我在OpenCV中找不到任何方法来支持度符号（º）特殊字符。请评论，如果有人发现任何方法相同。我已经解决了上述问题，画了一个圆圈来代替度数符号（º）。请在下面找到代码：
private setImageWithText（ImageView imageView）{

Bitmap icon = BitmapFactory.decodeResource(getResources(), drawableID);

    Mat mat = new Mat();
    Bitmap bmp32 = icon.copy(Bitmap.Config.ARGB_8888, true);
    Utils.bitmapToMat(bmp32, mat);
 

    Point position = new Point(300, 300);
    Scalar color = new Scalar(255.0, 0.0, 0.0);
    int font = Imgproc.FONT_HERSHEY_SIMPLEX;
    int scale = 1;
    int thickness = 3;
    //Adding text to the image
    Imgproc.cvtColor(mat2, mat, 1, 4);

    Imgproc.putText(mat, "98.452", position, font, scale, color, thickness);
    int baseline[] = {0};
    Size textSize = Imgproc.getTextSize("98.452", Imgproc.FONT_HERSHEY_SIMPLEX, 1.0, 3, baseline);
    //Drawing a Circle
    Imgproc.circle(
            mat,                 //Matrix obj of the image
            new Point(300 + textSize.width+20, 300 -(textSize.height+20)),    //Center of the circle
            7,                    //Radius
            new Scalar(255.0, 0.0, 0.0),  //Scalar object for color
            3                      //Thickness of the circle
    );
    Imgproc.putText(mat, "F",  new Point(300 + (textSize.width+textSize.height), 300), font, scale, color, thickness);
    Bitmap output = Bitmap.createBitmap(bmp32.getWidth(), bmp32.getHeight(), bmp32.getConfig());
    Utils.matToBitmap(mat, output);
    return output;

}

因为你使用的是Android，所以 Backbone.js 不可避免地是Java。尝试在字符串中使用Unicode \u00B0，然后将其写入图像。

String degrees = "100\u00B0";
Imgproc.putText(img, degrees, ...);

import cv2

import numpy as np

im = cv2.imread("image1.jpg")

im = cv2.circle(im, (70,80), 5, (255,100,0), 1)

im = cv2.putText(im, "100", (5,100), cv2.FONT_HERSHEY_SIMPLEX, 1, (255,100,0), 1, cv2.LINE_AA)

cv2.imshow("pl", im)

cv2.waitKey(0)