Infrared camera image brightness calibration device

Abstract

An infrared camera image brightness calibration device is characterized by comprising a first fixing device used for fixing a first infrared camera; the second fixing device is used for fixing a second infrared camera; when the first infrared camera is fixed on the first fixing device and the second infrared camera is fixed on the second fixing device, the first infrared camera and the second infrared camera are oppositely arranged and have the same optical axis; the third fixing device is used for fixing a grey card between the first fixing device and the second fixing device and enabling the grey card to be perpendicular to the optical axis direction; and the third fixing device at least can fix the grey card at two different positions. According to the invention, the image brightness of different infrared cameras can be rapidly kept consistent, and the consistency of the performance of products of the same model is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of infrared camera calibration, and in particular to an infrared camera image brightness calibration device. Background Art

[0002] During the production process of infrared camera modules with self-fill illumination, due to the specification errors of various components, there will be inconsistencies in image brightness even if the same parameters are used between modules.

[0003] When producing infrared camera modules with self-fill illumination, each component, including image sensor, infrared LED, driver IC, etc., will have certain errors within specifications. These errors may come from multiple aspects such as production process, material selection, measurement accuracy, etc.

[0004] First of all, as the core component of the module, the image sensor has certain fluctuation ranges in its performance parameters such as sensitivity, dark current, noise, etc. These fluctuations may cause the sensor to respond differently to light under different lighting conditions, thus affecting the overall brightness of the image.

[0005] Secondly, there will be certain errors in the luminous intensity and spectral characteristics of infrared LEDs. Although LEDs are strictly screened and tested before leaving the factory, in actual applications, the luminous performance of LEDs may change due to factors such as working environment, temperature, and aging. This change will directly affect the intensity and effect of the module's fill light, and thus affect the brightness of the image.

[0006] In addition, as an important component of the control module, the fluctuation of the performance parameters of the driver IC may also affect the image brightness. For example, the current control capability and output voltage stability of the driver IC will affect the light-emitting state of the LED, thereby affecting the brightness of the image.

[0007] When the errors of these components are superimposed in the module, there will be large differences in image brightness between modules even if the same parameters are used. This difference may appear as an overall dark or bright image, or obvious brightness unevenness in certain areas.

[0008] The disclosure of the above background technology content is only used to assist in understanding the inventive concept and technical solution of the present invention. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above content has been disclosed on the filing date of this patent application, the above background technology should not be used to evaluate the novelty and creativity of the present application. Summary of the invention

[0009] To this end, the present invention can simultaneously measure the gray card located on the third fixing device through the relatively arranged first fixing device and the second fixing device, and through the position change of the third fixing device, the first infrared camera and the second infrared camera can obtain gray card images at least two positions, so that the brightness of images of different infrared cameras can be quickly kept consistent, which is conducive to the consistency of performance of products of the same model.

[0010] The present invention provides an infrared camera image brightness calibration device, which is characterized by comprising:

[0011] A first fixing device, used for fixing the first infrared camera;

[0012] a second fixing device, used to fix the second infrared camera; when the first infrared camera is fixed on the first fixing device and the second infrared camera is fixed on the second fixing device, the first infrared camera and the second infrared camera are arranged opposite to each other and have the same optical axis;

[0013] A third fixing device, used to fix the gray card between the first fixing device and the second fixing device, and make the gray card perpendicular to the optical axis direction;

[0014] The third fixing device can at least fix the gray card at two different positions.

[0015] Optionally, the infrared camera image brightness calibration device is characterized in that it also includes: a slide rail for moving the gray card so that the gray card located on the optical axis stays at least at two different positions.

[0016] Optionally, the infrared camera image brightness calibration device is characterized by further comprising: a controller for controlling the first infrared camera and the second infrared camera to simultaneously capture the image of the gray card.

[0017] Optionally, the infrared camera image brightness calibration device is characterized in that, during calibration, it includes:

[0018] Step S1: placing the gray card at a first distance in front of the first infrared camera, and allowing the first infrared camera and the second infrared camera to capture a first image of the gray card with a current X;

[0019] Step S2: Calculate the brightness Y1 of the center frame of the first image to obtain a brightness coefficient β=Y1 / Y and a current amplification coefficient α=1 / β; wherein Y is the brightness of the center frame of the image captured by the standard module;

[0020] Step S3: loading the current amplification factor into the first infrared camera and the second infrared camera, setting the gray card at a second distance in front of the first infrared camera by the third fixing device, so that the first infrared camera and the second infrared camera capture the second image of the gray card with the current X*α;

[0021] Step S4: Calculate the brightness Y2 of the center frame of the second image to obtain a brightness coefficient β'=Y2 / Y;

[0022] Step S5: If β' is within a preset range, the current amplification factor α'=1 / β' is saved in the first infrared camera and the second infrared camera; otherwise, execute step S3.

[0023] Optionally, the infrared camera image brightness calibration device is characterized in that the center frame is a rectangular frame centered on the center of the image, and its size remains unchanged.

[0024] Optionally, the infrared camera image brightness calibration device is characterized in that the first infrared camera includes a projector and a receiver;

[0025] The projector is used to project infrared light;

[0026] The receiver is used to receive the reflected signal of the infrared light and expose it.

[0027] Optionally, the infrared camera image brightness calibration device is characterized in that the projector is a structured light projector; and the shortest side length of the rectangular frame is not less than 1 / 10 of the image side length.

[0028] Optionally, the infrared camera image brightness calibration device is characterized in that, when calculating the brightness Y1 of the center frame of the first image, it includes:

[0029] Step S21: extracting pixels of the central frame on the first image and performing binarization;

[0030] Step S22: obtaining the light spot area by threshold comparison;

[0031] Step S23: Calculate the average brightness of the light spot area on the first image as the brightness Y1 of the center frame of the first image.

[0032] Optionally, the infrared camera image brightness calibration device is characterized in that the projector is a floodlight projector; and the longest side length of the rectangular frame is not greater than 1 / 10 of the side length of the image.

[0033] Optionally, the infrared camera image brightness calibration device is characterized in that, when the first infrared camera can project both structured light and floodlight, the gray card is first set at the first distance to project the structured light and floodlight respectively, and then the gray card is set at the second distance to project the structured light and floodlight respectively, and the current amplification factor of the structured light and the current amplification factor of the floodlight are designed respectively, so that the structured light and the floodlight obtain consistent image brightness.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The present invention can calibrate two infrared cameras at the same time, and has a high calibration efficiency; at the same time, the test equipment is fixed by the fixing device, so the calibration accuracy can be guaranteed.

[0036] In view of the differences in infrared cameras, the present invention adopts gray cards to perform calibration at different positions, and adjusts the brightness of the infrared camera according to the brightness of the center point. By changing the distance of the gray card, the current amplification factor is iteratively updated, so that different modules can converge to the same image brightness level, ensuring the product consistency of the same model of infrared cameras. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings in the following descriptions are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without creative work. By reading the detailed description of the non-limiting embodiments with reference to the following drawings, other features, purposes and advantages of the present invention will become more obvious:

[0038] Figure 1 This is a schematic diagram of the structure of an infrared camera image brightness calibration device in an embodiment of the present invention;

[0039] Figure 2 It is a structural schematic diagram of another infrared camera image brightness calibration device in an embodiment of the present invention;

[0040] Figure 3 This is a flow chart of the calibration steps of an infrared camera image brightness calibration device in an embodiment of the present invention;

[0041] Figure 4 This is a schematic diagram of the structure of an infrared camera in an embodiment of the present invention;

[0042] Figure 5 This is a flow chart of steps for calculating the brightness Y1 of the center frame of the first image according to an embodiment of the present invention.

[0043] 1- first fixing device;

[0044] 2-First infrared camera;

[0045] 3- second fixing device;

[0046] 4- Second infrared camera;

[0047] 5- third fixing device;

[0048] 6-Gray card;

[0049] 7- Slide rail; DETAILED DESCRIPTION

[0050] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0051] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein, for example, can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0052] An infrared camera image brightness calibration device provided in an embodiment of the present invention is intended to solve the problems existing in the prior art.

[0053] The following specific embodiments are used to describe in detail the technical solution of the present invention and how the technical solution of the present application solves the above technical problems. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present invention will be described below in conjunction with the accompanying drawings.

[0054] The present invention can simultaneously measure the gray card located on the third fixing device through the relatively arranged first fixing device and the second fixing device, and through the position change of the third fixing device, the first infrared camera and the second infrared camera can obtain gray card images at least two positions, so that the brightness of images of different infrared cameras can be quickly kept consistent, which is conducive to the consistency of performance of products of the same model.

[0055] Since the image brightness and the infrared current value of each infrared camera are in a linear relationship under the same exposure gain, the present invention can perform rapid and accurate adjustments while keeping the parameters of the receiving end unchanged.

[0056] Figure 1 FIG. 1 is a schematic diagram of the structure of an infrared camera image brightness calibration device according to an embodiment of the present invention. Figure 1 As shown, an infrared camera image brightness calibration device in an embodiment of the present invention includes:

[0057] The first fixing device 1 is used to fix the first infrared camera 2 .

[0058] Specifically, the first fixing device ensures that the first infrared camera is in a stable position during the calibration process without movement or shaking, and that the direction of the first infrared camera is oriented in a specified direction. The first fixing device can be mechanically clamped, magnetically attracted, or other reliable fixing methods to accommodate infrared cameras of different models and sizes. At the same time, it also has an adjustment function that can fine-tune the position and angle of the camera to ensure the accuracy of the camera optical axis.

[0059] The second fixing device 3 is used to fix the second infrared camera 4; when the first infrared camera is fixed on the first fixing device and the second infrared camera is fixed on the second fixing device, the first infrared camera and the second infrared camera are arranged opposite to each other and have the same optical axis.

[0060] Specifically, the second fixture is arranged opposite to the first fixture. Similar to the first fixture, the second fixture also adopts a reliable fixing method and adjustment function. Importantly, the design of the two fixtures allows the optical axes of the two cameras to remain consistent when they are fixed, which is the key to ensure calibration accuracy. The optical axis is a straight line starting from the center of the camera lens and passing through the center of the imaging sensor. For two infrared cameras arranged opposite to each other, their optical axes should be parallel and aligned.

[0061] The third fixing device 5 is used to fix the gray card 6 between the first fixing device and the second fixing device, and make the gray card perpendicular to the optical axis. The third fixing device can at least fix the gray card in two different positions.

[0062] Specifically, the third fixture fixes the gray card between the first fixture and the second fixture, and ensures that the gray card is located at the center of the field of view of the two infrared cameras and perpendicular to their optical axis direction, as a reference during the calibration process. A gray card is a card with standard reflectivity, which is used to calibrate the exposure and color balance of the camera. The third fixture can fix the gray card in at least two different positions, which helps to simulate different shooting distances and angles during the calibration process, so as to more comprehensively evaluate the brightness performance of the camera. The gray card is fixed perpendicular to the optical axis to ensure that the image captured by the camera is standard and non-tilted, which helps to eliminate brightness differences caused by angle changes and improve the accuracy of calibration. The third fixture adopts a stable design to ensure that the gray card will not move or deform during the calibration process, which helps to maintain the consistency and reliability of the calibration results.

[0063] The third fixture usually contains a movable platform or bracket that allows the gray card to be moved between at least two different positions. This allows testing the camera's response at different distances or angles, or replacing gray cards with different reflectivity to accommodate different testing needs when necessary.

[0064] This embodiment aims to create a well-controlled environment where two infrared cameras can capture images under exactly the same conditions, making it possible to perform accurate brightness calibration by comparing their imaging results of the same target (i.e., gray card) at different distances. This is essential to ensure the accuracy and reliability of infrared imaging systems, especially in applications that require high-precision measurements, such as night vision equipment, thermal imagers, or other fields that rely on infrared technology.

[0065] In some embodiments, it also includes: a controller for controlling the first infrared camera and the second infrared camera to simultaneously capture the image of the gray card. The controller is used to control the first infrared camera and the second infrared camera to simultaneously capture the image of the gray card. By synchronous acquisition, it is ensured that the two cameras perform imaging under the same conditions, thereby improving the accuracy and reliability of calibration. The controller generally includes a microprocessor, a communication interface, and a control circuit. Its design needs to ensure high-precision synchronous control and have good anti-interference performance to adapt to various complex usage environments. The controller is connected to the two infrared cameras via a cable or wirelessly to transmit control signals and image data. This connection method requires low latency and high stability to ensure real-time performance and data integrity. The controller is widely used in situations where high-precision infrared imaging systems are required, such as night vision monitoring, thermal imaging analysis, and industrial detection. In these applications, the synchronous control capability of the controller is crucial.

[0066] Figure 2 FIG. 2 is a schematic diagram of the structure of another infrared camera image brightness calibration device according to an embodiment of the present invention. Figure 2As shown, another infrared camera image brightness calibration device in the embodiment of the present invention further includes:

[0067] The slide rail 7 is used to move the gray card so that the gray card located on the optical axis stays at least at two different positions.

[0068] Specifically, the slide rail is used in combination with the third fixture to allow the gray card to move on the optical axis and stay in at least two different positions, ensuring the calibration of the infrared camera at different positions and improving the accuracy and reliability of the calibration. The slide rail design allows the gray card to move easily on the optical axis and be precisely positioned at the desired position. The slide rail is usually made of high-precision, low-friction materials to ensure that the gray card remains stable and smooth during movement. The design of the slide rail also needs to consider easy installation and maintenance to facilitate the long-term use of the equipment.

[0069] The slide rail and the third fixture work closely together to ensure the fixation and stability of the gray card at different positions. This design allows the gray card to remain perpendicular to the optical axis during the calibration process, thereby providing an accurate calibration reference.

[0070] The slide rail is usually equipped with an adjustment mechanism that allows the user to adjust the position of the gray card as needed. This adjustment mechanism can be operated manually or electrically, providing flexibility and convenience to adapt to different calibration needs.

[0071] Slide rails are widely used in various infrared camera image brightness calibration devices, especially in situations where high precision and high stability are required. Through the use of slide rails, accurate evaluation and calibration of infrared camera performance can be achieved.

[0072] Figure 3 FIG. 1 is a flow chart of the calibration steps of an infrared camera image brightness calibration device according to an embodiment of the present invention. Figure 3 As shown, an infrared camera image brightness calibration device in an embodiment of the present invention includes:

[0073] Step S1: placing the gray card at a first distance in front of the first infrared camera, and enabling the first infrared camera and the second infrared camera to capture a first image of the gray card with a current X.

[0074] In this step, the gray card is a card with a specific reflectivity that is used to calibrate the color and white balance of the camera or camera. In infrared imaging, the gray card can also be used as a standard brightness reference. The first distance is pre-set to ensure that the gray card can occupy an appropriate part of the camera's field of view and maintain an appropriate distance from the camera when capturing the image. At the same time, it is necessary to ensure that the gray card is perpendicular to the optical axis of the two cameras in order to obtain accurate image data.

[0075] Next, the first and second infrared cameras are made to start working at the same time with the same current X through the control circuit or software instructions. The current X here refers to the standard current value when the camera is working normally. Under this current, the two cameras will synchronously capture images of the gray card, and these images will be used for subsequent brightness calculation and analysis. It should be noted that the data obtained by the first infrared camera and the second infrared camera are processed separately. For the convenience of description, this specification takes the current X as an example. In the actual implementation of the present invention, the current values ​​of the first infrared camera and the second infrared camera may be different.

[0076] Step S2: Calculate the brightness Y1 of the center frame of the first image to obtain a brightness coefficient β=Y1 / Y and a current amplification coefficient α=1 / β.

[0077] In this step, Y is the brightness of the center frame of the image captured by the standard module. By performing brightness analysis on the central area of ​​the first image, the average brightness value Y1 of the area can be obtained. This value reflects the imaging brightness of the gray card by the infrared camera under a given current X. Y is a known center frame brightness of a gray card image captured by the standard module under the same conditions. It is used as a reference value to compare and calibrate the module to be calibrated. The brightness coefficient β is the ratio of the brightness Y1 of the center frame of the image captured by the module to be calibrated to the brightness Y of the center frame of the image captured by the standard module. It reflects the difference in brightness performance between the module to be calibrated and the standard module. The current amplification factor α is the reciprocal of the brightness coefficient β, that is, α = 1 / β. This coefficient is used to adjust the working current of the module to be calibrated so that its imaging brightness is close to that of the standard module. The center frame is a rectangular frame centered on the center of the image, and its size remains unchanged. Due to the angle problem, the reflectivity of the center area of ​​the image is the most accurate, such as 60%, while the reflectivity accuracy of other points is not so high. Therefore, using the center area of ​​the image for standardization has better accuracy than using the entire image for adjustment.

[0078] Step S3: Load the current amplification factor into the first infrared camera and the second infrared camera, and set the gray card at a second distance in front of the first infrared camera through the third fixing device, so that the first infrared camera and the second infrared camera capture the second image of the gray card with the current X*α.

[0079] In this step, the current amplification factor α calculated in the second step is applied to the first and second infrared cameras. This means that the operating current of the camera will be adjusted from the original X to X*α, in order to obtain an image closer to the standard brightness. Subsequently, the gray card is moved to a new position, that is, the second distance in front of the first infrared camera, using a third fixing device. This new position also needs to ensure that the gray card is perpendicular to the optical axis direction of the two cameras. After that, the two cameras are again synchronized to capture the second image of the gray card with the adjusted current X*α.

[0080] Step S4: Calculate the brightness Y2 of the center frame of the second image to obtain a brightness coefficient β'=Y2 / Y.

[0081] In this step, by analyzing the brightness of the central area of ​​the second image, the average brightness value Y2 of the area can be obtained. This value reflects the imaging brightness of the gray card by the infrared camera under the adjusted working current. The brightness coefficient β' is the ratio of the brightness Y2 of the center frame of the image taken by the adjusted module to the brightness Y of the center frame of the image taken by the standard module. It is used to evaluate whether the brightness performance of the adjusted module is close to that of the standard module.

[0082] Step S5: If β' is within a preset range, the current amplification factor α'=1 / β' is saved in the first infrared camera and the second infrared camera; otherwise, execute step S3.

[0083] In this step, the preset range is a threshold range set according to actual needs, which is used to determine whether the adjusted module brightness meets the requirements. If the brightness coefficient β' is within the preset range, it means that the adjusted module brightness is close to the standard module. At this time, the current amplification factor α' (i.e. 1 / β') can be saved in the infrared camera for subsequent use. If the brightness coefficient β' is not within the preset range, it means that the adjusted module brightness still does not meet the requirements. At this time, step S3 needs to be repeated to further adjust the working current of the module until the requirements are met.

[0084] This embodiment introduces a gray card and a current amplification factor to accurately adjust the working current of the module, thereby ensuring that images taken by different modules under the same conditions have consistent brightness. Based on the differences between different infrared cameras, this embodiment uses a gray card to test the brightness of the center point of the image and iteratively adjusts the current, so that the brightness of images from different infrared cameras quickly remains consistent, which is conducive to the consistency of performance of products of the same model.

[0085] Figure 4 FIG. 1 is a schematic diagram of the structure of an infrared camera in an embodiment of the present invention. Figure 4 As shown, an infrared camera in an embodiment of the present invention includes a projector and a receiver;

[0086] The projector is used for projecting infrared light.

[0087] Specifically, the main function of the projector is to project infrared light onto the target scene. This infrared light usually has a specific wavelength range and is used to illuminate the scene so that the receiver can capture enough information. The projector contains an infrared light emitting diode (LED) or other type of infrared light source. When these light sources are activated, they emit infrared light, which is then projected onto the target scene. In the infrared camera image brightness calibration device, the projector ensures that the target scene is illuminated by sufficient and uniform infrared light. This is critical to the strength and consistency of the reflected signal received by the receiver.

[0088] The receiver is used to receive the reflected signal of the infrared light and expose it.

[0089] Specifically, the receiver is used to receive the reflected signal of the infrared light projected by the projector on the target scene and convert it into an electrical signal or a digital image. The receiver may contain an infrared sensor or an image sensor inside, which is sensitive to infrared light. When the reflected infrared light reaches the receiver, the sensor captures the light and converts it into an electrical signal. These signals are then processed and converted into a digital image.

[0090] In the infrared camera image brightness calibration device of this embodiment, the receiver is responsible for capturing the reflected infrared light signal and converting it into an image that can be used for analysis. By adjusting parameters such as the operating current of the projector and the exposure time of the receiver, the quality of the received image can be optimized, thereby improving the consistency of the image brightness.

[0091] In some embodiments, the projector is a structured light projector; the shortest side length of the rectangular frame is not less than 1 / 10 of the side length of the image. In an infrared camera, when the projector is designed as a structured light projector, it is not only used to simply illuminate the target scene, but also to emit a light with a specific pattern or structure. After this light is reflected by an object, its deformation or displacement can be captured and analyzed by a receiver to obtain three-dimensional information of the object.

[0092] The structured light projector contains a light source and an optical system that can produce complex light patterns. When the light source is activated, it emits light, which is projected into specific patterns (such as dots, lines, grids, etc.) through the optical system. After these patterns are reflected by objects, their shapes and positions change, and these changes can be captured by the receiver and used to calculate the three-dimensional shape of the object.

[0093] The shortest side of the rectangle should be at least one-tenth of the length of the entire image. This ratio ensures that the rectangle is large enough to contain enough image information for analysis, while not being too large to contain too much irrelevant information. This helps ensure the accuracy and consistency of the analysis results, especially when processing images taken at different distances and angles. The choice of structured light projector and rectangle plays an important role in the infrared camera image brightness calibration device. By combining these techniques, the accuracy and consistency of image analysis can be further improved.

[0094] In some embodiments, the projector is a flood projector; the longest side length of the rectangular frame is no greater than 1 / 10 of the side length of the image. When the projector is a flood projector, its main function is to project uniform and widely distributed infrared light to the target scene. This projection method is usually used to illuminate a larger area so that the receiver can capture more environmental details. Unlike a structured light projector, a flood projector does not produce a specific light pattern, but provides uniform and widespread infrared light illumination to enhance the receiver's ability to capture the target scene.

[0095] A flood projector contains one or more infrared light sources that diffuse or focus the light into a uniform beam that is projected onto the target scene. This uniform illumination helps the receiver capture a clearer image, especially in low-light environments.

[0096] The longest side length is no more than 1 / 10 of the image side length, which ensures that the rectangular box does not occupy too large a proportion of the image, thereby allowing sufficient context information to be retained in the image. At the same time, a smaller rectangular box is also easier to focus on the brightness of the center point of the image, thereby removing interference from external factors such as angles and improving accuracy.

[0097] In some embodiments, when the first infrared camera can project both structured light and floodlight, the gray card is first set at the first distance to project structured light and floodlight respectively, and then the gray card is set at the second distance to project structured light and floodlight respectively, and the current amplification factor of the structured light and the current amplification factor of the floodlight are designed respectively, so that the structured light and the floodlight obtain consistent image brightness. The gray card has a constant reflectivity and can ensure stable light intensity reflected under different lighting conditions. Two distances, namely the first distance and the second distance, are set to test the brightness performance of the structured light and the floodlight at different distances. Ensure that the module can project structured light and floodlight respectively, and has the function of adjusting the current amplification factor.

[0098] Test at the first distance:

[0099] Place the grey card at the first distance.

[0100] Project structured light and record image brightness.

[0101] Adjust the current amplification factor of the structured light to make the image brightness reach the preset value.

[0102] Cast a flood light and record the image brightness.

[0103] Adjust the current amplification factor of the floodlight to make the image brightness consistent with the image brightness of the structured light.

[0104] Test at the second distance:

[0105] Move the gray card to the second distance.

[0106] Repeat the above steps to adjust the current amplification factors of the structured light and flood light respectively to make the image brightness of the two consistent.

[0107] Determination of current amplification factor:

[0108] Structured light current amplification factor: At the first distance and the second distance, the current amplification factor required to make the brightness of the structured light image reach a preset value is recorded respectively.

[0109] Flood current amplification factor: At the first distance and the second distance, the current amplification factor required to make the flood image brightness consistent with the structured light image brightness is recorded respectively.

[0110] Through the above experimental steps, the current amplification factor required to obtain consistent image brightness for structured light and flood light at different distances can be determined. These factors can be applied in the production and debugging of infrared cameras to ensure that the module can provide high-quality image output under different lighting conditions.

[0111] Figure 5 This is a flow chart of steps for calculating the brightness Y1 of the center frame of the first image according to an embodiment of the present invention.

[0112] like Figure 5 As shown, in an embodiment of the present invention, a step of calculating the brightness Y1 of the center frame of the first image includes:

[0113] Step S21: extract pixels of the central frame on the first image and perform binarization.

[0114] In this step, the center box position on the first image is first determined. This is usually obtained through preset coordinates or dynamically calculated based on the image size. Next, all pixels covered by the center box are extracted from the image. Binarization is then performed. Binarization is the process of converting an image to contain only two pixel values ​​(usually 0 and 255). This helps to simplify the image and make it more suitable for subsequent processing.

[0115] In this step, we choose an appropriate threshold and compare the pixel values ​​within the center box with this threshold. Pixels above the threshold are set to 255 (white), while pixels below the threshold are set to 0 (black).

[0116] Step S22: Obtain the light spot area through threshold comparison.

[0117] In this step, a threshold is applied again in the binarized image (the same threshold as used in binarization). This threshold is used to distinguish the spot area (usually the brighter area) from the background area. Pixels above this threshold are considered to be part of the spot area. By comparing the thresholds, it can be determined which pixels belong to the spot area. These pixels will be used to calculate the brightness mean later. The spot area obtained in this step is a mask, which can be mapped to the first image to obtain the corresponding area.

[0118] Step S23: Calculate the average brightness of the light spot area on the first image as the brightness Y1 of the center frame of the first image.

[0119] In this step, since the spot area has been determined, it is necessary to calculate the average brightness of these pixels on the first image. The average brightness will be the arithmetic average of these pixel values, and the calculated average brightness will be used as the brightness Y1 of the center frame of the first image. This value can be used for subsequent comparison, analysis or calibration processes.

[0120] By following these steps, we can accurately calculate the brightness of the center frame of the first image captured by the infrared camera. These steps not only ensure the accuracy of the calculation, but also improve the processing efficiency and reliability.

[0121] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the embodiments can be referred to each other. The above description of the disclosed embodiments enables professionals and technicians in this field to implement or use the present invention. Various modifications to these embodiments will be obvious to professionals and technicians in this field, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown in this article, but will comply with the widest range consistent with the principles and novel features disclosed herein.

[0122] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art may make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. An infrared camera image brightness calibration device, characterized in that: include: A first fixing device, used for fixing the first infrared camera; a second fixing device, used to fix the second infrared camera; when the first infrared camera is fixed on the first fixing device and the second infrared camera is fixed on the second fixing device, the first infrared camera and the second infrared camera are arranged opposite to each other and have the same optical axis; A third fixing device, used to fix the gray card between the first fixing device and the second fixing device, and make the gray card perpendicular to the optical axis direction; The third fixing device can at least fix the gray card at two different positions.

2. The infrared camera image brightness calibration device according to claim 1, characterized in that: Also includes: The slide rail is used to move the gray card so that the gray card located on the optical axis stays at least at two different positions.

3. The infrared camera image brightness calibration device according to claim 1, characterized in that: Also includes: The controller is used to control the first infrared camera and the second infrared camera to simultaneously capture the image of the gray card.

4. The infrared camera image brightness calibration device according to claim 1, characterized in that: During calibration, include: Step S1: placing the gray card at a first distance in front of the first infrared camera, and making the first infrared camera and the second infrared camera capture a first image of the gray card with a current X; Step S2: Calculate the brightness Y1 of the center frame of the first image to obtain a brightness coefficient β=Y1 / Y and a current amplification coefficient α=1 / β; wherein Y is the brightness of the center frame of the image captured by the standard module; Step S3: loading the current amplification factor into the first infrared camera and the second infrared camera, setting the gray card at a second distance in front of the first infrared camera by the third fixing device, so that the first infrared camera and the second infrared camera capture the second image of the gray card with the current X*α; Step S4: Calculate the brightness Y2 of the center frame of the second image to obtain a brightness coefficient β'=Y2 / Y; Step S5: If β' is within a preset range, the current amplification factor α'=1 / β' is saved in the first infrared camera and the second infrared camera; otherwise, execute step S3.

5. The infrared camera image brightness calibration device according to claim 4, characterized in that: The center frame is a rectangular frame centered at the center of the image, and its size remains unchanged.

6. The infrared camera image brightness calibration device according to claim 4, characterized in that: The first infrared camera includes a projector and a receiver; The projector is used to project infrared light; The receiver is used to receive the reflected signal of the infrared light and expose it.

7. The infrared camera image brightness calibration device according to claim 6, characterized in that: The projector is a structured light projector; the shortest side length of the rectangular frame is not less than 1 / 10 of the side length of the image.

8. The infrared camera image brightness calibration device according to claim 4, characterized in that: The calculation of the brightness Y1 of the center frame of the first image includes: Step S21: extracting pixels of the central frame on the first image and performing binarization; Step S22: obtaining the light spot area by threshold comparison; Step S23: Calculate the average brightness of the light spot area on the first image as the brightness Y1 of the center frame of the first image.

9. The infrared camera image brightness calibration device according to claim 6, characterized in that: The projector is a floodlight projector; the longest side length of the rectangular frame is no greater than 1 / 10 of the side length of the image.

10. The infrared camera image brightness calibration device according to claim 4, characterized in that: When the first infrared camera can project both structured light and floodlight, the gray card is first set at the first distance to project the structured light and floodlight respectively, and then the gray card is set at the second distance to project the structured light and floodlight respectively, and the current amplification factor of the structured light and the current amplification factor of the floodlight are designed respectively, so that the structured light and the floodlight obtain consistent image brightness.

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