Log scale measuring system

Abstract

The utility model discloses a log gauge system which comprises a camera, a moving mechanism and one or more light emitters. The camera is used for shooting images of a plurality of log end faces in a view finding area; the moving mechanism at least comprises a driving mechanism and one or more moving blocks; the driving mechanism drives the moving block to do reciprocating motion; the light emitter is fixedly connected with the moving block; the light emitter is used for projecting light lines to a plurality of log end faces in the view finding area; when the moving mechanism drives the light emitter to move, light lines projected by the light emitter gradually and completely scan the end faces of all the logs, the camera records the scanning process, and a scanning process image shot by the camera is used for extracting the outline of the end faces of the logs and calibrating the size of the end faces of the logs.

Description

Technical Field

[0001] This utility model relates to the field of log measuring technology, and in particular to a log measuring system for acquiring log end face images and calibrating the dimensions of log end face images. Background Technology

[0002] Existing technologies typically employ a method of taking photos with a camera and performing image analysis to measure the end face dimensions of logs, i.e., sizing. The types of cameras used include monocular cameras, binocular cameras, depth cameras, etc., or a combination of cameras and other measurement methods such as LiDAR can be used for identification.

[0003] According to the measurement specifications, the outline shape of the log's end face must first be obtained, and then the minor and major diameters must be measured sequentially. Therefore, an accurate image of the log's end face outline, with its actual dimensions precisely calibrated, is essential basic data for image-based measurement operations. However, due to the complexity of the measurement environment, errors are often prone to occur, specifically including:

[0004] 1. In outdoor environments, the image quality is unstable due to changes such as sunlight, rain, fog, and shadows. Image analysis and deep learning of a large amount of raw data are required to improve recognition accuracy, but contour recognition errors may still occur.

[0005] 2. In order to improve work efficiency, it is necessary to measure a number of logs in batches. At this time, the positions of the end face of each log and the camera are different, some are bright and some are dark, and they may overlap in the image, making it difficult to uniformly calibrate the size.

[0006] 3. Due to the cutting of logs, some logs may have bark interference spreading outwards at the edge of the end face. It is difficult to determine the nature of this part through image recognition or lidar scanning.

[0007] Therefore, there is a need to provide a log measuring system and a corresponding image processing method to solve the above problems. Utility Model Content

[0008] This utility model relates to a log measuring device. Utilizing the near-planar nature of log end faces, one or more light rays are projected onto several log end faces within the camera's viewfinder using a light emitter. A moving mechanism then causes the light rays to move relative to the log end faces at a uniform speed or a fixed distance, ensuring the projection trajectory of the light rays completely covers the entire log end face. The entire process is then captured by a camera and analyzed. Based on the changes in the light rays, the contours of each log end face are extracted. Finally, the actual size of the log corresponding to the image of each light ray, and / or the spacing between the light rays, is accurately calibrated. This solves the measurement error problem mentioned in the background art.

[0009] To achieve the above objectives, this utility model provides the following technical solution: a log measuring system, comprising a camera, a moving mechanism, and one or more light emitters;

[0010] The camera is used to capture images of several log end faces within the viewfinder area;

[0011] The moving mechanism includes at least a drive mechanism and one or more moving blocks; the drive mechanism drives the moving blocks to reciprocate.

[0012] The light emitter is fixedly connected to the movable block;

[0013] The light emitter is used to project light lines onto several log end faces within the framing area;

[0014] When the moving mechanism drives the light emitter to move, the light lines projected by the light emitter gradually and completely scan each end face of the log, and the camera records the scanning process. The scan process images captured by the camera are used to extract the log end face contours and size calibration.

[0015] Preferably, the camera is a monocular camera, a binocular camera, or a depth camera.

[0016] Preferably, the light emitter is a laser emitter.

[0017] Preferably, any one of the light emitters can emit one or multiple intersecting light rays simultaneously.

[0018] Preferably, when there are multiple light emitters, the one or more light rays emitted by each light emitter are in one-to-one correspondence and are parallel to each other.

[0019] Preferably, the light emitter emits two mutually perpendicular light rays, and the angle between the two light rays and the moving trajectory of the moving block is 45°.

[0020] Preferably, the plane formed by the projection path of any light ray projected by the light emitter is perpendicular to the image sensor in the camera.

[0021] Preferably, the moving direction of the moving mechanism is consistent with the horizontal or vertical direction of the image sensor in the camera, and the moving trajectory of the moving block is parallel to the image sensor in the camera.

[0022] Furthermore, the moving mechanism is a moving mechanism that enables the moving block to move at a constant speed or to move at a specified distance, and is used to calculate the actual distance of light lines at different positions based on the shooting interval when comparing images taken by the camera at different time points.

[0023] Alternatively, when there are multiple light emitters, a fixed distance value is set between the multiple light emitters for sizing the images captured by the camera.

[0024] Preferably, a laser rangefinder is installed in parallel with the light emitter in the same direction. The laser rangefinder is fixedly connected to the moving block. The distance data measured by the laser rangefinder provides reference data for the dimension calibration of the log end face and is used to determine the length of the log.

[0025] Preferably, the camera is fixedly mounted, or moves and takes pictures following the light emitter.

[0026] To address the problems described in the background art, the following processing methods are provided in relation to the aforementioned log measuring system.

[0027] A method for extracting the contour image of the end face of a log includes the following steps:

[0028] S101, one or more cameras are aimed at one or more end faces of logs to take pictures;

[0029] S102, one or more light emitters project light lines onto the end face of the log within the shooting area; then, the light emitters are moved relative to the end face of the log.

[0030] This allows the light rays projected by the light emitter to gradually and completely scan each end face of the log;

[0031] S103, the camera continuously captures images and records the scanning process of the light emitter on the end face of the log to form a scanning process image sequence;

[0032] S104, compare and analyze the image sequence of the scanning process, and combine the light segments projected on the end face of the log to form a complete outline of the end face of the log.

[0033] Furthermore, the method for marking the end face contour of the log includes the following steps:

[0034] S201, Extract images from different time points in the image sequence of the scanning process to obtain the pixel spacing Dpix between the light line segments projected onto the end face of the log.

[0035] S202, acquire the movement distance data Dlen at different time points during the movement of the light emitter;

[0036] S203, divide the pixel spacing Dpix within the log end face contour by the corresponding moving distance data Dlen to obtain the end face pixel accuracy of the log end face.

[0037] Alternatively, a method for marking the end face contour of a log includes the following steps:

[0038] S301, sets up several fixedly installed light emitters with an installation spacing of Dlen1, simultaneously projecting several, or several groups of mutually parallel light lines.

[0039] Several, or several sets of corresponding light lines are formed on the end face of the log;

[0040] S302, obtain the pixel spacing Dpix1 between corresponding light line segments;

[0041] S303, divide the pixel spacing Dpix1 within the log end face contour by the corresponding installation spacing Dlen1 to obtain the end face pixel accuracy of the log end face.

[0042] It should be noted that because the actual distance between each log end face and the camera varies, the pixel precision of each log end face at different coordinate positions on the image will be different. Therefore, it is necessary to calculate them separately. The pixel precision of the end face can be expressed in "pixels per centimeter".

[0043] Furthermore, when multiple cameras are used simultaneously for shooting, each camera captures a portion of the entire viewfinder area; the shooting areas of each camera overlap, and the images captured by each camera are stitched together to form an image of the complete viewfinder area.

[0044] It should be noted that in some scenarios, the measurement distance is limited, and it is impossible to capture images of all the ends of the logs completely using a single camera, which can easily lead to occlusion. Therefore, by using multiple cameras to shoot in different areas, the shooting distance can be shortened and the phenomenon of logs occluding each other can be reduced.

[0045] Furthermore, the plane formed by the projection path of any light ray projected by the light emitter is perpendicular to the plane of the image sensor in the camera.

[0046] Furthermore, the direction of movement of the light emitter is consistent with the horizontal or vertical direction of the image sensor in the camera, and the movement trajectory is parallel to the plane of the image sensor in the camera.

[0047] Furthermore, the moving mechanism used to drive the light emitter to move is a moving mechanism capable of moving at a constant speed or moving a specified distance.

[0048] Furthermore, the light emitter can emit one or more intersecting light lines to acquire multi-directional log contour data during movement.

[0049] Furthermore, when there are differences in the pixel precision of the end face at different positions in the log end face contour image, the end face contour image is stretched, or / and compressed, or / and rotated in three-dimensional space through a correction algorithm, so that the actual pixel precision at different positions in the log end face contour image tends to be consistent.

[0050] Furthermore, when executing the correction algorithm, the pixel precision of the end face at some typical positions or all positions is extracted, and the average pixel precision is obtained as the pixel precision value that the correction algorithm aims to achieve in the end.

[0051] It should be noted that because the positional relationship between each log end face and the image sensor plane in the camera is not perfectly parallel, each log end face may be distorted in the image. Specifically, this manifests as differences in pixel precision at different locations, requiring correction algorithms. This highlights the advantage of simultaneously projecting multiple intersecting light lines, facilitating image correction from more angles and saving time on mobile scanning. Furthermore, when there are features within the log end face that affect the light lines, such as dents or cracks, images of the corresponding locations can be extracted for identification by algorithms or manual verification, and / or confirmation.

[0052] Furthermore, the laser rangefinder is used in conjunction with the light emitter. The distance data measured by the laser rangefinder provides reference data for the dimension calibration of the log end face and is used to determine the length of the log.

[0053] Furthermore, the log measuring system and method are applied to vehicle-mounted log measuring systems, log-carrying machine log measuring systems, stacked log measuring systems, or spread-out log measuring systems.

[0054] Compared with the prior art, the beneficial effects of this utility model are:

[0055] 1. This system has a simple structure and is easy to implement, without requiring extensive deep learning and training on log images; it is particularly designed for log measurement applications, achieving the effect of "non-contact physical scanning";

[0056] 2. The light emitter, taking a laser emitter as an example, projects a line segment onto the end face of the log that is very different from the end face of the log itself, making it easy to identify and adaptable to various complex on-site environmental conditions; the laser emitter can form a precise dynamic scale on each end face of the log and achieve size calibration; it can be applied to various application scenarios such as vehicle-mounted log measurement, stacked log measurement, and spread-out log measurement.

[0057] 3. Experiments have shown that the laser lines have a strong contrast with the end face of the log, making them easily identifiable even in outdoor environments; furthermore, the visibility of the laser lines can be improved by increasing the laser emission power.

[0058] 4. By increasing the number of light emitters, the moving distance of the light emitters can be shortened, thus increasing the scanning speed and making the response speed faster;

[0059] 5. It can measure the object distance between each log end face and the camera, thereby indirectly obtaining accurate log length data based on the pre-obtained distance between the cameras on both sides of the log end face. Attached Figure Description

[0060] Figure 1 This is a schematic diagram of the structure of the present invention. Figure 1 (Including a diagram showing the light emitter in two different locations);

[0061] Figure 2 This is a schematic diagram of the structure of the present invention. Figure 2 ;

[0062] Figure 3 To and Figure 2 Corresponding application scenario diagrams (including a 3D diagram of a log stack);

[0063] Figure 4 To and Figure 1 The corresponding image processing procedure and calculation results of the log end face;

[0064] Figure 5 To and Figure 2 The corresponding image processing procedure and calculation results of the log end face;

[0065] In the diagram: 1. Camera, 2. Moving mechanism, 3. Light emitter, 201. Drive mechanism, 202. Moving block;

[0066] The arrows La1 and La2 indicate the range of the camera's viewfinder;

[0067] Arrow Lb indicates the direction in which the ray emitter projects light when it is in the first position, and arrow Lbm indicates the direction in which the ray emitter projects light when it has moved a distance Dlen to the second position; the distance between the first and second positions is Dlen;

[0068] The two arrows, Lb1 and Lb2, indicate the directions in which the light rays are projected by the two light emitters, with the installation distance between the two light emitters being Dlen1. Detailed Implementation

[0069] To provide a clearer understanding of the technical features, objectives, and effects of this utility model, the specific embodiments of this utility model are now described with reference to the accompanying drawings.

[0070] Example 1:

[0071] like Figure 1 As shown, a log measuring system includes a camera 1, a moving mechanism 2, and a light emitter 3. The camera 1 is used to capture images of several log end faces within a viewing area. The moving mechanism 2 includes at least a drive mechanism 201 and one or more moving blocks 202. The drive mechanism 201 drives the moving blocks 202 to reciprocate. The light emitter 3 is fixedly connected to the moving blocks 202. The light emitter 3 projects light lines onto several log end faces within the viewing area. When the moving mechanism 2 drives the light emitter 3 to move, the light lines projected by the light emitter 3 gradually and completely scan each log end face, and the camera 1 records the scanning process. The scan images captured by the camera 1 are used to extract the log end face contours and size calibration. The camera 1 is a monocular camera, a binocular camera, or a depth camera. The light emitter 3 is a laser emitter.

[0072] The moving mechanism 2 moves in the same direction as the image sensor in the camera 1, either horizontally or vertically, and the moving block 202 moves parallel to the image sensor in the camera 1. When the light emitter 3 moves, the emitted light rays completely sweep across each log end face. In the image captured by the camera 1, at the edge contour of the log end face, the light rays will form significant breaks or bends. Thus, the contours of each log end face can be accurately extracted through image analysis.

[0073] It should be noted that, since the end face of a log is approximately flat and the positions of each log end face are not completely aligned, the light rays projected onto a single log end face will appear as a straight line segment, which can serve as a reliable basis for image recognition and analysis. After splicing together the straight line segments at different positions, a complete log end face outline can be formed.

[0074] The moving mechanism 2 in this embodiment adopts a stepper motor slide table as used in the prior art, including a stepper motor (i.e., drive mechanism 201), a lead screw, and a nut; the stepper motor drives the lead screw to rotate, and the lead screw drives the nut to reciprocate. This mechanism has good motion accuracy and can realize uniform speed movement or fixed distance movement of the nut (i.e., sliding block).

[0075] In this embodiment, as Figure 4 As shown, the light emitter 3 projects a line of light onto the end face of the log, and the camera 1 captures corresponding images when the sliding block moves to different positions. Figure 4As shown, the image captured by the sliding block at the first position (solid line) is P01, and the image captured by the sliding block at the second position (dashed line) is P02. The distance between the first and second positions is Dlen = 10 cm. Images P01 and P02 are superimposed to form PX01. Image analysis is used to calculate the pixel spacing Dpix between the two light line segments on the log end face. The actual measured Dpix is ​​181 pixels. Dividing the pixel spacing Dpix within the log end face contour by the corresponding moving distance Dlen yields the end face pixel accuracy: 181 pixels / 10 cm = 18.1 pixels / cm. Therefore, the resolution (physical size of a single pixel) of this image area is approximately 0.55 mm, fully meeting the measurement accuracy requirements for log measurement. The end face pixel accuracy is used to calculate the actual dimensions of the log end face corresponding to the log end face contour image.

[0076] like Figure 4 As shown, although the placement of the logs is not very intuitive from the image, the actual placement of each log in the image is at different distances from camera 1, which is reflected in the different pixel precision of each log end face.

[0077] Furthermore, for applications involving a large number of logs to be inspected, multiple cameras 1, along with matching moving mechanisms 2 and light emitters 3, are used in groups to form a combined system. This expands the data acquisition range without affecting processing speed and also reduces the system's installation size.

[0078] Example 2:

[0079] like Figure 2 and Figure 3 As shown, a log measuring system includes a camera 1, a moving mechanism 2, and two light emitters 3 (or more). The camera 1 is used to capture images of several log end faces within a viewing area. The moving mechanism 2 includes at least a drive mechanism 201 and one or more moving blocks 202. The drive mechanism 201 drives the moving blocks 202 to reciprocate. The light emitters 3 are fixedly connected to the moving blocks 202. The light emitters 3 are used to project light lines onto several log end faces within the viewing area. When the moving mechanism 2 drives the light emitters 3 to move, the light lines projected by the light emitters 3 gradually and completely scan each log end face, and the camera 1 records the scanning process. The scan images captured by the camera 1 are used to extract the log end face contours and size calibration. The camera 1 is a monocular camera 1, a binocular camera 1, or a depth camera 1. The light emitters 3 are laser emitters.

[0080] The moving mechanism 2 in this embodiment uses a stepper motor slide, including a stepper motor (i.e., drive mechanism 201), a lead screw, and a nut. The stepper motor drives the lead screw to rotate, which in turn drives the nut to reciprocate. This mechanism has good motion accuracy and can achieve uniform or fixed-distance movement of the nut (i.e., sliding block). A platform is fixedly installed on the nut for mounting two light emitters 3, with a mounting distance of Dlen1. In this embodiment, the light emitters 3 emit two intersecting light lines to acquire multi-directional log contour data during movement.

[0081] The two light beams emitted by the light emitter 3 are perpendicular to each other and each forms a 45° angle with the direction of movement of the light emitter 3. Furthermore, the two light beams emitted by the two light emitters 3 are in one-to-one correspondence and are parallel to each other. This is equivalent to scanning the log end face contour twice from two directions in a single scan, enabling mutual verification and confirmation of the scan data.

[0082] It should be noted that by using two or more light emitters 3 that are fixed at equal distances to move in coordination, the moving distance of the moving mechanism 2 can be shortened, which greatly improves the processing efficiency of the system.

[0083] In this embodiment, the light emitter 3 projects two sets of two light rays onto the end face of the log. For example... Figure 5 As shown, in any image captured by camera 1, when two sets of light rays appear simultaneously on the end face of a log, the pixel accuracy of that end face can be obtained. At this time, two sets of corresponding light ray segments are formed on the end face of the log (since the end face of the log is approximately planar, the corresponding light ray segments are parallel to each other); the pixel spacing Dpix1 between the corresponding light ray segments is obtained; then, the pixel spacing Dpix1 within the outline of the end face of the log is divided by the corresponding installation spacing Dlen1 to obtain the pixel accuracy of the end face of the log.

[0084] Although the placement of the logs is not very intuitive from the image, the actual placement of each log in the image varies in distance from camera 1, which is reflected in the different pixel precision of each log end face.

[0085] like Figure 5 As shown, the installation distance between the two light emitters 3 is Dlen1=10 cm. Taking the image P11 taken by the camera 1 at a certain position as an example, the light lines are projected onto the end faces of the two logs a and b respectively, forming several different line segments, which can be analyzed and processed separately.

[0086] Furthermore, since the end face of the log is not completely perpendicular to the shooting direction of the camera, the image may be distorted. When there are differences in the pixel precision of the end face at different positions in the log end face contour image, the end face contour image is stretched, or / and compressed, or / and rotated in three-dimensional space through a correction algorithm, so that the actual pixel precision at different positions in the log end face contour image tends to be consistent, so as to facilitate size calculation and correct image distortion.

[0087] Furthermore, a laser rangefinder is installed in parallel with the light emitter 3 in the same direction. The laser rangefinder is fixedly connected to the moving block 202. The distance data measured by the laser rangefinder provides reference data for the dimension calibration of the log end face and is used to determine the length of the log.

[0088] In addition, to prevent the light emitter 3 from interfering with the laser rangefinder, lasers of different wavelengths can be used.

[0089] Because the gauging process requires simultaneously measuring the dimensions and diameter of both ends of the log; therefore, if Figure 3 The diagram shows that the log end faces need to be scanned from both sides. At this time, the distance between the log end faces and the laser rangefinders on both sides can be obtained through the laser rangefinders on both sides. When the distance between the laser rangefinders on both sides is known or is a fixed value, the length of the log can be calculated.

[0090] Similarly, for applications involving a large number of logs to be inspected, multiple cameras 1, along with matching moving mechanisms 2 and light emitters 3, are used in groups to form a combined system. This expands the data acquisition range without affecting processing speed and also reduces the system's installation size.

[0091] The above are merely illustrative embodiments of this utility model and are not intended to limit the scope of this utility model. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of this utility model should fall within the protection scope of this utility model. Furthermore, it should be noted that the components of this utility model are not limited to the overall application described above. Each technical feature described in the specification can be used individually or in combination as needed. Therefore, this utility model naturally covers other combinations and specific applications related to the points of this utility model.

Claims

1. A log measuring system, characterized in that: Includes a camera, a moving mechanism, and one or more light emitters; The camera is used to capture images of several log end faces within the viewfinder area; The moving mechanism includes at least a drive mechanism and one or more moving blocks; the drive mechanism drives the moving blocks to reciprocate. The light emitter is fixedly connected to the movable block; The light emitter is used to project light lines onto several log end faces within the framing area; When the moving mechanism drives the light emitter to move, the light lines projected by the light emitter gradually and completely scan each end face of the log, and the camera records the scanning process. The scan process images captured by the camera are used to extract the log end face contours and size calibration.

2. The log measuring system according to claim 1, characterized in that: The light emitter is a laser emitter.

3. The log measuring system according to claim 1, characterized in that: Each of the aforementioned light emitters can emit one or multiple intersecting light rays simultaneously.

4. The log measuring system according to claim 3, characterized in that: When there are multiple light emitters, the one or more light rays emitted by each light emitter are in one-to-one correspondence and are parallel to each other.

5. A log measuring system according to claim 3, characterized in that: The plane formed by the projection path of any light ray projected by the light emitter is perpendicular to the image sensor in the camera.

6. A log measuring system according to claim 3, characterized in that: The light emitter emits two mutually perpendicular light rays, and the angle between the two light rays and the moving trajectory of the moving block is 45°.

7. A log measuring system according to claim 1, characterized in that: The moving mechanism moves in the same direction as the image sensor in the camera, either horizontally or vertically, and the moving block moves along a trajectory parallel to the image sensor in the camera.

8. A log measuring system according to claim 1, characterized in that: The moving mechanism is a mechanism that enables the moving block to move at a constant speed or at a specified distance. It is used to calculate the actual distance of light lines at different positions based on the shooting interval when comparing images taken by the camera at different time points.

9. A log measuring system according to claim 1, characterized in that: When there are multiple light emitters, a fixed distance value is set between the multiple light emitters for dimensional calibration of the images captured by the camera.

10. A log measuring system according to claim 1, characterized in that: A laser rangefinder is installed in parallel with the light emitter in the same direction. The laser rangefinder is fixedly connected to the moving block. The distance data measured by the laser rangefinder provides reference data for the dimension calibration of the log end face and is used to determine the length of the log.

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