Tag：feature vector

Time：20211113
(original title: ten minutes to understand the essence of linear algebra Author: Great Chen Haoyu) The essence of linear algebra First, let’s talk about the most important thing. What is linear algebra? The essence of linear algebra is actually a transformation in highdimensional space. Although this sentence is simple, what does it mean. Don’t […]

Time：20211024
Recently, when learning LDA, we need to calculate eigenvalues and eigenvectors, so we re learned a wave The calculation of eigenvalues is relatively simple in Python, and the linalg calculation of numpy needs to be imported.Linalg is the abbreviation of linear algebra. Import numpy first import numpy as np Randomly generate a matrix A A […]

Time：20211017
1. Power iterative algorithm (power method for short) (1) Dominant eigenvalue and dominant eigenvector Known matrix\(\bm{A} \in \R^{n \times n}\), \(\bm{A}\)The dominant eigenvalue of is\(\bm{A}\)Other eigenvalues (absolute values) of are large eigenvalues\(\lambda\), if such eigenvalues exist, and\(\lambda\)The relevant eigenvectors are called dominant eigenvectors. (2) Properties of dominant eigenvalues and dominant eigenvectors If a vector is […]

Time：202155
brief introduction Singular value is a very important concept in matrix, which is generally obtained by singular value decomposition. Singular value decomposition is an important matrix decomposition method in linear algebra and matrix theory, which is very important in statistics and signal processing. Before we get to singular values, let’s look at the concept of […]

Time：2021210
Overview of map search system Image search by image refers to searching images with similar content according to image content. Building a map search system needs to solve two key problems: first, extracting image features; second, feature data search engine, that is, building feature data into database and providing the function of similarity search. Image […]

Time：2020128
1、 Face detection 1. Face detection using OpenCV Opencv uses the algorithm of object detection framework named Viola Jones for face detection. Step 1: Download opencv Library pip install opencvpython i https://pypi.tuna.tsinghua.edu.cn/simple Step 2: find the default pre training weight file 1. Generally, there is a haarcascade in / lib / python3.7/sitepackages/cv2/data directory of the […]

Time：20201128
Engineering practice of map search system I wrote an overview before: an overview of image search system. The main problems to be solved in the system are as follows Extracting image feature vector (using eigenvector to represent an image) Similarity calculation of feature vectors (searching for images with similar contents) The corresponding engineering practices are […]

Time：20201118
By Nathan LambertCompile  VKSource: toward Data Science How can the basic principles of linear algebra be used in deep reinforcement learning? The answer is to solve the iterative update in Markov decision process. Reinforcement learning (RL) is a series of intelligent methods for iterative learning tasks. Because computer science is a computing field, this […]

Time：2020831
Through the deep learning neural network model, unstructured data such as pictures, videos, voice, and text can be transformed into feature vectors. In addition to structured vectors, these data often need to add other attributes. For example, for face images, you can add labels such as gender, whether you wear glasses or not, and picture […]

Time：2020724
Principal component analysis(PCA) Chinese is principal component analysis. When learning mathematical modeling, this method is divided into evaluation class (I really can’t see that it belongs to unsupervised learning in machine learning)Dimension reduction methodA kind oflinearDimension reduction method.Take the simplest chestnut (as shown in the figure below, if the twodimensional data is reduced to one […]

Time：202059
Foreword This series of articles is the reading notes of deep learning. This book is an excellent learning reference book for deep learning, which has certain difficulties. Therefore, this series of articles need to be read together with the original book, with better effect. If you do not read the original book, it is assumed […]

Time：2020228
Summary Through the neural network model of deep learning, unstructured data such as pictures, videos, voice, and texts can be transformed into feature vectors. In addition to structured vectors, these data often need to add other attributes. For example, for face images, labels such as gender, whether to wear glasses or not, and image capture […]