I have solved in this way, It is working perfectly.
Oimg1 = cvLoadImage(Image1, 0);
if(Oimg1 == NULL) {return 0;}
unsigned char* imgdata1 = new unsigned char[Oimg1->width*Oimg1->height*Oimg1->nChannels];
GetImageDataFromOpenCV(Oimg1, imgdata1);
Fl_RGB_Image *rgb_img0 = new Fl_RGB_Image((const uchar *) imgdata1, Oimg1->width, Oimg1->height, Oimg1->nChannels);
FLTKimg[0] = (Fl_Shared_Image *)rgb_img0;