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  1. 28th October 2014, 01:55 #1
    rcmandar
    rcmandar is offline Beginner
    Join Date
    Oct 2014
    Posts
    4
    Qt products
    Qt5
    Platforms
    Unix/X11 Windows

    Default slider and color filtering or thresholding

    hello guys,


    i want to make an app to track an Object.

    I am using opencv. I want change color threshold values using QSliders. However, i am unable to do so.
    Please see attached pic along with the code.

    Notice all the zeros in plainTextedit. Even if i change the slider position my variables ch1_min and others change. However, i still have 0 numbers for this in inRange function in the code.

    Please help.

    Qt Code: 
    1. #include "dialog.h"
    2. #include "ui_dialog.h"
    3.  
    4. //////////////////////////////////////////////////////////////////////////
    5. /// \brief -> this is the Constructor
    6. /// \param parent
    7. //////////////////////////////////////////////////////////////////////////
    8.  
    9. Dialog::Dialog(QWidget *parent) : QDialog(parent), ui(new Ui::Dialog)
    10. {
    11.     ui->setupUi(this);
    12.     timer1 = new QTimer(this);
    13.     connect(timer1, SIGNAL(timeout()), this, SLOT(ShowCamera()));
    14.     ch1_min = ch2_min = ch3_min = 0;
    15.     ch1_max = ch2_max = ch3_max = 255;
    16. }
    17. //////////////////////////////////////////////////////////////////////////
    18. /// \brief -> this is the Deconstructor
    19. //////////////////////////////////////////////////////////////////////////
    20. Dialog::~Dialog()
    21. {
    22.     delete ui;
    23. }
    24. /////////////////////////////////////////////////////////////////////////////
    25. /// \brief Dialog::Dialog::paintEvent -> putText function
    26. /// \param e
    27. /////////////////////////////////////////////////////////////////////////////
    28. /*void Dialog::putText(QPaintEvent *e)
    29. {
    30.     QPainter painter(&tempframe);
    31.     QPen ourpen(Qt::magenta);
    32.     ourpen.setWidth(2);
    33.     painter.setPen(ourpen);
    34.     painter.setFont(QFont("Times", 20, QFont::Bold));
    35.     painter.drawText(outputView.rect(), "THIS!!"); ////////////// doesn't work
    36. }*/
    37. //////////////////////////////////////////////////////////////////////////////////////////////
    38. /// \brief Dialog::on_dispButton_clicked -> this function starts or stops the camera.
    39. ///
    40. ///
    41. /////////////////////////////////////////////////////////////////////////////////////////////
    42.  
    43. void Dialog::on_dispButton_clicked()
    44. {
    45.     if(timer1->isActive() == true)
    46.     {
    47.         ui->dispButton->setText("Start camView");
    48.         timer1->stop();
    49.         cameraFeed.release();
    50.         ui->camView->setText("Your camera view will be available here.");
    51.  
    52.     }
    53.     else
    54.     {
    55.         ui->dispButton->setText("Stop camView");
    56.         timer1->start(30);
    57.         Camera.open(0);
    58.  
    59.     }
    60.  
    61. }
    62.  
    63.  
    64.  
    65. //////////////////////////////////////////////////////////////////////////////////////////////
    66. /// \brief all sliderMoved to change channel min and max
    67. /// \param ch1_min ch2_min ch3_min ch1_max ch2_max ch3_max
    68. /////////////////////////////////////////////////////////////////////////////////////////////
    69. void Dialog::on_ch1min_sliderMoved(int ch1_min)
    70. {
    71.     ui->ch1min->valueChanged(ch1_min);
    72.     if(ch1_min < ch1_max)
    73.     {
    74.  
    75.         ch1_min_string = QString::number(ch1_min);
    76.         ui->dsp_ch1_min->clear();
    77.         ui->dsp_ch1_min->appendPlainText(ch1_min_string);
    78.     }
    79.     else
    80.     {
    81.         ch1_min = ch1_max-1;
    82.         ui->ch1min->valueChanged(ch1_min);
    83.         ch1_min_string = QString::number(ch1_min);
    84.         ui->dsp_ch1_min->clear();
    85.         ui->dsp_ch1_min->appendPlainText(ch1_min_string);
    86.     }
    87. }
    88.  
    89. void Dialog::on_ch2min_sliderMoved(int ch2_min)
    90. {
    91.     ui->ch2min->valueChanged(ch2_min);
    92.     if(ch2_min < ch2_max)
    93.     {
    94.  
    95.         ch2_min_string = QString::number(ch2_min);
    96.         ui->dsp_ch2_min->clear();
    97.         ui->dsp_ch2_min->appendPlainText(ch2_min_string);
    98.     }
    99.     else
    100.     {
    101.         ch2_min = ch2_max-1;
    102.         ui->ch2min->valueChanged(ch2_min);
    103.         ch2_min_string = QString::number(ch2_min);
    104.         ui->dsp_ch2_min->clear();
    105.         ui->dsp_ch2_min->appendPlainText(ch2_min_string);
    106.     }
    107. }
    108.  
    109. void Dialog::on_ch3min_sliderMoved(int ch3_min)
    110. {
    111.     ui->ch3min->valueChanged(ch3_min);
    112.     if(ch3_min < ch3_max)
    113.     {
    114.  
    115.         ch3_min_string = QString::number(ch3_min);
    116.         ui->dsp_ch3_min->clear();
    117.         ui->dsp_ch3_min->appendPlainText(ch3_min_string);
    118.     }
    119.     else
    120.     {
    121.         ch3_min = ch3_max-1;
    122.         ui->ch3min->valueChanged(ch3_min);
    123.         ch3_min_string = QString::number(ch3_min);
    124.         ui->dsp_ch3_min->clear();
    125.         ui->dsp_ch3_min->appendPlainText(ch3_min_string);
    126.     }
    127. }
    128.  
    129. void Dialog::on_ch1max_sliderMoved(int ch1_max)
    130. {
    131.     ui->ch1max->valueChanged(ch1_max);
    132.     if(ch1_max > ch1_min)
    133.     {
    134.         ch1_max_string = QString::number(ch1_max);
    135.         ui->dsp_ch1_max->clear();
    136.         ui->dsp_ch1_max->appendPlainText(ch1_max_string);
    137.     }
    138.     else
    139.     {
    140.         ch1_max= ch1_min+1;
    141.         ch1_max_string = QString::number(ch1_max);
    142.         ui->dsp_ch1_max->clear();
    143.         ui->dsp_ch1_max->appendPlainText(ch1_max_string);
    144.     }
    145.  
    146. }
    147.  
    148. void Dialog::on_ch2max_sliderMoved(int ch2_max)
    149. {
    150.     ui->ch2max->valueChanged(ch2_max);
    151.     if(ch2_max>ch2_min)
    152.     {
    153.         ch2_max_string = QString::number(ch2_max);
    154.         ui->dsp_ch2_max->clear();
    155.         ui->dsp_ch2_max->appendPlainText(ch2_max_string);
    156.     }
    157.     else
    158.     {
    159.         ch2_max = ch2_min+1;
    160.         ch2_max_string = QString::number(ch2_max);
    161.         ui->dsp_ch2_max->clear();
    162.         ui->dsp_ch2_max->appendPlainText(ch2_max_string);
    163.     }
    164. }
    165.  
    166. void Dialog::on_ch3max_sliderMoved(int ch3_max)
    167. {
    168.     ui->ch3max->valueChanged(ch3_max);
    169.     if(ch3_max>ch3_min)
    170.     {
    171.         ch3_max_string = QString::number(ch3_max);
    172.         ui->dsp_ch3_max->clear();
    173.         ui->dsp_ch3_max->appendPlainText(ch3_max_string);
    174.     }
    175.     else
    176.     {
    177.         ch3_max=ch3_min+1;
    178.         ch3_max_string = QString::number(ch3_max);
    179.         ui->dsp_ch3_max->clear();
    180.         ui->dsp_ch3_max->appendPlainText(ch3_max_string);
    181.     }
    182. }
    183.  
    184. ////////////////////////////////////////////////////////////////////////////////////////////////
    185. /// \brief Dialog::ShowCamera -> here we read frames and show them in label called camView
    186. /// temp is used only to make use of visual representation of image in Qt using QImage.
    187. ///
    188. ////////////////////////////////////////////////////////////////////////////////////////////////
    189. void Dialog::ShowCamera()
    190. {
    191.     Camera.read(cameraFeed);           
    192.  
    193.     ui->plainTextEdit->appendPlainText((QString::number(ch1_min))); ////this is the reason of all the zeros in plainTextEdit. for this function changed values do not appear updated
    194.  
    195.     cv::inRange(cameraFeed,cv::Scalar(ch1_min,ch2_min,ch3_min),cv::Scalar(ch1_max,ch2_max,ch3_max),thresholdFeed);
    196.     if(cameraFeed.empty() == true) return;
    197.  
    198.                 ////////////////// visualization of image acquired from camera
    199.  
    200.                 cameraFeed.copyTo(temp);
    201.                 cv::cvtColor(temp, temp, CV_BGR2RGB);
    202.                 QImage qimgOriginal((uchar*) temp.data, temp.cols, temp.rows, temp.step, QImage::Format_RGB888);
    203.  
    204.  
    205.                 ////////////////// visualization of binary image
    206.  
    207.                 QImage qimgProcessed((uchar*) thresholdFeed.data, thresholdFeed.cols, thresholdFeed.rows, thresholdFeed.step, QImage::Format_Indexed8);
    208.                 ui->camView->setPixmap(QPixmap::fromImage(qimgOriginal));
    209.                 ui->outputView->setPixmap(QPixmap::fromImage(qimgProcessed));
    210.  
    211.  
    212.  
    213. }
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