目标

在本教程中，你将学习如何：

使用 OpenCV cv::inRange 函数执行基本阈值化操作。
根据 HSV 颜色空间中像素值的范围检测对象。

理论

在前面的教程中，我们学习了如何使用 cv::threshold 函数进行阈值化。
在本教程中，我们将学习如何使用 cv::inRange 函数进行此操作。
概念保持不变，但现在我们添加了所需像素值的范围。

HSV 颜色空间

HSV（色相、饱和度、值）颜色空间是一种类似于 RGB 颜色模型表示颜色空间的模型。由于色相通道对颜色类型进行建模，因此它在需要根据颜色分割对象的图像处理任务中非常有用。饱和度的变化范围从不饱和到表示灰色阴影和完全饱和（无白色分量）。值通道描述了颜色的亮度或强度。下图显示了 HSV 圆柱体。

由 SharkD 衍生作品: SharkD [CC BY-SA 3.0 或 GFDL]，通过维基共享资源

由于 RGB 颜色空间中的颜色使用三个通道进行编码，因此在图像中根据颜色分割对象更困难。

由 SharkD [GFDL 或 CC BY-SA 4.0]，来自维基共享资源

使用 cv::cvtColor 函数从一个颜色空间转换为另一个颜色空间的公式在颜色转换中描述

代码

本教程代码如下所示。您也可以从此处下载

#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 值阈值的轨迹条
    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);
        // 根据 HSV 范围值检测对象
        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;
}

本教程代码如下所示。您也可以从此处下载

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("无法打开摄像头: " + cameraDevice);
System.exit(0);
        }
        if (!cap.read(matFrame)) {
System.err.println("无法读取摄像头流。");
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("容器未使用 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) {
        // 加载本地 OpenCV 库
System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
 
        // 安排事件调度线程上的作业
        // 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);
            }
        });
    }
}

本教程代码如下所示。您也可以从此处下载

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 = '视频捕获'
window_detection_name = '对象检测'
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='用于 inRange 阈值化操作教程的代码。')
parser.add_argument('--camera', help='摄像头设备编号。', 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

解释

让我们检查程序的总体结构

从默认或提供的捕获设备捕获视频流。

C++

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

Java

cap = new VideoCapture(cameraDevice);

Python

cap = cv.VideoCapture(args.camera)
创建窗口以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)
创建轨迹条以设置 HSV 值的范围

C++

// 用于设置 HSV 值阈值的轨迹条

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);

// 根据 HSV 范围值检测对象

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（例如色相值）的轨迹条

C++

static void on_low_H_thresh_trackbar(int, void *)

{

low_H = min(high_H-1, low_H);

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

}
对于控制上限范围（例如色相值）的轨迹条

C++

static void on_high_H_thresh_trackbar(int, void *)

{

high_H = max(high_H, low_H+1);

setTrackbarPos("高 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)
有必要找到最大值和最小值，以避免出现诸如阈值的高值小于低值之类的不一致情况。

结果

编译此程序后，运行它。程序将打开两个窗口
当您从轨迹条设置范围值时，结果帧将在另一个窗口中可见。


原作者	Lorena García
兼容性	Rishiraj Surti

目录

目标

理论

HSV 颜色空间

代码

解释

结果