Four-axis lifting workbench carrying adjustable light source and used for monitoring camera image calibration

Abstract

The utility model provides a four-axis lifting workbench carrying an adjustable light source and used for monitoring camera image calibration, and belongs to the technical field of camera shooting calibration equipment. The workbench comprises a frame body, four sliding rails are arranged on a cross beam of the frame body, and the sliding rails extend in the vertical direction; sliding blocks matched with the sliding rails are arranged on a cross beam of the light source fixing frame, the sliding rails are arranged on the sliding blocks in a penetrating mode, the sliding blocks are suitable for sliding on the sliding rails, and the sliding blocks are distributed at the four corners of the light source fixing frame. The adjustable light source plate is placed on the light source fixing frame; the light-transmitting glass is placed on the light source fixing frame; the target paper is placed on one surface, facing the adjustable light source plate, of the light-transmitting glass; and the object placing plate is placed on the frame body, is located below the light source fixing frame and is suitable for placing camera shooting equipment. And high-precision level maintenance of the adjustable light source plate and the target paper in the lifting process is realized through the four-axis linkage adjusting structure, so that the stability and accuracy of image calibration of the monitoring camera are improved.

Description

Technical Field

[0001] This application belongs to the technical field of camera calibration equipment, specifically relating to a four-axis lifting worktable equipped with an adjustable light source for calibrating images from a surveillance camera. Background Technology

[0002] Currently, when performing image calibration for surveillance cameras, an adjustable light source board is placed on a light source mounting bracket. The adjustable light source board illuminates the target paper and provides supplemental lighting for the surveillance camera. The adjustable light source board provides appropriate illumination as the light source mounting bracket is raised and lowered to facilitate imaging.

[0003] In industrial applications, the commonly used light source mounting brackets are 2-axis worktables. These devices may exhibit slight tilting during lifting and lowering. This instability can easily introduce errors into the calibration of high-pixel surveillance cameras, affecting the final image quality. The limitations of traditional 2-axis worktables are particularly evident in applications requiring precise calibration, restricting their application range and effectiveness. Utility Model Content

[0004] To address at least one of the technical problems existing in the background art, this application provides a four-axis lifting worktable equipped with an adjustable light source for monitoring camera image calibration. Through a four-axis linkage adjustment structure, the adjustable light source plate and the target paper are kept at a high level during the lifting process, thereby improving the stability and accuracy of monitoring camera image calibration.

[0005] The technical solution adopted in this application is as follows:

[0006] This application provides a four-axis lifting worktable equipped with an adjustable light source for calibrating surveillance camera images, including:

[0007] The frame has four slide rails on its crossbeams, wherein the slide rails extend in the vertical direction;

[0008] A light source mounting bracket, wherein a slider matching the slide rail is provided on the crossbeam of the light source mounting bracket, the slide rail passes through the slider, and the slider is adapted to slide on the slide rail, wherein the slider is distributed at the four corners of the light source mounting bracket;

[0009] An adjustable light source board is placed on the light source mounting bracket;

[0010] A translucent glass is placed on the light source mounting bracket;

[0011] The target paper is placed on the side of the transparent glass facing the adjustable light source plate;

[0012] The adjustable light source plate and the light-transmitting glass are distributed sequentially from top to bottom;

[0013] A shelf is placed on the frame, the shelf is located below the light source mounting bracket, and the shelf is suitable for placing camera equipment.

[0014] According to the embodiments of this application, a four-axis lifting worktable equipped with an adjustable light source for monitoring camera image calibration is provided. The frame serves as the basic support for the entire device, and four vertically extending slide rails are provided on the crossbeam to ensure the stability and verticality of the overall structure. The light source fixing bracket matches the slide rails with sliders at its four corners, allowing it to maintain horizontal movement when adjusting the height, avoiding the tilting problem that may occur with traditional two-axis worktables. The adjustable light source plate is placed on the upper part of the light source fixing bracket, providing uniform and adjustable intensity illumination for the target paper, which helps to improve image quality. The light-transmitting glass is located below the adjustable light source plate, providing a flat support surface for the target paper while allowing light to pass through for imaging by the camera equipment, ensuring that the pattern on the target paper is clearly visible. The target paper is placed directly on the side of the light-transmitting glass facing the light source, facilitating quick and easy replacement and calibration operations. The shelf is located below the light source fixing bracket and is specifically used to place the camera equipment, ensuring the stability of the camera during testing. In summary, this four-axis lifting stage not only solves the problem of errors that easily occur during calibration in traditional two-axis stages, but also achieves a high-precision and stable image calibration environment by precisely adjusting the height and brightness of the light source board, greatly improving the efficiency and accuracy of surveillance camera image calibration, and is especially suitable for the precise calibration needs of high-pixel cameras.

[0015] According to one embodiment of this application, the crossbeam of the frame is provided with a mounting base suitable for fixing the slide rail;

[0016] The mounting base is detachably connected to the crossbeam of the frame, and the end of the slide rail passes through the mounting base.

[0017] According to one embodiment of this application, the slider is detachably connected to the crossbeam of the light source mounting bracket.

[0018] According to one embodiment of this application, the slider is provided with a locking screw, which is adapted to abut against the slide rail after the light source mounting bracket is adjusted, so as to fix the slider at a specified height position of the slide rail.

[0019] According to one embodiment of this application, the slide rail is provided with scale markings.

[0020] According to one embodiment of this application, a limiting protrusion is formed on the slide rail.

[0021] According to one embodiment of this application, the distance between the adjustable light source plate and the light-transmitting glass ranges from 10 mm to 13 mm.

[0022] According to one embodiment of this application, the frame is further provided with a computer shelf, which is located below the shelf.

[0023] According to one embodiment of this application, the bottom of the frame is provided with casters.

[0024] According to one embodiment of this application, angle irons are provided at the connection between the crossbeams and longitudinal beams of the frame. Attached Figure Description

[0025] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0026] Figure 1 This is a schematic diagram of a four-axis lifting worktable equipped with an adjustable light source for image calibration of a surveillance camera, provided in an embodiment of this application.

[0027] Figure 2 This is a cross-sectional view of the light source mounting bracket provided in an embodiment of this application.

[0028] in,

[0029] 11. Frame; 111. Slide rail; 112. Mounting base; 113. Computer storage rack; 114. Casters; 115. Angle iron; 12. Light source mounting bracket; 121. Slider; 13. Adjustable light source plate; 14. Transparent glass; 15. Shelf. Detailed Implementation

[0030] To more clearly illustrate the overall concept of this application, a detailed explanation is provided below with reference to the accompanying drawings.

[0031] Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of this application is not limited to the specific embodiments disclosed below. It should be noted that, unless otherwise specified, the embodiments of this application and the features thereof can be combined with each other.

[0032] Furthermore, it should be understood in the description of this application that the terms "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0033] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0034] In this application, unless otherwise expressly specified and limited, the "above" or "below" of the second feature can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. In the description of this specification, references to terms such as "an embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples.

[0035] like Figures 1 to 2 As shown, this application embodiment provides a four-axis lifting worktable equipped with an adjustable light source for monitoring camera image calibration, comprising:

[0036] The frame 11 has four slide rails 111 on its crossbeams, with the slide rails 111 extending vertically.

[0037] The light source mounting bracket 12 has a slider 121 that matches the slide rail 111 on its crossbeam. The slide rail 111 passes through the slider 121, and the slider 121 is adapted to slide on the slide rail 111. The slider 121 is distributed at the four corners of the light source mounting bracket 12.

[0038] Adjustable light source plate 13 is placed on light source fixing bracket 12;

[0039] The light-transmitting glass 14 is placed on the light source mounting bracket 12;

[0040] The target paper is placed on the side of the transparent glass 14 facing the adjustable light source plate 13;

[0041] Among them, the adjustable light source plate 13 and the light-transmitting glass 14 are distributed from top to bottom;

[0042] A shelf 15 is placed on the frame 11. The shelf 15 is located below the light source mounting bracket 12 and is suitable for placing camera equipment.

[0043] The frame 11 is the basic support structure of the entire device, typically made of high-strength metal materials (such as aluminum alloy or steel), possessing excellent stability and resistance to deformation. Four vertically extending slide rails 111 are installed on its crossbeam, providing guidance and a movement path for the light source mounting bracket 12. The slide rails 111 are manufactured using precision machining processes to ensure minimal straightness and parallelism errors; the four slide rails 111 are rectangularly distributed, forming a stable four-point support structure, preventing tilting or offset caused by gravity or external vibration. The light source mounting bracket 12 is the core component supporting the light source board, the transparent glass 14, and the target paper. Slider blocks 121, matching the slide rails 111, are installed on its crossbeam, allowing the light source mounting bracket 12 to slide smoothly up and down on the slide rails 111. The four sliders 121 are located at the four corners of the light source mounting bracket 12, achieving four-point synchronous guidance. The light source mounting bracket 12 is designed with lightweight, high-strength materials, ensuring structural rigidity while facilitating lifting and lowering operations. Each slider 121 integrates a ball bearing or linear guide module to reduce friction and improve operational stability. The adjustable light source board 13 is an illumination device with an LED array; its brightness, color temperature, and other parameters can be adjusted as needed to simulate lighting conditions under different environments. The adjustable light source board 13 supports multi-level brightness adjustment and color temperature switching (such as cool white light and warm white light), and can be remotely adjusted via a controller. The light source is evenly distributed and covers a wide area, meeting the supplementary lighting needs of various camera specifications. The adjustable light source board 13 can flexibly adjust the light source intensity and color according to actual testing needs, providing a standardized and controllable lighting environment for the camera, thereby improving the consistency and accuracy of image acquisition, especially suitable for high-definition image calibration scenarios sensitive to light. The light-transmitting glass 14, located below the adjustable light source board 13, is a high-transmittance optical glass with a smooth, distortion-free surface, serving as the support substrate for the target paper. The glass material undergoes optical polishing, possessing excellent light transmission and low reflection characteristics, preventing light scattering or refraction during propagation and affecting image quality. Meanwhile, its surface is easy to clean, facilitating target paper replacement. The translucent glass 14 not only provides a flat support surface for the target paper but also effectively transmits light from the light source plate, ensuring the target paper pattern is clearly visible and reducing image blurring or distortion caused by uneven media. The target paper is a standard pattern used in image calibration to calibrate parameters such as camera focal length, distortion, and color reproduction. It is typically printed with standard graphics such as black and white squares, circles, and crosshairs. The target paper can be quickly replaced to adapt to the calibration needs of cameras of different sizes and types. Its pattern design conforms to ISO standards or other industry specifications, ensuring the authority and universality of calibration data. The target paper is placed on the side of the translucent glass 14 facing the light source, facilitating clear capture by the camera after illumination, improving the accuracy of image recognition, and also facilitating maintenance and replacement, enhancing the flexibility and practicality of the equipment. The shelf 15 is located below the light source holder 12 and fixed to the frame 11, specifically for placing the camera equipment to be calibrated.The mounting plate 15 can be configured with positioning slots, fixtures, or rotating platforms as needed to accommodate cameras of different shapes and sizes. Some advanced versions can also integrate an autofocus assist module or communication interface to achieve automated calibration processes. The mounting plate 15 provides a stable and reliable placement platform for camera equipment, preventing image shifts caused by vibration or displacement during calibration, thus helping to improve calibration efficiency and consistency, and is particularly suitable for mass production and automated inspection scenarios.

[0044] According to the embodiments of this application, a four-axis lifting worktable equipped with an adjustable light source for monitoring camera image calibration is provided. The frame 11 serves as the basic support for the entire device, and four vertically extending slide rails 111 are provided on the crossbeam to ensure the stability and verticality of the overall structure. The light source fixing bracket 12 matches the slide rails 111 through sliders 121 at its four corners, allowing it to maintain horizontal movement when adjusting the height, avoiding the tilting problem that may occur with traditional two-axis worktables. The adjustable light source plate 13 is placed on the upper part of the light source fixing bracket 12, providing uniform and adjustable intensity illumination for the target paper, which helps to improve image quality. The light-transmitting glass 14 is located below the adjustable light source plate 13, providing a flat support surface for the target paper and allowing light to pass through for imaging by the camera equipment, ensuring that the pattern on the target paper is clearly visible. The target paper is placed directly on the side of the light-transmitting glass 14 facing the light source, facilitating quick and easy replacement and calibration operations. The shelf 15 is located below the light source fixing bracket 12 and is specifically used to place the camera equipment, ensuring the stability of the camera during the testing process. In summary, this four-axis lifting stage not only solves the problem of errors that easily occur during calibration in traditional two-axis stages, but also achieves a high-precision and stable image calibration environment by precisely adjusting the height and brightness of the light source board, greatly improving the efficiency and accuracy of surveillance camera image calibration, and is especially suitable for the precise calibration needs of high-pixel cameras.

[0045] like Figure 1 As shown, in some embodiments of this application, the crossbeam of the frame 11 is provided with a mounting base 112 suitable for fixing the slide rail 111.

[0046] The mounting base 112 is detachably connected to the crossbeam of the frame 11, and the end of the slide rail 111 passes through the mounting base 112.

[0047] Mounting base 112 is a component specifically designed to secure slide rail 111, ensuring that slide rail 111 is firmly and accurately positioned on the crossbeam of frame 11. The design of mounting base 112 takes into account the stability and precision requirements of slide rail 111, helping to maintain the accuracy and stability of the entire lifting system during operation.

[0048] The mounting base 112 is detachably connected to the crossbeam of the frame 11, which means that the slide rail 111 can be installed or removed in a simple manner. This design not only facilitates the assembly, debugging, and maintenance of the equipment, but also allows users to adjust or replace the slide rail 111 according to actual needs to adapt to different application scenarios.

[0049] The end of the slide rail 111 passes directly through the mounting base 112, ensuring the straightness and perpendicularity of the slide rail 111 along its entire length. In this way, it can be ensured that the light source mounting bracket 12 and its components (such as the adjustable light source plate 13, the light-transmitting glass 14, etc.) remain horizontal during vertical movement, avoiding the skew problem that may occur with traditional 2-axis worktables, thereby improving the accuracy and efficiency of monitoring camera image calibration.

[0050] like Figure 1 As shown, in some embodiments of this application, the slider 121 is detachably connected to the crossbeam of the light source mounting bracket 12. The slider 121 can be installed and removed using simple tools or manual operation. When it is necessary to replace or repair the slider 121, no complicated procedures are required, which greatly simplifies the maintenance process and reduces downtime.

[0051] The detachable design allows users to adjust the position of slider 121 according to specific application needs, or replace it with slider 121 of different specifications when necessary to adapt to different load requirements or accuracy standards. For example, in applications requiring higher precision, a more precise slider 121 can be selected to improve the overall performance of the system.

[0052] By changing the number or position of the sliders 121, the distribution of support points of the light source holder 12 can be flexibly adjusted, thereby affecting its stability and smoothness of movement. This is particularly important for meeting the requirements of image calibration equipment for surveillance cameras of different sizes and weights.

[0053] In some embodiments of this application, a locking screw is provided on the slider 121. The locking screw is adapted to abut against the slide rail 111 after the light source mounting bracket 12 is adjusted, so as to fix the slider 121 at a specified height position of the slide rail 111.

[0054] Once the height of the light source mounting bracket 12 is adjusted to the desired position, the position of the slider 121 can be fixed by tightening the locking screw on the slider 121. The locking screw is designed to ensure that the slider 121 is firmly pressed against the slide rail 111, thereby preventing the slider 121 from moving accidentally due to external force or equipment vibration.

[0055] Users can easily lock and unlock slider 121 by simply rotating the locking screw, making height adjustment quick and convenient. This convenient operation is especially important when precise calibration or replacement of cameras of different specifications is required.

[0056] By locking the slider 121 with a locking screw, the light source holder 12 and its supported components (such as the adjustable light source plate 13, the light-transmitting glass 14, and the target paper) can be kept stable at a specified height. This ensures high accuracy and stability during surveillance camera image calibration, even in the presence of external vibrations or other interference factors.

[0057] The locking mechanism not only improves the safety of equipment use but also extends its service life. It avoids unnecessary wear or damage caused by loose slider 121 and also reduces maintenance frequency.

[0058] In some embodiments of this application, the slide rail 111 is provided with scale markings. The scale markings on the slide rail 111 allow users to accurately read the current height position of the light source holder 12. These markings are typically in millimeters or inches and are evenly distributed along the length of the slide rail 111, providing a standardized measurement system.

[0059] By referring to the scale markings on the slide rail 111, users can more precisely adjust the light source holder 12 to the required height position. This is especially important for applications requiring high-precision calibration, such as ensuring that the distance between the target paper and the camera is consistent during the image calibration process of a surveillance camera, which is crucial for obtaining accurate calibration results.

[0060] The graduated markings make height adjustment simpler and faster. Operators can achieve precise height settings without relying on additional measuring tools such as rulers or rangefinders. This not only improves work efficiency but also reduces human error that may be introduced by using external tools.

[0061] In some embodiments of this application, limiting protrusions are formed on the slide rail 111. These limiting protrusions can be located at both ends of the slide rail 111 or at specific positions, acting as physical barriers to prevent the slider 121 from moving further. For example, the protrusions at both ends prevent the slider 121 from completely disengaging from the slide rail 111, or at certain specific positions to define the working range of the slider 121. This design ensures that the slider 121 will not detach from one end of the slide rail 111 due to misoperation or other reasons, thereby protecting the equipment from damage and ensuring the safety of the operator.

[0062] For users, knowing that slider 121 has a defined range of motion allows them to make height adjustments with greater confidence, without worrying about potential problems from excessive movement.

[0063] like Figure 2 As shown, in some embodiments of this application, the distance between the adjustable light source plate 13 and the light-transmitting glass 14 ranges from 10 mm to 13 mm. Maintaining an appropriate distance between the light source plate and the light-transmitting glass 14 helps to achieve uniform and sufficient illumination, which is crucial for obtaining clear, shadow-free images. This directly relates to whether the camera can accurately capture details on the target paper, thus affecting the final calibration results. A reasonable spacing setting helps to reduce errors caused by changes in the light propagation path, ensuring that the light conditions received by the camera during calibration are as consistent as possible. This improves the repeatability and accuracy of the calibration process, and is particularly suitable for the fine calibration work of high-pixel cameras. The spacing range of 10 mm to 13 mm provides a certain degree of flexibility, which can be adjusted according to different types of camera sensors and lens characteristics. Whether for imaging needs at close range or slightly longer distances, the most suitable lighting configuration can be found within this range.

[0064] like Figure 1 As shown, in some embodiments of this application, a computer shelf 113 is also provided on the frame 11, located below the shelf 15. The computer shelf 113 is positioned below the shelf 15, so it does not interfere with the operation or adjustment of the camera equipment placed on the shelf 15. At the same time, this layout optimizes space utilization, making the overall structure more compact and efficient. The computer shelf 113 is mainly used to place computer equipment used to control or monitor the camera calibration process. It can be a simple flat stand or a professional shelf equipped with anti-slip pads, straps, and other fixing devices to ensure the computer is placed stably and safely.

[0065] like Figure 1 As shown, in some embodiments of this application, casters 114 are provided at the bottom of the frame 11. The casters 114 are installed at the four corners of the bottom of the frame 11, allowing the entire device to move easily in any direction. Each caster 114 may also be equipped with a locking mechanism to fix its position when needed, preventing the device from sliding accidentally.

[0066] To adapt to different ground conditions and load-bearing requirements, different types of casters 114 can be selected, such as wheels with rubber tires to reduce noise and protect the floor, or heavy-duty industrial-grade wheels to support heavier loads.

[0067] like Figure 1 As shown, in some embodiments of this application, angle irons 115 are provided at the connection points between the crossbeams and longitudinal beams of the frame 11. Angle irons 115 are common reinforcing elements, typically made of metal, and are L-shaped or right-angled. Installing them at the connection points between the crossbeams and longitudinal beams of the frame 11 can significantly enhance the strength and stability of these critical connection points.

[0068] Angle iron 115 can be securely installed at the intersection of the crossbeam and the longitudinal beam through welding, bolting, or other mechanical connections. This ensures that it will not loosen or separate even during long-term use.

[0069] By strengthening the stability of the connection points, safety hazards caused by structural failure are reduced. For example, during high-precision camera calibration, even the slightest movement can affect the final result; the robust angle iron 115 connection minimizes the occurrence of such problems.

[0070] For any parts not mentioned in this application, existing technologies may be used or referenced.

[0071] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0072] The above description is merely an embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A four-axis lifting platform carrying an adjustable light source for monitoring camera image calibration, characterized in that, include: The frame has four slide rails on its crossbeams, wherein the slide rails extend in the vertical direction; A light source mounting bracket, wherein a slider matching the slide rail is provided on the crossbeam of the light source mounting bracket, the slide rail passes through the slider, and the slider is adapted to slide on the slide rail, wherein the slider is distributed at the four corners of the light source mounting bracket; An adjustable light source board is placed on the light source mounting bracket; A translucent glass is placed on the light source mounting bracket; The target paper is placed on the side of the transparent glass facing the adjustable light source plate; The adjustable light source plate and the light-transmitting glass are distributed sequentially from top to bottom; A shelf is placed on the frame, the shelf is located below the light source mounting bracket, and the shelf is suitable for placing camera equipment.

2. The four-axis lift table with onboard dimmable light source for monitoring camera image calibration of claim 1, wherein, The frame is provided with a mounting base suitable for fixing the slide rail on the crossbeam; The mounting base is detachably connected to the crossbeam of the frame, and the end of the slide rail passes through the mounting base.

3. The four-axis lift table with onboard dimmable light source for monitoring camera image calibration of claim 1, wherein, The slider is detachably connected to the crossbeam of the light source mounting bracket.

4. The four-axis lift table with onboard dimmable light source for monitoring camera image calibration of claim 3, wherein, The slider is provided with a locking screw, which is adapted to abut against the slide rail after the light source mounting bracket is adjusted, so as to fix the slider at a specified height position of the slide rail.

5. The four-axis lift table with onboard dimmable light source for monitoring camera image calibration of claim 4, wherein, The slide rail is equipped with scale markings.

6. The four-axis lift table with onboard dimmable light source for monitoring camera image calibration of claim 4, wherein, Limiting protrusions are formed on the slide rail.

7. The four-axis lift table with onboard dimmable light source for monitoring camera image calibration of claim 1, wherein, The distance between the adjustable light source plate and the light-transmitting glass ranges from 10 mm to 13 mm.

8. The four-axis lifting table with a dimmable light source for monitoring camera image calibration according to any one of claims 1 to 7, characterized in that, The frame is also equipped with a computer storage rack, which is located below the storage board.

9. The four-axis lifting table with a dimmable light source for monitoring camera image calibration according to any one of claims 1 to 7, characterized in that, The bottom of the frame is equipped with casters.

10. The four-axis lift table with onboard dimmable light source for monitoring camera image calibration of any one of claims 1 to 7, wherein, Angle irons are installed at the connection points between the crossbeams and longitudinal beams of the frame.

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