pyCV Codes

import numpy as np
import cv2

img = cv2.imread('./images/trex.png')
cv2.imshow('image', img)
cv2.waitKey(0)
cv2.destroyAllWindows()

cv2.namedWindow('image', cv2.WINDOW_NORMAL)
cv2.imshow('image', img)
cv2.waitKey(0)
cv2.destroyAllWindows()

cv2.imwrite('trex.jpg', img)

import cv2

image = cv2.imread('./images/trex.png')
cv2.imshow("Original", image)

(b, g, r) = image[0, 0]
print("Pixel at (0, 0) - Red: {}, Green: {}, Blue: {}".format(r, g, b))
image[0, 0] = (0, 0, 255)
(b, g, r) = image[0, 0]
print("Pixel at (0, 0) - Red: {}, Green: {}, Blue: {}".format(r, g, b))

corner = image[0:100, 0:100]
cv2.imshow("Corner", corner)
image[0:100, 0:100] = (0, 255, 0)
cv2.imshow("Updated", image)
cv2.waitKey(0)

import numpy as np
import cv2

canvas = np.zeros((300, 300, 3), dtype="uint8")

green = (0, 255, 0)
cv2.line(canvas, (0, 0), (300, 300), green)
cv2.imshow("Canvas", canvas)
cv2.waitKey(0)

red = (0, 0, 255)
cv2.line(canvas, (300, 0), (0, 300), red, 3)
cv2.imshow("Canvas", canvas)
cv2.waitKey(0)

cv2.rectangle(canvas, (10, 10), (60, 60), green)
cv2.imshow("Canvas", canvas)
cv2.waitKey(0)

cv2.rectangle(canvas, (50, 200), (200, 225), red, 5)
cv2.imshow("Canvas", canvas)
cv2.waitKey(0)

blue = (255, 0, 0)
cv2.rectangle(canvas, (200, 50), (225, 125), blue, -1)
cv2.imshow("Canvas", canvas)
cv2.waitKey(0)

canvas = np.zeros((300, 300, 3), dtype="uint8")
(centerX, centerY) = (canvas.shape[1] // 2, canvas.shape[0] // 2)
white = (255, 255, 255)

for r in range(0, 175, 25):
    cv2.circle(canvas, (centerX, centerY), r, white)
cv2.imshow("Canvas", canvas)
cv2.waitKey(0)

for i in range(0, 25):
    radius = np.random.randint(5, high=200)
    color = np.random.randint(0, high=256, size=(3,)).tolist()
    pt = np.random.randint(0, high=300, size=(2,))
    cv2.circle(canvas, tuple(pt), radius, color, -1)
cv2.imshow("Canvas", canvas)
cv2.waitKey(0)

import imutils
import cv2

image = cv2.imread('./images/trex.png')
cv2.imshow("Original", image)

(h, w) = image.shape[:2]
center = (w // 2, h // 2)

M = cv2.getRotationMatrix2D(center, 45, 1.0)
rotated = cv2.warpAffine(image, M, (w, h))
cv2.imshow("Rotated by 45 Degrees", rotated)

M = cv2.getRotationMatrix2D(center, -90, 1.0)
rotated = cv2.warpAffine(image, M, (w, h))
cv2.imshow("Rotated by -90 Degrees", rotated)

rotated = imutils.rotate(image, 180)
cv2.imshow("Rotated by 180 Degrees", rotated)
cv2.waitKey(0)

import imutils
import cv2

image = cv2.imread('./images/trex.png')
cv2.imshow("Original", image)

r = 150.0 / image.shape[1]
dim = (150, int(image.shape[0] * r))

resized = cv2.resize(image, dim, interpolation = cv2.INTER_AREA)
cv2.imshow("Resized (Width)", resized)

r = 50.0 / image.shape[0]
dim = (int(image.shape[1] * r), 50)

resized = cv2.resize(image, dim, interpolation = cv2.INTER_AREA)
cv2.imshow("Resized (Height)", resized)
cv2.waitKey(0)

resized = imutils.resize(image, width = 100)
cv2.imshow("Resized via Function", resized)
cv2.waitKey(0)

resized = imutils.resize(image, height = 50)
cv2.imshow("Resized via Function h=50", resized)
cv2.waitKey(0)

import cv2

image = cv2.imread('./images/trex.png')
cv2.imshow("Original", image)

flipped = cv2.flip(image, 1)
cv2.imshow("Flipped Horizontally", flipped)

flipped = cv2.flip(image, 0)
cv2.imshow("Flipped Vertically", flipped)

flipped = cv2.flip(image, -1)
cv2.imshow("Flipped Horizontally & Vertically", flipped)
cv2.waitKey(0)

import cv2

image = cv2.imread('./images/trex.png')
cv2.imshow("Original", image)

cropped = image[30:120, 240:335]
cv2.imshow("T-Rex Face", cropped)
cv2.waitKey(0)

import numpy as np
import cv2

image = cv2.imread('./images/trex.png')
cv2.imshow("Original", image)
print("max of 255: {}".format(cv2.add(np.uint8([200]), np.uint8([100]))))
print("min of 0: {}".format(cv2.subtract(np.uint8([50]), np.uint8([100]))))

print("wrap around: {}".format(np.uint8([200]) + np.uint8([100])))
print("wrap around: {}".format(np.uint8([50]) - np.uint8([100])))

M = np.ones(image.shape, dtype = "uint8") * 100
added = cv2.add(image, M)
cv2.imshow("Added", added)

M = np.ones(image.shape, dtype = "uint8") * 50
subtracted = cv2.subtract(image, M)
cv2.imshow("Subtracted", subtracted)
cv2.waitKey(0)

import numpy as np
import cv2

rectangle = np.zeros((300, 300), dtype = "uint8")
cv2.rectangle(rectangle, (25, 25), (275, 275), 255, -1)
cv2.imshow("Rectangle", rectangle)

circle = np.zeros((300, 300), dtype = "uint8")
cv2.circle(circle, (150, 150), 150, 255, -1)
cv2.imshow("Circle", circle)

bitwiseAnd = cv2.bitwise_and(rectangle, circle)
cv2.imshow("AND", bitwiseAnd)
cv2.waitKey(0)

bitwiseOr = cv2.bitwise_or(rectangle, circle)
cv2.imshow("OR", bitwiseOr)
cv2.waitKey(0)

bitwiseXor = cv2.bitwise_xor(rectangle, circle)
cv2.imshow("XOR", bitwiseXor)
cv2.waitKey(0)

bitwiseNot = cv2.bitwise_not(circle)
cv2.imshow("NOT", bitwiseNot)
cv2.waitKey(0)

import numpy as np
import cv2

image = cv2.imread('./images/beach.png')
cv2.imshow("Original", image)

mask = np.zeros(image.shape[:2], dtype="uint8")
(cX, cY) = (image.shape[1] // 2, image.shape[0] // 2)
cv2.rectangle(mask, (cX - 75, cY - 75), (cX + 75, cY + 75), 255, -1)
cv2.imshow("Mask", mask)

masked = cv2.bitwise_and(image, image, mask=mask)
cv2.imshow("Mask Applied to Image", masked)
cv2.waitKey(0)

mask = np.zeros(image.shape[:2], dtype="uint8")
cv2.circle(mask, (cX, cY), 100, 255, -1)
masked = cv2.bitwise_and(image, image, mask=mask)
cv2.imshow("Mask", mask)
cv2.imshow("Mask Applied to Image", masked)
cv2.waitKey(0)

import numpy as np
import cv2

image = cv2.imread('./images/beach.png')
(B, G, R) = cv2.split(image)

cv2.imshow("Red", R)
cv2.imshow("Green", G)
cv2.imshow("Blue", B)
cv2.waitKey(0)

merged = cv2.merge([B, G, R])
cv2.imshow("Merged", merged)
cv2.waitKey(0)
cv2.destroyAllWindows()

zeros = np.zeros(image.shape[:2], dtype = "uint8")
cv2.imshow("Red", cv2.merge([zeros, zeros, R]))
cv2.imshow("Green", cv2.merge([zeros, G, zeros]))
cv2.imshow("Blue", cv2.merge([B, zeros, zeros]))
cv2.waitKey(0)

import cv2

image = cv2.imread('./images/beach.png')
cv2.imshow("Original", image)

gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
cv2.imshow("Gray", gray)

hsv = cv2.cvtColor(image, cv2.COLOR_BGR2HSV)
cv2.imshow("HSV", hsv)

lab = cv2.cvtColor(image, cv2.COLOR_BGR2LAB)
cv2.imshow("L*a*b*", lab)
cv2.waitKey(0)

from matplotlib import pyplot as plt
import cv2

image = cv2.imread('./images/beach.png')

image = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
cv2.imshow("Original", image)

hist = cv2.calcHist([image], [0], None, [256], [0, 256])

plt.figure()
plt.title("Grayscale Histogram")
plt.xlabel("Bins")
plt.ylabel("# of Pixels")
plt.plot(hist)
plt.xlim([0, 256])
plt.show()
cv2.waitKey(0)

from matplotlib import pyplot as plt
import cv2

image = cv2.imread('./images/beach.png')
cv2.imshow("Original", image)

chans = cv2.split(image)
colors = ("b", "g", "r")
plt.figure()
plt.title("’Flattened’ Color Histogram")
plt.xlabel("Bins")
plt.ylabel("# of Pixels")

for (chan, color) in zip(chans, colors):
    hist = cv2.calcHist([chan], [0], None, [256], [0, 256])
    plt.plot(hist, color=color)
    plt.xlim([0, 256])

fig = plt.figure()

ax = fig.add_subplot(131)
hist = cv2.calcHist([chans[1], chans[0]], [0, 1], None, [32, 32], [0, 256, 0, 256])
p = ax.imshow(hist, interpolation="nearest")
ax.set_title("2D Color Histogram for G and B")
plt.colorbar(p)

ax = fig.add_subplot(132)
hist = cv2.calcHist([chans[1], chans[2]], [0, 1], None, [32, 32], [0, 256, 0, 256])
p = ax.imshow(hist, interpolation="nearest")
ax.set_title("2D Color Histogram for G and R")
plt.colorbar(p)

ax = fig.add_subplot(133)
hist = cv2.calcHist([chans[0], chans[2]], [0, 1], None, [32, 32], [0, 256, 0, 256])
p = ax.imshow(hist, interpolation="nearest")
ax.set_title("2D Color Histogram for B and R")
plt.colorbar(p)

print("2D histogram shape: {}, with {} values".format(hist.shape, hist.flatten().shape[0]))
hist = cv2.calcHist([image], [0, 1, 2], None, [8, 8, 8], [0, 256, 0, 256, 0, 256])
print("3D histogram shape: {}, with {} values".format(hist.shape, hist.flatten().shape[0]))

plt.show()

import numpy as np
import cv2

image = cv2.imread('./images/beach.png')
image = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)

eq = cv2.equalizeHist(image)

cv2.imshow("Histogram Equalization", np.hstack([image, eq]))
cv2.waitKey(0)

from matplotlib import pyplot as plt
import numpy as np
import cv2


def plot_histogram(image, title, mask=None):
    chans = cv2.split(image)
    colors = ("b", "g", "r")
    plt.figure()
    plt.title(title)
    plt.xlabel("Bins")
    plt.ylabel("# of Pixels")

    for (chan, color) in zip(chans, colors):
        hist = cv2.calcHist([chan], [0], mask, [256], [0, 256])
        plt.plot(hist, color=color)
        plt.xlim([0, 256])


image = cv2.imread('./images/beach.png')
cv2.imshow("Original", image)
plot_histogram(image, "Histogram for Original Image")

mask = np.zeros(image.shape[:2], dtype="uint8")
cv2.rectangle(mask, (15, 15), (130, 100), 255, -1)
cv2.imshow("Mask", mask)

masked = cv2.bitwise_and(image, image, mask=mask)
cv2.imshow("Applying the Mask", masked)

plot_histogram(image, "Histogram for Masked Image", mask=mask)
plt.show()

import numpy as np
import cv2

image = cv2.imread('./images/trex.png')
cv2.imshow("Original", image)

blurred = np.hstack([cv2.blur(image, (3, 3)), cv2.blur(image, (5, 5)), cv2.blur(image, (7, 7))])

cv2.imshow("Averaged", blurred)
cv2.waitKey(0)

blurred = np.hstack([cv2.GaussianBlur(image, (3, 3), 0), cv2.GaussianBlur(image, (5, 5), 0), cv2.GaussianBlur(image, (7, 7), 0)])

cv2.imshow("Gaussian", blurred)
cv2.waitKey(0)

blurred = np.hstack([cv2.medianBlur(image, 3), cv2.medianBlur(image, 5), cv2.medianBlur(image, 7)])
cv2.imshow("Median", blurred)
cv2.waitKey(0)

blurred = np.hstack([cv2.bilateralFilter(image, 5, 21, 21), cv2.bilateralFilter(image, 7, 31, 31), cv2.bilateralFilter(image, 9, 41, 41)])
cv2.imshow("Bilateral", blurred)
cv2.waitKey(0)

import cv2

image = cv2.imread('./images/coins.png')
image = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
blurred = cv2.GaussianBlur(image, (5, 5), 0)
cv2.imshow("Image", image)

(T, thresh) = cv2.threshold(blurred, 155, 255, cv2.THRESH_BINARY)
cv2.imshow("Threshold Binary", thresh)

(T, threshInv) = cv2.threshold(blurred, 155, 255, cv2. THRESH_BINARY_INV)
cv2.imshow("Threshold Binary Inverse", threshInv)
cv2.imshow("Coins", cv2.bitwise_and(image, image, mask = threshInv))
cv2.waitKey(0)

import mahotas
import cv2

image = cv2.imread('./images/coins.png')
image = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
blurred = cv2.GaussianBlur(image, (5, 5), 0)
cv2.imshow("Image", image)

T = mahotas.thresholding.otsu(blurred)
print("Otsu’s threshold: {}".format(T))

thresh = image.copy()
thresh[thresh > T] = 255

thresh[thresh < 255] = 0
thresh = cv2.bitwise_not(thresh)
cv2.imshow("Otsu", thresh)

T = mahotas.thresholding.rc(blurred)
print("Riddler-Calvard: {}".format(T))
thresh = image.copy()
thresh[thresh > T] = 255
thresh[thresh < 255] = 0
thresh = cv2.bitwise_not(thresh)
cv2.imshow("Riddler-Calvard", thresh)
cv2.waitKey(0)

import numpy as np
import cv2

image = cv2.imread('./images/coins.png')
image = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
cv2.imshow("Original", image)

lap = cv2.Laplacian(image, cv2.CV_64F)
lap = np.uint8(np.absolute(lap))
cv2.imshow("Laplacian", lap)
cv2.waitKey(0)

sobelX = cv2.Sobel(image, cv2.CV_64F, 1, 0)
sobelY = cv2.Sobel(image, cv2.CV_64F, 0, 1)

sobelX = np.uint8(np.absolute(sobelX))
sobelY = np.uint8(np.absolute(sobelY))

sobelCombined = cv2.bitwise_or(sobelX, sobelY)

cv2.imshow("Sobel X", sobelX)
cv2.imshow("Sobel Y", sobelY)
cv2.imshow("Sobel Combined", sobelCombined)
cv2.waitKey(0)

import cv2

image = cv2.imread('./images/coins.png')
image = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
image = cv2.GaussianBlur(image, (5, 5), 0)
cv2.imshow("Blurred", image)

canny = cv2.Canny(image, 30, 150)
cv2.imshow("Canny", canny)
cv2.waitKey(0)

import numpy as np
import cv2

image = cv2.imread('./images/coins.png')
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
blurred = cv2.GaussianBlur(gray, (11, 11), 0)
cv2.imshow("Image", image)

edged = cv2.Canny(blurred, 30, 150)
cv2.imshow("Edges", edged)

(_, cnts, _) = cv2.findContours(edged.copy(), cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
print("I count {} coins in this image".format(len(cnts)))

coins = image.copy()
cv2.drawContours(coins, cnts, -1, (0, 255, 0), 2)
cv2.imshow("Coins", coins)
cv2.waitKey(0)

cv2.drawContours(coins, cnts, 0, (0, 255, 0), 2)
cv2.drawContours(coins, cnts, 1, (0, 255, 0), 2)
cv2.drawContours(coins, cnts, 2, (0, 255, 0), 2)

for (i, c) in enumerate(cnts):
    (x, y, w, h) = cv2.boundingRect(c)
    print("Coin #{}".format(i + 1))
    coin = image[y:y + h, x:x + w]
    cv2.imshow("Coin", coin)
    mask = np.zeros(image.shape[:2], dtype="uint8")
    ((centerX, centerY), radius) = cv2.minEnclosingCircle(c)
    cv2.circle(mask, (int(centerX), int(centerY)), int(radius), 255, -1)
    mask = mask[y:y + h, x:x + w]
    cv2.imshow("Masked Coin", cv2.bitwise_and(coin, coin, mask=mask))
    cv2.waitKey(0)