A laser time-of-flight ranging method for polyp measurement

Abstract

The application discloses a kind of laser time-of-flight (TOF) ranging method for endoscopic polyp measurement, belong to endoscopic accurate measurement and medical optical imaging technical field.This method is integrated at least two TOF laser emission and receiving units in front end of endoscope, two lasers are fixed as preset angle in structure.System respectively emits pulsed laser to two measurement points of polyp surface, calculates the distance AB,AC of endoscope end to polyp two points by recording laser round trip time difference;Again, according to fixed angle θ, using cosine theorem BC²=AB²+AC²‑2·AB·AC·cosθ obtains polyp actual size BC, to realize the fast, non-contact measurement of key parameters such as polyp width, diameter.The double-point ranging process uses synchronous sampling mechanism, avoids error caused by cavity peristalsis;Laser reflection point is automatically identified by system, improves clinical operation efficiency.

Description

Technical Field

[0001] This invention relates to the field of medical endoscopy-assisted measurement technology, and in particular to a laser time-of-flight ranging method for measuring polyps. Background Technology

[0002] Currently, clinical endoscopic assessment of polyp size primarily relies on:

[0003] Visual inspection based on experience has a large margin of error, and there are significant differences between doctors.

[0004] The clamp-and-jaw method requires close proximity to the lesion, which can easily cause bleeding and affect the procedure.

[0005] Ruler-type endoscopes or markers are complex and limited by viewing angle.

[0006] However, the size of the polyp is an important indicator for determining whether to remove it, what removal method to choose (cold cut, hot cut), and predicting the risk level. If the measurement error exceeds 1-2mm, it may directly lead to deviations in the treatment plan.

[0007] In recent years, optical ranging technology has developed rapidly, but the space inside an endoscope is extremely limited, and traditional structured light and binocular vision ranging still face challenges in the complex environment of the digestive tract.

[0008] Measurements depend on texture and image quality and are susceptible to interference from mucus and blood.

[0009] The device is bulky and difficult to integrate into the front end;

[0010] Geometric calculations are greatly affected by the perspective.

[0011] Therefore, there is an urgent need for a polyp measurement method that can be integrated into the tip of a narrow endoscope, can operate in a slippery cavity environment, and has high precision. Summary of the Invention

[0012] This invention provides a three-dimensional measurement method for polyps based on laser time-of-flight (TOF). Combining multi-point laser synchronous ranging with a fixed-angle optical path configuration, it calculates the true size of the polyp through geometric triangulation, achieving rapid measurement with an accuracy of ±0.1 mm. This solves the technical problem of existing endoscopic measurements relying on visual estimation and being inaccurate.

[0013] A laser time-of-flight ranging method for measuring polyps, characterized by comprising:

[0014] At least two laser time-of-flight ranging units are arranged at the front end of the endoscope, and the emission angle between the two laser beams is a preset fixed value; the distances AB and AC from the front end of the endoscope to the two ends of the polyp are obtained by laser time-of-flight ranging; the actual size B between the two ends of the polyp is calculated according to the cosine theorem BC²=AB²+AC²-2·AB·AC·cosθ.

[0015] As a further preferred embodiment of the present invention, the laser is a pulsed TOF laser with an emission wavelength of 850-940nm.

[0016] As a further preferred embodiment of the present invention, the emission angle θ is fixedly calibrated to 20°-60°.

[0017] As a further preferred embodiment of the present invention, the ranging error is controlled within ±0.1mm.

[0018] As a further preferred embodiment of the invention, the two laser ranging processes are performed simultaneously to ensure that the AB and AC measurements have a common time reference.

[0019] As a further preferred embodiment of the present invention, the measurement points at both ends of the polyp are automatically identified and locked by laser reflection points.

[0020] As a further preferred embodiment of the present invention, it also includes using three or more laser beams for simultaneous ranging and performing three-dimensional reconstruction based on multiple distance points.

[0021] As a further preferred embodiment of the present invention, the three-dimensional reconstruction obtains the polyp height, volume and base width by spatial fitting of multi-point ranging.

[0022] As a further preferred embodiment of the present invention, a polyp measurement system includes a laser emitting unit, a laser receiving unit, an endoscope imaging processor, and a real-time computing module.

[0023] Beneficial effects

[0024] This invention provides a laser time-of-flight ranging method for measuring polyps. It has the following beneficial effects:

[0025] High measurement accuracy: TOF directly measures distance with an accuracy of ±0.05-0.1mm, without relying on image texture.

[0026] No need to touch the polyp: avoids bleeding and reduces misdiagnosis.

[0027] Rigorous and reliable geometric calculations: Triangulation with fixed included angle and two-point distance measurement can automatically calculate the actual size.

[0028] Strong anti-interference ability: The effects of cavity liquid, blurring, light reflection, etc. on TOF are minimal, which is superior to structured light / binocular parallax method.

[0029] Real-time 3D reconstruction is possible: Multiple laser beams can quickly construct a height map of the polyp surface to help determine the degree of protrusion.

[0030] Easy to integrate: The laser emitter / receiver module can be miniaturized to fit endoscopes with a diameter of 2.6-12mm.

[0031] Wide range of applications: It can measure polyps, bulges, mucosal hyperplasia, and minor lesions. Detailed Implementation

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0033] This invention provides a technical solution: a laser time-of-flight ranging method for measuring polyps.

[0034] The core idea is to use two or more TOF lasers to simultaneously measure distances within a very small space at the tip of the endoscope, and then obtain the true size of the polyp through geometric calculations.

[0035] The entire technology system consists of the following three parts:

[0036] TOF (Time-of-Flight) laser ranging, a multi-beam laser fixed-angle structure design, and trigonometric measurement based on the cosine theorem to calculate the true size of polyps, these three elements work together to enable the endoscope to maintain high-precision measurements even in humid, reflective, curved, and irregular cavities.

[0037] Time-of-Flight (TOF) distance measurement uses the following formula to obtain the distance:

[0038] Distance = (Time difference between laser emission and reception × Speed ​​of light) ÷ 2

[0039] The principle is similar to sonar ranging, but with higher accuracy.

[0040] The laser emitter sends out an extremely short pulse, which hits the polyp, is reflected, and is then captured by the receiver. By measuring the time difference between emission and reflection, the absolute physical distance between the polyp surface and the endoscope tip can be obtained.

[0041] Unlike image textures, the cavity is often covered by mucus, has uneven lighting, and is prone to liquid floating, which can lead to: structured light failure; loss of texture in binocular vision; and unstable scale reference. TOF lasers only consider time, not images, and are unaffected by liquids or reflections.

[0042] The laser can be collimated and focused. This allows for the insertion of a miniature emitter into the inner lens, ensuring a stable beam directed at the lesion. Distance measurement is absolutely precise, with a theoretical error of <0.05mm. Medical-grade chips can achieve picosecond-level temporal resolution.

[0043] Dual-laser fixed angle structure. A single rangefinder can only obtain distance, not dimension. Therefore, this invention uses two laser beams fixedly mounted at the front end of the endoscope:

[0044] Laser L1 → Measurement of polyp point B

[0045] Laser L2 → Measurement of polyp point C

[0046] The angle θ between the two laser beams is fixed at the factory, for example: 20°, 30°, 45°.

[0047] The included angle is structurally fixed and calibrated and will not change during surgery.

[0048] A fixed angle plus the distance between two points can uniquely determine the length of the polyp. Two known sides (AB, AC) plus a fixed angle (∠BAC) can uniquely deduce the third side BC.

[0049] This structure makes the computation an absolute geometric quantity, rather than an image quantity.

[0050] The true size of the polyp is rigorously calculated using the law of cosines. Assume: A = laser reference point at the endoscope tip, B = left edge of the polyp, C = right edge of the polyp. Two TOF measurements yield: AB = d1, AC = d2. The factory-calibrated fixed angle θ = ∠BAC. Substituting these values ​​into the law of cosines, we obtain: BC² = AB² + AC² - 2·AB·AC·cos(θ). Calculating BC gives the true diameter of the polyp.

[0051] The synchronous ranging mechanism addresses the slight movement between the polyp and the endoscope due to factors such as respiration, peristalsis, and fluid fluctuations. If the two distances are not measured at the same time, the triangle will be distorted. Innovation:

[0052] All laser emitters and receivers perform distance measurement simultaneously, with sampling synchronization accuracy down to less than 1 μs. This ensures that AB and AC correspond to the spatial state at the same moment, guaranteeing the validity of the triangular geometric relationship.

[0053] Reflection recognition and automatic point locking are key to clinical usability. TOF ranging requires the laser to hit different points on the polyp surface. The laser reflection points form bright spots in the endoscopic image. The system automatically identifies these bright spots and marks them as ranging points B / C. Doctors do not need to manually align; they only need to: aim at the polyp → the system automatically locks the point → automatically calculate B / C, improving operational efficiency.

[0054] Multi-point laser and 3D measurement extension: Based on dual laser, it is extended to three or four lasers, such as a triangular pattern: the central laser measures the most prominent point of the polyp, and the three lateral lasers measure its contour points. The triangular mesh fits the point cloud → generates a 3D shape, which can output: polyp height, base diameter, maximum transverse diameter, and volume estimate. It is helpful to determine: whether it is a raised lesion, whether it can be cold-cut, and whether there is a possibility of cancer.

[0055] Example 1: Polyp Size Measurement Method Using Dual-Laser Fixed Angle Distance Measurement

[0056] The equipment consists of the following components installed in the central area at the front end of the endoscope: laser emitters L1 and L2 (pulsed TOF lasers), and laser receivers R1 and R2. The included angle θ between the emitters is fixed at 30° (factory calibration).

[0057] The laser wavelength should be selected between 850-940nm to avoid interfering with the field of vision.

[0058] In the ranging step, the endoscope emits time-coded laser pulses sequentially towards the two ends B and C of the polyp.

[0059] The receiver records the return times tB and tC of the reflected pulse.

[0060] Calculate distance:

[0061] AB = c·tB / 2

[0062] AC = c·tC / 2

[0063] (c is the speed of light)

[0064] Polyp size calculation

[0065] Forming triangle ABC, where:

[0066] A: Laser reference point at the tip of the endoscope;

[0067] B: Point 1 at the edge of the polyp;

[0068] C: Point 2 at the edge of the polyp;

[0069] According to the Law of Cosines:

[0070] BC=(AB²+AC²-2·AB·AC·cosθ)

[0071] The system automatically outputs BC, which is the actual width of the polyp.

[0072] Example 2: Multi-laser ranging + 3D polyp reconstruction

[0073] To further obtain three-dimensional parameters such as polyp height and volume, the laser rangefinder was expanded to a four-beam (center + three-point triangular layout).

[0074] Measurement steps:

[0075] Four laser beams are emitted simultaneously, resulting in four distances d1, d2, d3, and d4.

[0076] Based on the known spatial relative positions of four points, a local point cloud of the polyp surface is obtained through spatial fitting.

[0077] A 3D model of the polyp can be generated through interpolation;

[0078] The 3D model can be used to calculate: maximum diameter, height, base width, and lesion volume, for more accurate clinical judgment.

[0079] Example 3: Automated Measurement Procedure (Applicable to Clinical Endoscopy Systems) The doctor lightly touches the two ends of the lesion on the screen (automatically tracking the reflected laser points). The system automatically triggers dual-point TOF distance measurement, automatically calculates AB and AC, automatically substitutes them into the cosine theorem to calculate BC, and displays the actual size of the polyp (e.g., 6.3mm) on the screen in real time.

[0080] The entire process takes less than 0.2 seconds, making it suitable for rapid surgical assessment.

[0081] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or basic characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0082] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A laser time-of-flight ranging method for measuring polyps, characterized in that, include: At least two laser time-of-flight ranging units are arranged at the front end of the endoscope, and the emission angle between the two laser beams is a preset fixed value. The distances AB and AC from the tip of the endoscope to the two ends of the polyp were obtained by laser time-of-flight ranging. Calculate the actual size B between the two ends of the polyp using the Law of Cosines: BC² = AB² + AC² - 2·AB·AC·cosθ.

2. The method according to claim 1, characterized in that: The laser is a pulsed TOF laser with an emission wavelength of 850-940nm.

3. The method according to claim 1, characterized in that: The emission angle θ is fixed at 20°-60°.

4. The method according to claim 1, characterized in that: The ranging error is controlled within ±0.1mm.

5. The method according to claim 1, characterized in that: The two laser ranging processes are performed simultaneously to ensure that the AB and AC measurements have a common time reference.

6. The method according to claim 1, characterized in that: The measurement points at both ends of the polyp are automatically identified and locked by the laser reflection points.

7. The method according to claim 1, characterized in that: It also includes using three or more laser beams for simultaneous ranging and performing three-dimensional reconstruction based on multiple distance points.

8. The method according to claim 1, characterized in that: The 3D reconstruction obtains the polyp height, volume, and base width through spatial fitting of multi-point ranging.

9. A polyp measurement system based on the method of any one of claims 1-8, characterized in that: It includes a laser emitting unit, a laser receiving unit, an endoscope imaging processor, and a real-time computing module.