opencv矩阵进入共享内存 [英] opencv matrix into shared memory
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问题描述
我想在两个 linux 进程之间共享一个 CvMat 对象(OpenCV 库中的一个矩阵)，为此我使用共享内存.一个进程(服务器)将从网络摄像头捕获一帧(矩阵)，将其转换为灰度，使用共享内存进行共享并在屏幕上显示该帧.另一个进程(客户端)将读取共享帧并执行一些操作.请参阅下面的代码.
I want to share between two linux processes a CvMat object (a matrix in the OpenCV library), for that I'm using shared memory. One process (server) will capture a frame (matrix) from the webcam, convert it to gray scale, share it using shared memory and show the frame on the screen. The other process (client) will read the shared frame and perform some operations. See the code below.
问题似乎是客户端没有读取信息，因为 'rows' 和 'cols' 为零(或者服务器没有写入共享内存).无论如何，我没有收到任何错误消息，也不知道自己做错了什么.有什么想法吗?
The problem seems to be that the client doesn't read the information since 'rows' and 'cols' are zero (or the server is not writing in the shared memory). Anyway I'm not getting any error message and I don't know what I'm doing wrong. Any idea?
非常感谢！
这是服务器的代码:
#include <iostream>
#include <cv.h>
#include <highgui.h>
using namespace std;
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <stdio.h>
#include "2cam.h"
int sizeofmat(CvMat *mat) {
return mat->rows * mat->cols * CV_ELEM_SIZE(mat->type);
}
int main() {
int shmid;
key_t key = 5678;
CvMat *vdisp = cvCreateMat(240, 320, CV_8U);
const size_t vdispsize = sizeofmat(vdisp);
CvMat *s = cvCreateMat(240, 320, CV_8U);
CvMat stub;
CvSize imageSize = cvSize(320, 240);
IplImage *color = cvCreateImage(imageSize, 8, 3);
IplImage *gray = cvCreateImage(imageSize, 8, 1);
/* Create the segment */
if ((shmid = shmget(key, vdispsize, IPC_CREAT | 0666)) < 0) {
perror("shmget");
exit(1);
}
/* Attach the segment to our data space */
if ((vdisp = (CvMat *)shmat(shmid, NULL, 0)) == (CvMat *)-1) {
perror("shmat");
exit(1);
}
/* Put CvMat into the memory to be read for other processes */
s = vdisp;
/* Create camera */
Camera c("/dev/video0", 320, 240, 30);
while (1) {
/* Get one frame */
c.Update();
c.toIplImage(color);
/* Convert color frame to grayscale */
cvCvtColor(color, gray, CV_BGR2GRAY);
/* Get matrix from the gray frame and write the matrix in shared memory*/
s = cvGetMat(gray, &stub, 0, 0);
/* Show frame */
cvNamedWindow("result", CV_WINDOW_AUTOSIZE);
cvShowImage("result", s);
/* Wait for escape key */
if ((cvWaitKey(10) & 255) == 27)
break;
}
/* free memory */
cvDestroyWindow("result");
cvReleaseImage(&color);
cvReleaseImage(&gray);
//cvReleaseMat(&vdisp);
//cvReleaseMat(&s);
return 0;
}
<小时>
这里是客户端的代码:
And here the client's code:
#include <iostream>
#include <cv.h>
#include <highgui.h>
using namespace std;
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <stdio.h>
int sizeofmat(CvMat *mat) {
return mat->rows * mat->cols * CV_ELEM_SIZE(mat->type);
}
int main() {
int shmid;
key_t key = 5678;
CvMat *vdisp = cvCreateMat(240, 320, CV_8U);
const size_t vdispsize = sizeofmat(vdisp);
CvMat *s = cvCreateMat(240, 320, CV_8U);
/* Locate the segment */
if ((shmid = shmget(key, vdispsize, 0666)) < 0) {
perror("shmget");
exit(1);
}
/* Now we attach the segment to our data space */
if ((vdisp = (CvMat *)shmat(shmid, NULL, 0)) == (CvMat *) -1) {
perror("shmat");
exit(1);
}
s = vdisp;
cout << "rows: " << s->rows << endl;
cout << "cols: " << s->cols << endl;
return 0;
}
推荐答案
感谢 larsmans，他为我指明了正确的方向.无论如何，我回答了自己以防万一有人需要相同的解决方案.
Thanks to larsmans, that he pointed me in the right direction. Anyway, I answered myself just in case someone need the same solution.
这是服务器的代码:
#include <iostream>
#include <cv.h>
#include <highgui.h>
using namespace std;
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <stdio.h>
#include "2cam.h"
int sizeofmat(CvMat *mat) {
return mat->rows * mat->step;
}
int main() {
int shmid;
key_t key = 5678;
uchar *vdisp;
CvMat *s = cvCreateMat(240, 320, CV_8U);
CvMat *tmp = cvCreateMat(240, 320, CV_8U);
const size_t vdispsize = sizeofmat(s);
CvMat stub;
CvSize imageSize = cvSize(320, 240);
IplImage *color = cvCreateImage(imageSize, 8, 3);
IplImage *gray = cvCreateImage(imageSize, 8, 1);
/* Create the segment */
if ((shmid = shmget(key, vdispsize, IPC_CREAT | 0666)) < 0) {
perror("shmget");
exit(1);
}
/* Attach the segment to our data space */
if ((vdisp = (uchar *) shmat(shmid, NULL, 0)) == (uchar *) -1) {
perror("shmat");
exit(1);
}
s->data.ptr = vdisp;
/* Create camera */
Camera c("/dev/video0", 320, 240, 30);
while (1) {
/* Get one frame */
c.Update();
c.toIplImage(color);
/* Convert color frame to grayscale */
cvCvtColor(color, gray, CV_BGR2GRAY);
/* Get matrix from the gray frame and write the matrix in shared memory*/
tmp = cvGetMat(gray, &stub, 0, 0);
for (int row = 0; row < tmp->rows; row++) {
const uchar* ptr = (const uchar*) (tmp->data.ptr + row * tmp->step);
memcpy((uchar*)(s->data.ptr + row * s->step), ptr, tmp->step);
}
/* Show frame */
cvNamedWindow("result", CV_WINDOW_AUTOSIZE);
cvShowImage("result", s);
/* Wait for escape key */
if ((cvWaitKey(10) & 255) == 27)
break;
}
/* free memory */
cvDestroyWindow("result");
cvReleaseImage(&color);
cvReleaseImage(&gray);
return 0;
}
这里是客户的代码:
#include <iostream>
#include <cv.h>
#include <highgui.h>
using namespace std;
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <stdio.h>
int sizeofmat(CvMat *mat) {
return mat->rows * mat->step;
}
int main() {
int shmid;
key_t key = 5678;
uchar *vdisp;
CvMat *s = cvCreateMat(240, 320, CV_8U);
const size_t vdispsize = sizeofmat(s);
/* Locate the segment */
if ((shmid = shmget(key, vdispsize, 0666)) < 0) {
perror("shmget");
exit(1);
}
/* Now we attach the segment to our data space */
if ((vdisp = (uchar *)shmat(shmid, NULL, 0)) == (uchar *) -1) {
perror("shmat");
exit(1);
}
s->data.ptr = vdisp;
cvNamedWindow("result", CV_WINDOW_AUTOSIZE);
cvShowImage("result", s);
cvWaitKey(10000);
cvDestroyWindow("result");
return 0;
}
这篇关于opencv矩阵进入共享内存的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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