Novel camera calibration board

Abstract

The invention discloses a novel event camera calibration board which comprises a substrate, a calibration board, an LED lamp and a flickering circuit board. The calibration board, the LED lamp and the flicker circuit board are arranged on the substrate; the calibration plate is embedded in the substrate, and the upper surface of the calibration plate is flush with the upper surface of the substrate; a plurality of grooves are uniformly distributed in the connecting surface of the substrate and the calibration plate, and a fixed distance is formed between every two adjacent grooves; the LED lamp is installed in the groove, and the flickering circuit board is located below the LED lamp in the groove and connected with the LED lamp. According to the novel event camera calibration board provided by the invention, calibration of event camera equipment can be realized, and key point capture is more accurate and stable.

Description

Technical Field

[0001] The invention relates to the technical field of event camera calibration, and in particular to a novel event camera calibration board. Background Art

[0002] Calibration plates play a great role in applications such as machine vision, image measurement, photogrammetry, and 3D reconstruction. Its main functions are to correct lens distortion, determine the conversion relationship between physical size and pixels, determine the relationship between the 3D geometric position of a point on the surface of a spatial object and the corresponding point in the image, and establish a geometric model for camera imaging. Ordinary cameras are favored for their low cost, light weight, and low energy consumption, but they also have defects such as high latency, motion blur, and low dynamic range. Event cameras have the advantages of high dynamic range and high temporal resolution, which can make up for the defects of ordinary cameras in many working environments, so it is necessary to design a new type of calibration plate for event cameras.

[0003] The physical structure of an event camera is similar to that of a traditional camera, so the event camera calibration method can use the same camera intrinsic parameter model for calibration. However, traditional cameras use images of static calibration plates to establish 2D-3D correspondences for intrinsic parameter calibration. Since event cameras generate event information asynchronously, this mature calibration technology cannot be directly applied to the calibration of event cameras.

[0004] Therefore, there is an urgent need to find a new calibration board to meet the event camera calibration needs. Summary of the invention

[0005] The purpose of the present invention is to provide a novel event camera calibration plate.

[0006] The technical solution for achieving the purpose of the present invention is: a new type of event camera calibration board, including a substrate, a calibration board, an LED light and a flashing circuit board; the calibration board, the LED light and the flashing circuit board are arranged on the substrate; the calibration board is embedded in the substrate, and the upper surface of the calibration board is flush with the upper surface of the substrate; a plurality of grooves are evenly distributed at the connecting surface of the substrate and the calibration board, and there is a fixed distance between adjacent grooves; the LED light is installed in the groove, and the flashing circuit board is located below the LED light in the groove and connected to the LED light.

[0007] Furthermore, the calibration plate and the base plate are both rectangular plates, and the calibration plate is nested in the base plate to ensure that the calibration plate and the base plate are stably connected.

[0008] Furthermore, the substrate is black, the calibration plate is black and white squares, and the side length of each square is consistent with the spacing between adjacent grooves on the substrate.

[0009] Furthermore, a power line hole is provided below the groove, and the flashing circuit board is connected to a power source through the power line hole.

[0010] Furthermore, a 555 timer is used to act as an oscillator to output a pulse signal, thereby realizing a high-frequency stable flashing function of the circuit.

[0011] Furthermore, the flashing circuit board contains a transformer which can reduce the 220V voltage to 5V voltage.

[0012] Furthermore, the size of the LED lamp is 40 mm×40 mm×2 mm.

[0013] Furthermore, the calibration plate is made of acrylic.

[0014] Furthermore, the substrate is made of phenolic laminated paperboard material, with a length of 78 cm to 82 cm and a width of 65 cm to 70 cm.

[0015] Compared with the prior art, the present invention has the following significant advantages: 1. The substrate is made of phenolic laminated paperboard material, which has high mechanical strength and high temperature resistance, and effectively prevents the substrate from being deformed or damaged due to heat or strength during operation. 2. The LED light strip is 2mm wide, and the calibration error is small. 3. The use of a flashing circuit board can effectively control the flashing of the LED and ensure the stability of the LED light's stroboscopic performance. 4. The LED light in the calibration board is white, and the substrate composed of phenolic laminated paperboard material is black. The two materials are different in color, and can be used for event camera calibration, as well as for calibration of visible light, binocular vision, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of a novel event camera calibration board of the present invention.

[0017] Figure 2 It is a side view of a novel event camera calibration plate of the present invention.

[0018] Figure 3 This is a top view of a novel event camera calibration plate of the present invention.

[0019] Figure 4 This is a schematic diagram of connecting the LED light of a novel event camera calibration board of the present invention to the power supply in the flashing device.

[0020] Figure 5 This is a structural diagram of a scintillation circuit board of a novel event camera calibration board of the present invention. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] In view of the many problems existing in traditional calibration plates in event camera calibration, the new event camera calibration plate proposed in the present invention can realize the calibration of event camera equipment by flashing the calibration plate to generate asynchronous information, and the key point capture is more accurate and stable.

[0023] like Figure 1 As shown, a new camera calibration board includes a substrate 1, a flashing device and a flashing circuit board 4. The flashing device and the flashing circuit board 4 are both arranged on the substrate 1. The substrate 1 is used to install the flashing device and the flashing circuit board 4. The flashing device is connected to the flashing circuit board 4. The flashing device includes a plurality of LED lights 3. The LED lights 3 are embedded in the substrate 1. The LED lights 3 can light up so as to produce a difference in brightness with the substrate 1. The LED lights 3 are connected to the flashing circuit board 4. The flashing circuit board 4 controls the lighting of the LED lights 3 to ensure the stability of the brightness of each LED light 3, so that the LED lights 3 and the substrate 1 form different brightnesses, which can be used for the calibration of event cameras.

[0024] Preferably, the substrate 1 is a board made of phenolic laminated paperboard material, which has high mechanical strength and high temperature resistance, and can ensure that deformation or damage caused by high temperature or collision will not occur during operation. The LED lamp 3 emits light stably and the flashing can be controlled, which can effectively solve the problem that the event camera cannot collect effective calibration points, and can make the key point capture during calibration more accurate and stable.

[0025] Preferably, if Figure 1 and Figure 3 As shown, there are several grooves evenly distributed on the substrate 2, and the size of the substrate 2 is 200mm×200mm×3mm. The size of the LED lamp 3 is 40mm×40mm×2mm, and the LED lamp 3 is embedded in the groove of the substrate 2. 10mm is reserved at the edge of the substrate 2, and the middle part is divided into a 7×7 square matrix according to the chessboard type, and the non-adjacent square blocks are made into grooves, and the size of each square block is 25mm×25mm. The square blocks are hollowed out to form 25 grooves of 40mm×40mm×2mm for the installation of the LED lamp 3. The LED lamp 3 is embedded in the groove of the substrate 2.

[0026] Preferably, if Figure 4As shown, the LED lamp 3 is connected to the power supply in the flashing device, and a power line hole 5 is provided below the groove, through which the LED lamp 3 is connected to the power supply. A power line hole 5 with a diameter of 2 mm is made at 12 mm from the left and right edges below the groove formed by each hollowed-out block, for the power line of the power supply to pass through and connect to the LED lamp 3, while ensuring the flatness and neatness of the calibration surface. After the power line of the LED lamp 3 passes through the power line hole 5, the power line is fixed to the rear of the substrate 1.

[0027] Preferably, the color of the substrate 1 is black, and the color of the LED 3 light is white. The two materials have different colors and can be used for calibration of visible light cameras, binocular vision, etc. The LED light 1 and the substrate 2 form a checkerboard. The calibration board composed of different brightness differences between the LED light 3 and the substrate 1 can be used for calibration of visible light cameras, event cameras, binocular vision, etc.

[0028] like Figure 1 As shown, the flashing circuit board 4 is a circuit board, which is arranged outside the calibration board and controls the flashing result through wires and LED lights 3.

[0029] In this circuit, the pins 2 and 6 of the 555 timer are connected together. When the pin 2 detects that the voltage is lower than 1 / 3 of the power supply voltage, the 555 timer outputs a high level. When the pin 6 detects that the voltage is greater than 2 / 3 of the power supply voltage, the 555 timer outputs a high level. When the voltage is between 1 / 3 and 2 / 3 of the power supply voltage, the output remains unchanged. At this time, the output of the 555 timer is not a stable value, but can act as an oscillator to output pulse signals. These signals are transmitted to the LED lamp 3 to realize the flashing control of the LED lamp 3.

[0030] Preferably, the flashing of each LED light 3 can be accurately controlled by the circuit, which is more conducive to the calibration of event cameras and the like.

[0031] Preferably, the circuit board is constructed as follows Figure 5As shown, the LED light can be controlled to flash. The material of the circuit board is FR-4 epoxy glass cloth laminate, and the tg value should be between 130-140. A 5mm process margin is left on the edge of the circuit board, and mounting holes are drilled at the four corners of the circuit board. The diameter of the mounting hole is about 3mm. The reference points are placed diagonally. The placement of the reference points must ensure that they are asymmetrical about the center for fool-proof design. The size of the vias on the circuit board is 8mil inner diameter and 14mil outer diameter. The spacing between the vias should be 0.5mm, and the vias are treated with via cover oil. The surface treatment of the pad is lead-free tin spraying, the minimum line width on the circuit board is set to 6mil, and the inner and outer copper thicknesses are both 1oz. Finally, the finished product is 1.6mm thick, and the size of a single flicker control unit is about 25*25mm. 12 flicker control units can be integrated on a 120*80mm circuit board to meet the flicker requirements of the flicker calibration board.

[0032] The present invention is more accurate and stable in capturing key points for calibration of equipment such as event cameras; moreover, the present invention is also widely used and can be used for calibration of various situations such as visible light cameras, event cameras, binocular vision, etc.

[0033] After some LED lights 3 are working, the event camera is used to shoot the picture and after black and white processing, the picture can be obtained.

[0034] The effect diagram shows that: under the event camera shooting, the present invention successfully completes the calibration work of the event camera, the substrate 1 and the LED lamp 3 are clearly distinguished in the picture taken by the event camera, and there is no problem of being unable to collect effective calibration points due to uneven brightness, which proves that the present invention has excellent performance in the calibration work of the event camera.

[0035] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A new event camera calibration board, characterized by: The invention comprises a substrate (1), a calibration plate (2), an LED lamp (3) and a flashing circuit board (4); the calibration plate (2), the LED lamp (3) and the flashing circuit board (4) are arranged on the substrate (1); the calibration plate (2) is embedded in the substrate (1), and the upper surface of the calibration plate (2) is flush with the upper surface of the substrate (1); a plurality of grooves are evenly distributed at the connection surface between the substrate (1) and the calibration plate (2), and a fixed spacing is provided between adjacent grooves; the LED lamp (3) is installed in the groove, and the flashing circuit board (4) is located below the LED lamp (3) in the groove and is connected to the LED lamp (3).

2. The novel event camera calibration board according to claim 1, characterized in that: The calibration plate (2) and the base plate (1) are both rectangular plates, and the calibration plate (2) is nested in the base plate (1), thereby ensuring that the calibration plate (2) and the base plate (1) are stably connected.

3. The novel event camera calibration plate according to claim 1, characterized in that: The substrate (1) is black, and the calibration plate (2) is black and white squares, with the side length of each square being consistent with the spacing between adjacent grooves on the substrate (1).

4. The novel event camera calibration plate according to claim 1, characterized in that: A power line hole (5) is provided below the groove, and the flashing circuit board (4) is connected to a power source via the power line hole (5).

5. The novel event camera calibration board according to claim 4, characterized in that: The 555 timer is used as an oscillator to output a pulse signal to achieve the high-frequency stable flashing function of the circuit.

6. The new camera calibration plate according to claim 4, characterized in that: The flashing circuit board (4) contains a transformer which can reduce the 220V voltage to 5V voltage.

7. The new camera calibration plate according to claim 1, characterized in that: The size of the LED lamp (3) is 40 mm×40 mm×2 mm.

8. The new camera calibration plate according to claim 1, characterized in that: The calibration plate (2) is made of acrylic material.

9. The new camera calibration plate according to claim 1, characterized in that: The base plate (1) is made of phenolic laminated paperboard material, with a length of 78 cm to 82 cm and a width of 65 cm to 70 cm.

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