5 results about "Absolute scale" patented technology

The present invention discloses a method and device for determining a critical rainfall threshold for landslide prediction, the method comprising: determining a landslide kernel density spatial distribution map based on a complete catalog of landslides caused by extreme rainfall clusters; obtaining regional rainfall data corresponding to each landslide in the clusters based on a preset time window, the regional rainfall data including previous rainfall data and current day rainfall data; performing correlation processing on the landslide kernel density spatial distribution map and the regional rainfall data using the Pearson correlation coefficient to determine the optimal regional rainfall data; determining an optimal fitting curve based on the optimal regional rainfall data and the landslide surface density spatial distribution map, and converting the optimal fitting curve into a probability distribution function based on a rainfall interval range, the probability distribution function being specifically a probability distribution function relationship curve between landslide surface density and rainfall; using the landslide surface density as an absolute scale, generating an early warning matrix based on the probability distribution function, thereby improving the accuracy and applicability of the critical rainfall threshold for landslide prediction and alarm.

The invention provides a kinematics equation linearization method of normalized time, which converts a time variable under an absolute scale into a relative scale, thereby facilitating derivation and numerical calculation of an optimal control problem. Converting free time into time with boundary conditions by using normalized time, and converting time serving as a differential term in the motion equation into a multiplication term, so as to realize transformation of the motion equation; and according to the motion equation after time normalization, the time after normalization is optimized, and equivalent solution of an optimal control problem is realized. Equivalent solution of an original optimal control problem is realized, and derivation and numerical calculation of the optimal control problem are facilitated.

The application discloses a geometric consistency and instrument anchoring three-dimensional reconstruction and polyp measurement method of an endoscope. The method first projects monocular image features to a Riemannian manifold space through a geometric consistency perception module, generates a high-fidelity relative depth map by using a manifold-constrained latent diffusion model, and maintains cross-domain structural consistency. Secondly, by using a scale estimation module based on instrument anchoring, biopsy forceps in a field of view are automatically identified and key points are extracted, a PnP solver and a Bayesian regression are used to solve six degrees of freedom of the instrument, and finally, geometric constraint equations are constructed based on the known physical size of the biopsy forceps, a global absolute scale factor is solved, and the relative depth map is converted into a metric three-dimensional point cloud. A few-sample linear calibration mechanism is introduced, and linear deviation caused by domain offset can be eliminated by using a small amount of clinical frames. According to the application, sub-millimeter polyp size measurement can be realized under monocular endoscopy by using conventional surgical instruments without additional hardware.

The invention belongs to the technical field of navigation positioning, and discloses an initialization method suitable for a monocular VIO system under low motion excitation, and the initialization method comprises the following steps: screening N key frames from a video stream shot by a visual camera; calculating relative pose transformation and three-dimensional space point coordinates between two adjacent key frames one by one to obtain SfM of a fuzzy scale; updating the SfM of the fuzzy scale to the SfM of the absolute scale by using the scale factor; and adjusting and optimizing the SfM of the absolute scale by using an improved bundle method, combining the optimized SfM with IMU pre-integration in the monocular VIO system, constructing a maximum posterior probability estimation function, and solving the maximum posterior probability estimation function to obtain initialization parameters of the monocular VIO system, the initialization parameters at least comprise a rotation matrix in the gravity direction, zero offset of an accelerometer, zero offset of a gyroscope and the speed of each frame in the N key frame sets. According to the method, parameter initialization of the VIO system can still be completed under the condition that motion excitation is insufficient, and good robustness is achieved.

The invention provides a radioactive substance content measuring method and device and a neutron coincidence measuring device, and relates to the technical field of nuclear measurement. The method comprises the following steps: establishing a geometric model of a measurement object according to the appearance of the measurement object with a to-be-measured radioactive substance attached in a predetermined area; obtaining relative position information of a geometric model of the measurement object and a measurement model comprising the simulated neutron detector, obtaining material information corresponding to the measurement object, and associating the material information to the geometric model; according to the information of the simulated measurement object, obtaining a detection result of a simulated neutron detector simulated based on a generalized semi-Markov process simulation method on neutrons generated by simulated radioactive substance fission; and obtaining a calibration coefficient of the measurement object according to the simulated mass of the simulated radioactive substance and the detection result, and measuring the content of the radioactive substance to be measured by using a measurement device corresponding to the measurement model according to the calibration coefficient. The method improves the accuracy of radioactive substance content measurement.