1. Rotation matrix (right-handed coordinate system) Rotate around the x-axis Rotation matrix: The matrix on the right is the original coordinates of the point cloud, and the matrix on the left is the rotation matrix Visualization: Rotate 90 degrees around the x-axis Code: import vtk import numpy as np import math def pointPolydataCreate(pointCloud): points = […]
Tag: projection
Projection of the world coordinate system to the pixel coordinate system [python experiment]
For three-dimensional vision, it is necessary to clearly understand the correspondence between the world coordinate system and the pixel coordinate system. This article uses python for experiments. For the mathematical derivation of internal and external parameters of the camera, please see my previous blog “[AI Mathematics] Internal Parameters of Camera Imaging” “, “[AI Mathematics] Parameters […]
Exquisite explanation of OpenCV algorithm: based on Python and C++, geometric transformation-projection transformation
Exquisite explanation of OpenCV algorithm: based on Python and C++, geometric transformation-projection transformation Opencv_C_algorithm/perspective at master · ZouJiu1/Opencv_C_algorithm (github.com)?github.com/ZouJiu1/Opencv_C_algorithm/tree/master/perspective “OpenCV Algorithm Exquisite Analysis: Based on Python and C++” (edited by Zhang Ping) [Introduction_Book Review_Online Reading] – Dangdang Books (dangdang.com)?product.dangdang.com/25182999.html Affine transformation The affine transformation of 2dim space can be expressed by the formula ( x […]
Code implementation of projection transformation in OpenCV
Table of Contents introduction technical background transformation process Complete code display operation result Introduction Projective transformation is one of the commonly used techniques in the fields of computer vision and image processing. It can be used to map images from one perspective relationship to another. Common applications include image correction, depth of field changes, and […]
Image processing: Histogram – Backprojection OpenCV v4.8.0
Previous tutorial: Histogram comparison Next tutorial: Template matching Original author Ana Huamán Compatibility OpenCV >= 3.0 Goals In this tutorial you will learn What is backprojection and its uses How to calculate backprojection using OpenCV function cv::calcBackProject How to mix different channels of an image using the OpenCV function cv::mixChannels Theory What is backprojection? Backprojection […]
java js longitude and latitude conversion, geodetic coordinates (Gaussian projection coordinates) and longitude and latitude conversion to each other
In the project, there is a need to convert between geodetic coordinates (Gaussian projection coordinates) and longitude and latitude. I wrote a tool class; There are java and js codes As shown in the figure, the coordinate system and bandwidth have been passed into the method as parameters in the java code. When using it, […]
Histogram projection method to determine crack trend (crack type)
Crack type There are many types of cracks. Here we only judge linear cracks and network cracks. Linear cracks can be divided into transverse cracks, longitudinal cracks and oblique cracks according to their trends. I think everyone should have this awareness. In the face of network cracks, do its two-dimensional parameters make sense? The answer […]
Explore ClickHouse – Using Projection to Speed Up Querying
Outline download file Check files Move files Create table View Files Use client to connect to server Create table Import Data Check data Check the number of data rows Check the disk occupied Inquire Add PROJECTION Query after optimization References Before testing Projection, we need to create a table and import a large amount of […]
WebGL model view projection matrix
WebGL Perspective Projection_Hawthorn Tree’s Blog – One problem with the PerspectiveView code in the CSDN blog is that we use a long section of boring code to define all vertex and color data. There are only 6 triangles in the example. We can still manage this data manually, but if the number of triangles increases […]
Map projection 4490, 4326, 3857
1. Geodesy Geodesy is the discipline of measuring and describing the Earth’s surface, including determining the Earth’s gravity field and ocean floor topography. 1.1 Geoid (geoid) The geoid is the shape of the ocean surface after excluding other influences such as wind and tide, and only considering the influence of gravity and rotation. This shape […]