FRC vision

ref:

LimeLight, a hardware
GRIP, a PC application
FRCVision from WPILib, a raspberry pi image
OpenSight, a raspberry pi image
Chameleon Vision, a server run on raspbian

GRIP

a image processing pipeline GUI editor runs on PC

Image Not Showing Possible Reasons

The image file may be corrupted
The server hosting the image is unavailable
The image path is incorrect
The image format is not supported

FRCVision from WPILib

很單純的camera server, stream到Driver Station上
可調整基本的相機參數存檔匯入

Image Not Showing Possible Reasons

The image file may be corrupted
The server hosting the image is unavailable
The image path is incorrect
The image format is not supported

OpenSight

類似GRIP，跑在pi server，使用網頁介面提供GUI editor
好像很容易crash…?

Image Not Showing Possible Reasons

The image file may be corrupted
The server hosting the image is unavailable
The image path is incorrect
The image format is not supported

Chameleon Vision

I cannot run it…
no web server is running

build from scratch! 自幹王道!

tools

GRIP, 又是它

Image Not Showing Possible Reasons

The image file may be corrupted
The server hosting the image is unavailable
The image path is incorrect
The image format is not supported

基本流程

ref: https://docs.wpilib.org/en/stable/docs/software/vision-processing/introduction/identifying-and-processing-the-targets.html

架好硬體: 綠光燈圍繞在鏡頭周圍，越靠近鏡頭越好
camera所有數值的自動調整都關閉，並把亮度調到極低，眼裡只剩反光條反射回綠色(如果過曝會是白色)
(optional) blur + downsample 縮小圖片:降低運算量並去雜訊
在HSV色域篩選出綠色目標
(optional) dilate + erode 去除小凹凸邊緣
找出contour
剔除過大或過小的區塊(雜訊)
(optional) 辨別形狀: approxPolyDP 或各種ad hoc方法
由bounding box或各種ad hoc方法計算目標位置(視角的上下左右)及距離
把數值用NetworkTable傳回給RoboRIO

3D pose estimation

ref: https://docs.opencv.org/master/d7/d53/tutorial_py_pose.html
ref: https://github.com/frc7589/Vision-2020/blob/master/pose estimation/pose.py

camera calibration 取得內部矩陣

1~8. 同'基本流程'

找出頂點: cornerSubPix
建立頂點在世界座標的位置
將頂點的2D(影像)座標及3D(世界)座標送入solvePnP求出外部矩陣
由目標點的世界座標及相機外部矩陣求出相對方位