OpenCV-Python教程、源码迁移 2018年10月2日

Author: ex2tron

.gitignore

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+wiki/

01. 简介与安装/cv2_contrast_brightness_time.cpp

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+// More: http://ex2tron.top
+
+#include "stdafx.h"
+#include <opencv2\opencv.hpp>
+
+using namespace cv;
+using namespace std;
+
+int main()
+{
+	// 开始计时
+	int start = getTickCount();
+
+	// 读入一张图片并调整对比度和亮度
+	Mat gSrcImage = imread("lena.jpg");
+	Mat gDstImage = Mat::zeros(gSrcImage.size(), gSrcImage.type());
+
+	//1.访问每一个像素的方式
+	for (int y = 0; y < gSrcImage.rows; y++)
+	{
+		for (int x = 0; x < gSrcImage.cols; x++)
+		{
+			for (int c = 0; c < 3; c++)
+			{
+				gDstImage.at<Vec3b>(y, x)[c] = saturate_cast<uchar>(0.8 * gSrcImage.at<Vec3b>(y, x)[c] + 80);
+			}
+		}
+	}
+
+	//2.最快速的方式
+	//gSrcImage.convertTo(gDstImage, -1, 0.8, 80);
+
+	// 停止计时
+	int end = getTickCount();
+
+	// 单位：s
+	double time = (end - start) / getTickFrequency();
+	printf("%f", time);
+
+	getchar();
+	return 0;
+}

01. 简介与安装/cv2_contrast_brightness_time.py

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+# More: http://ex2tron.top
+
+import cv2
+import numpy as np
+
+# 开始计时
+start = cv2.getTickCount()
+
+# 读入一张图片并调整对比度和亮度
+img = cv2.imread('lena.jpg')
+res = np.uint8(np.clip((0.8 * img + 80), 0, 255))
+
+# 停止计时
+end = cv2.getTickCount()
+
+# 单位：s
+print((end - start) / cv2.getTickFrequency())

01. 简介与安装/cv2_read_image_time.cpp

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+// More: http://ex2tron.top
+
+#include "stdafx.h"
+#include <opencv2\opencv.hpp>
+
+using namespace cv;
+using namespace std;
+
+int main()
+{
+	// 开始计时
+	int start = getTickCount();
+
+	// 读入一张图片
+	Mat gSrcImage = imread("lena.jpg");
+
+	// 停止计时
+	int end = getTickCount();
+
+	// 单位：s
+	double time = (end - start) / getTickFrequency();
+	printf("%f", time);
+
+	getchar();
+    return 0;	
+}

01. 简介与安装/cv2_read_image_time.py

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+# More: http://ex2tron.top
+
+import cv2
+
+# 开始计时
+start = cv2.getTickCount()
+
+# 读入一张图片
+img = cv2.imread('lena.jpg')
+
+# 停止计时
+end = cv2.getTickCount()
+
+# 单位：s
+print((end - start) / cv2.getTickFrequency())

01. 简介与安装/lena.jpg

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+# More: http://ex2tron.top
+
+import cv2
+
+img = cv2.imread('lena.jpg')
+cv2.imshow('lena', img)
+
+k = cv2.waitKey(0)
+# ord用来获取某个字符的编码
+if k == ord('s'):
+    cv2.imwrite('lena_save.bmp', img)

02. 基本元素-图片/cv2_excises1.py

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+# More: http://ex2tron.top
+
+import cv2
+
+# 1.灰度图加载一张彩色图
+img = cv2.imread('lena.jpg', 0)
+
+
+# 2.显示图片
+cv2.imshow('lena', img)
+cv2.waitKey(0)
+
+# 先定义窗口，后显示图片
+cv2.namedWindow('lena2', cv2.WINDOW_NORMAL)
+cv2.imshow('lena2', img)
+cv2.waitKey(0)
+
+
+# 3.保存图片
+cv2.imwrite('lena_gray.jpg', img)

02. 基本元素-图片/cv2_getting_start_with_images.py

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+# More: http://ex2tron.top
+
+import cv2
+
+# 1.打开摄像头
+capture = cv2.VideoCapture(2)
+
+# 2.获取捕获的分辨率
+width, height = capture.get(3), capture.get(4)
+print(width, height)
+# 以原分辨率的一倍来捕获，
+# 参数1可以直接写数字，或者OpenCV符号表示
+capture.set(cv2.CAP_PROP_FRAME_WIDTH, width * 2)
+capture.set(cv2.CAP_PROP_FRAME_HEIGHT, height * 2)
+
+while(True):
+    # 获取一帧
+    ret, frame = capture.read()
+    # 将这帧转换为灰度图
+    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
+
+    cv2.imshow('frame', gray)
+    if cv2.waitKey(1) == ord('q'):
+        break