使用 TensorFlow.js 从图像中计算对象

Question

我正在研究用于对象检测的预训练模型 coco-SSD。我已经成功地从图像中检测到物体，但现在我必须计算特定物体的数量谁能帮忙

public async predictWithCocoModel()
{
    const model = await cocoSSD.load();
    this.detectFrame(this.video,model);
}
detectFrame = (video, model) => {
model.detect(video).then(predictions => {
this.renderPredictions(predictions);
requestAnimationFrame(() => {
this.detectFrame(video, model);});
});
}
renderPredictions = predictions => {
    const canvas = <HTMLCanvasElement> document.getElementById ("canvas");

    const ctx = canvas.getContext("2d");
    canvas.width  = 300;
    canvas.height = 300;
    ctx.clearRect(0, 0, ctx.canvas.width, ctx.canvas.height);
    // Fonts
    const font = "16px sans-serif";
    ctx.font = font;
    ctx.textBaseline = "top";
    ctx.drawImage(this.video,0, 0,300,300);
    predictions.forEach(prediction => {
    const x = prediction.bbox[0];
    const y = prediction.bbox[1];
    const width = prediction.bbox[2];
    const height = prediction.bbox[3];
    // Bounding box
    ctx.strokeStyle = "#00FFFF";
    ctx.lineWidth = 2;
    ctx.strokeRect(x, y, width, height);
    // Label background
    ctx.fillStyle = "#00FFFF";
    const textWidth = ctx.measureText(prediction.class).width;
    const textHeight = parseInt(font, 10); // base 10
    ctx.fillRect(x, y, textWidth + 4, textHeight + 4);
    });
    predictions.forEach(prediction => {

    const x = prediction.bbox[0];
    const y = prediction.bbox[1];
    ctx.fillStyle = "#000000";
    ctx.fillText(prediction.class, x, y);});
};

这是我正在使用的代码。这仅显示检测到的对象上的矩形，但我必须计算特定对象的数量并将它们存储在变量中以备将来使用，例如 person:3

Answer 1

预测对象包含预测框的class。计数器可以与条件语句一起使用，用于对某个 class.

的检测对象进行计数

let i = 0
predictions.forEach(prediction => {
    const x = prediction.bbox[0];
    const y = prediction.bbox[1];
    const width = prediction.bbox[2];
    const height = prediction.bbox[3];
    // check for class
    if (prediction.class === 'classOfInterest') {
      i++
    }

});

使用 TensorFlow.js 从图像中计算对象

Object Counting from image using TensorFlow.js

javascript

tensorflow

machine-learning

tensorflow.js