目標

このチュートリアルでは、以下の方法を学ぶ:

OpenCV の cv::inRange 関数を使って基本的なしきい値処理を行う。
HSV 色空間におけるピクセル値の範囲に基づいてオブジェクトを検出する。

理論

前のチュートリアルでは、cv::threshold 関数を使ってしきい値処理を行う方法を学んだ。
このチュートリアルでは、cv::inRange 関数を使ってそれを行う方法を学ぶ。
概念は同じだが、今回は必要なピクセル値の範囲を追加する。

HSV 色空間

HSV (hue, saturation, value) 色空間は、RGB カラーモデルに似た色空間を表すモデルである。色相(hue)チャンネルが色の種類をモデル化するため、色に基づいてオブジェクトを領域分割する必要がある画像処理タスクで非常に有用である。彩度(saturation)の変化は、灰色の濃淡を表す無彩色から、完全に彩度の高い状態(白成分なし)まで及ぶ。明度(value)チャンネルは色の明るさや強度を表す。次の画像は HSV 円柱を示している。

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

RGB 色空間の色は3つのチャンネルを使って符号化されるため、色に基づいて画像内のオブジェクトを領域分割するのはより難しい。

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

cv::cvtColor 関数を使ってある色空間から別の色空間に変換する際に用いる式は、色変換で説明されている

コード

チュートリアルのコードを以下の行に示す。ここからダウンロードすることもできる

#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);
 
 // Trackbars to set thresholds for HSV values
 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;
        }
 
 // Convert from BGR to HSV colorspace
 cvtColor(frame, frame_HSV, COLOR_BGR2HSV);
 // Detect the object based on HSV Range Values
 inRange(frame_HSV, Scalar(low_H, low_S, low_V), Scalar(high_H, high_S, high_V), frame_threshold);
 
 // Show the frames
 imshow(window_capture_name, frame);
 imshow(window_detection_name, frame_threshold);
 
 char key = (char) waitKey(30);
 if (key == 'q' || key == 27)
        {
 break;
        }
    }
 return 0;
}

チュートリアルのコードを以下の行に示す。ここからダウンロードすることもできる

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);
        }
 
 // Create and set up the window.
        frame = new JFrame(WINDOW_NAME);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.addWindowListener(new WindowAdapter() {
            @Override
 public void windowClosing(WindowEvent windowEvent) {
                captureTask.cancel(true);
            }
        });
 // Set up the content pane.
        Image img = HighGui.toBufferedImage(matFrame);
        addComponentsToPane(frame.getContentPane(), img);
 // Use the content pane's default BorderLayout. No need for
 // setLayout(new BorderLayout());
 // Display the window.
        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) {
 // Load the native OpenCV library
        System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
 
 // Schedule a job for the event dispatch thread:
 // creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            @Override
 public void run() {
 new ThresholdInRange(args);
            }
        });
    }
}

チュートリアルのコードを以下の行に示す。ここからダウンロードすることもできる

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 = 'Video Capture'
window_detection_name = 'Object Detection'
low_H_name = 'Low H'
low_S_name = 'Low S'
low_V_name = 'Low V'
high_H_name = 'High H'
high_S_name = 'High S'
high_V_name = 'High 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='Code for Thresholding Operations using inRange tutorial.')
parser.add_argument('--camera', help='Camera divide number.', 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

解説

プログラムの全体的な構造を確認しよう:

デフォルトの、または指定されたキャプチャデバイスからビデオストリームを取得する。

C++

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

Java

cap = new VideoCapture(cameraDevice);

Python

cap = cv.VideoCapture(args.camera)
デフォルトのフレームとしきい値処理後のフレームを表示するためのウィンドウを作成する。

C++

namedWindow(window_capture_name);

namedWindow(window_detection_name);

Java

// Create and set up the window.

frame = new JFrame(WINDOW_NAME);

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.addWindowListener(new WindowAdapter() {

@Override

public void windowClosing(WindowEvent windowEvent) {

captureTask.cancel(true);

}

});

// Set up the content pane.

Image img = HighGui.toBufferedImage(matFrame);

addComponentsToPane(frame.getContentPane(), img);

// Use the content pane's default BorderLayout. No need for

// setLayout(new BorderLayout());

// Display the window.

frame.pack();

frame.setVisible(true);

Python

cv.namedWindow(window_capture_name)

cv.namedWindow(window_detection_name)
HSV 値の範囲を設定するためのトラックバーを作成する

C++

// Trackbars to set thresholds for HSV values

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)
ユーザーがプログラムを終了したくなるまで、次の処理を行う

C++

cap >> frame;

if(frame.empty())

{

break;

}

// Convert from BGR to HSV colorspace

cvtColor(frame, frame_HSV, COLOR_BGR2HSV);

// Detect the object based on HSV Range Values

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))
画像を表示する

C++

// Show the frames

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)
下限の範囲を制御するトラックバー、例えば色相値の場合:

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);

}
上限の範囲を制御するトラックバー、例えば色相値の場合:

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)
しきい値の上限が下限より小さくなるといった矛盾を避けるため、最大値と最小値を求める必要がある。

結果

このプログラムをコンパイルした後、実行する。プログラムは2つのウィンドウを開く
トラックバーで範囲の値を設定すると、結果のフレームがもう一方のウィンドウに表示される。


原著者	Lorena García
互換性	Rishiraj Surti

目次

目標

理論

HSV 色空間

コード

解説

結果