A profile following transmission optical detection device and method

Abstract

The application discloses a kind of profiled servo transmission optical detection device and method, the transmission optical detection device includes: rack, conveying component, servo light source unit, servo detection unit and spectral acquisition and processing unit;Conveying component is installed on rack, for conveying sample along conveying direction;Servo light source unit and servo detection unit are respectively arranged in the upper and lower sides of the conveying path of conveying component, and each includes support part, guide assembly, floating platform and elastic element, support part is installed on rack;Guide assembly is fixedly connected with support part;Floating platform is slidably connected with guide assembly, guide assembly restricts floating platform only along the direction perpendicular to conveying path to approach or away from sample;Elastic element is connected between support part and floating platform;Light source assembly is installed on the floating platform of servo light source unit, and detection assembly is installed on the floating platform of servo detection unit;Spectral acquisition and processing unit are optically connected with detection assembly.

Description

Technical Field

[0001] This invention relates to the field of online non-destructive testing of agricultural products and optomechanical integrated equipment technology, and in particular to a contour-following transmission optical testing device and method. Background Technology

[0002] Vis / NIR transmission spectroscopy has the potential for non-destructive testing of internal defects (such as browning, moldy core, and black core) and physicochemical properties (such as dry matter and moisture content) in agricultural products. However, transmission measurements are highly sensitive to geometric boundary conditions: changes in the distance from the incident light source end face to the sample surface, the distance from the exit sample surface to the detector end face, and the equivalent penetration thickness (optical path length) can lead to changes in coupling efficiency, effective sampling volume, and stray light path, resulting in uncontrollable fluctuations in transmission intensity and scattering components, thus disrupting the stable mapping between the spectrum and quality variables.

[0003] In industrial production lines, agricultural products commonly exhibit problems such as large size ranges, non-standard shapes (ellipsoids, elongated shapes, uneven surfaces), and surface deposits (soil / water film). If a fixed optical head (with the light source and detector fixed in place) is used, the "support height" of the sample during transport will randomly drift with its diameter / shape, causing random perturbations in the transmitted optical path and the entrance / exit air gap, thus reducing the robustness of the model. Compensation relying solely on algorithms such as spectral preprocessing is insufficient to physically eliminate the orders-of-magnitude differences in light intensity caused by geometric fluctuations and the signal-to-noise ratio degradation due to bypass leakage.

[0004] In existing engineering solutions, active servo motors (motors / cylinders / electric slides) can achieve position adjustment, but in high-speed cycles and dusty, high-humidity environments, they are prone to problems such as phase lag, complex maintenance, and limited cost and reliability.

[0005] Therefore, there is an urgent need for a transmission optical detection device that can physically stabilize the boundary conditions of transmission measurement, has a simple structure, and is suitable for online agricultural operations. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention draws upon the "contour following / homogeneous" concept widely used in the field of agricultural machinery. This concept often achieves passive following and positioning control of external contours through linkages, springs, and damping (for example, the header contour following system achieves terrain following and positioning through mechanism kinematics and spring elements), and has advantages such as simple structure, fast response, and high reliability. This invention introduces it into the field of transmission optical detection, focusing on the sensitivity of transmission spectra to geometric boundary conditions, and proposes and implements a passive homogeneous scheme of "boundary condition uniformity": taking the air gap on the incident side and the air gap on the exit side (or the equivalent compression / sealing state of the light shield) as the stable objects, through a purely mechanical passive homogeneous mechanism, the height disturbance caused by sample size and morphology is transformed into coaxial and equidistant homing of the optical head, suppressing the coupling efficiency changes, light leakage bypass, and effective sampling volume fluctuations caused by distance drift at the physical level, thereby improving the repeatability of transmission spectra and model robustness.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A contour-following transmission optical detection device includes: a frame; a conveying assembly mounted on the frame for conveying a sample along a conveying direction; a follow-up light source unit and a follow-up detection unit, the follow-up light source unit and the follow-up detection unit being respectively disposed on the upper and lower sides of the conveying path of the conveying assembly; each of the follow-up light source unit and the follow-up detection unit includes a support, a guide assembly, a floating platform, and an elastic element, wherein: the support is mounted on the frame; the guide assembly is fixedly connected to the support; the floating platform is slidably connected to the guide assembly, the guide assembly constraining the floating platform to approach or move away from the sample only in a direction perpendicular to the conveying path; the elastic element is connected between the support and the floating platform; a light source assembly is mounted on the floating platform of the follow-up light source unit, and a detection assembly is mounted on the floating platform of the follow-up detection unit; and a spectral acquisition and processing unit optically connected to the detection assembly.

[0009] The conveying assembly is a V-shaped support conveying assembly, which includes two conveyor belts. The two conveyor belts are arranged at an angle to each other to form a V-shaped support surface. A light-transmitting window is opened on the V-shaped support surface for the light path of the follow-up detection unit to pass through.

[0010] A sealing light-shielding ring is fixedly installed at the end of the floating platform of the follow-up detection unit. The sealing light-shielding ring surrounds the optical end face of the follow-up detection component, and the free end of the sealing light-shielding ring protrudes from the optical end face.

[0011] The guiding assembly consists of multiple parallel guide rods; the elastic element is a compression spring or a constant force spring, the elastic element is fitted onto the guide rod, one end of the elastic element is connected to the floating platform, and the other end of the elastic element is connected to the support part.

[0012] The follow-up light source unit and / or the follow-up detection unit further includes a damping element, which is arranged in series with the elastic element between the support and the floating platform, and the damping element is located on the side of the elastic element closer to the floating platform.

[0013] The follow-up light source unit and / or the follow-up detection unit further include a zero-position fine-tuning mechanism, which is installed on the support and its movable end abuts against the floating platform to adjust the initial position of the floating platform in the absence of samples.

[0014] The contour-following transmission optical detection device further includes a triggering and control component, which includes a photoelectric sensor, a position sensor, and a displacement sensor. The photoelectric sensor is mounted on the frame and located at the entrance of the detection station. The position sensor is connected to the drive shaft of the conveying component or mounted on the frame. The displacement sensor is connected to the floating platform of the follow-up light source unit or the follow-up detection unit.

[0015] The spectral acquisition and processing unit includes a light source driver, a spectrometer, and a processor. The light source driver is electrically connected to the light source assembly, the spectrometer is optically connected to the detection assembly, and the processor is electrically connected to the spectrometer.

[0016] The contour-following transmission optical inspection device also includes an inspection dark box, which is fixedly installed on the frame and surrounds the inspection station. The inspection dark box has through holes for the follow-up light source unit and the follow-up detection unit to pass through.

[0017] The present invention also provides a contour-following transmission optical detection method, which employs the above-mentioned contour-following transmission optical detection device and includes the following steps:

[0018] In the initial setting step, the zero-position fine-tuning mechanism is adjusted so that the relative position between the optical end face of the light source component of the follow-up light source unit and the optical end face of the detection component of the follow-up detection unit reaches the preset calibration gap in the absence of samples.

[0019] The startup step involves activating the transport assembly, causing the sample to move with the transport assembly to the detection station between the follow-up light source unit and the follow-up detection unit;

[0020] In the passive contour-following step, the upper surface of the sample pushes the floating platform of the follow-up light source unit to compress the elastic element of the follow-up light source unit to move upward, and the lower surface of the sample pushes the floating platform of the follow-up detection unit to compress the elastic element of the follow-up detection unit to move downward, so that the follow-up light source unit and the follow-up detection unit respectively perform passive contour-following of the upper and lower surfaces of the sample.

[0021] The spectrum acquisition step is triggered when the sample moves to the detection station. The triggering and control component triggers the spectrum acquisition and processing unit to acquire the transmission spectrum and records the displacement at the same time.

[0022] In the output step, the spectral acquisition and processing unit preprocesses the transmission spectrum, determines whether the current spectral acquisition is valid based on the comparison result between the follow-up displacement and the preset threshold, and outputs the detection result.

[0023] In the reset step, after the sample leaves the detection station, the floating platforms of the follow-up light source unit and the follow-up detection unit return to their initial positions under the restoring force of their respective elastic elements.

[0024] Furthermore, the triggering spectral acquisition step also includes: detecting the sample's arrival and triggering spectral acquisition through the photoelectric sensor of the triggering and control component, and recording the follow-up displacement through the displacement sensor; the output step also includes: the spectral acquisition and processing unit comparing the follow-up displacement with a preset overtravel threshold and a sealing displacement threshold, and comparing the rate of change of the follow-up displacement with a preset vibration threshold, and discarding or marking spectral data that do not meet the corresponding threshold conditions.

[0025] Furthermore, after the initial setting step, an acquisition step is also included, comprising: acquiring a dark field spectrum by blocking the optical path of the detection component in the absence of a sample; and acquiring a reference spectrum by placing a standard white board between the follow-up light source unit and the follow-up detection unit.

[0026] As can be seen from the above technical solutions, the advantages of the present invention are:

[0027] The present invention provides a contour-following transmission optical detection device by setting passive contour-following structures (including a follow-up light source unit and a follow-up detection unit) at both the upper and lower ends. This ensures that the incident side gap and the exit side gap (or the compression amount of the sealing light-shielding ring) remain constant within a set tolerance zone, or meet a preset constant bias relationship. This significantly reduces the coupling efficiency fluctuations, receiving solid angle changes, and equivalent optical path disturbances caused by changes in sample size / morphology. It improves the consistency and comparability of transmission spectra at the source, providing stable physical boundary conditions for online detection of mixed lines of multiple varieties and particle sizes.

[0028] This invention does not rely on high-speed servo and complex closed-loop control. The follow-up response is directly driven by contact force / gravity, which has engineering advantages such as simple structure, fast response, zero phase lag, low maintenance cost, and adaptability to dusty and humid working conditions. It is suitable for continuous detection in high-speed production lines. At the same time, the device can record observable measurements such as follow-up displacement and trigger timing, construct consistency criteria, and automatically mark / reject abnormal spectrum acquisition such as overtravel, unsealed, and severe vibration, thereby improving the availability of online data and deployment robustness. Attached Figure Description

[0029] Figure 1 This is a structural diagram of a transmission optical detection device provided in an embodiment of the present invention;

[0030] Figure 2 Another structural diagram of a transmission optical detection device provided in an embodiment of the present invention;

[0031] Figure 3 A perspective view (I) of a portion of the structure of a transmission optical detection device provided in an embodiment of the present invention.

[0032] Figure 4 A perspective view (II) of a portion of the structure of a transmission optical detection device provided in an embodiment of the present invention;

[0033] Figure 5 for Figure 1 Structural diagram of the central follower light source unit;

[0034] Figure 6 for Figure 1 Structural diagram of the servo detection unit;

[0035] Figure 7 for Figure 1 A schematic diagram of the connection between the triggering and control components;

[0036] Figure 8 for Figure 2 A schematic diagram of the connection of the spectral acquisition and processing unit;

[0037] Figure 9 A flowchart (I) of a transmission optical detection method provided in another embodiment of the present invention; Figure 10 A flowchart (II) of a transmission optical detection method provided in another embodiment of the present invention;

[0038] In the attached figures, the following labels are used:

[0039] 1-Rack;

[0040] 2-Conveying assembly; 20-V-shaped support surface; 21-Light transmission window;

[0041] 3-Detection dark box; 30-Support;

[0042] 4-Follow-up light source unit; 41-First support part; 42-First guide rod; 43-First floating platform; 430-First mounting part; 431-First arc-shaped part; 44-Compression spring; 45-First damping element; 46-First stroke limit; 47-First zero-position fine adjustment mechanism; 48-Light source assembly; 49-I-beam bracket;

[0043] 5- Follow-up detection unit; 51- Second support part; 52- Second guide rod; 53- Second floating platform; 530- Second mounting part; 531- Second arc-shaped part; 54- Compression spring; 55- Second damping element; 56- Second stroke limit; 57- Second zero-position fine adjustment mechanism; 58- Detection assembly; 59- Sealing light shielding ring;

[0044] 6-Triggering and control components; 60-Photoelectric switch; 61-Encoder; 62-Communication interface; 63-Host computer; 64-PLC; 65-I / O module;

[0045] 7-Spectrum acquisition and processing unit; 70-Light source driver; 71-Electro-optical conversion unit; 72-Spectrometer; 73-Processing module;

[0046] 8-Drive motor;

[0047] 90 - Host computer;

[0048] 91-External selection system. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0050] This invention provides a transmissive optical detection device and method for online agricultural product contour-following. Its core idea revolves around the sensitivity of the transmission spectrum to geometric boundary conditions, proposing and implementing a passive follow-up scheme with "boundary condition uniformity": using the air gap on the incident side and the air gap on the exit side (or equivalent light-shielding ring compression / sealing state) as stable objects, a purely mechanical passive follow-up mechanism transforms the height disturbance caused by sample size and morphology into coaxial, equidistant follow-up of the optical head. This physically suppresses changes in coupling efficiency, light leakage bypass, and fluctuations in effective sampling volume caused by distance drift, thereby improving the repeatability of the transmission spectrum and the robustness of the model.

[0051] like Figures 1 to 4The diagram shown is a structural diagram of a contour-following transmission optical detection device provided in an embodiment of the present invention. The transmission optical detection device includes a frame 1, a conveying assembly 2, a detection dark box 3, a follow-up light source unit 4, a follow-up detection unit 5, a triggering and control assembly 6, a spectrum acquisition and processing unit 7, and a drive motor 8.

[0052] The frame 1 is used to support other components of the transmission optical inspection device. It is preferably made of profile frame and equipped with multiple adjustable feet 10 (four in this embodiment) to achieve leveling of the whole machine.

[0053] The conveying assembly 2 is a V-shaped support conveying assembly, including two conveyor belts and rotating rollers 22. The two conveyor belts are arranged at relative inclinations to form a V-shaped support surface 20, which is used to continuously convey samples to the testing station along the conveying direction at industrial pace and to provide passive centering / support boundaries.

[0054] The drive motor 8 is mounted on the frame 1. A drive wheel 80 is mounted on the output shaft of the drive motor 8. The drive wheel 80 is connected to the driven wheel (not shown in the figure) at the end of the drive roller 22 via a transmission belt (such as a synchronous belt) or a chain. When the drive motor 8 rotates, the drive wheel 80 drives the driven wheel to rotate, thereby driving the rotating roller 22 to rotate. The rotating roller 22 drives the two conveyor belts to run synchronously.

[0055] A light-transmitting window 21 is provided on the V-shaped support surface 20 for the light path of the follow-up detection unit 5 to pass through. The light-transmitting window 21 is located directly below the detection station and is coaxially arranged with the optical end face of the detection component 58 of the follow-up detection unit 5, so that the light transmitted from the lower surface of the sample can pass through the light-transmitting window 21 in sequence and then be incident on the optical end face of the detection component 58.

[0056] The detection dark box 3 is fixedly installed on the frame 1 and surrounds the detection station to isolate the ambient light and splash contamination, and to provide the detection station. The detection dark box 3 has a reserved optical path channel for the follow-up light source unit 4 and the follow-up detection unit 5, and a through hole (not shown in the figure) is opened at the corresponding position for the follow-up light source unit 4 and the follow-up detection unit 5 to pass through.

[0057] The follower light source unit 4 and the follower detection unit 5 are respectively located on the upper and lower sides of the transport path of the transport assembly 2. Both adopt a "one-degree-of-freedom vertical floating platform with guiding constraints" structure, and realize the contour-following movement of the sample surface under the action of their respective elastic elements. Specifically, the follower light source unit 4 is installed above the transport assembly 2 to output incident light and perform contour-following movement of the upper surface of the sample; the follower detection unit 5 is installed below the transport assembly 2 (for example, below the light transmission window 21) to receive transmitted light and perform contour-following movement of the lower surface of the sample.

[0058] Each of the follow-up light source unit 4 and the follow-up detection unit 5 includes a support, a guide assembly, a floating platform, an elastic element, a damping element, a travel limit, and a zero-position fine-tuning mechanism. Specifically: the support is mounted on the frame 1; the guide assembly is fixedly connected to the support; the floating platform is slidably connected to the guide assembly, which constrains the floating platform to only approach or move away from the sample in a direction perpendicular to the transport path; the elastic element is connected between the support and the floating platform; the damping element is arranged in series with the elastic element between the support and the floating platform, with the damping element located on the side of the elastic element closer to the floating platform; the travel limit is mounted on the support and located at the end of the elastic element away from the floating platform, used to limit the maximum movement of the floating platform; the zero-position fine-tuning mechanism is mounted on the support, with its movable end abutting against the floating platform, used to adjust the initial position of the floating platform in the absence of a sample. A light source assembly 48 is mounted on the floating platform of the follow-up light source unit 4, and a detection assembly 58 is mounted on the floating platform of the follow-up detection unit 5.

[0059] Specifically, such as Figure 5 As shown, the follow-up light source unit 4 includes: a first support part 41, a first guide assembly, a first floating platform 43, a first elastic element, a first damping element 45, a first stroke limit 46, a first zero-position fine-tuning mechanism 47, and a light source assembly 48.

[0060] The first support part 41 is used to fix the follower light source unit 4 to the detection dark box 3 or the frame 1, and can be an L-shaped or gate-shaped bracket. In this embodiment, the first support part 41 is an L-shaped bracket, which is fixed to the frame 1 by an I-beam bracket 49. The first support part 41 serves as the fixed installation reference part for the follower light source unit 4. The first guide assembly, the first elastic element, the first damping element 45, the first travel limit 46, and the first zero-position fine adjustment mechanism 47 are all mounted on the first support part 41 or are arranged in conjunction with the first support part 41.

[0061] The first guiding component consists of multiple parallel guide rods or miniature linear guides, used to guide and constrain the first floating platform 43, ensuring that the first floating platform 43 performs a single-degree-of-freedom reciprocating motion relative to the first support 41 only in the vertical direction. In this embodiment, the first guiding component consists of two parallel first guide rods 42, which are vertically arranged and horizontally spaced and fixed to the first support 41. The first floating platform 43 is equipped with a first slider (not shown in the figure), which slides in cooperation with the two first guide rods 42. The first guide rods 42 constrain the first floating platform 43 to perform a single-degree-of-freedom translation only in the vertical direction (i.e., in the direction perpendicular to the conveying path), preventing the first floating platform 43 from tilting, swaying, or deflecting during the follow-up process, thereby ensuring the stability of the optical end face attitude of the follow-up light source unit 4.

[0062] The first floating platform 43 is generally stern-shaped, comprising an upper first mounting portion 430 and a lower first arc-shaped portion 431. The upper first mounting portion 430 is substantially horizontal, with a flat or near-flat top for fixing the light source assembly 48, the first slider, etc. The lower first arc-shaped portion 431 extends obliquely downward from the first mounting portion 430, with its outer surface being a convex arc-shaped surface for direct contact with the upper surface of the sample during movement. The curvature of the first arc-shaped portion 431 is adapted to the typical surface curvature of spherical or ellipsoidal agricultural products (such as potatoes, onions, tomatoes, etc.), allowing the upper surface of the sample to smoothly propel the first floating platform 43 upward. One edge of the first arc-shaped portion 431 is tapered (i.e., pointed at one end) to accommodate the surface contours of samples of different sizes and reduce contact friction. Optionally, a flexible cushioning material may be attached to the surface of the first arc-shaped portion 431 to further reduce sample damage.

[0063] The first elastic element provides a preload force to the first floating platform 43 in the direction of the sample and provides a restoring force after the sample surface height changes. The first elastic element is a compression spring or a constant force spring / coil spring to achieve an approximately constant force output, and is mounted on the first guide rod 42. One end of the first elastic element is connected to the first floating platform 43, and the other end is connected to the first support part 41. In this embodiment, the first elastic element consists of two parallel compression springs 44, each mounted on the outside of two parallel first guide rods 42. In addition to providing linear guidance to the first floating platform 43, the first guide rods 42 also guide and prevent swaying of the compression springs 44 located on their outer periphery.

[0064] The first damping element 45 can be a viscous damper, a friction damping plate, or a magnetic eddy current damping structure, used to provide damping for the follow-up displacement of the first floating platform 43, so as to suppress vibration, rebound, and secondary oscillation under high-speed conveying conditions. In this embodiment, the first damping element 45 includes two damping elements, which are respectively arranged in a one-to-one correspondence with two compression springs 44. The first damping element 45 is disposed between the compression springs 44 and the first floating platform 43. One end of the compression spring 44 is connected to or abuts against the first support part 41, and the other end is connected to or abuts against one end of the first damping element 45. The other end of the first damping element 45 is connected to or abuts against the first floating platform 43, thereby forming an independent force branch on both sides of the two first guide rods 42. Each force branch is a series force transmission path of "first support part 41 - compression spring 44 - first damping element 45 - first floating platform 43". Thus, the elastic restoring force provided by the two compression springs 44 is transmitted to the first floating platform 43 through their respective damping elements. The first floating platform 43 then drives the first slider and the light source assembly 48 to move synchronously. When there are height fluctuations on the sample surface, the light source assembly 48 drives the first floating platform 43 to rise and fall along the first guide rod 42. The displacement of the first floating platform 43 acts on the two damping elements, and the two damping elements then drive the corresponding compression springs 44 to compress or release, thereby achieving buffering and energy dissipation while ensuring pre-tensioned follow-up.

[0065] The first stroke limiter 46 is mounted on the first support portion 41, located at the end of the compression spring 44 away from the first floating platform 43. It limits the maximum travel of the first floating platform 43 relative to the first support portion 41, preventing the guiding, elastic, and damping components from overtraveling. Preferably, the first stroke limiter 46 includes an upper limiter and a lower limiter (not shown). The upper and lower limiters can be disposed on the first support portion 41 or on the first guide rod 42, and respectively cooperate with the corresponding limiting surfaces on the first floating platform 43 or the first slider. The upper limit component is used to limit the maximum upward stroke of the first floating platform 43 to prevent the floating platform from moving too far when the sample protrusion is too large, which would cause the two compression springs 44 to be over-compressed, the corresponding damping component to overtravel, or the light source assembly 48 to collide with the internal components of the detection dark box 3. The lower limit component is used to limit the maximum downward stroke of the first floating platform 43 to prevent the first slider 430 from leaving the effective guiding range of the first guide rod 42 and to prevent the two compression springs 44 from completely losing their preload, so as to ensure that the follow-up light source unit 4 maintains a stable initial standby position when there is no sample or a thin sample.

[0066] The first zero-position fine-tuning mechanism 47 is used to set the target air gap (or offset) between the follow-up light source unit 4 and the sample surface. It is preferably a lead screw + locking nut structure to adapt to the calibration of different varieties / sizes. The first zero-position fine-tuning mechanism 47 is mounted on the first support part 41, and its movable end abuts against the first floating platform 43. It is used to adjust the initial position of the first floating platform 43 relative to the first support part 41 in the absence of a sample, so as to set the initial working distance of the light source assembly 48 relative to the sample surface and adjust the preload of the two compression springs 44.

[0067] Furthermore, the first zero-position fine-tuning mechanism 47 may include an adjusting screw (not shown) threadedly engaged with the first support portion 41 and a locking member (not shown) for locking. The inner end of the adjusting screw is connected to or abuts against the first floating platform 43 or a force-bearing portion (not shown) disposed on the first floating platform 43. By rotating the adjusting screw, the initial height position of the first floating platform 43 can be changed, thereby synchronously changing the initial working state of the two series force-bearing branches, so that the two compression springs 44 obtain the required preload and the two damping elements are in a suitable initial stroke range. After adjustment, the adjusting screw is locked by the locking member to prevent zero-position drift.

[0068] The light source assembly 48 can be a halogen lamp / LED + fiber optic coupling / collimating lens structure; preferably, fiber optic output is used to insulate heat and improve maintenance convenience. The light source assembly 48 is fixedly installed on the lower side of the first floating platform 43 and rises and falls synchronously with the first floating platform 43 as a whole.

[0069] The follow-up mechanism of the follow-up light source unit 4: When the sample enters the detection station, the upper surface of the sample acts as the "input contour" to push the first floating platform 43 to move upward; under the action of the compression spring 44, the light source assembly 48 always maintains an approximately constant relative position relationship with the sample surface, thereby stabilizing the incident side boundary conditions.

[0070] like Figure 6As shown, the follow-up detection unit 5 includes: a second support part 51, a second guide assembly, a second floating platform 53, a second elastic element, a second damping element 55, a second stroke limit 56, a second zero-position fine-tuning mechanism 57, a detection assembly 58, and a sealing light-shielding ring 59. The structural principles of the second guide assembly, second floating platform 53, second elastic element, second damping element 55, second stroke limit 56, and second zero-position fine-tuning mechanism 57 are basically the same as those of the corresponding first guide assembly, first floating platform 43, first elastic element, first damping element 45, first stroke limit 46, and first zero-position fine-tuning mechanism 47 in the follow-up light source unit 4. Specifically, the second guide assembly is fixedly connected to the second support part 51; the second floating platform 53 is slidably connected to the second guide assembly and can only move in a direction perpendicular to the conveying path; the second elastic element is connected between the second support part 51 and the second floating platform 53; the second damping element 55 and the second stroke limit 56 are respectively installed on the second support part 51 and located at both ends of the second elastic element; and the second zero-position fine-tuning mechanism 57 is installed on the second support part 51 and abuts against the second floating platform 53, used to adjust the initial position of the second floating platform 53 in the absence of samples. In this embodiment, the second guide assembly consists of two parallel second guide rods 52, which cooperate with the second slider (not shown) of the second floating platform 53. The second elastic element consists of two parallel compression springs 54, which are respectively sleeved on the outside of two parallel second guide rods 52, enabling the second floating platform 53 to have the ability to "push upward".

[0071] The following only explains the differences between the follow-up detection unit 5 and the follow-up light source unit 4:

[0072] The second support part 51 is an inverted U-shaped base, which is used to fix the follow-up detection unit 5 on the support 30 inside the detection dark box 3.

[0073] The second floating platform 53 is shaped like an inverted stern, and its size is smaller than that of the first floating platform 43. The second floating platform 53 includes a lower second mounting portion 530 and an upper second arc-shaped portion 531. The lower second mounting portion 530 is essentially horizontal, with a flat or near-flat bottom for fixing the detection component 58, the second slider, etc. The upper second arc-shaped portion 531 extends obliquely upward from the second mounting portion 530, with its outer surface being a convex arc surface for direct contact with the lower surface of the sample during movement. The curvature of the second arc-shaped portion 531 is adapted to the typical surface curvature of spherical or ellipsoidal agricultural products (such as potatoes, onions, tomatoes, etc.), allowing the lower surface of the sample to smoothly propel the second floating platform 53 upward. One edge of the second arc-shaped portion 531 is tapered (i.e., pointed at one end) to adapt to the surface contours of samples of different sizes and reduce contact friction. Optionally, a flexible cushioning material may be attached to the surface of the second arc-shaped portion 531 to further reduce sample damage.

[0074] Furthermore, a sealing light-shielding ring 59 is fixedly provided at the end of the second floating platform 53 of the follow-up detection unit 5. This sealing light-shielding ring 59 surrounds the optical end face of the detection component 58, and its free end protrudes from the optical end face, which is used to limit the receiving aperture and suppress bypass light, forming a partially enclosed dark cavity. In other embodiments, the follow-up detection unit 5 is provided with other light-limiting structures to form a partially enclosed dark cavity during the follow-up process, cutting off bypass light leakage channels such as the sample-environment and sample-band gaps.

[0075] The detection component 58 is preferably connected to the spectrometer via a receiving optical fiber and a collimation / focusing structure; the detection end face and the upper light source end face are arranged coaxially to form a transmission optical path. The detection component 58 is fixedly installed on the upper side of the second floating platform 53, corresponding to the light source component 48, and rises and falls synchronously with the second floating platform 53 as a whole.

[0076] Follow-up mechanism of follow-up detection unit 5: After the sample enters the detection station, the sealing light shielding ring 59 is in contact or close to the lower surface of the sample under the action of the second elastic element; the change of the lower surface contour of the sample will drive the second floating platform 53 to follow, thereby stabilizing the boundary conditions on the emission side.

[0077] To achieve a constant air gap between the optical window end face and the sample surface, this invention preferably employs a "contact ring-fixed offset optical window end face" structure. A fixed step or shim is provided between the sealing light-shielding ring (contact ring) and the optical end face, so that when the light-shielding ring is compressed to the designed compression amount, a target gap (e.g., 0.5–2.0 mm) is formed between the optical window end face and the sample surface. This structure transforms uncertain morphological excitation into definite end face boundary conditions, avoiding the complex control of "adjusting angle / focus during follow-up." Furthermore, the sealing light-shielding ring can adopt a replaceable consumable structure (pressure ring snap or threaded cap) to adapt to cleaning and maintenance in dusty and muddy environments.

[0078] The light transmission window 21 is located directly above the optical end face of the detector component 48, so that the light transmitted from the lower surface of the sample passes through the light transmission window 21 in sequence and then enters the optical end face.

[0079] The optical end face described in this invention refers to the exit surface of the light source assembly 48 that emits light to the sample, or the incident surface of the detection assembly 58 that receives transmitted light from the sample. When the light source assembly 48 uses fiber optic output, the optical end face is the exit surface of the fiber optic; when a collimating lens structure is used, the optical end face is the surface of the exit lens of the collimating lens; when direct LED illumination is used, the optical end face is the light-emitting surface of the LED. The optical end face of the detection assembly 58 is similar.

[0080] The triggering and control component 6 is mounted on the second floating platform 53. The triggering and control component 6 includes a photoelectric sensor, a position sensor, and a displacement sensor; the photoelectric sensor is mounted on the frame 1 and located at the entrance of the detection station, which refers to the spatial position between the follow-up light source unit 4 and the follow-up detection unit 5 when the sample is having its spectrum collected; the position sensor is connected to the drive shaft of the conveying component 2 or mounted on the frame 1; the displacement sensor is connected to the floating platform of the follow-up light source unit 4 or the follow-up detection unit 5 and is used to record the follow-up displacement.

[0081] In this embodiment, as Figure 7 As shown, the photoelectric sensor is a photoelectric switch 60, used to detect the sample entering the detection station and output a positioning signal; the position sensor is an encoder 61 or a travel contact (not shown in the figure), used to acquire the transport position / cycle information, or to limit the position triggering condition of the sample in the effective sampling window and trigger spectrum acquisition; the displacement sensor 62 is used to measure the servo displacement of the servo light source unit 4 or the servo detection unit 5 at the time of spectrum acquisition, so as to record the detection geometric boundary conditions (such as servo compression, relative displacement of the optical head, etc.), and can be used for subsequent spectral data consistency judgment, anomaly rejection or compensation calculation.

[0082] The core control module of the triggering and control component 6 is, for example, a PLC (Programmable Logic Controller) 63. The input signals of the PLC 63 include the position signal of the photoelectric switch 60, the pulse / speed signal of the encoder 61, the safety interlock signal of the limit travel (including the first limit travel 46 and the second limit travel 56), and the follow-up displacement signal of the displacement sensor 62. It is connected to a host computer 90 or a human-machine interface via a communication interface 64 (Ethernet / serial port). The outputs of the triggering and control component 6 are connected to the drive motor 8, the light source component 48, and the spectrum acquisition and processing unit 7.

[0083] Specifically, the PLC63 integrates all input signals (including position signals, conveying position / cycle information, follow-up displacement, safety interlocks, etc.), performs logical judgment, and outputs switch / dimming signals to the drive motor 8 and the light source assembly 48 to control their start / stop or brightness; it outputs spectrum acquisition trigger / synchronization signals to the spectrum acquisition and processing unit 7 through the I / O module 65, and receives detection results or system status information from the spectrum acquisition and processing unit 7, so as to realize linkage with external structures (such as sorting actuators or upper management systems) to realize sample position determination, spectrum acquisition triggering and follow-up displacement recording.

[0084] like Figure 8As shown, the spectral acquisition and processing unit 7 includes a light source driver 70, an electro-optical conversion unit 71, a spectrometer 72 (e.g., a fiber optic spectrometer), and a processing module 73 (e.g., an industrial computer / embedded processor), used to realize transmission spectrum acquisition, preprocessing, and output of detection results. The light source driver 70 is electrically connected to the electro-optical conversion unit 71, providing stable driving power (e.g., constant current / constant voltage drive) for electro-optical conversion, and can perform switching / power modulation after receiving control commands from the trigger and control component 6 or the processing module 73. The electro-optical conversion unit 71 is connected to the light source component 48 of the follow-up light source unit 4 via an optical fiber. The electro-optical conversion unit 71 is a light source module (e.g., halogen lamp, LED or other broadband light source), used to convert electrical energy into incident light and output it to the detection station via the transmitting optical fiber. The spectrometer 72 is connected to the detection component 58 of the follow-up detection unit 5 via an optical fiber, used to receive the light signal after sample transmission and form spectral data output. The processing module 73 is electrically connected to the spectrometer 72, used to complete dark field / reference correction, spectral preprocessing and quality parameter / defect identification model inference, and output the detection results to the trigger and control component 6 or the external sorting system 91.

[0085] Specifically, the light source driver 70 first provides stable power to the light source assembly 48. Driven by this power, the light source module (such as a halogen lamp or LED) emits incident light, which is then transmitted through an optical fiber to the sample at the detection station. The light transmitted through the sample is received by the detection assembly 58. The detection assembly 58 transmits the transmitted light to the spectrometer 72 (whose function is array detection / spectral calculation), converting it into spectral data. This data is then sent to the processing module 73 (e.g., an industrial computer, whose function is preprocessing / modeling). The processing module 73 sequentially performs dark field correction, reference correction, and spectral preprocessing. The system performs calculations and analysis based on quality parameters or defect identification models to generate detection results. Simultaneously, a trigger signal is input to the data interface (USB / Ethernet) and storage module. This data interface and storage module interact with the spectrometer 72 and processing module 73. After data transmission and storage are completed, the system outputs the discrimination results through classification / regression. In addition, there is also a data flow between the spectrometer 72 and the processing module 73 (spectral data is provided for analysis by the processing module). The information processed by the processing module 73 is also transmitted to the data interface and storage, and finally, the data interface and storage output the detection results.

[0086] Throughout the process, the light source driver 70 can receive control commands from the triggering and control component 6 or the processing module 73 to switch the light source component 48 on or off or modulate its power. The detection results obtained by the processing module 73 can be output to the triggering and control component 6 or further transmitted to an external sorting system to achieve coordinated operation of the entire detection and sorting process.

[0087] The drive motor 8 is mounted on the frame 1 and is used to drive the conveying assembly 2, the follow-up light source unit 4, the follow-up detection unit 5, the triggering and control assembly 6, and the spectrum acquisition and processing unit 7.

[0088] Without departing from the spirit of this invention, the following modifications can be made: the first and second elastic elements can be gas springs or magnetic compensation structures; the follow-up light source unit 4 can achieve near-constant force contact through gravity compensation. The light source assembly 48 can be a halogen lamp, an LED array, or a broadband laser source; the detection assembly 58 can be a single spectrometer, a multi-channel detector, or an imaging receiver. The triggering method can be "position trigger (photoelectric)," "time trigger (encoder)," "stability trigger (displacement change rate threshold)," or a combination thereof. The applicable objects are not limited to potatoes, but can be extended to near-spherical fruits and vegetables such as onions, tomatoes, and apples.

[0089] In summary, the key structural mechanism of the passive contour-following transmission optical device of the present invention is as follows: Linear guidance (guide rod / linear bearing / guide rail, etc.) ensures vertical translational movement, thereby guaranteeing the stability of the optical end face attitude (avoiding tilt angles introduced by the follow-up motion); controlled normal force is provided by elastic elements (compression spring, constant force spring, or equivalent flexible mechanism) to ensure the light-shielding ring is in close or near contact with the sample surface; a zero-position fine-tuning mechanism is used to set the sample-free reference position, ensuring the incident and exit gaps (or the light-shielding ring compression) fall within the target tolerance zone; damping / friction tuning suppresses platform follow-up oscillations, reducing dynamic distance fluctuations and jitter within the spectral acquisition window.

[0090] The following are method embodiments corresponding to the above-described device embodiments. These embodiments can be implemented in conjunction with the above-described embodiments. The relevant technical details mentioned in the above embodiments remain valid in these embodiments, and will not be repeated here to avoid repetition. Correspondingly, the relevant technical details mentioned in these embodiments can also be applied to the above embodiments.

[0091] like Figure 9 As shown, another embodiment of the present invention provides a contour-following transmission optical detection method, which adopts the transmission optical detection device in the above embodiment. The core of this transmission fiber detection method is: taking the "incident side air gap / outcrystal side air gap (or the compression amount of the sealing light shield)" as the stable object, a locally closed dark cavity is formed by purely mechanical passive following, thereby realizing the consistency of the boundary conditions of transmission measurement and suppressing the coupling efficiency fluctuation and bypass light leakage caused by the change of sample diameter and contour undulation.

[0092] The transmission optical detection method in this embodiment includes the following steps:

[0093] Initial setting step S10: Adjust the zero-position fine-tuning mechanism so that the relative position between the optical end face of the light source component of the follow-up light source unit and the optical end face of the detection component of the follow-up detection unit in the absence of samples reaches the preset calibration gap.

[0094] Specifically, in the absence of samples, the operator first performs the system zero-position setting and spectral calibration process: the initial installation height of the follow-up light source unit 4 and the follow-up detection unit 5 is adjusted by the first zero-position fine-tuning mechanism 47 and the second zero-position fine-tuning mechanism 57 so that the upper target incident gap and the lower target exit gap reach the set value; or, in the case where the light-shielding and sealing are the main constraints, the target compression amount of the sealing light-shielding ring 59 is set so that it can form a stable light-shielding contact condition during subsequent follow-up bonding.

[0095] In this embodiment, as Figure 10 As shown, after the initial setting step S10, there is also a data acquisition step S11, which includes: acquiring dark field spectra by blocking the optical path of the detection component in the absence of samples; and placing a standard white board between the follow-up light source unit and the follow-up detection unit to acquire reference spectra.

[0096] Specifically, after the zero-position setting is completed, the spectral acquisition and processing unit 7 acquires the dark field spectrum and the reference spectrum under the coordination of the triggering and control component 6. Among them, the light source driver is used to power the light source and stabilize the output, the electro-optic conversion unit and the fiber optic spectrometer 70 are used to complete the acquisition of the transmission spectrum signal, and the processing module 73 is used to complete the dark field subtraction, reference correction and preparation work for subsequent model inference.

[0097] Start-up step S20: Start the transport component to move the sample to the detection station between the follow-up light source unit and the follow-up detection unit.

[0098] Specifically, the conveyor assembly 2 is activated, causing the sample (not shown in the figure) to enter the detection station area defined by the detection dark box 3 along with the conveyor belt.

[0099] Passive contouring and following step S30: The upper surface of the sample pushes the floating platform of the follower light source unit to compress the elastic element of the follower light source unit to move upward, and the lower surface of the sample pushes the floating platform of the follower detection unit to compress the elastic element of the follower detection unit to move downward, so that the follower light source unit and the follower detection unit perform passive contouring and following of the upper and lower surfaces of the sample respectively.

[0100] Specifically, when the sample enters the vicinity of the detection window at the detection station, the sealing light-shielding ring 59 forms a close or near-close relationship with the sample surface under the normal force provided by the second elastic element; simultaneously, the first floating platform 43 and the second floating platform 53 undergo passive follow-up displacement in the vertical direction under the constraint of their respective guide components. Through this passive follow-up process, the device converts the "sample surface contour change" into "coaxial follow-up of the first and second floating platforms (43, 53)," so that the optical end face of the follow-up light source unit 4 and the optical end face of the follow-up detection unit 5 maintain a constant gap (or satisfy a constant bias relationship) relative to the sample surface, thereby forming mutually opposed closed / quasi-closed local dark cavities on the upper and lower sides of the sample, significantly weakening the bypass light leakage path between the sample-environment-probe, making the detection signal mainly based on the transmission component that actually penetrates the sample, improving the acquisition signal-to-noise ratio and reducing the contamination of the spectrum by geometric drift.

[0101] Triggering spectral acquisition step S40: When the sample moves to the detection station, the spectral acquisition and processing unit is triggered by the triggering and control component to acquire the transmission spectrum, and the displacement is recorded at the same time.

[0102] Optionally, the triggering spectrum acquisition step S40 further includes: detecting the sample's arrival and triggering spectrum acquisition by the photoelectric sensor of the triggering and control component 6, and recording the follow-up displacement by the displacement sensor.

[0103] Specifically, in terms of sample arrival determination and spectrum acquisition triggering, the triggering and control component 6 includes at least: a photoelectric switch 60, an encoder 61 or a travel contact, and a displacement sensor (not shown in the figure). The photoelectric switch 60 is used to determine that the sample has entered the detection window and is close to the center position; the encoder 61 or the travel contact is used to provide a transport displacement / time reference or to determine the "window center" position; the displacement sensor is used to record the follow-up displacement amount for stability and consistency evaluation of the follow-up state. When the triggering and control component 6 determines that the sample has met the spectrum acquisition conditions, it outputs a trigger signal to the spectrum acquisition and processing unit 7, which then initiates the transmission spectrum acquisition process to complete the acquisition of the transmission spectrum data of the current sample.

[0104] Output step S50: The spectral acquisition and processing unit preprocesses the transmission spectrum and determines whether the current spectral acquisition is valid based on the comparison result between the follow-up displacement and the preset threshold, and outputs the detection result.

[0105] Optionally, the output step S50 further includes: the spectral acquisition and processing unit compares the follow-up displacement with a preset overtravel threshold and a sealing displacement threshold, and compares the change rate of the follow-up displacement with a preset vibration threshold, and discards or marks the spectral data that does not meet the corresponding threshold conditions.

[0106] While completing the transmission spectrum acquisition, the system records the follow-up displacement: the displacement information output by the displacement sensor, together with the initial settings of the first zero-position adjustment mechanism 47 and the second zero-position fine-tuning mechanism 57, constitutes the geometric consistency criterion, which can be used to calculate the equivalent diameter / thickness of the sample or to determine whether there are abnormal working conditions such as overtravel, unsealing, or severe vibration. For data that does not meet the consistency threshold, the processing module 73 can perform rejection, marking, or weight reduction processing; for data that meets the consistency threshold, the processing module 73 inputs its transmission spectrum into, for example, a black-heart / dry matter detection model and outputs the detection results, and if necessary, further links with external sorting execution mechanisms to complete online grading and sorting.

[0107] Specifically, in output step S50, the spectral acquisition and processing unit 7 performs a consistency judgment based on the recorded follow-up displacement, which includes:

[0108] Overtravel detection: The displacement measured by the displacement sensor is compared with a preset upper limit threshold for displacement (i.e., overtravel threshold). If the displacement exceeds the upper limit threshold, it indicates that the sample size is outside the detection range or that the servo mechanism is malfunctioning, and is determined to be an overtravel anomaly.

[0109] Seal establishment determination: The displacement is compared with the minimum compression threshold required for the sealing light-shielding ring to adhere (i.e., the sealing displacement threshold). If the displacement is lower than the minimum compression threshold, it indicates that the sealing light-shielding ring 59 has failed to form an effective fit with the sample surface, posing a risk of bypass light leakage, and the seal is deemed invalid.

[0110] Vibration severity assessment: Calculate the rate of change of the servo displacement within the spectral acquisition window (e.g., fluctuation amplitude or standard deviation per unit time) and compare it with a preset vibration threshold. If the rate of change exceeds the vibration threshold, it indicates severe vibration in the sample or servo mechanism, affecting the stability of the spectral signal, and is thus determined as severe vibration.

[0111] For spectral data that does not meet any of the above consistency thresholds, the spectral acquisition and processing unit 7 performs elimination, labeling, or weight reduction processing and does not use it for subsequent quality model prediction or grading and sorting; for spectral data that meets all consistency thresholds, the spectral acquisition and processing unit 7 inputs it into the trained internal quality prediction model, outputs the detection results, and can link with external sorting execution agencies to complete online grading and sorting.

[0112] Reset step S60: After the sample leaves the detection station, the floating platforms of the follow-up light source unit and the follow-up detection unit return to their initial positions under the restoring force of their respective elastic elements.

[0113] Specifically, after the sample leaves the testing station, the first floating platform 43 and the second floating platform 53 automatically return to their original positions under the action of the first elastic element (compression spring 44) and the second elastic element (compression spring 54), respectively, restoring them to the initial working positions set by the first zero-position fine-tuning mechanism 47 and the second zero-position fine-tuning mechanism 57, and then enter the continuous testing cycle for the next sample. Through the above process, this embodiment achieves passive contour following and stabilization of double-ended geometric boundary conditions for multi-size, irregular contour samples without introducing active servo adjustment, thereby improving the robustness and repeatability of transmission spectra under industrial online conditions.

[0114] The transmission optical detection method of this invention follows a main line of "no sample calibration → sample entry → passive follow-up to form a dark cavity → trigger spectrum acquisition → consistency criterion → output result → return cycle," achieving "consistency of boundary conditions at the moment of transmission spectrum acquisition" under continuous online detection conditions. Specifically, the follow-up displacement output by the displacement sensor or travel contact can serve as an indirect representation of the sample's equivalent thickness / diameter, used to establish consistency criteria (such as anomaly identification like overtravel, seal failure, excessive vibration, etc.), thereby enhancing the quality control capability of the online system.

[0115] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims, and all of these forms fall within the scope of protection of the present invention.

Claims

1. A contour-following transmission optical detection device, characterized in that, include: frame; A conveying assembly, mounted on the frame, is used to convey samples along the conveying direction; A follow-up light source unit and a follow-up detection unit are respectively disposed on the upper and lower sides of the conveying path of the conveying assembly; Each of the following light source unit and the following detection unit includes a support, a guide assembly, a floating platform, and an elastic element, wherein: the support is mounted on the frame; the guide assembly is fixedly connected to the support; the floating platform is slidably connected to the guide assembly, and the guide assembly constrains the floating platform to move closer to or away from the sample only in a direction perpendicular to the transport path; the elastic element is connected between the support and the floating platform; The servo light source unit has a light source component mounted on its floating platform, and the servo detection unit has a detection component mounted on its floating platform. And a spectral acquisition and processing unit, which is optically connected to the detection component.

2. The contour-following transmission optical detection device according to claim 1, characterized in that, The conveying assembly is a V-shaped support conveying assembly, which includes two conveyor belts. The two conveyor belts are arranged at an angle to each other to form a V-shaped support surface. A light-transmitting window is opened on the V-shaped support surface for the light path of the follow-up detection unit to pass through.

3. The contour-following transmission optical detection device according to claim 1, characterized in that, A sealing light-shielding ring is fixedly installed at the end of the floating platform of the follow-up detection unit. The sealing light-shielding ring surrounds the optical end face of the follow-up detection component, and the free end of the sealing light-shielding ring protrudes from the optical end face.

4. The contour-following transmission optical detection device according to claim 1, characterized in that, The guiding assembly consists of multiple parallel guide rods; the elastic element is a compression spring or a constant force spring, the elastic element is fitted onto the guide rod, one end of the elastic element is connected to the floating platform, and the other end of the elastic element is connected to the support part.

5. The contour-following transmission optical detection device according to claim 1, characterized in that, The follow-up light source unit and / or the follow-up detection unit further includes a damping element, which is arranged in series with the elastic element between the support and the floating platform, and the damping element is located on the side of the elastic element closer to the floating platform.

6. The contour-following transmission optical detection device according to claim 1, characterized in that, The follow-up light source unit and / or the follow-up detection unit also include a travel limiter, which is installed on the support and located at one end of the elastic element to limit the maximum movement stroke of the floating platform.

7. The contour-following transmission optical detection device according to claim 1, characterized in that, The follow-up light source unit and / or the follow-up detection unit further include a zero-position fine-tuning mechanism, which is installed on the support and its movable end abuts against the floating platform to adjust the initial position of the floating platform in the absence of samples.

8. The contour-following transmission optical detection device according to claim 1, characterized in that, It also includes a triggering and control component, which includes a photoelectric sensor, a position sensor, and a displacement sensor; the photoelectric sensor is mounted on the frame and located at the entrance of the detection station; the position sensor is connected to the drive shaft of the conveying component or mounted on the frame; the displacement sensor is connected to the floating platform of the follow-up light source unit or the follow-up detection unit.

9. The contour-following transmission optical detection device according to claim 1, characterized in that, The spectral acquisition and processing unit includes a light source driver, a spectrometer, and a processor. The light source driver is electrically connected to the light source assembly, the spectrometer is optically connected to the detection assembly, and the processor is electrically connected to the spectrometer.

10. The contour-following transmission optical detection device according to claim 1, characterized in that, It also includes a detection dark box, which is fixedly installed on the frame and surrounds the detection station. The detection dark box has through holes for the follow-up light source unit and the follow-up detection unit to pass through.

11. A contour-following transmission optical detection method, employing the contour-following transmission optical detection device according to any one of claims 1 to 10, characterized in that, Includes the following steps: In the initial setting step, the zero-position fine-tuning mechanism is adjusted so that the relative position between the optical end face of the light source component of the follow-up light source unit and the optical end face of the detection component of the follow-up detection unit reaches the preset calibration gap in the absence of samples. The startup step involves activating the transport assembly, causing the sample to move with the transport assembly to the detection station between the follow-up light source unit and the follow-up detection unit; In the passive contour-following step, the upper surface of the sample pushes the floating platform of the follow-up light source unit to compress the elastic element of the follow-up light source unit to move upward, and the lower surface of the sample pushes the floating platform of the follow-up detection unit to compress the elastic element of the follow-up detection unit to move downward, so that the follow-up light source unit and the follow-up detection unit respectively perform passive contour-following of the upper and lower surfaces of the sample. The spectrum acquisition step is triggered when the sample moves to the detection station. The triggering and control component triggers the spectrum acquisition and processing unit to acquire the transmission spectrum and records the displacement at the same time. In the output step, the spectral acquisition and processing unit preprocesses the transmission spectrum, determines whether the current spectral acquisition is valid based on the comparison result between the follow-up displacement and the preset threshold, and outputs the detection result. In the reset step, after the sample leaves the detection station, the floating platforms of the follow-up light source unit and the follow-up detection unit return to their initial positions under the restoring force of their respective elastic elements.

12. The contour-following transmission optical detection method according to claim 11, characterized in that, The triggering spectrum acquisition step further includes: detecting the sample's arrival at position using the photoelectric sensor of the triggering and control component and triggering spectrum acquisition, and recording the follow-up displacement using a displacement sensor; The output step further includes: the spectral acquisition and processing unit compares the follow-up displacement with a preset overtravel threshold and a sealing displacement threshold, and compares the rate of change of the follow-up displacement with a preset vibration threshold, and discards or marks spectral data that do not meet the corresponding threshold conditions.

13. The contour-following transmission optical detection method according to claim 11, characterized in that, Following the initial setup step, a data acquisition step is also included, comprising: In the absence of samples, the optical path of the detection component is blocked to collect dark-field spectra; A standard whiteboard is placed between the follow-up light source unit and the follow-up detection unit to collect a reference spectrum.

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