如何仅查找图像上棕色区域的轮廓？

Question

我一直在尝试寻找框架上棕色区域的轮廓。

我试图在for循环中找到这些轮廓。

    for c in cntrs:
        area = cv2.contourArea(c)
        if area > 1200:   # i obtanied threshold with trial end error
            x, y, w, h = cv2.boundingRect(c) #find coordinates of brown area
            roi2 = results[y:y + h, x:x + w] #copy these parts to the another image

但是我只能看到一个轮廓

我不明白为什么我只看到一个轮廓。因为当我打印一些阈值轮廓时，我会看到2

这是我尝试过的

import cv2
import numpy as np
cv2.destroyAllWindows()
capture = cv2.VideoCapture(0) ##masaustunde 1, laptopta 0


def nothing(x):
    pass

roi = cv2.imread('savedImage.jpg')
cv2.imshow('input', roi)
hsv = cv2.cvtColor(roi, cv2.COLOR_RGB2HSV)

lower_green = np.array([0, 0, 0])
upper_green = np.array([40, 255, 255])

mask = cv2.inRange(hsv, lower_green, upper_green)
mask_inv = cv2.bitwise_not(mask)

fg = cv2.bitwise_and(roi, roi, mask=mask_inv)

gray = cv2.cvtColor(fg, cv2.COLOR_BGR2GRAY)
gray = cv2.cvtColor(fg, cv2.COLOR_BGR2GRAY)
thresh = cv2.threshold(gray, 32, 255, 0)[1]
cntrs = cv2.findContours(thresh, cv2.RETR_LIST, cv2.CHAIN_APPROX_SIMPLE)
cntrs = cntrs[0] if len(cntrs) == 2 else cntrs[1]
area_thresh = 0
syc = 0
results = fg.copy()
for c in cntrs:
    area = cv2.contourArea(c)
    if area > 1200: #esige dikkat
        syc = syc + 1
        x, y, w, h = cv2.boundingRect(c)
        roi2 = results[y:y + h, x:x + w]
cv2.imshow('roi2', roi2)

cv2.waitKey(0)


capture.release()  # release the camera from video capture
cv2.destroyAllWindows()

Answer 1

您正在循环中覆盖结果（roi2），而无需等待查看每个结果。您必须将waitKey（）放入循环中。

正如我之前所说，您的区域阈值太高。

我还选择了更好的上下限。 （我保存了hsv文件，然后在GUI工具中测量了它的值）

这在Python / OpenCV中对我有用。显示每个roi2后，按返回键可继续进行下一个。

import cv2
import numpy as np

roi = cv2.imread('green_areas.jpg')
#cv2.imshow('input', roi)

hsv = cv2.cvtColor(roi, cv2.COLOR_RGB2HSV)
#cv2.imshow('hsv', hsv)

lower_green = np.array([30, 30, 30])
upper_green = np.array([60, 140, 100])

mask = cv2.inRange(hsv, lower_green, upper_green)
#cv2.imshow('mask', mask)

mask_inv = cv2.bitwise_not(mask)

fg = cv2.bitwise_and(roi, roi, mask=mask_inv)
#cv2.imshow('fg', fg)

gray = cv2.cvtColor(fg, cv2.COLOR_BGR2GRAY)
thresh = cv2.threshold(gray, 32, 255, 0)[1]
#cv2.imshow('thresh', thresh)

cntrs = cv2.findContours(thresh, cv2.RETR_LIST, cv2.CHAIN_APPROX_SIMPLE)
cntrs = cntrs[0] if len(cntrs) == 2 else cntrs[1]
area_thresh = 0
syc = 0
results = fg.copy()
for c in cntrs:
    area = cv2.contourArea(c)
    if area > 500: #esige dikkat
        syc = syc + 1
        x, y, w, h = cv2.boundingRect(c)
        roi2 = results[y:y + h, x:x + w]
        cv2.imshow('roi2', roi2)
        cv2.waitKey(0)

cv2.destroyAllWindows()