find_circles_240828.py

"""
HOUGH_GRADIENT_ALT (Scharr algorithm) 의 경우
파라메터 권장값이 소개되어 있어서 이를 적용해 본다.

"""

from functools import partial
from time import perf_counter

import cv2
import numpy as np


def find_circles_240828(
    image,
    *,
    sf, #=2.0,  # 이미지를 1/2 으로 축소한 후 탐색
    channel=1,  # G 채널을 gray로 사용
    gb_ksize=7,  # gaussian blur kernel size
    gb_sigma=1.5,  # gaussian blur sigma
    hc_dp=1.5,  # 3.65,  # image / accumulator ratio for hough circle
    hc_min_dist_r=1.5,  # 한 화면에 한개 서클
    hc_param1=300,  # HOUGH_GRADIENT_ALT (Scharr algo) >300
    hc_param2=0.8,  # HOUGH_GRADIENT_ALT 에서 "perfectness" 0.8~0.9
    hc_min_dia_r=0.2,  # 최소 0.2 크기
    hc_max_dia_r=0.4,  # 최대 0.4 크기
    hc_method=cv2.HOUGH_GRADIENT_ALT,
    circ_pad=0.0,  # 내부 패딩 비율
    _debug=None,
    verbose=False,
):
    log = partial(print, "find_circles_240828:") if verbose else (lambda *a, **k: None)

    inp = resized = cv2.resize(
        image, None, fx=1 / sf, fy=1 / sf, interpolation=cv2.INTER_AREA
    )
    inp = gray = np.ascontiguousarray(inp[:, :, channel]) if inp.ndim > 2 else inp
    inp = blur = cv2.GaussianBlur(inp, ksize=(gb_ksize, gb_ksize), sigmaX=gb_sigma)

    # 상대크기를 픽셀크기로 변환
    image_size = min(*blur.shape[:2])
    hough_circles_fn = partial(
        cv2.HoughCircles,
        method=hc_method,
        dp=hc_dp,
        param1=hc_param1,
        param2=hc_param2,
        minDist=max(1, hc_min_dist_r * image_size),  # 1 보다 작을 수는 없다
        minRadius=int(0.5 * hc_min_dia_r * image_size),
        maxRadius=int(0.5 * hc_max_dia_r * image_size),
    )

    # hough circle 탐색
    circles = hough_circles_fn(inp)
    # prevent 'None'
    if circles is None:
        circles = (np.zeros((0, 3), dtype=np.uint32),)
    log("hough_circles.shapes:", tuple(c.shape for c in circles))

    if len(circles) > 0:
        circles0 = circles[0]
        circles0 = circles0 * [sf, sf, sf / (1.0 - circ_pad)]
        circles0 = sorted(circles0, key=lambda it: -it[2])  # 반지름 역순 정렬
        circles0 = np.uint32(np.around(circles0))
        log("(circles0):", (circles0,))
        circles = (circles0,)

    if _debug is not None:
        _debug.update(locals())
        del _debug["_debug"]

    log("circles:", circles)

    return circles