root/samples/winrt_universal/VideoCaptureXAML/video_capture_xaml/video_capture_xaml.Shared/main.cpp

DEFINITIONS

1. cvMain
2. cvFilterColor
3. cvFilterCanny
4. cvDetectFaces

// main.cpp

// Copyright (c) Microsoft Open Technologies, Inc.
// All rights reserved.
//
// (3 - clause BSD License)
//
// Redistribution and use in source and binary forms, with or without modification, are permitted provided that
// the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the
// following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
// following disclaimer in the documentation and/or other materials provided with the distribution.
// 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or
// promote products derived from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
// WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
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// DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES(INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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// POSSIBILITY OF SUCH DAMAGE.

#include "pch.h"

#include <opencv2/core.hpp>
#include <opencv2/imgproc.hpp>
#include <opencv2/objdetect.hpp>
#include <opencv2/features2d.hpp>
#include <opencv2/videoio.hpp>
#include <opencv2/videoio/cap_winrt.hpp>

// Switch definitions below to apply different filters
// TODO: add UX controls to manipulate filters at runtime

//#define COLOR
#define CANNY
//#define FACES

using namespace cv;

namespace video_capture_xaml {

    // forward declaration
    void cvFilterColor(Mat &frame);
    void cvFilterCanny(Mat &frame);
    void cvDetectFaces(Mat &frame);

    CascadeClassifier face_cascade;
    String face_cascade_name = "Assets/haarcascade_frontalface_alt.xml";

    void cvMain()
    {
        //initializing frame counter used by face detection logic
        long frameCounter = 0;

        // loading classifier for face detection
        face_cascade.load(face_cascade_name);

        // open the default camera
        VideoCapture cam;
        cam.open(0);

        Mat frame;

        // process frames
        while (1)
        {
            // get a new frame from camera - this is non-blocking per spec
            cam >> frame;
            frameCounter++;

            // don't reprocess the same frame again
            // if commented then flashing may occur
            if (!cam.grab()) continue;

            // image processing calculations here
            // Mat frame is in RGB24 format (8UC3)

            // select processing type
    #if defined COLOR
            cvFilterColor(frame);
    #elif defined CANNY
            cvFilterCanny(frame);
    #elif defined FACES
            // processing every other frame to reduce the load
            if (frameCounter % 2 == 0) {
                cvDetectFaces(frame);
            }
    #endif

            // important step to get XAML image component updated
            winrt_imshow();
        }
    }

    // image processing example #1
    // write color bar at row 100 for 200 rows
    void cvFilterColor(Mat &frame)
    {
        auto ar = frame.ptr(100);
        int bytesPerPixel = 3;
        int adjust = (int)(((float)30 / 100.0f) * 255.0);
        for (int i = 0; i < 640 * 100 * bytesPerPixel;)
        {
            ar[i++] = adjust;           // R
            i++;                        // G
            ar[i++] = 255 - adjust;     // B
        }
    }

    // image processing example #2
    // apply edge detection aka 'canny' filter
    void cvFilterCanny(Mat &frame)
    {
        Mat edges;
        cvtColor(frame, edges, COLOR_RGB2GRAY);
        GaussianBlur(edges, edges, Size(7, 7), 1.5, 1.5);
        Canny(edges, edges, 0, 30, 3);
        cvtColor(edges, frame, COLOR_GRAY2RGB);
    }

    // image processing example #3
    // detect human faces
    void cvDetectFaces(Mat &frame)
    {
        Mat faces;
        std::vector<cv::Rect> facesColl;
        cvtColor(frame, faces, COLOR_RGB2GRAY);
        equalizeHist(faces, faces);
        face_cascade.detectMultiScale(faces, facesColl, 1.1, 2, 0 | CV_HAAR_SCALE_IMAGE, cv::Size(1, 1));
        for (unsigned int i = 0; i < facesColl.size(); i++)
        {
            auto face = facesColl[i];
            cv::rectangle(frame, face, cv::Scalar(0, 255, 255), 3);
        }
    }