カメラから複数のフレームをつかむ方法は?
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12-11-2019 - |
質問
カメラキャプチャーフェイスの顔認識を実装しようとしています。
#include"cv.h"
#include"highgui.h"
#include <iostream>
using namespace cv;
// Grab the next camera frame. Waits until the next frame is ready, and
// provides direct access to it, so do NOT modify or free the returned image!
// Will automatically initialize the camera on the first frame.
#include"highgui.h"
#include<iostream>
using namespace cv;
IplImage* getCameraFrame(CvCapture* &camera);
int main()
{
CvCapture* camera = 0; // The camera device.
while ( cvWaitKey(10) != 27 )
{ // Quit on "Escape" key.
IplImage *frame = getCameraFrame(camera);
cvSaveImage("Frame:",frame);
}
return 0;
}
IplImage* getCameraFrame(CvCapture* &camera)
{
IplImage *frame;
int w, h;
// If the camera hasn't been initialized, then open it.
if (!camera) {
printf("Acessing the camera ...\n");
camera = cvCreateCameraCapture( 0 );
if (!camera) {
printf("Couldn't access the camera.\n");
exit(1);
}
// Try to set the camera resolution to 320 x 240.
cvSetCaptureProperty(camera, CV_CAP_PROP_FRAME_WIDTH, 320);
cvSetCaptureProperty(camera, CV_CAP_PROP_FRAME_HEIGHT, 240);
// Get the first frame, to make sure the camera is initialized.
frame = cvQueryFrame( camera );
if (frame) {
w = frame->width;
h = frame->height;
printf("Got the camera at %dx%d resolution.\n", w, h);
}
// Wait a little, so that the camera can auto-adjust its brightness.
Sleep(1000); // (in milliseconds)
}
// Wait until the next camera frame is ready, then grab it.
frame = cvQueryFrame( camera );
if (!frame) {
printf("Couldn't grab a camera frame.\n");
exit(1);
}
return frame;
}
.
しかしCVSaveImageでは、保存するイメージに名前を付ける必要があります。名前は一意であるべきではあります。 この問題を解決するにはどうすればいいですか?
解決
you can use a integer variable for counting sequence
int counter = 0;
char *filename = "Photo"
while ( cvWaitKey(10) != 27 )
{ // Quit on "Escape" key.
IplImage *frame = getCameraFrame(camera);
counter++;
filename = getNextName(counter);
cvSaveImage(filename ,frame);
}
in the getNextName()
function you can do an integer conversion and a string concat .jpg
char* getNextName(int counter)
{
char buf[5];
char *filename = "Photo";
// convert 123 to string [buf]
itoa(counter, buf, 10); // int to char
strcat(filename, buf); // concat "Photo" + "1" = "Photo1"
strcat(filename, ".jpg"); // concat "Photo1" + ".jpg" = "Photo1.jpg"
return filename;
}
it will automatically save your image using a new name with sequence of number.
他のヒント
You can simply us ffmpeg for that. Following code will turn a video to X images
ffmpeg -i video.mpg image%d.jpg
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