C++ Opencv - Image handling after get it through sockets - c++

Question

My question is about this previous question (unfortunely, the answer doesn't work for me): https://stackoverflow.com/questions/20314524/c-opencv-image-sending-through-socket
After get the image, the code shows only a grey picture. Am I doing the correct image handling when sending and receive the image?
Sender and receiver codes:
Image sender:
#undef UNICODE
#define WIN32_LEAN_AND_MEAN
#include <stdlib.h>
#include <stdio.h>
#include <iostream>
#include <string.h>
#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <opencv2/objdetect/objdetect.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
// Need to link with Ws2_32.lib
#pragma comment (lib, "Ws2_32.lib")
// #pragma comment (lib, "Mswsock.lib")
#define DEFAULT_BUFLEN 512
#define IMG_BUFLEN 1243897
#define DEFAULT_PORT "27015"
using namespace std;
using namespace cv;
int main(void)
{
WSADATA wsaData;
int iResult;
SOCKET ListenSocket = INVALID_SOCKET;
SOCKET ClientSocket = INVALID_SOCKET;
struct addrinfo *result = NULL;
struct addrinfo hints;
int iSendResult;
char recvbuf[DEFAULT_BUFLEN];
unsigned char * imgbuf;
int recvbuflen = DEFAULT_BUFLEN;
// Initialize Winsock
iResult = WSAStartup(MAKEWORD(2,2), &wsaData);
if (iResult != 0) {
printf("WSAStartup failed with error: %d\n", iResult);
return 1;
}
ZeroMemory(&hints, sizeof(hints));
hints.ai_family = AF_INET;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;
hints.ai_flags = AI_PASSIVE;
// Resolve the server address and port
iResult = getaddrinfo(NULL, DEFAULT_PORT, &hints, &result);
if ( iResult != 0 ) {
printf("getaddrinfo failed with error: %d\n", iResult);
WSACleanup();
return 1;
}
// Create a SOCKET for connecting to server
ListenSocket = socket(result->ai_family, result->ai_socktype, result->ai_protocol);
if (ListenSocket == INVALID_SOCKET) {
printf("socket failed with error: %ld\n", WSAGetLastError());
freeaddrinfo(result);
WSACleanup();
return 1;
}
// Setup the TCP listening socket
iResult = bind( ListenSocket, result->ai_addr, (int)result->ai_addrlen);
if (iResult == SOCKET_ERROR) {
printf("bind failed with error: %d\n", WSAGetLastError());
freeaddrinfo(result);
closesocket(ListenSocket);
WSACleanup();
return 1;
}
freeaddrinfo(result);
iResult = listen(ListenSocket, SOMAXCONN);
if (iResult == SOCKET_ERROR) {
printf("listen failed with error: %d\n", WSAGetLastError());
closesocket(ListenSocket);
WSACleanup();
return 1;
}
// Accept a client socket
ClientSocket = accept(ListenSocket, NULL, NULL);
if (ClientSocket == INVALID_SOCKET) {
printf("accept failed with error: %d\n", WSAGetLastError());
closesocket(ListenSocket);
WSACleanup();
return 1;
}
// No longer need server socket
closesocket(ListenSocket);
// Receive until the peer shuts down the connection
do {
iResult = recv(ClientSocket, recvbuf, recvbuflen, 0);
if (iResult > 0) {
printf("SERVER - bytes: %d\n", iResult);
//char * temp = (char *) malloc(9); memcpy(temp,recvbuf,8);
if (strcmp(recvbuf, "ASK"))
{
int retTamImg;
Mat captureFrame;
int imgSize = 0;
VideoCapture captureDevice;
captureDevice.open(0);
if(!captureDevice.isOpened() )
{
printf("Nao pode ler o video");
getchar();
}
captureDevice>>captureFrame;
//---------------- SEND IMAGE ----------------//
if (captureFrame.data != NULL)
{
retTamImg = captureFrame.total() * captureFrame.elemSize();
iSendResult = send( ClientSocket, (const char *) captureFrame.data, retTamImg, 0 );
if (iSendResult == SOCKET_ERROR) {
printf("resposta de pedido de face falhou. erro: %d\n", WSAGetLastError());
closesocket(ClientSocket);
WSACleanup();
return 1;
}
else
printf("resposta de pedido de face enviada com suceso. Bytes: %d\n", iSendResult);
}
//FECHA CAMERA
captureDevice.release();
}
}
else if (iResult == 0)
printf("Connection closing...\n");
else {
printf("recv failed with error: %d\n", WSAGetLastError());
closesocket(ClientSocket);
WSACleanup();
getchar();
return 1;
}
} while (iResult > 0);
// shutdown the connection since we're done
iResult = shutdown(ClientSocket, SD_SEND);
if (iResult == SOCKET_ERROR) {
printf("shutdown failed with error: %d\n", WSAGetLastError());
closesocket(ClientSocket);
WSACleanup();
getchar();
return 1;
}
// cleanup
closesocket(ClientSocket);
WSACleanup();
return 0;
}
Image receiver:
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdlib.h>
#include <stdio.h>
#include <opencv2/core/core.hpp>
#include <opencv2/objdetect/objdetect.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
// Need to link with Ws2_32.lib, Mswsock.lib, and Advapi32.lib
#pragma comment (lib, "Ws2_32.lib")
#pragma comment (lib, "Mswsock.lib")
#pragma comment (lib, "AdvApi32.lib")
#define DEFAULT_BUFLEN 512
#define IMG_BUFLEN 1243897
#define DEFAULT_PORT "27015"
using namespace std;
using namespace cv;
int __cdecl main(int argc, char **argv)
{
WSADATA wsaData;
SOCKET ConnectSocket = INVALID_SOCKET;
struct addrinfo *result = NULL,
*ptr = NULL,
hints;
char sendbuf [DEFAULT_BUFLEN];
char recvbuf[DEFAULT_BUFLEN];
char * imgbuf;
int iResult;
int recvbuflen = DEFAULT_BUFLEN;
// Initialize Winsock
iResult = WSAStartup(MAKEWORD(2,2), &wsaData);
if (iResult != 0) {
printf("WSAStartup failed with error: %d\n", iResult);
getchar();
return 1;
}
ZeroMemory( &hints, sizeof(hints) );
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;
// Resolve the server address and port
iResult = getaddrinfo("127.0.0.1", DEFAULT_PORT, &hints, &result);
if ( iResult != 0 ) {
printf("getaddrinfo failed with error: %d\n", iResult);
WSACleanup();
return 1;
}
// Attempt to connect to an address until one succeeds
for(ptr=result; ptr != NULL ;ptr=ptr->ai_next) {
// Create a SOCKET for connecting to server
ConnectSocket = socket(ptr->ai_family, ptr->ai_socktype,
ptr->ai_protocol);
if (ConnectSocket == INVALID_SOCKET) {
printf("socket failed with error: %ld\n", WSAGetLastError());
WSACleanup();
getchar();
return 1;
}
// Connect to server.
iResult = connect( ConnectSocket, ptr->ai_addr, (int)ptr->ai_addrlen);
if (iResult == SOCKET_ERROR) {
closesocket(ConnectSocket);
ConnectSocket = INVALID_SOCKET;
continue;
}
break;
}
freeaddrinfo(result);
if (ConnectSocket == INVALID_SOCKET) {
printf("Unable to connect to server!\n");
WSACleanup();
getchar();
return 1;
}
//----------------- ASK FOR THE IMAGE ----------------------//
strncpy(sendbuf, "ASK", 8);
// Send an initial buffer
iResult = send( ConnectSocket, sendbuf, (int)strlen(sendbuf), 0 );
if (iResult == SOCKET_ERROR) {
printf("send ASK FACE failed with error: %d\n", WSAGetLastError());
closesocket(ConnectSocket);
WSACleanup();
getchar();
return 1;
}
printf("ASK FACE SENT Bytes Sent: %ld\n", iResult);
//----------------- GET THE IMAGE ----------------------//
Mat img = Mat::zeros( 480,640, CV_8UC3);
int imgSize = (int) (img.total()*img.elemSize());
char * sockData;
sockData = (char *) malloc (sizeof(char) * imgSize + 1);
for (int i = 0; i < imgSize; i += iResult)
{
iResult = recv(ConnectSocket, sockData +i, imgSize - i, 0);
if ( iResult > 0 )
printf("CLIENTE - retorno do ASK FACE (%d/%d)- Bytes received: %d\n", i, imgSize, iResult);
else if ( iResult == 0 )
printf("CLIENTE - retorno do ASK FACE - Connection closed\n");
else
printf("CLIENTE - retorno do ASK FACE - error: %d\n", WSAGetLastError());
}
// Assign pixel value to img
int iptr=0;
for (int i = 0; i < img.rows; i++) {
for (int j = 0; j < img.cols; j++) {
img.at<cv::Vec3b>(i,j) = Vec3b(sockData[iptr+ 0],sockData[iptr+1],sockData[iptr+2]);
iptr=iptr+3;
}
}
namedWindow("outputCapture", 1);
imshow("outputCapture", img);
// imwrite("C:\\Users\\USUARIO\\Documents\\VISAO\\servidor_imagens_cam\\imagem_salva.jpg",img);
// shutdown the connection since no more data will be sent
iResult = shutdown(ConnectSocket, SD_SEND);
if (iResult == SOCKET_ERROR) {
printf("shutdown failed with error: %d\n", WSAGetLastError());
closesocket(ConnectSocket);
WSACleanup();
return 1;
}
// cleanup
closesocket(ConnectSocket);
WSACleanup();
getchar();
return 0;
}

Answer 1

After some time here with your code, i finally found the error. You have to use waitkey() and not getchar(). Besides this, the program it's running fine.