const cv = require('opencv4nodejs');
創(chuàng)建矩陣
const rows = 100; // height
const cols = 100; // width
var emptyMat = new cv.Mat(rows, cols, cv.CV_8UC3);
8位無符號(hào)3通道矩陣,就是常見的RGB數(shù)組[0-255,0-255,0-255]
var whiteMat = new cv.Mat(rows, cols, cv.CV_8UC1, 255);
var blueMat = new cv.Mat(rows, cols, cv.CV_8UC3, [255, 0, 0]);
使用Array創(chuàng)建
const matData = [
[[255, 0, 0], [255, 0, 0], [255, 0, 0]],
[[0, 0, 0], [0, 0, 0], [0, 0, 0]],
[[255, 0, 0], [255, 0, 0], [255, 0, 0]]
];
var matFromArray = new cv.Mat(matData, cv.CV_8UC3);使用Buffer創(chuàng)建
const charData = [255, 0, ...];
const matFromArray = new cv.Mat(Buffer.from(charData), rows, cols, cv.CV_8UC3);創(chuàng)建一個(gè)點(diǎn)
const pt2 = new cv.Point(100, 100);
const pt3 = new cv.Point(100, 100, 0.5);創(chuàng)建一個(gè)向量
const vec2 = new cv.Vec(100, 100);
const vec3 = new cv.Vec(100, 100, 0.5);
const vec4 = new cv.Vec(100, 100, 0.5, 0.5);
矩陣、向量操作
const mat0 = new cv.Mat(...);
const mat1 = new cv.Mat(...);
四則運(yùn)算
const matMultipliedByScalar = mat0.mul(0.5); 標(biāo)量乘法
const matDividedByScalar = mat0.div(2); 標(biāo)量除法
const mat0PlusMat1 = mat0.add(mat1); 矩陣加法
const mat0MinusMat1 = mat0.sub(mat1); 矩陣減法
const mat0MulMat1 = mat0.hMul(mat1); 矩陣乘法
const mat0DivMat1 = mat0.hDiv(mat1); 矩陣除法矩陣邏輯運(yùn)算操作
const mat0AndMat1 = mat0.and(mat1);
const mat0OrMat1 = mat0.or(mat1);
const mat0bwAndMat1 = mat0.bitwiseAnd(mat1);
const mat0bwOrMat1 = mat0.bitwiseOr(mat1);
const mat0bwXorMat1 = mat0.bitwiseXor(mat1);
const mat0bwNot = mat0.bitwiseNot();
訪問矩陣、向量數(shù)據(jù)
const matBGR = new cv.Mat(..., cv.CV_8UC3);
const matGray = new cv.Mat(..., cv.CV_8UC1);
獲取到像素點(diǎn)的值
const vec3 = matBGR.at(200, 100);
const grayVal = matGray.at(200, 100);使用解構(gòu)賦值語法獲取值
const [b, g, r] = matBGR.atRaw(200, 100);設(shè)置單個(gè)像素點(diǎn)的值
matBGR.set(50, 50, [255, 0, 0]);
matBGR.set(50, 50, new Vec(255, 0, 0));
matGray.set(50, 50, 255);得到一個(gè)偏移量為( 50, 50)矩陣區(qū)域的25x25的小區(qū)域
const width = 25;
const height = 25;
const region = matBGR.getRegion(new cv.Rect(50, 50, width, height));
const matAsBuffer = matBGR.getData();
const matAsArray = matBGR.getDataAsArray();
IO
讀取圖片
const mat = cv.imread('./path/img.jpg');
cv.imreadAsync('./path/img.jpg', (err, mat) => {})保存圖片
cv.imwrite('./path/img.png', mat);
cv.imwriteAsync('./path/img.jpg', mat,(err) => {})展示圖片
cv.imshow('a window name', mat);
cv.waitKey();加載base64編碼的圖片
const base64text='data:image/png;base64,R0lGO..'; //base64字符串
const base64data =base64text.replace('data:image/jpeg;base64','')
const buffer = Buffer.from(base64data,'base64');
const image = cv.imdecode(buffer);
轉(zhuǎn)換矩陣為base64編碼的圖片
const outBase64 = cv.imencode('.jpg', croppedImage).toString('base64');
const htmlImg='<img src=data:image/jpeg;base64,'+outBase64 + '>'; //Create insert into HTML compatible <img> tag捕獲webcam資源
const devicePort = 0;
const wCap = new cv.VideoCapture(devicePort);捕獲視頻資源
const vCap = new cv.VideoCapture('./path/video.mp4');讀取幀
const frame = vCap.read();
vCap.readAsync((err, frame) => {});循環(huán)獲取
const delay = 10;
let done = false;
while (!done) {
? let frame = vCap.read();
? if (frame.empty) {
? ? vCap.reset();
? ? frame = vCap.read();
? }
? ? const key = cv.waitKey(delay);
? ? done = key !== 255;
}類型轉(zhuǎn)換
const matSignedInt = matBGR.convertTo(cv.CV_32SC3);
const matDoublePrecision = matBGR.convertTo(cv.CV_64FC3);轉(zhuǎn)換顏色制度
const matGray = matBGR.bgrToGray();
const matHSV = matBGR.cvtColor(cv.COLOR_BGR2HSV);
const matLab = matBGR.cvtColor(cv.COLOR_BGR2Lab);調(diào)整矩陣大小
const matHalfSize = matBGR.rescale(0.5);
const mat100x100 = matBGR.resize(100, 100);
const matMaxDimIs100 = matBGR.resizeToMax(100);獲取通道、通過通道構(gòu)建矩陣
const [matB, matG, matR] = matBGR.splitChannels();
const matRGB = new cv.Mat([matR, matB, matG]);