the rectangle is equivalent to a convex mirror. The second rectangular lens has negative refractive power. The convex surface of the first rectangular lens faces the object side, and the concave surface of the second rectangular lens faces the image side; In the first lens, the area between the upper and lower 15° angles of the two central axes parallel to the horizontal and vertical axes is a plane lens with curvature approaching infinity, and does not magnify the image. The other areas are convex lenses that have a magnifying effect. At the four corners of the first rectangular lens, the curvature of the convex lens surface and the focal length are changed by altering the curvature of the diagonal lines, thereby correcting image distortion, as detailed below: The first rectangular lens is divided into eight regions by eight dividing lines from the center point of the lens to the edge of the lens, namely two central axis lines of symmetry passing through the center point of the lens and two diagonal lines. Each region corresponds to a different curvature, resulting in different magnification. For the cross-sectional shape of each diagonal of the first rectangular lens, when the diameter D of the first rectangular lens is set to 2.5mm to 5mm, the width W of the groove in the radial direction from the optical axis of the first rectangular lens toward the outer periphery of the lens is set to 0.05um or more and 5um or less, and the depth d of the groove is set to 0.05um or more and 2.5um or less. In the convex surface of the first rectangular lens, the radius of curvature of the line connecting the center point of the lens to the four corners is controlled within 200mm to correct the image distortion at the four corners of the first rectangular lens. For the center point of the convex surface of the first rectangular lens and one of the connecting lines of the four corners, the angle between the connecting lines on both sides of the two lens regions formed by the connecting line and the two adjacent connecting lines is 60°. When the angle between the object image and the center line of the lens is 65°, the left and right sides of the pincushion distortion pattern are magnified to repair the distortion. The angle between the connecting lines on both sides of the other lens area is 120°, which is used to amplify the distortion depressions on the upper and lower sides.

2. The non-uniformly corrected rectangular camera according to claim 1, characterized in that, The first, second, and third lenses are all rectangular lenses, which fit the rear CDC better than ordinary circular lenses.

3. The non-uniformly corrected rectangular camera according to claim 1, characterized in that, The second lens is a double-sided convex lens, with both the object side and the image side being convex lenses, and both sides being spherical mirrors.

4. The non-uniformly corrected rectangular camera according to claim 1, characterized in that, The object-side surface of the third lens is a convex lens, and the image-side surface is a planar base.

5. The non-uniformly corrected rectangular camera according to claim 1, characterized in that, The thickness of the first lens is between 0.6 and 0.9 mm, the thickness of the second lens is between 0.5 and 0.84 mm, and the thickness of the third lens is between 0.86 and 1.54 mm. The distance between the first lens and the second lens should be set between 0.245 and 0.433 mm, depending on the thickness of the first lens and the second lens. The distance between the second lens and the third lens should be set between 0.125 and 0.455 mm, depending on the thickness of the second and third lenses. The equivalent lens formed by the combination of the first, second, and third lenses, along the four diagonals that form the initial image, increases linearly from the center of the image towards the four corners when the object and the lens are at the same horizontal level. y=kx, where k is determined by the focal length of the equivalent lens and the distance between the equivalent lenses. y and x represent the magnification and the distance between the object and the equivalent lens, respectively. When the distance between the object and the equivalent lens is a standard distance of 20 meters, the magnification increases from 0.34 to 0.

863.

6. The non-uniformly corrected rectangular camera according to claim 1, characterized in that, Ordinary lenses can cause barrel distortion due to uneven magnification after forming an image. Therefore, according to ISO standard data, the lens curvature is increased in areas with insufficient magnification to improve the magnification, thereby ensuring that the magnification is equal in all areas of the image and eliminating distortion.

7. An electronic rearview mirror system (CMS) comprising a rectangular camera with non-uniform correction as described in any one of claims 1 to 6, characterized in that, It includes an image sensor, an ARM subsystem, and an FPGA subsystem. The ARM subsystem and the FPGA subsystem are connected via a bus. The ARM subsystem includes an ARM microprocessor; the FPGA subsystem includes an FPGA processor. The FPGA processor connects to the image sensor to perform image acquisition and preprocessing, and converts the image into video image data which is then input into the ARM microprocessor. The ARM microprocessor receives the video image data and passes it to the FPGA processor for accelerated processing.

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