目标

在本教程中，你将学习如何：

使用 OpenCV cv::inRange 函数执行基本的阈值操作。
基于 HSV 颜色空间中像素值的范围检测物体。

理论

在之前的教程中，我们学习了如何使用 cv::threshold 函数执行阈值操作。
在本教程中，我们将学习如何使用 cv::inRange 函数来实现。
概念保持不变，但现在我们添加了所需的像素值范围。

HSV 颜色空间

HSV（色相、饱和度、明度）颜色空间是一个类似于 RGB 颜色模型的色彩空间表示模型。由于色相通道模拟颜色类型，因此它在需要根据颜色分割物体的图像处理任务中非常有用。饱和度的变化是从不饱和到表示灰度，以及完全饱和（没有白色成分）。明度通道描述颜色的亮度或强度。下图显示了 HSV 圆柱体。

By SharkDderivative work: SharkD [CC BY-SA 3.0 or GFDL], via Wikimedia Commons

由于 RGB 颜色空间中的颜色使用三个通道编码，因此基于其颜色分割图像中的物体更加困难。

By SharkD [GFDL or CC BY-SA 4.0], from Wikimedia Commons

使用 cv::cvtColor 函数在不同的颜色空间之间转换的公式在颜色转换中描述。

代码

教程代码如下所示。你也可以从这里下载。

#include "opencv2/imgproc.hpp"
#include "opencv2/highgui.hpp"
#include "opencv2/videoio.hpp"
#include <iostream>
 
using namespace cv;
 
const int max_value_H = 360/2;
const int max_value = 255;
const String window_capture_name = "Video Capture";
const String window_detection_name = "Object Detection";
int low_H = 0, low_S = 0, low_V = 0;
int high_H = max_value_H, high_S = max_value, high_V = max_value;
 
static void on_low_H_thresh_trackbar(int, void *)
{
low_H = min(high_H-1, low_H);
setTrackbarPos("Low H", window_detection_name, low_H);
}
 
static void on_high_H_thresh_trackbar(int, void *)
{
high_H = max(high_H, low_H+1);
setTrackbarPos("High H", window_detection_name, high_H);
}
 
static void on_low_S_thresh_trackbar(int, void *)
{
low_S = min(high_S-1, low_S);
setTrackbarPos("Low S", window_detection_name, low_S);
}
 
static void on_high_S_thresh_trackbar(int, void *)
{
high_S = max(high_S, low_S+1);
setTrackbarPos("High S", window_detection_name, high_S);
}
 
static void on_low_V_thresh_trackbar(int, void *)
{
low_V = min(high_V-1, low_V);
    setTrackbarPos("Low V", window_detection_name, low_V);
}
 
static void on_high_V_thresh_trackbar(int, void *)
{
high_V = max(high_V, low_V+1);
    setTrackbarPos("High V", window_detection_name, high_V);
}
 
int main(int argc, char* argv[])
{
    VideoCapture cap(argc > 1 ? atoi(argv[1]) : 0);
 
    namedWindow(window_capture_name);
    namedWindow(window_detection_name);
 
    // 用于设置 HSV 值阈值的滚动条
    createTrackbar("Low H", window_detection_name, &low_H, max_value_H, on_low_H_thresh_trackbar);
    createTrackbar("High H", window_detection_name, &high_H, max_value_H, on_high_H_thresh_trackbar);
    createTrackbar("Low S", window_detection_name, &low_S, max_value, on_low_S_thresh_trackbar);
    createTrackbar("High S", window_detection_name, &high_S, max_value, on_high_S_thresh_trackbar);
    createTrackbar("Low V", window_detection_name, &low_V, max_value, on_low_V_thresh_trackbar);
    createTrackbar("High V", window_detection_name, &high_V, max_value, on_high_V_thresh_trackbar);
 
    Mat frame, frame_HSV, frame_threshold;
    while (true) {
cap >> frame;
        if(frame.empty())
        {
            break;;
        }
 
        // 从 BGR 转换为 HSV 颜色空间
        cvtColor(frame, frame_HSV, COLOR_BGR2HSV);
        // 基于 HSV 范围值检测物体
        inRange(frame_HSV, Scalar(low_H, low_S, low_V), Scalar(high_H, high_S, high_V), frame_threshold);
 
        // 显示帧
        imshow(window_capture_name, frame);
        imshow(window_detection_name, frame_threshold);
 
        char key = (char) waitKey(30);
        if (key == 'q' || key == 27)
        {
            break;;
        }
    }
    return 0;
}

教程代码如下所示。您也可以从这里下载。

import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.Image;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.util.List;
 
import javax.swing.BoxLayout;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JSlider;
import javax.swing.SwingWorker;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
 
import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.core.Scalar;
import org.opencv.highgui.HighGui;
import org.opencv.imgproc.Imgproc;
import org.opencv.videoio.VideoCapture;
 
public class ThresholdInRange {
    private static int MAX_VALUE = 255;
    private static int MAX_VALUE_H = 360/2;
    private static final String WINDOW_NAME = "Thresholding Operations using inRange demo";
    private static final String LOW_H_NAME = "Low H";
    private static final String LOW_S_NAME = "Low S";
    private static final String LOW_V_NAME = "Low V";
    private static final String HIGH_H_NAME = "High H";
    private static final String HIGH_S_NAME = "High S";
    private static final String HIGH_V_NAME = "High V";
    private JSlider sliderLowH;
    private JSlider sliderHighH;
    private JSlider sliderLowS;
    private JSlider sliderHighS;
    private JSlider sliderLowV;
    private JSlider sliderHighV;
    private VideoCapture cap;
    private Mat matFrame = new Mat();
    private JFrame frame;
    private JLabel imgCaptureLabel;
    private JLabel imgDetectionLabel;
    private CaptureTask captureTask;
 
    public ThresholdInRange(String[] args) {
        int cameraDevice = 0;
        if (args.length > 0) {
cameraDevice = Integer.parseInt(args[0]);
        }
cap = new VideoCapture(cameraDevice);
        if (!cap.isOpened()) {
System.err.println("Cannot open camera: " + cameraDevice);
System.exit(0);
        }
        if (!cap.read(matFrame)) {
System.err.println("Cannot read camera stream.");
System.exit(0);
        }
 
        // 创建并设置窗口。
frame = new JFrame(WINDOW_NAME);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.addWindowListener(new WindowAdapter() {
@Override
            public void windowClosing(WindowEvent windowEvent) {
captureTask.cancel(true);
            }
        });
        // 设置内容窗格。
Image img = HighGui.toBufferedImage(matFrame);
addComponentsToPane(frame.getContentPane(), img);
        // 使用内容窗格的默认BorderLayout。无需
        // setLayout(new BorderLayout());
        // 显示窗口。
frame.pack();
frame.setVisible(true);
 
captureTask = new CaptureTask();
captureTask.execute();
    }
 
    private class CaptureTask extends SwingWorker<Void, Mat> {
@Override
        protected Void doInBackground() {
Mat matFrame = new Mat();
 
            while (!isCancelled()) {
                if (!cap.read(matFrame)) {
                    break;;
                }
publish(matFrame.clone());
            }
            return null;
        }
 
@Override
        protected void process(List<Mat> frames) {
Mat frame = frames.get(frames.size() - 1);
Mat frameHSV = new Mat();
Imgproc.cvtColor(frame, frameHSV, Imgproc.COLOR_BGR2HSV);
Mat thresh = new Mat();
Core.inRange(frameHSV, new Scalar(sliderLowH.getValue(), sliderLowS.getValue(), sliderLowV.getValue()),
                    new Scalar(sliderHighH.getValue(), sliderHighS.getValue(), sliderHighV.getValue()), thresh);
update(frame, thresh);
        }
    }
 
    private void addComponentsToPane(Container pane, Image img) {
        if (!(pane.getLayout() instanceof BorderLayout)) {
pane.add(new JLabel("Container doesn't use BorderLayout!"));
            return;
        }
 
JPanel sliderPanel = new JPanel();
sliderPanel.setLayout(new BoxLayout(sliderPanel, BoxLayout.PAGE_AXIS));
 
sliderPanel.add(new JLabel(LOW_H_NAME));
sliderLowH = new JSlider(0, MAX_VALUE_H, 0);
sliderLowH.setMajorTickSpacing(50);
sliderLowH.setMinorTickSpacing(10);
sliderLowH.setPaintTicks(true);
sliderLowH.setPaintLabels(true);
sliderPanel.add(sliderLowH);
 
sliderPanel.add(new JLabel(HIGH_H_NAME));
sliderHighH = new JSlider(0, MAX_VALUE_H, MAX_VALUE_H);
sliderHighH.setMajorTickSpacing(50);
sliderHighH.setMinorTickSpacing(10);
sliderHighH.setPaintTicks(true);
sliderHighH.setPaintLabels(true);
sliderPanel.add(sliderHighH);
 
sliderPanel.add(new JLabel(LOW_S_NAME));
sliderLowS = new JSlider(0, MAX_VALUE, 0);
sliderLowS.setMajorTickSpacing(50);
sliderLowS.setMinorTickSpacing(10);
sliderLowS.setPaintTicks(true);
sliderLowS.setPaintLabels(true);
sliderPanel.add(sliderLowS);
 
sliderPanel.add(new JLabel(HIGH_S_NAME));
sliderHighS = new JSlider(0, MAX_VALUE, MAX_VALUE);
sliderHighS.setMajorTickSpacing(50);
sliderHighS.setMinorTickSpacing(10);
sliderHighS.setPaintTicks(true);
sliderHighS.setPaintLabels(true);
sliderPanel.add(sliderHighS);
 
sliderPanel.add(new JLabel(LOW_V_NAME));
sliderLowV = new JSlider(0, MAX_VALUE, 0);
sliderLowV.setMajorTickSpacing(50);
sliderLowV.setMinorTickSpacing(10);
sliderLowV.setPaintTicks(true);
sliderLowV.setPaintLabels(true);
sliderPanel.add(sliderLowV);
 
sliderPanel.add(new JLabel(HIGH_V_NAME));
sliderHighV = new JSlider(0, MAX_VALUE, MAX_VALUE);
sliderHighV.setMajorTickSpacing(50);
sliderHighV.setMinorTickSpacing(10);
sliderHighV.setPaintTicks(true);
sliderHighV.setPaintLabels(true);
sliderPanel.add(sliderHighV);
 
sliderLowH.addChangeListener(new ChangeListener() {
@Override
            public void stateChanged(ChangeEvent e) {
JSlider source = (JSlider) e.getSource();
                int valH = Math.min(sliderHighH.getValue()-1, source.getValue());
sliderLowH.setValue(valH);
            }
        });
sliderHighH.addChangeListener(new ChangeListener() {
@Override
            public void stateChanged(ChangeEvent e) {
JSlider source = (JSlider) e.getSource();
                int valH = Math.max(source.getValue(), sliderLowH.getValue()+1);
sliderHighH.setValue(valH);
            }
        });
sliderLowS.addChangeListener(new ChangeListener() {
@Override
            public void stateChanged(ChangeEvent e) {
JSlider source = (JSlider) e.getSource();
                int valS = Math.min(sliderHighS.getValue()-1, source.getValue());
sliderLowS.setValue(valS);
            }
        });
sliderHighS.addChangeListener(new ChangeListener() {
@Override
            public void stateChanged(ChangeEvent e) {
JSlider source = (JSlider) e.getSource();
                int valS = Math.max(source.getValue(), sliderLowS.getValue()+1);
sliderHighS.setValue(valS);
            }
        });
sliderLowV.addChangeListener(new ChangeListener() {
@Override
            public void stateChanged(ChangeEvent e) {
JSlider source = (JSlider) e.getSource();
                int valV = Math.min(sliderHighV.getValue()-1, source.getValue());
sliderLowV.setValue(valV);
            }
        });
sliderHighV.addChangeListener(new ChangeListener() {
@Override
            public void stateChanged(ChangeEvent e) {
JSlider source = (JSlider) e.getSource();
                int valV = Math.max(source.getValue(), sliderLowV.getValue()+1);
sliderHighV.setValue(valV);
            }
        });
 
pane.add(sliderPanel, BorderLayout.PAGE_START);
JPanel framePanel = new JPanel();
imgCaptureLabel = new JLabel(new ImageIcon(img));
framePanel.add(imgCaptureLabel);
imgDetectionLabel = new JLabel(new ImageIcon(img));
framePanel.add(imgDetectionLabel);
pane.add(framePanel, BorderLayout.CENTER);
    }
 
    private void update(Mat imgCapture, Mat imgThresh) {
imgCaptureLabel.setIcon(new ImageIcon(HighGui.toBufferedImage(imgCapture)));
imgDetectionLabel.setIcon(new ImageIcon(HighGui.toBufferedImage(imgThresh)));
frame.repaint();
    }
 
    public static void main(String[] args) {
        // 加载原生OpenCV库
System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
 
        // 为事件派发线程安排一个任务
        // 创建并显示此应用程序的GUI。
javax.swing.SwingUtilities.invokeLater(new Runnable() {
@Override
            public void run() {
                new ThresholdInRange(args);
            }
        });
    }
}

教程代码如下所示。您也可以从这里下载。

from __future__ import print_function
import cv2 as cv
import argparse
 
max_value = 255
max_value_H = 360//2
low_H = 0
low_S = 0
low_V = 0
high_H = max_value_H
high_S = max_value
high_V = max_value
window_capture_name = '视频捕捉'
window_detection_name = '目标检测'
low_H_name = '低 H'
low_S_name = '低 S'
low_V_name = '低 V'
high_H_name = '高 H'
high_S_name = '高 S'
high_V_name = '高 V'
 
 
def on_low_H_thresh_trackbar(val):
    global low_H
    global high_H
low_H = val
low_H = min(high_H-1, low_H)
    cv.setTrackbarPos(low_H_name, window_detection_name, low_H)
 
 
 
def on_high_H_thresh_trackbar(val):
    global low_H
    global high_H
high_H = val
high_H = max(high_H, low_H+1)
    cv.setTrackbarPos(high_H_name, window_detection_name, high_H)
 
 
def on_low_S_thresh_trackbar(val):
    global low_S
    global high_S
low_S = val
low_S = min(high_S-1, low_S)
    cv.setTrackbarPos(low_S_name, window_detection_name, low_S)
 
def on_high_S_thresh_trackbar(val):
    global low_S
    global high_S
high_S = val
high_S = max(high_S, low_S+1)
    cv.setTrackbarPos(high_S_name, window_detection_name, high_S)
 
def on_low_V_thresh_trackbar(val):
    global low_V
    global high_V
low_V = val
low_V = min(high_V-1, low_V)
    cv.setTrackbarPos(low_V_name, window_detection_name, low_V)
 
def on_high_V_thresh_trackbar(val):
    global low_V
    global high_V
high_V = val
high_V = max(high_V, low_V+1)
    cv.setTrackbarPos(high_V_name, window_detection_name, high_V)
 
parser = argparse.ArgumentParser(description='使用inRange教程进行阈值操作的代码。')
parser.add_argument('--camera', help='摄像头编号。', default=0, type=int)
args = parser.parse_args()
 
 
cap = cv.VideoCapture(args.camera)
 
 
 
cv.namedWindow(window_capture_name)
cv.namedWindow(window_detection_name)
 
 
 
cv.createTrackbar(low_H_name, window_detection_name , low_H, max_value_H, on_low_H_thresh_trackbar)
cv.createTrackbar(high_H_name, window_detection_name , high_H, max_value_H, on_high_H_thresh_trackbar)
cv.createTrackbar(low_S_name, window_detection_name , low_S, max_value, on_low_S_thresh_trackbar)
cv.createTrackbar(high_S_name, window_detection_name , high_S, max_value, on_high_S_thresh_trackbar)
cv.createTrackbar(low_V_name, window_detection_name , low_V, max_value, on_low_V_thresh_trackbar)
cv.createTrackbar(high_V_name, window_detection_name , high_V, max_value, on_high_V_thresh_trackbar)
 
 
while True:
    
ret, frame = cap.read()
    if frame is None:
        break;
 
frame_HSV = cv.cvtColor(frame, cv.COLOR_BGR2HSV)
frame_threshold = cv.inRange(frame_HSV, (low_H, low_S, low_V), (high_H, high_S, high_V))
    
 
    
    cv.imshow(window_capture_name, frame)
    cv.imshow(window_detection_name, frame_threshold)
    
 
key = cv.waitKey(30)
    if key == ord('q') or key == 27:
        break;

说明

让我们检查程序的总体结构

从默认或提供的采集设备捕获视频流。

C++

VideoCapture cap(argc > 1 ? atoi(argv[1]) : 0);

Java

cap = new VideoCapture(cameraDevice);

Python

cap = cv.VideoCapture(args.camera)
创建一个窗口来显示默认帧和阈值帧。

C++

namedWindow(window_capture_name);

namedWindow(window_detection_name);

Java

// 创建并设置窗口。

frame = new JFrame(WINDOW_NAME);

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.addWindowListener(new WindowAdapter() {

@Override

public void windowClosing(WindowEvent windowEvent) {

captureTask.cancel(true);

}

});

// 设置内容窗格。

Image img = HighGui.toBufferedImage(matFrame);

addComponentsToPane(frame.getContentPane(), img);

// 使用内容窗格的默认BorderLayout。无需

// setLayout(new BorderLayout());

// 显示窗口。

frame.pack();

frame.setVisible(true);

Python

cv.namedWindow(window_capture_name)

cv.namedWindow(window_detection_name)
创建轨迹条来设置HSV值的范围

C++

// 用于设置 HSV 值阈值的滚动条

createTrackbar("Low H", window_detection_name, &low_H, max_value_H, on_low_H_thresh_trackbar);

createTrackbar("High H", window_detection_name, &high_H, max_value_H, on_high_H_thresh_trackbar);

createTrackbar("Low S", window_detection_name, &low_S, max_value, on_low_S_thresh_trackbar);

createTrackbar("High S", window_detection_name, &high_S, max_value, on_high_S_thresh_trackbar);

createTrackbar("Low V", window_detection_name, &low_V, max_value, on_low_V_thresh_trackbar);

createTrackbar("High V", window_detection_name, &high_V, max_value, on_high_V_thresh_trackbar);

Java

sliderPanel.add(new JLabel(LOW_H_NAME));

sliderLowH = new JSlider(0, MAX_VALUE_H, 0);

sliderLowH.setMajorTickSpacing(50);

sliderLowH.setMinorTickSpacing(10);

sliderLowH.setPaintTicks(true);

sliderLowH.setPaintLabels(true);

sliderPanel.add(sliderLowH);

sliderPanel.add(new JLabel(HIGH_H_NAME));

sliderHighH = new JSlider(0, MAX_VALUE_H, MAX_VALUE_H);

sliderHighH.setMajorTickSpacing(50);

sliderHighH.setMinorTickSpacing(10);

sliderHighH.setPaintTicks(true);

sliderHighH.setPaintLabels(true);

sliderPanel.add(sliderHighH);

sliderPanel.add(new JLabel(LOW_S_NAME));

sliderLowS = new JSlider(0, MAX_VALUE, 0);

sliderLowS.setMajorTickSpacing(50);

sliderLowS.setMinorTickSpacing(10);

sliderLowS.setPaintTicks(true);

sliderLowS.setPaintLabels(true);

sliderPanel.add(sliderLowS);

sliderPanel.add(new JLabel(HIGH_S_NAME));

sliderHighS = new JSlider(0, MAX_VALUE, MAX_VALUE);

sliderHighS.setMajorTickSpacing(50);

sliderHighS.setMinorTickSpacing(10);

sliderHighS.setPaintTicks(true);

sliderHighS.setPaintLabels(true);

sliderPanel.add(sliderHighS);

sliderPanel.add(new JLabel(LOW_V_NAME));

sliderLowV = new JSlider(0, MAX_VALUE, 0);

sliderLowV.setMajorTickSpacing(50);

sliderLowV.setMinorTickSpacing(10);

sliderLowV.setPaintTicks(true);

sliderLowV.setPaintLabels(true);

sliderPanel.add(sliderLowV);

sliderPanel.add(new JLabel(HIGH_V_NAME));

sliderHighV = new JSlider(0, MAX_VALUE, MAX_VALUE);

sliderHighV.setMajorTickSpacing(50);

sliderHighV.setMinorTickSpacing(10);

sliderHighV.setPaintTicks(true);

sliderHighV.setPaintLabels(true);

sliderPanel.add(sliderHighV);

Python

cv.createTrackbar(low_H_name, window_detection_name , low_H, max_value_H, on_low_H_thresh_trackbar)

cv.createTrackbar(high_H_name, window_detection_name , high_H, max_value_H, on_high_H_thresh_trackbar)

cv.createTrackbar(low_S_name, window_detection_name , low_S, max_value, on_low_S_thresh_trackbar)

cv.createTrackbar(high_S_name, window_detection_name , high_S, max_value, on_high_S_thresh_trackbar)

cv.createTrackbar(low_V_name, window_detection_name , low_V, max_value, on_low_V_thresh_trackbar)

cv.createTrackbar(high_V_name, window_detection_name , high_V, max_value, on_high_V_thresh_trackbar)
直到用户希望程序退出，执行以下操作

C++

cap >> frame;

if(frame.empty())

{

break;;

}

// 从 BGR 转换为 HSV 颜色空间

cvtColor(frame, frame_HSV, COLOR_BGR2HSV);

// 基于 HSV 范围值检测物体

inRange(frame_HSV, Scalar(low_H, low_S, low_V), Scalar(high_H, high_S, high_V), frame_threshold);

Java

private class CaptureTask extends SwingWorker<Void, Mat> {

@Override

protected Void doInBackground() {

Mat matFrame = new Mat();

while (!isCancelled()) {

if (!cap.read(matFrame)) {

break;;

}

publish(matFrame.clone());

}

return null;

}

@Override

protected void process(List<Mat> frames) {

Mat frame = frames.get(frames.size() - 1);

Mat frameHSV = new Mat();

Imgproc.cvtColor(frame, frameHSV, Imgproc.COLOR_BGR2HSV);

Mat thresh = new Mat();

Core.inRange(frameHSV, new Scalar(sliderLowH.getValue(), sliderLowS.getValue(), sliderLowV.getValue()),

new Scalar(sliderHighH.getValue(), sliderHighS.getValue(), sliderHighV.getValue()), thresh);

update(frame, thresh);

}

}

Python

ret, frame = cap.read()

if frame is None:

break;

frame_HSV = cv.cvtColor(frame, cv.COLOR_BGR2HSV)

frame_threshold = cv.inRange(frame_HSV, (low_H, low_S, low_V), (high_H, high_S, high_V))
显示图像

C++

// 显示帧

imshow(window_capture_name, frame);

imshow(window_detection_name, frame_threshold);

Java

imgCaptureLabel.setIcon(new ImageIcon(HighGui.toBufferedImage(imgCapture)));

imgDetectionLabel.setIcon(new ImageIcon(HighGui.toBufferedImage(imgThresh)));

frame.repaint();

Python

cv.imshow(window_capture_name, frame)

cv.imshow(window_detection_name, frame_threshold)
对于控制下限范围的轨迹条，例如色调值

C++

static void on_low_H_thresh_trackbar(int, void *)

{

low_H = min(high_H-1, low_H);

setTrackbarPos("Low H", window_detection_name, low_H);

}

Java

sliderLowH.addChangeListener(new ChangeListener() {

@Override

public void stateChanged(ChangeEvent e) {

JSlider source = (JSlider) e.getSource();

int valH = Math.min(sliderHighH.getValue()-1, source.getValue());

sliderLowH.setValue(valH);

}

});

Python

def on_low_H_thresh_trackbar(val):

global low_H

global high_H

low_H = val

low_H = min(high_H-1, low_H)

cv.setTrackbarPos(low_H_name, window_detection_name, low_H)

static void on_low_H_thresh_trackbar(int, void *)

{

low_H = min(high_H-1, low_H);

setTrackbarPos("Low H", window_detection_name, low_H);

}
对于控制上限范围的轨迹条，例如色调值

C++

static void on_high_H_thresh_trackbar(int, void *)

{

high_H = max(high_H, low_H+1);

setTrackbarPos("High H", window_detection_name, high_H);

}

Java

sliderHighH.addChangeListener(new ChangeListener() {

@Override

public void stateChanged(ChangeEvent e) {

JSlider source = (JSlider) e.getSource();

int valH = Math.max(source.getValue(), sliderLowH.getValue()+1);

sliderHighH.setValue(valH);

}

});

Python

def on_high_H_thresh_trackbar(val):

global low_H

global high_H

high_H = val

high_H = max(high_H, low_H+1)

cv.setTrackbarPos(high_H_name, window_detection_name, high_H)
需要找到最大值和最小值，以避免出现诸如阈值高值小于低值之类的差异。

结果

编译此程序后运行它。程序将打开两个窗口
设置轨迹条的范围值后，结果帧将显示在另一个窗口中。


原作者	Lorena García
兼容性	Rishiraj Surti

目录

目标

理论

HSV 颜色空间

代码

说明

结果