opencv图像亮度调整

本文介绍了一种使用OpenCV库调整图片对比度的方法,通过修改图片上每个点的RGB值来增强图像细节,提供了具体的C++代码实现。

先上代码:

#include "opencv2/core/core.hpp"
#include "opencv2/highgui/highgui.hpp"

using namespace cv;

int contrast = 300;

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    Mat srcImg = imread("../imgs/a.jpeg");
    namedWindow("Display Image", CV_WINDOW_AUTOSIZE );
    imshow("Display Image", srcImg);

    Mat destImg = Mat::zeros(srcImg.size(), srcImg.type());

    for(int i =0; i < srcImg.rows; i++)
    {
        for(int j = 0; j < srcImg.cols; j++)
        {
            for(int c = 0 ; c < 3; c++)
            {
                destImg.at<cv::Vec3b>(i,j)[c] = srcImg.at<cv::Vec3b>(i,j)[c];
                destImg.at<cv::Vec3b>(i,j)[c] = \
                        saturate_cast<uchar>(srcImg.at<cv::Vec3b>(i,j)[c] * contrast * 0.001);
            }
        }
    }

    namedWindow("Display Image", CV_WINDOW_AUTOSIZE );
    imshow("Display Image", destImg);

    return a.exec();
}

他的本质上就是在修改图片上每个点的GBR值

### 使用 OpenCV 调整图像亮度 通过线性变换可以实现图像亮度调整。具体来说,对于输入像素值 \( V \),新的像素值可以通过下面公式获得: \[ V' = aV + b \] 其中 \( a \) 是对比度因子而 \( b \) 则是亮度偏移量[^2]。 下面是具体的 Python 和 OpenCV 实现代码来展示如何增加或减少图片的整体亮度水平: ```python import cv2 import numpy as np def adjust_brightness(image, brightness=0): """ Adjust the brightness of an image. :param image: Input image (numpy array). :param brightness: Brightness adjustment value (-255 to 255). :return: Image with adjusted brightness. """ if brightness == 0: return image # Clip values between -255 and 255 for valid pixel range after addition/subtraction brightened_image = np.clip(image.astype(np.int16) + int(brightness), 0, 255).astype(np.uint8) return brightened_image # Load sample image using imread function from cv2 module image_path = "path_to_your_image.jpg" img = cv2.imread(image_path) if img is None: raise ValueError(f"Image at {image_path} could not be loaded.") # Apply positive or negative offset to change brightness level accordingly brighter_img = adjust_brightness(img, brightness=60) # Increase brightness by 60 units darker_img = adjust_brightness(img, brightness=-30) # Decrease brightness by 30 units # Display original alongside modified images side-by-side within one window named 'Brightness Adjustment' combined_images = np.hstack((img, brighter_img, darker_img)) cv2.imshow('Brightness Adjustment', combined_images) cv2.waitKey(0) cv2.destroyAllWindows() ``` 这段脚本定义了一个 `adjust_brightness` 函数用于修改给定图像对象的亮度属性,并展示了如何应用此函数创建更亮或更暗版本的同一张照片[^3]。
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