• Classification of machine learning: prediction bias


    The logistic regression prediction should be unbiased. That is, the “predicted average” should be approximately equal to the “observed average”Prediction deviationIt refers to the difference between the two averages. Namely:Forecast deviation = forecast average – the average of the corresponding labels in the datasetNote: “forecast deviation” is not the same as “Deviation” (“B” in “Wx […]

  • Simple music recognition with STM32 F103 and LM386 sound sensor


      Simple music recognition with STM32 F103 and LM386 sound sensor 1. Preface     In early December 2019, there will be a biped robot competition in the Chinese robot skills competition, which means robotRecognize the music and dance with corresponding rhythmThree songs randomly selected from five music, music stop, robot stop.     New competition, new project, difficulty […]

  • In depth evaluation: Android’s free bank card identification SDK, Huawei HMS mlkit or card IO?


    1 Introduction Two previous articles have introduced the bank card identification function of Huawei HMS mlkit. The first one is about how to integrate the bank card identification and realize the bank card binding function. The second article introduces the difference and relationship between the bank card identification and other text type identification services. For […]

  • Debugging method of NTP time calibration server


    NTP time calibration server design at the beginning of the use of the concept of fool operation, in the procurement time do not need to worry too much about debugging, this paper will focus on how to receive the time calibration server debugging, for user reference. 1、Put the mushroom head antennaThe BNC interface is inserted […]

  • Ubuntu Install kitti2bag


    The project needs to test the mapping effect, but at present, the effect of our own semantic segmentation training is not very good, and the accuracy of external parameter matrix calibration is not high, so we plan to use Kitti data set as test. Therefore, we need to convert the Kitti data set into bag […]

  • Detailed explanation of priority bitmap algorithm


    stayReview of embedded operating systemIn the task scheduling section, we mentioned the basic knowledge of μ C / OS-IIPriority bitmap algorithmThis paper introduces the principle and implementation of the algorithm in detail.Link to original text 1、Brief introduction of μ C / OS-II task priorityThere are 64 priorities in μ C / OS-II (0 ~ 63 […]

  • Chapter 2 bjrobot IMU automatic calibration


    1、Lay the car flat on the floor and open a terminal with the virtual machine in the data ssh In the past, the main control terminal startedroslaunch znjrobot bringup.launch 。 2、Open another terminal,ssh Past main control terminal,stay ~/catkin_ws/src/znjrobot_project/znjrobot/param/imu Under the pathstart-up imu Correction command.rosrun imu_calib do_calib 3、Press enter to complete the calibration. Remember: runimuAutomatic correction, must jump to~/catkin_ ws/src/znjrobot_ Run […]

  • Introduction to camera OTP


    With the application of 5meg, 8meg, 12meg and other high pixel cameras in mobile phones more and more widely, terminal customers have higher and higher requirements on the imaging effect and quality of camera. How to improve the consistency and performance of camera modules is particularly important. Today, we will introduce OTP technology which is […]

  • Multi screen interaction – H5 intermediate advanced


    Preface With the popularity of smart hardware, mobile phones, tablets, PCs and even roadside electronic billboards, modern browsers are everywhere. It’s not enough to weave our own world in the browser, but H5 gives the browser too many new features, waiting for us to use. This article introduces how to use the compass API of […]

  • JS verify decimal or integer


    Use regular expression to check whether it is a decimal or an integer. Without much nonsense, go to demo directly (this regular expression cannot check negative numbers and numbers starting with 00). PS: (if there is something wrong, please criticize and instruct) checkNumber Please enter the number of judgment: <span style=”background-color: #f5f5f5; color: #000000;”> $(</span><span […]