A fruit three-dimensional point cloud reconstruction device based on lateral multi-view imaging

Abstract

The application discloses a fruit three-dimensional point cloud reconstruction device based on lateral multi-view imaging. The application comprises an illumination box, a rotating platform, three cameras and a host computer; the rotating platform is installed at the center of the inside of the illumination box and is used for placing fruits; the three cameras are respectively a top-view camera C1, a horizontal-view camera C2 and an overhead camera C3; the top-view camera C1, the horizontal-view camera C2 and the overhead camera C3 are sequentially installed on the circumferential side of the illumination box from top to bottom; the optical axes of the top-view camera C1, the horizontal-view camera C2 and the overhead camera C3 all point to the fruits; and the top-view camera C1, the horizontal-view camera C2 and the overhead camera C3 are all connected with the host computer. The device constructed by the application can form a good illumination environment, effectively solves the overexposure problem caused by the reflection of the fruit surface, and is suitable for the reconstruction of fruit point clouds with various fruit shapes such as water droplet shape, spherical shape, ellipsoidal shape and pear shape.

Description

Technical Field

[0001] This invention relates to a fruit point cloud reconstruction device, and more particularly to a fruit three-dimensional point cloud reconstruction device based on lateral multi-view imaging. Background Technology

[0002] my country is a major fruit producer in the world, and as the country with the largest pomelo planting area, it ranks first in the world in pomelo production. In 2019, pomelo production reached 5.08 million tons, accounting for 61.41% and 51.45% of the world's total pomelo cultivation area and production, respectively. Currently, the quality grading of pomelos is mainly based on weight. Huang Risheng et al. (2015) (Huang Risheng, Zhu Donghuang, Lin Jinxing, Shen Hong, Li Jian. Research on Grading Standards of Pomelo Fruit [J]. Southern China Fruits, 2015, 44(03):28-31+34.) showed that using volume as a grading indicator is more scientific than weight, and the volume of the fruit has the strongest correlation with internal quality, corresponding to the highest granulation rate of juice vesicles. Therefore, estimating the volume of pomelos for commercial grading is of great significance.

[0003] Traditional methods for estimating fruit volume mainly rely on manual measurement, such as the displacement method. However, manual measurement is labor-intensive, inefficient, and time-consuming. In recent years, with the development of 3D measurement technology and consumer-grade image acquisition equipment, many researchers have adopted methods such as monocular multi-view and laser scanning to measure the 3D model of fruits, and then measure the volume and other external geometric features of the fruits. For example, Wang Ke (2015) (Wang Ke. 3D Reconstruction of Plant Fruits and Leaves Based on Xtion Sensor and Extraction of Its Size Parameters [D]. Kunming University of Science and Technology, 2015.) measured the volume of star fruit and purple eggplant based on the reconstructed 3D point cloud. The results showed that compared with the true value, the average relative error of the estimated volume of star fruit was 6.63%, and the average relative error of the estimated volume of purple eggplant was 7.23%. Yamamoto et al. (2018)(Yamamoto S, Karkee M, Kobayashi Y, et al. 3D reconstruction of apple fruits using consumer-grade RGB-depth sensor[J]. Engineering in Agriculture, Environment and Food, 2018, 11(4): 159-168.) addressed the problem of unreliable depth information from consumer-grade sensors by extracting regions of interest from two-dimensional images and then correcting them on three-dimensional point clouds. Through experimental evaluation on more than 100 apples, they found that the root mean square error of volume and maximum longitudinal diameter was less than 6 cm3 and 1 mm, respectively. Ni et al. (2021) (Ni X, Li C, Jiang H, et al. Three-dimensional photogrammetry with deep learning instance segmentation to extract berry fruit harvestability traits[J]. ISPRS Journal of Photogrammetry and Remote Sensing, 2021, 171: 297-309.) reconstructed point clouds of four blueberry varieties based on SFM and MVS, calculated the compactness of blueberries using minimum bounding boxes, and estimated the number, volume, and maturity of blueberries. The results showed that the accuracy of blueberry fruit quantity detection reached 97.3%.

[0004] However, the above studies all focused on ellipsoidal or spherical fruits, making them unsuitable for estimating the volume of pomelos, which have diverse fruit shapes such as teardrop, sphere, ellipsoid, and pear. Furthermore, they suffer from unstable lighting conditions. Therefore, for fruits like pomelos, whose peels are covered with oil cells and exhibit reflective properties, making them prone to overexposure, constructing a point cloud measurement device with uniform lighting is of great significance. Summary of the Invention

[0005] To address the problems and needs in the background technology, the present invention provides a fruit 3D point cloud reconstruction device based on lateral multi-view imaging.

[0006] The technical solution of the present invention is as follows:

[0007] This invention includes a light box, a rotating platform, three cameras, and a main unit;

[0008] A rotating platform is installed in the center of the light box, which is used to place the fruit. There are three cameras: a top-view camera C1, a level-view camera C2, and a bottom-view camera C3. The top-view camera C1, the level-view camera C2, and the bottom-view camera C3 are installed on the circumference of the light box from top to bottom. The optical axes of the top-view camera C1, the level-view camera C2, and the bottom-view camera C3 all point towards the fruit. The top-view camera C1, the level-view camera C2, and the bottom-view camera C3 are all connected to the main unit.

[0009] The light box includes a chassis module, a circumferential rotation module, a longitudinal lifting module, a light guide film, a top LED light source, a transparent acrylic cylinder, a radial advance and retreat module, an axial rotation module, and a bottom LED light source;

[0010] A transparent acrylic cylinder is placed on the chassis module. At least one circumferential rotating module is installed between the chassis module and the transparent acrylic cylinder. The outer circumferential side of the transparent acrylic cylinder is covered with a light guide film. A top LED light source and a bottom LED light source are respectively installed on the upper and lower end faces of the transparent acrylic cylinder. Each circumferential rotating module is equipped with a corresponding radial advance / retreat module, a corresponding longitudinal lifting module, a corresponding axial rotating module, and a corresponding camera. A rectangular observation hole is opened on the circumferential side of the transparent acrylic cylinder. The camera is inserted into the rectangular observation hole of the transparent acrylic cylinder to photograph the fruit placed on the rotating platform. Each circumferential rotating module rotates circumferentially on the chassis module, and each circumferential rotating module synchronously drives the corresponding radial advance / retreat module, longitudinal lifting module, and axial rotating module.

[0011] The chassis module includes a bottom disc and a bottom radial fixing frame;

[0012] Multiple mounting feet are fixedly installed at equal intervals on the lower surface of the bottom disc. Each mounting foot is connected to the bottom disc via a support frame, and each mounting foot is threaded to its corresponding support frame. A circumferential rotating module is installed between the bottom disc and the transparent acrylic cylinder. A bottom radial fixing frame is provided inside the bottom disc, and the bottom radial fixing frame is fixedly connected to the multiple mounting feet. A rotating platform is placed on the bottom radial fixing frame. At least one fan-shaped through slot is formed on the outer edge of the bottom disc, and the inner surface of the fan-shaped through slot is configured as a rack.

[0013] The circumferential rotation module includes a circumferential adjustment handle and a circumferential fixing plate. The circumferential adjustment handle is installed on the lower end face of the circumferential fixing plate, and a radial advance / retreat module is installed on the upper end face of the circumferential fixing plate. The middle part of the circumferential adjustment handle is configured as a gear. After the lower end of the circumferential adjustment handle passes through the fan-shaped through slot, the gear in the middle of the circumferential adjustment handle meshes with the rack of the fan-shaped through slot to form a gear and rack pair. The rotation of the lower end of the circumferential adjustment handle drives the circumferential fixing plate to rotate circumferentially.

[0014] The radial advance / retreat module includes a radial adjusting screw, a radial guide rod, a radial adjusting handle, and a radial guide block;

[0015] A radial guide rod is fixedly installed on the circumferential rotation module, and a radial adjusting screw is also installed on the circumferential rotation module. The radial guide rod and the radial adjusting screw are arranged parallel to each other and spaced apart. A radial guide block is sleeved in the radial guide rod and the radial adjusting screw. The end of the radial adjusting screw away from the bottom disk is connected to the radial adjusting handle by a thread, and the end of the radial adjusting screw near the bottom disk is fixedly connected to the radial guide block. A longitudinal lifting module is installed on the radial guide block. The rotation of the radial adjusting handle causes the radial guide block to slide along the radial guide rod, thereby causing the longitudinal lifting module on the radial guide block to move radially.

[0016] The longitudinal lifting module includes a longitudinal fixing frame, a longitudinal adjusting screw, and a longitudinal adjusting handle;

[0017] One end of the longitudinal fixing frame is fixedly installed on the radial advance and retreat module, and the other end of the longitudinal fixing frame is equipped with a longitudinal adjustment handle. A longitudinal adjustment screw is set in the middle of the longitudinal fixing frame. The end of the longitudinal adjustment screw away from the radial advance and retreat module is connected to the longitudinal adjustment handle by a thread. The axial rotation module is fitted in the longitudinal fixing frame and the longitudinal adjustment screw. The rotation of the longitudinal adjustment handle drives the axial rotation module to rise and fall along the longitudinal fixing frame.

[0018] The axial rotation module includes an axial rotation block, an axial rotation fixing slot plate, a camera mounting side plate, and a camera mounting base plate.

[0019] The axial rotating block has longitudinal holes and longitudinal lifting screw holes. After the longitudinal lifting module passes through the longitudinal holes and longitudinal lifting screw holes, the axial rotating block is installed in the longitudinal lifting module. An axial rotating fixing slot plate is fixedly installed on the side of the axial rotating block. The side of the axial rotating fixing slot plate has an arc groove. The bolts of the camera mounting side plate pass through the arc groove of the axial rotating fixing slot plate, so that the camera mounting side plate is installed on the axial rotating fixing slot plate. The camera mounting base plate is fixedly installed at the bottom of the camera mounting side plate. The camera mounting side plate and the camera mounting base plate form an L-shaped mounting seat for fixing the camera. The adjustment of the bolts causes the camera mounting side plate to rotate along the arc groove, thereby adjusting the optical axis direction of the camera.

[0020] The transparent acrylic cylinder also has a square inlet / outlet opening on its circumferential side for fruit to enter and exit.

[0021] A reflective cloth is laid on the top and bottom of the transparent acrylic cylinder.

[0022] The beneficial effects of this invention are as follows:

[0023] The present invention constructs a fruit 3D point cloud reconstruction device based on lateral multi-view imaging, which can form a good lighting environment and effectively solve the problem of local overexposure caused by surface reflection of fruit. It is suitable for point cloud reconstruction of fruits with various shapes such as teardrop, sphere, ellipsoid, and pear, represented by pomelo. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the image acquisition system structure of the present invention.

[0025] Figure 2 This is a structural diagram of the light box of the present invention.

[0026] Figure 3 This is an isometric view of the chassis module of the present invention.

[0027] Figure 4 This is an isometric view of the circumferential rotation module of the present invention.

[0028] Figure 5 This is a top view of the radial advance / retreat module of the present invention.

[0029] Figure 6 This is an isometric view of the longitudinal lifting module of the present invention.

[0030] Figure 7 This is an isometric view of the axial rotation module of the present invention.

[0031] Figure 8 This is an isometric view of the transparent acrylic cylinder of the present invention.

[0032] Figure 9 This is a schematic diagram of the lighting scheme of the present invention.

[0033] Figure 10 This is the V component diagram of the present invention.

[0034] Figure 11 This is the ROI region brightness distribution map of the present invention.

[0035] Figure 12 This is a cross-sectional view of the device of the present invention.

[0036] Figure 13 This is a schematic diagram of the axial module installation of the present invention.

[0037] In the diagram: 1. Light box; 1.1. Chassis module; 1.1.1. Mounting feet; 1.1.2. Support frame; 1.1.3. Bottom disc; 1.1.4. Support column flange; 1.1.5. Bottom radial fixing frame; 1.1.6. Circumferential fan-shaped guide groove; 1.2. Support column; 1.3. Circumferential rotation module; 1.3.1. Circumferential rolling shaft; 1.3.2. Circumferential adjustment handle; 1.3.3. Circumferential fixing plate; 1.4. Longitudinal lifting module; 1.4.1. Longitudinal fixing frame; 1.4.2. Longitudinal adjusting screw; 1.4.3. Longitudinal adjusting handle; 1.5. Light guide film; 1.6. Top LED light source; 1.7. Top bracket; 1.8. Transparent acrylic cylinder. 1.8.1 Rectangular observation hole; 1.8.2 Square inlet / outlet channel; 1.8.3 LED light source embedding slot; 1.9 Radial advance / retreat module; 1.9.1 Radial adjustment screw; 1.9.2 Radial guide rod; 1.9.3 Radial adjustment handle; 1.9.4 Radial guide block; 1.10 Axial rotation module; 1.10.1 Axial rotation block; 1.10.2 Longitudinal hole; 1.10.3 Longitudinal lifting screw hole; 1.10.4 Axial rotation fixing slot plate; 1.10.5 Camera mounting side plate; 1.10.6 Camera mounting base plate; 1.11 Bottom LED light source; 2. Rotating platform; 3. Fruit; 4. Camera; 5. Main unit; 6. Monitor. Detailed Implementation

[0038] The present invention will be further described below using pomelo as an example, in conjunction with the accompanying drawings and embodiments.

[0039] like Figure 1 , Figure 2 , Figure 3 and Figure 12 As shown, the present invention includes a light box 1, a rotating platform 2, three industrial cameras 4, a display 6, and a host 5;

[0040] A rotating platform 2 is installed at the center of the light box 1. The rotating platform 2 is used to place the fruit 3. Three cameras 4 are installed, namely a top-view camera C1, a level-view camera C2, and a bottom-view camera C3. The top-view camera C1, level-view camera C2, and bottom-view camera C3 are installed sequentially from top to bottom along the circumferential side of the light box 1. The optical axes of the top-view camera C1, level-view camera C2, and bottom-view camera C3 all point towards the fruit 3, that is, there is an angle between the optical axes of the top-view camera C1, level-view camera C2, and bottom-view camera C3. The circumferential positions of the top-view camera C1, level-view camera C2, and bottom-view camera C3 are not fixed. For example, the top-view camera C1, level-view camera C2, and bottom-view camera C3 can be on the same axis or arranged at equal intervals in the circumferential direction. The top-view camera C1, level-view camera C2, and bottom-view camera C3 are all connected to the main unit 5, and the main unit 5 is connected to the display 6.

[0041] The light box 1 includes a chassis module 1.1, a support column 1.2, a top bracket 1.7, a circumferential rotation module 1.3, a longitudinal lifting module 1.4, a light guide film 1.5, a top LED light source 1.6, a transparent acrylic cylinder 1.8, a radial advance and retreat module 1.9, an axial rotation module 1.10, and a bottom LED light source 1.11;

[0042] A transparent acrylic cylinder 1.8 is placed on the chassis module 1.1. At least one circumferential rotating module 1.3 is installed between the chassis module 1.1 and the transparent acrylic cylinder 1.8, with the circumferential rotating module 1.3 and the transparent acrylic cylinder 1.8 arranged at intervals. The outer circumferential side of the transparent acrylic cylinder 1.8 is covered with a light guide film 1.5. LED light source embedding slots 1.8.3 are respectively opened on the upper and lower end faces of the transparent acrylic cylinder 1.8. The upper and lower LED light source embedding slots 1.8.3 are respectively equipped with a top LED light source 1.6 and a bottom LED light source 1.11 as light sources. In specific implementation, the LED light source is a flexible light strip, which is attached around the upper and lower end faces of the transparent acrylic cylinder 1.8. The circumferential side of the transparent acrylic cylinder 1.8 also has a square inlet / outlet channel 1.8.2 for fruit to enter and exit. A reflective cloth is laid on the top and bottom of the transparent acrylic cylinder 1.8 to enhance the light intensity inside the transparent acrylic cylinder 1.8. A top bracket 1.7 is also installed on the top of the transparent acrylic cylinder 1.8. The top bracket 1.7 is fixedly connected to the chassis module 1.1 by multiple support columns 1.2. The multiple support columns 1.2 are installed at equal intervals on the chassis module 1.1 outside the transparent acrylic cylinder 1.8. The top bracket 1.7 is used to mount the top camera.

[0043] Each circumferential rotation module 1.3 is equipped with a corresponding radial advance / retreat module 1.9, each radial advance / retreat module 1.9 is equipped with a corresponding longitudinal lifting module 1.4, each longitudinal lifting module 1.4 is equipped with a corresponding axial rotation module 1.10, and each axial rotation module 1.10 is equipped with a corresponding camera 4. A rectangular observation hole 1.8.1 is opened on the circumferential side of the transparent acrylic cylinder 1.8. Figure 8 As shown, camera 4 extends into the rectangular observation hole 1.8.1 of the transparent acrylic cylinder 1.8 and then photographs the fruit 3 placed on the rotating platform; each circumferential rotation module 1.3 rotates circumferentially on the chassis module 1.1, and each circumferential rotation module 1.3 synchronously drives the corresponding radial advance / retreat module 1.9, longitudinal lifting module 1.4 and axial rotation module 1.10. The radial advance / retreat module 1.9 is used to adjust the radial distance between camera 4 and the center of the transparent acrylic cylinder 1.8, the longitudinal lifting module 1.4 is used to adjust the axial height of camera 4, and the axial rotation module 1.10 is used to adjust the optical axis direction of camera 4.

[0044] In specific implementation, three circumferential rotating modules 1.3 are installed at equal intervals between the chassis module 1.1 and the transparent acrylic cylinder 1.8. Each circumferential rotating module 1.3 has an axial rotating module 1.10 installed on its corresponding longitudinal lifting module 1.4. If there is only one circumferential rotating module 1.3 in the device, then three axial rotating modules 1.10 are installed on the corresponding longitudinal lifting module 1.4, and each axial rotating module 1.10 has a camera mounted on it. The circumferential rotating module 1.3 can control the camera to rotate 60° around the center of the chassis module 1.1. The longitudinal lifting module 1.4 has a lifting range of 0–600 mm. The radial advance / retreat module 1.9 can independently adjust the advance / retreat range of the top-view camera C1, the level camera C2, and the bottom-view camera C3 from the center of the chassis module 1.1 to 450–850 mm. The axial rotating module 1.10 can independently adjust the pitch angle of the camera mount 1.8 to ±60°.

[0045] like Figure 3 As shown, the chassis module 1.1 includes mounting feet 1.1.1, support frame 1.1.2, support column flange 1.1.4, bottom disc 1.1.3, and bottom radial fixing frame 1.1.5;

[0046] Multiple mounting feet 1.1.1 are fixedly installed at equal intervals on the lower surface of the bottom disc 1.1.3. Each mounting foot 1.1.1 is connected to the bottom disc 1.1.3 through a support frame 1.1.2, and each mounting foot 1.1.1 is connected to the corresponding support frame 1.1.2 through a threaded connection, so that the mounting foot 1.1.1 can rotate in place, and the overall device can be raised and lowered for adjustment. Support column flanges 1.1.4 are fixedly installed at equal intervals on the upper surface of the bottom disc 1.1.3. The support column flanges 1.1.4 are connected to the corresponding support columns 1.2. A circumferential rotating module 1.3 is installed between the bottom disc 1.1.3 and the transparent acrylic cylinder 1.8. A bottom radial fixing frame 1.1.5 is provided inside the bottom disc 1.1.3. The bottom radial fixing frame 1.1.5 is fixedly connected to multiple mounting feet 1.1.1. A rotating platform 2 is placed on the bottom radial fixing frame 1.1.5. At least one fan-shaped through groove is opened on the outer edge of the bottom disc 1.1.3. The inner side of the fan-shaped through groove is set as a rack. In specific implementation, three fan-shaped through grooves are opened on the outer edge of the bottom disc 1.1.3, which are arranged at equal intervals along the circumference.

[0047] like Figure 4 and Figure 13 As shown, the circumferential rotation module 1.3 includes a circumferential rolling shaft 1.3.1, a circumferential adjusting handle 1.3.2, and a circumferential fixing plate 1.3.3. The circumferential adjusting handle 1.3.2 is mounted on the lower end face of the circumferential fixing plate 1.3.3, and a radial advance / retreat module 1.9 is mounted on the upper end face of the circumferential fixing plate 1.3.3. A gear is configured in the middle of the circumferential adjusting handle 1.3.2. After the lower end of the circumferential adjusting handle 1.3.2 passes through the fan-shaped through slot, the gear in the middle of the circumferential adjusting handle 1.3.2 meshes with the rack of the fan-shaped through slot to form a gear and rack pair. The rotation of the lower end of the circumferential adjusting handle 1.3.2 drives the circumferential fixing plate 1.3.3 to rotate circumferentially. Multiple circumferential rolling shafts 1.3.1 are also mounted on both sides of the circumferential adjusting handle 1.3.2 on the lower end face of the circumferential fixing plate 1.3.3 to support the circumferential fixing plate 1.3.3 and slide on the bottom disc 1.1.3.

[0048] like Figure 5 As shown, the radial advance / retreat module 1.9 includes a radial adjusting screw 1.9.1, a radial guide rod 1.9.2, a radial adjusting handle 1.9.3, and a radial guide block 1.9.4;

[0049] A radial guide rod 1.9.2 is fixedly installed on the upper surface of the circumferential fixing plate 1.3.3 of the circumferential rotation module 1.3. The axial direction of the radial guide rod 1.9.2 is radial to the bottom disk 1.1.3. A radial adjusting screw 1.9.1 is also installed on the upper surface of the circumferential fixing plate 1.3.3 of the circumferential rotation module 1.3. The radial guide rod 1.9.2 and the radial adjusting screw 1.9.1 are parallel and spaced apart. A radial guide block 1.9.4 is fitted between the radial guide rod 1.9.2 and the radial adjusting screw 1.9.1. The radial adjusting screw 1.9.1 is located away from the radial guide rod 1.9.2 and the radial adjusting screw 1.9.1. One end of the bottom disc 1.1.3 is connected to the radial adjustment handle 1.9.3 by a thread. The end of the radial adjustment screw 1.9.1 near the bottom disc 1.1.3 is fixedly connected to the radial guide block 1.9.4. The longitudinal fixing frame 1.4.1 of the longitudinal lifting module 1.4 is installed on the radial guide block 1.9.4. The rotation of the radial adjustment handle 1.9.3 causes the radial guide block 1.9.4 to slide along the radial guide rod 1.9.2, thereby causing the longitudinal lifting module 1.4 on the radial guide block 1.9.4 to move radially.

[0050] like Figure 6 As shown, the longitudinal lifting module 1.4 includes a longitudinal fixing frame 1.4.1, a longitudinal adjusting screw 1.4.2, and a longitudinal adjusting handle 1.4.3. One end of the longitudinal fixing frame 1.4.1 is fixedly mounted on the radial guide block 1.9.4 of the radial advance / retreat module 1.9, and the other end of the longitudinal fixing frame 1.4.1 is equipped with the longitudinal adjusting handle 1.4.3. The longitudinal adjusting screw 1.4.2 is located in the middle of the longitudinal fixing frame 1.4.1, and the end of the longitudinal adjusting screw 1.4.2 away from the radial advance / retreat module 1.9 is... The axial rotation block 1.10.1 of the axial rotation module 1.10 is connected to the longitudinal adjustment handle 1.4.3 by threads. It is respectively fitted into the longitudinal fixing frame 1.4.1 and the longitudinal adjusting screw 1.4.2. The axial rotation module 1.10 slides between itself and the longitudinal fixing frame 1.4.1. The axial rotation module 1.10 and the longitudinal adjusting screw 1.4.2 are connected by threads. The rotation of the longitudinal adjustment handle 1.4.3 drives the axial rotation module 1.10 to rise and fall along the longitudinal fixing frame 1.4.1.

[0051] like Figure 7 As shown, the axial rotation module 1.10 includes an axial rotation block 1.10.1, an axial rotation fixing slot plate 1.10.4, a camera mounting side plate 1.10.5, and a camera mounting base plate 1.10.6;

[0052] The axial rotating block 1.10.1 has a longitudinal hole 1.10.2 and a longitudinal lifting screw hole 1.10.3. The longitudinal fixing bracket 1.4.1 and the longitudinal adjusting screw 1.4.2 of the longitudinal lifting module 1.4 pass through the longitudinal hole 1.10.2 and the longitudinal lifting screw hole 1.10.3 respectively, allowing the axial rotating block 1.10.1 to be installed in the longitudinal lifting module 1.4. An axial rotating fixing slot plate 1.10.4 is fixedly installed on the side of the axial rotating block 1.10.1. The side of the axial rotating fixing slot plate 1.10.4 has an arc groove. After the bolts of the camera mounting side plate 1.10.5 pass through the arc groove of the axial rotation fixing slot plate 1.10.4, the camera mounting side plate 1.10.5 is mounted on the axial rotation fixing slot plate 1.10.4; the camera mounting base plate 1.10.6 is fixedly mounted on the bottom of the camera mounting side plate 1.10.5. The camera mounting side plate 1.10.5 and the camera mounting base plate 1.10.6 form an L-shaped mounting seat for fixing the camera 4. Adjusting the bolts causes the camera mounting side plate 1.10.5 to rotate along the arc groove, thereby adjusting the optical axis direction of the camera 4.

[0053] like Figure 9 As shown, in this embodiment, the soft strip light source is a 2835 LED light source. When the 2835 LED light source is lit, the black arrow light source light propagates along the transparent acrylic cylinder 1.8, and is refracted through the laser perforation point on the light guide film 1.5. The gray guided light light is scattered into the interior of the transparent acrylic cylinder 1.8, and finally forms an internal lighting environment with excellent uniformity.

[0054] In this embodiment, the fruit is a pomelo. The rotation speed of the rotating platform 2 is set to 1° / s. The total field of view of the top-view camera C1, the level-view camera C2, and the bottom-view camera C3 covers the entire pomelo. All three cameras are connected to a trigger plate via trigger control lines. The trigger plate is connected to an NPN type laser sensor. Through soft triggering by the camera's host computer, the camera triggers to acquire images every 1 second, collecting 3 sets of images, totaling 1080 original pomelo images. Based on these 1080 original pomelo images, the host computer uses Structure From Motion (SFM) and Multi View Stereo (MVS) methods to reconstruct the current 3D point coordinates of the pomelo, obtaining a dense point cloud and achieving 3D point cloud reconstruction.

[0055] The color image of the pomelo taken by the head-up camera C2 was converted from RGB space to HSV space, and then the V component image was extracted, as follows: Figure 10 As shown. Next, a rectangular area of ​​the V component image is selected as the Region of Interest (ROI), and then the brightness values ​​of all pixels within the ROI are counted pixel by pixel to obtain the ROI region brightness distribution map, as shown. Figure 11As shown, the mean luminance (MEAN) and standard deviation (STD) are calculated. In this embodiment, MEAN = 196.1, STD = 5.8.

[0056] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any minor modifications, equivalent substitutions, and improvements made to the above embodiments based on the technical essence of the present invention should be included within the protection scope of the present invention.

Claims

1. A fruit 3D point cloud reconstruction device based on lateral multi-view imaging, characterized in that, It includes a light box (1), a rotating platform (2), three cameras (4) and a main unit (5); A rotating platform (2) is installed in the center of the light box (1). The rotating platform (2) is used to place fruit (3). The three cameras (4) are top-down cameras. Head-up camera With an upward-looking camera The top-view cameras are installed sequentially from top to bottom on the circumferential side of the light box (1). Head-up camera With an upward-looking camera overhead camera Head-up camera With an upward-looking camera The optical axes all point towards the fruit (3), viewed from above by the camera. Head-up camera and upward-looking camera All are connected to the host (5); The light box (1) includes a chassis module (1.1), a circumferential rotation module (1.3), a longitudinal lifting module (1.4), a light guide film (1.5), a top LED light source (1.6), a transparent acrylic cylinder (1.8), a radial advance and retreat module (1.9), an axial rotation module (1.10), and a bottom LED light source (1.11). A transparent acrylic cylinder (1.8) is placed on the chassis module (1.1). At least one circumferential rotating module (1.3) is installed between the chassis module (1.1) and the transparent acrylic cylinder (1.8). The outer circumferential side of the transparent acrylic cylinder (1.8) is covered with a light guide film (1.5). A top LED light source (1.6) and a bottom LED light source (1.11) are respectively installed on the upper and lower ends of the transparent acrylic cylinder (1.8). Each circumferential rotating module (1.3) is equipped with a corresponding radial advance / retreat module (1.9), and each radial advance / retreat module (1.9) is equipped with a corresponding longitudinal lifting module (1.4). (1.4) is equipped with a corresponding axial rotation module (1.10), and a corresponding camera (4) is installed on the axial rotation module (1.10). A rectangular observation hole (1.8.1) is opened on the circumferential side of the transparent acrylic cylinder (1.8). The camera (4) is inserted into the rectangular observation hole (1.8.1) of the transparent acrylic cylinder (1.8) to take pictures of the fruit (3) placed on the rotating platform. Each circumferential rotation module (1.3) rotates circumferentially on the chassis module (1.1). Each circumferential rotation module (1.3) synchronously drives the corresponding radial advance and retreat module (1.9), longitudinal lifting module (1.4) and axial rotation module (1.10).

2. The fruit 3D point cloud reconstruction device based on lateral multi-view imaging according to claim 1, characterized in that, The chassis module (1.1) includes a bottom disc (1.1.3) and a bottom radial fixing frame (1.1.5). Multiple mounting feet are fixedly installed at equal intervals on the lower surface of the bottom disc (1.1.3). 1.1.1), each mounting foot (1.1.1) is connected to the bottom disc (1.1.3) via a support frame (1.1.2), and each mounting foot (1.1.1) is connected to the corresponding support frame (1.1.2) via a threaded connection. A circumferential rotating module (1.3) is installed between the bottom disc (1.1.3) and the transparent acrylic cylinder (1.8). A bottom radial fixing frame (1.1.5) is provided inside the bottom disc (1.1.3), and the bottom radial fixing frame (1.1.5) is fixedly connected to multiple mounting feet (1.1.1). A rotating platform (2) is placed on the bottom radial fixing frame (1.1.5). At least one fan-shaped through groove is opened on the outer edge of the bottom disc (1.1.3), and the inner side of the fan-shaped through groove is set as a rack. The circumferential rotation module (1.3) includes a circumferential adjustment handle (1.3.2) and a circumferential fixing plate (1.3.3). The circumferential adjustment handle (1.3.2) is installed on the lower end face of the circumferential fixing plate (1.3.3), and a radial advance / retreat module (1.9) is also installed on the upper end face of the circumferential fixing plate (1.3.3). The middle part of the circumferential adjustment handle (1.3.2) is set as a gear. After the lower end of the circumferential adjustment handle (1.3.2) passes through the fan-shaped through slot, the gear in the middle of the circumferential adjustment handle (1.3.2) meshes with the rack of the fan-shaped through slot to form a gear rack pair. The rotation of the lower end of the circumferential adjustment handle (1.3.2) drives the circumferential fixing plate (1.3.3) to rotate circumferentially.

3. The fruit 3D point cloud reconstruction device based on lateral multi-view imaging according to claim 1, characterized in that, The radial advance / retreat module (1.9) includes a radial adjusting screw (1.9.1), a radial guide rod (1.9.2), and a radial adjusting handle (1.9.3). 1.9.3) and radial guide block (1.9.4); A radial guide rod (1.9.2) is fixedly installed on the circumferential rotation module (1.3). A radial adjusting screw (1.9.1) is also installed on the circumferential rotation module (1.3). The radial guide rod (1.9.2) and the radial adjusting screw (1.9.1) are arranged parallel to each other and spaced apart. A radial guide block (1.9.4) is sleeved in the radial guide rod (1.9.2) and the radial adjusting screw (1.9.1). The end of the radial adjusting screw (1.9.1) away from the bottom disc (1.1.3) is connected to the radial adjusting handle (1.9.4) by a thread. Connected to 1.9.3), the radial adjusting screw (1.9.1) near the bottom disc (1.1.3) is fixedly connected to the radial guide block (1.9.4), and the longitudinal lifting module (1.4) is installed on the radial guide block (1.9.4); the rotation of the radial adjusting handle (1.9.3) causes the radial guide block (1.9.4) to slide along the radial guide rod (1.9.2), thereby causing the longitudinal lifting module (1.4) on the radial guide block (1.9.4) to move radially.

4. The fruit three-dimensional point cloud reconstruction device based on lateral multi-view imaging according to claim 1, characterized in that the longitudinal lifting module (1.4) includes a longitudinal fixing frame (1.4.1), a longitudinal adjusting screw (1.4.2), and a longitudinal adjusting handle (1.4.3). One end of the longitudinal fixing bracket (1.4.1) is fixedly mounted on the radial advance / retreat module (1.9), and the other end of the longitudinal fixing bracket (1.4.1) is equipped with a longitudinal adjusting handle (1.4.3). A longitudinal adjusting screw (1.4.2) is provided in the middle of the longitudinal fixing bracket (1.4.1). The end of the longitudinal adjusting screw (1.4.2) away from the radial advance / retreat module (1.9) is threaded to the longitudinal adjusting handle (1.4.3). Connected to 1.4.3), the axial rotation module (1.10) is fitted in the longitudinal fixing frame (1.4.1) and the longitudinal adjusting screw (1.4.2). The rotation of the longitudinal adjusting handle (1.4.3) drives the axial rotation module (1.10) to rise and fall along the longitudinal fixing frame (1.4.1).

5. The fruit 3D point cloud reconstruction device based on lateral multi-view imaging according to claim 1, characterized in that, The axial rotation module (1.10) includes an axial rotation block (1.10.1), an axial rotation fixing slot plate (1.10.4), a camera mounting side plate (1.10.5), and a camera mounting base plate (1.10.6). The axial rotating block (1.10.1) has a longitudinal hole (1.10.2) and a longitudinal lifting screw hole (1.10.3). The longitudinal lifting module (1.4) passes through the longitudinal hole (1.10.2) and the longitudinal lifting screw hole (1.10.3), allowing the axial rotating block (1.10.1) to be installed in the longitudinal lifting module (1.4). An axial rotating fixing slot plate (1.10.4) is fixedly installed on the side of the axial rotating block (1.10.1). The side of the axial rotating fixing slot plate (1.10.4) has an arc groove. The camera mounting side plate (1.10.5) is also provided. After the bolt passes through the arc groove of the axial rotation fixing slot plate (1.10.4), the camera mounting side plate (1.10.5) is mounted on the axial rotation fixing slot plate (1.10.4); the camera mounting base plate (1.10.6) is fixedly mounted on the bottom of the camera mounting side plate (1.10.5). The camera mounting side plate (1.10.5) and the camera mounting base plate (1.10.6) form an L-shaped mounting seat for fixing the camera (4). The adjustment of the bolt causes the camera mounting side plate (1.10.5) to rotate along the arc groove, thereby adjusting the optical axis direction of the camera (4).

6. The fruit 3D point cloud reconstruction device based on lateral multi-view imaging according to claim 1, characterized in that, The transparent acrylic cylinder (1.8) also has a square inlet / outlet opening (1.8.2) on its circumferential side for fruit to enter and exit.

7. The fruit 3D point cloud reconstruction device based on lateral multi-view imaging according to claim 1, characterized in that, A reflective cloth is laid on the top and bottom of the transparent acrylic cylinder (1.8).

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