corner detection

Author: JimmyHHua

README.md

@@ -119,3 +119,6 @@ code_077 | [Video Read, Write and Process](python/code_077/opencv_077.py)   | 
 code_078 | [Identify and Track Specific Color Objects in Video](python/code_078)   | ✔️
 code_079 | [Video Analysis-Background/Foreground Extraction](python/code_079/opencv_079.py)   | ✔️
 code_080 | [Video Analysis–Background Subtraction and ROI Extraction of the Foreground](python/code_080)   | ✔️
+code_081 | [Corner Detection-Harris](python/code_081)   | ✔️
+code_082 | [Corner Detection-Shi-Tomas](python/code_082)   | ✏️
+code_083 | [Corner Detection-Sub-Pixel ](python/code_083)   | ✔️

README_CN.md

@@ -118,3 +118,6 @@ code_077 | [视频读写和处理](python/code_077/opencv_077.py)   | ✏️
 code_078 | [识别与跟踪视频中的特定颜色对象](python/code_078)   | ✔️
 code_079 | [视频分析-背景/前景 提取](python/code_079/opencv_079.py)   | ✔️
 code_080 | [视频分析–背景消除与前景ROI提取](python/code_080)   | ✔️
+code_081 | [角点检测-Harris角点检测](python/code_081)   | ✔️
+code_082 | [角点检测-Shi-Tomas角点检测](python/code_082)   | ✏️
+code_083 | [角点检测-亚像素角点检测](python/code_083)   | ✔️

python/code_081/README.md

@@ -0,0 +1,2 @@
+#### More Detail, please check the blog of zhihu as below
+✈️ ✈️ ✈️ [OpenCV图像处理- 角点检测](https://zhuanlan.zhihu.com/p/68571164)

python/code_081/chessboard.jpg

@@ -0,0 +1,47 @@
+import numpy as np
+import cv2 as cv
+
+
+def harris(image, opt=1):
+    # Detector parameters
+    blockSize = 2
+    apertureSize = 3
+    k = 0.04
+    # Detecting corners
+    gray = cv.cvtColor(image, cv.COLOR_BGR2GRAY)
+    dst = cv.cornerHarris(gray, blockSize, apertureSize, k)
+    # Normalizing
+    dst_norm = np.empty(dst.shape, dtype=np.float32)
+    cv.normalize(dst, dst_norm, alpha=0, beta=255, norm_type=cv.NORM_MINMAX)
+    
+    # Drawing a circle around corners
+    for i in range(dst_norm.shape[0]):
+        for j in range(dst_norm.shape[1]):
+            if int(dst_norm[i, j]) > 120:
+                cv.circle(image, (j, i), 2, (0, 255, 0), 2)
+    # output
+    return image
+
+
+src = cv.imread("chessboard.jpg")
+cv.imshow("input", src)
+result = harris(src)
+cv.imshow('result', result)
+cv.imwrite('result.jpg', result)
+cv.waitKey(0)
+cv.destroyAllWindows()
+"""
+# For video:
+cap = cv.VideoCapture(0)
+while True:
+    ret, frame = cap.read()
+    cv.imwrite("input.png", frame)
+    cv.imshow('input', frame)
+    result = harris(frame)
+    cv.imshow('result', result)
+    k = cv.waitKey(5)&0xff
+    if k == 27:
+        break
+cap.release()
+cv.destroyAllWindows()
+"""

python/code_081/opencv_081.py

@@ -0,0 +1,2 @@
+#### More Detail, please check the blog of zhihu as below
+✈️ ✈️ ✈️ [OpenCV图像处理- 角点检测](https://zhuanlan.zhihu.com/p/68571164)

python/code_081/result.jpg

@@ -0,0 +1,28 @@
+import numpy as np
+import cv2
+
+
+def process(image, opt=1):
+    # Detecting corners
+    gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
+    corners = cv2.goodFeaturesToTrack(gray, 35, 0.05, 10)
+    print(len(corners))
+    for pt in corners:
+        print(pt)
+        b = np.random.random_integers(0, 256)
+        g = np.random.random_integers(0, 256)
+        r = np.random.random_integers(0, 256)
+        x = np.int32(pt[0][0])
+        y = np.int32(pt[0][1])
+        cv2.circle(image, (x, y), 5, (int(b), int(g), int(r)), 2)
+    # output
+    return image
+
+
+src = cv2.imread("blox.jpg")
+cv2.imshow("input", src)
+result = process(src)
+cv2.imshow('result', result)
+cv2.imwrite('result.jpg',result)
+cv2.waitKey(0)
+cv2.destroyAllWindows()

python/code_082/README.md

@@ -0,0 +1,2 @@
+#### More Detail, please check the blog of zhihu as below
+✈️ ✈️ ✈️ [OpenCV图像处理- 角点检测](https://zhuanlan.zhihu.com/p/68571164)

python/code_082/blox.jpg

@@ -0,0 +1,54 @@
+import numpy as np
+import cv2 as cv
+
+
+def process(image, opt=1):
+    # Detecting corners
+    gray = cv.cvtColor(image, cv.COLOR_BGR2GRAY)
+    corners = cv.goodFeaturesToTrack(gray, 100, 0.05, 10)
+    print(len(corners))
+    for pt in corners:
+        print(pt)
+        b = np.random.random_integers(0, 256)
+        g = np.random.random_integers(0, 256)
+        r = np.random.random_integers(0, 256)
+        x = np.int32(pt[0][0])
+        y = np.int32(pt[0][1])
+        cv.circle(image, (x, y), 5, (int(b), int(g), int(r)), 2)
+
+    # detect sub-pixel
+    winSize = (3, 3)
+    zeroZone = (-1, -1)
+
+    # Stop condition
+    criteria = (cv.TERM_CRITERIA_EPS + cv.TermCriteria_COUNT, 40, 0.001)
+    # Calculate the refined corner locations
+    corners = cv.cornerSubPix(gray, corners, winSize, zeroZone, criteria)
+    # display
+    for i in range(corners.shape[0]):
+        print(" -- Refined Corner [", i, "]  (", corners[i, 0, 0], ",", corners[i, 0, 1], ")")
+    return image
+
+src = cv.imread("tyt.png")
+cv.imshow("input", src)
+result = process(src)
+cv.imshow('result', result)
+cv.imwrite('result.jpg',result)
+cv.waitKey(0)
+cv.destroyAllWindows()
+
+'''
+cap = cv.VideoCapture(0)
+while True:
+    ret, frame = cap.read()
+    frame = cv.flip(frame, 1)
+    cv.imwrite("input.png", frame)
+    cv.imshow('input', frame)
+    result = process(frame)
+    cv.imwrite('result.png', result)
+    k = cv.waitKey(5)&0xff
+    if k == 27:
+        break
+cap.release()
+cv.destroyAllWindows()
+'''