vision utils

Various utilities for OpenCV.

Documentation

fps.py

• class FPSCounter: utility for measuring frames per second (FPS) with a rolling average
  • FPSCounter(avg_len=30): create a new FPS counter that averages avg_len measurements
  • got_frame(): tell the counter that a frame was processed
  • fps(): get the average FPS
  • draw_fps(self, img, pos=(10,30), prec=1, size=2, thickness=2, color=(255,255,255), fmt='%.1f FPS'): draw the FPS on an image
    • img: the image to draw on
    • pos: the position to draw the text at
    • prec: the number of decimal digits to display
    • size: the size of the text
    • thickness: the thickness of the text
    • color: the color of the text
    • fmt: the format string for the text. Must format a float.

colors.py

Color-related utilities

• hex2bgr(h): converts a hexadecimal color into a BGR numpy array. E.g. 0x00FF01 -> [1, 255, 0]
• cvtPixel(color, code): converts a color into another color space.
  • color: the color to convert. Can be a list, numpy array, or tuple – e.g. (255, 0, 0)
  • code: an OpenCV color conversion code, e.g. cv2.COLOR_HSV2BGR
• Color constants (in BGR): MAROON, RED, ORANGE, YELLOW, OLIVE, GREEN, PURPLE, FUCHSIA, LIME, TEAL, AQUA, BLUE, NAVY, BLACK, GRAY, SILVER, WHITE.

contours.py

• sort_contour(contour): sorts a contour's points in clockwise order.
  • contour: a numpy array of points with shape (n_points, 1, 2)
• center(contour): returns the center of a contour as tuple (cx, cy)
• iou(contour1, contour2): returns the intersection over union (IOU) of two contours. IOU = (area of intersection) / (area of union)