python中cv2.putText参数详解
cv2.putText(img, str(i), (123,456)), font, 2, (0,255,0), 3)
各参数依次是：图片，添加的文字，左上角坐标，字体，字体大小，颜色，字体粗细
其中字体可以选择
FONT_HERSHEY_SIMPLEX
Python: cv.FONT_HERSHEY_SIMPLEX
normal size sans-serif font
FONT_HERSHEY_PLAIN
Python: cv.FONT_HERSHEY_PLAIN
small size sans-serif font
FONT_HERSHEY_DUPLEX
Python: cv.FONT_HERSHEY_DUPLEX
normal size sans-serif font (more complex than FONT_HERSHEY_SIMPLEX)
FONT_HERSHEY_COMPLEX
Python: cv.FONT_HERSHEY_COMPLEX
normal size serif font
FONT_HERSHEY_TRIPLEX
Python: cv.FONT_HERSHEY_TRIPLEX
normal size serif font (more complex than FONT_HERSHEY_COMPLEX)
FONT_HERSHEY_COMPLEX_SMALL
Python: cv.FONT_HERSHEY_COMPLEX_SMALL
smaller version of FONT_HERSHEY_COMPLEX
FONT_HERSHEY_SCRIPT_SIMPLEX
Python: cv.FONT_HERSHEY_SCRIPT_SIMPLEX
hand-writing style font
FONT_HERSHEY_SCRIPT_COMPLEX
Python: cv.FONT_HERSHEY_SCRIPT_COMPLEX
more complex variant of FONT_HERSHEY_SCRIPT_SIMPLEX
FONT_ITALIC
Python: cv.FONT_ITALIC
flag for italic font
字体大小，数值越大，字体越大
字体粗细，越大越粗，数值表示描绘的线条占有的直径像素个数
Python:
img =cv.putText(img, text, org, fontFace,fontScale,color[, thickness[, lineType[, bottomLeftOrigin]]])