Histograms – OpenCV 3.4 with python 3 Tutorial 11

Source code: [python] import cv2 import numpy as np from matplotlib import pyplot as plt img = cv2.imread("sea_beach.jpg") b, g, r = cv2.split(img) cv2.imshow("img", img) cv2.imshow("b", b) cv2.imshow("g", g) cv2.imshow("r", r) plt.hist(b.ravel(), 256, [0, 256]) plt.hist(g.ravel(), 256, [0, 256]) plt.hist(r.ravel(), 256, [0, 256]) plt.show() [/python] Files: sea.jpg sea_beach.jpg Sergio CanuHi there, I’m the founder of […]

Basic Thresholding – OpenCV 3.4 with python 3 Tutorial 10

Threshold: [python] import cv2 import numpy as np img = cv2.imread("black_to_white.jpeg", cv2.IMREAD_GRAYSCALE) _, threshold_binary = cv2.threshold(img, 128, 255, cv2.THRESH_BINARY) _, threshold_binary_inv = cv2.threshold(img, 128, 255, cv2.THRESH_BINARY_INV) _, threshold_trunc = cv2.threshold(img, 128, 255, cv2.THRESH_TRUNC) _, threshold_to_zero = cv2.threshold(img, 12, 255, cv2.THRESH_TOZERO) cv2.imshow("Image", img) cv2.imshow("th binary", threshold_binary) cv2.imshow("th binary inv", threshold_binary_inv) cv2.imshow("th trunc", threshold_trunc) cv2.imshow("th to zero", […]

Trackbars – OpenCV 3.4 with python 3 Tutorial 8

Source code: [python] import cv2 import numpy as np def nothing(x): pass cap = cv2.VideoCapture(0) cv2.namedWindow("frame") cv2.createTrackbar("test", "frame", 50, 500, nothing) cv2.createTrackbar("color/gray", "frame", 0, 1, nothing) while True: _, frame = cap.read() test = cv2.getTrackbarPos("test", "frame") font = cv2.FONT_HERSHEY_COMPLEX cv2.putText(frame, str(test), (50, 150), font, 4, (0, 0, 255)) s = cv2.getTrackbarPos("color/gray", "frame") if s == […]

Bitwise Operators – OpenCV 3.4 with python 3 Tutorial 7

Source code: [python] import cv2 import numpy as np img1 = cv2.imread("drawing_1.png") img2 = cv2.imread("drawing_2.png") bit_and = cv2.bitwise_and(img2, img1) bit_or = cv2.bitwise_or(img2, img1) bit_xor = cv2.bitwise_xor(img1, img2) bit_not = cv2.bitwise_not(img1) bit_not2 = cv2.bitwise_not(img2) cv2.imshow("img1", img1) cv2.imshow("img2", img2) cv2.imshow("bit_and", bit_and) cv2.imshow("bit_or", bit_or) cv2.imshow("bit_xor", bit_xor) cv2.imshow("bit_not", bit_not) cv2.imshow("bit_not2", bit_not2) cv2.waitKey(0) cv2.destroyAllWindows() [/python]   Files: drawing_1.png drawing_2.png Sergio […]

Blending images – OpenCV 3.4 with python 3 Tutorial 6

Source code: [python] import cv2 import numpy as np img1 = cv2.imread("road.jpg") img2 = cv2.imread("car.jpg") img2_gray = cv2.cvtColor(img2, cv2.COLOR_BGR2GRAY) ret, mask = cv2.threshold(img2_gray, 240, 255, cv2.THRESH_BINARY) mask_inv = cv2.bitwise_not(mask) road = cv2.bitwise_and(img1, img1, mask=mask) car = cv2.bitwise_and(img2, img2, mask=mask_inv) result = cv2.add(road, car) cv2.imshow("img1", img1) cv2.imshow("img2", img2) cv2.imshow("road background", road) cv2.imshow("car no background", car) cv2.imshow("mask", […]

Add images and Threshold – OpenCV 3.4 with python 3 Tutorial 5

We’re going to learn in this tutorial how to add two images using Python and Opencv. First let’s take two images. There is one condition, the images need to have the exact same size. Add images There are two different functions to add the images together.The function cv2.add (see line below) that adds rispectively the […]

Loading Video and Webcam – OpenCV 3.4 with python 3 Tutorial 2

In this tutorial we’re going to see how to load the video from it’s source whether it’s a webcam or a video file. The process is relatively simple. After we import the libraries cv2 and numpy, we need to define the cap object. To load the frames from the webcam: cap = cv2.VideoCapture(0) The number […]