Convertir IplImage en JPEG sans utiliser CvSaveImage dans OpenCV

Question

Je souhaite convertir un IplImage en une image JPEG dans la mémoire (afin de le diffuser en tant que trame M-JPEG sur des sockets). Je sais que je peux utiliser CvSaveImage pour cela, créer un fichier jpeg, le relire, puis le diffuser sur le réseau. Je souhaite éviter ces opérations de lecture d'écriture sur disque supplémentaires pour un fonctionnement plus rapide. Des idées?

Answer 1

Si votre tag est correct et qu'il est en C# alors vous devriez vérifier OpenCVSharp.

http://code.google.com/p/opencvsharp/

Avec elle, vous pouvez le faire ...

IplImage ipl = new IplImage("foo.png", LoadMode.Color); 
Bitmap bitmap = ipl.ToBitmap(); 

Je trouve aussi un exemple de quelqu'un faire en utilisant VC++. NET

//IplImage -> Bitmap 
void Fill_Bitmap(Bitmap* bitmap, IplImage* image){ 
    int nl= image->height; 
    int nc= image->width * image->nChannels; 
    int step= image->widthStep; 
    unsigned char* data=reinterpret_cast<unsigned char*>(image->imageData); 
    for(int i=0; i<nl; i++){ 
     for(int j=0; j<nc; j+= image->nChannels){ 
      bitmap->SetPixel(j/3,i,Color::FromArgb(data[j],data[j+1],data[j+2])); 
     } 
     data+= step; 
    } 

}; 

Assume that in your main function: 

void main(){ 
    ... 
    imRGB=cvCreateImage(cvSize(col,row), 8, 3); 
    Tbitmap=new Bitmap(col,row,PixelFormat::Format24bppRgb); 
    ... 
    Fill_Bitmap(Tbitmap,imRGB); 
} 

Bonne chance!

Answer 2

utilisation CxImage http://www.codeproject.com/KB/graphics/cximage.aspx

Answer 3

Check out this question. Je ne sais pas comment vous pouvez utiliser la solution en C#, mais peut-être que cela peut aider.

Answer 4

assez simple

Tout ce que vous devez charger des fichiers de la mémoire tampon est un autre gestionnaire src (libjpeg). J'ai testé le code suivant dans Ubuntu 8.10.

/******************************** First define mem buffer function bodies **************/ 
/* 
* memsrc.c 
* 
* Copyright (C) 1994-1996, Thomas G. Lane. 
* This file is part of the Independent JPEG Group's software. 
* For conditions of distribution and use, see the accompanying README file. 
* 
* This file contains decompression data source routines for the case of 
* reading JPEG data from a memory buffer that is preloaded with the entire 
* JPEG file. This would not seem especially useful at first sight, but 
* a number of people have asked for it. 
* This is really just a stripped-down version of jdatasrc.c. Comparison 
* of this code with jdatasrc.c may be helpful in seeing how to make 
* custom source managers for other purposes. 
*/ 

/* this is not a core library module, so it doesn't define JPEG_INTERNALS */ 
include "jinclude.h" 
include "jpeglib.h" 
include "jerror.h" 


/* Expanded data source object for memory input */ 

typedef struct { 
    struct jpeg_source_mgr pub; /* public fields */ 

    JOCTET eoi_buffer[2];  /* a place to put a dummy EOI */ 
} my_source_mgr; 

typedef my_source_mgr * my_src_ptr; 


/* 
* Initialize source --- called by jpeg_read_header 
* before any data is actually read. 
*/ 

METHODDEF(void) 
init_source (j_decompress_ptr cinfo) 
{ 
    /* No work, since jpeg_memory_src set up the buffer pointer and count. 
    * Indeed, if we want to read multiple JPEG images from one buffer, 
    * this *must* not do anything to the pointer. 
    */ 
} 


/* 
* Fill the input buffer --- called whenever buffer is emptied. 
* 
* In this application, this routine should never be called; if it is called, 
* the decompressor has overrun the end of the input buffer, implying we 
* supplied an incomplete or corrupt JPEG datastream. A simple error exit 
* might be the most appropriate response. 
* 
* But what we choose to do in this code is to supply dummy EOI markers 
* in order to force the decompressor to finish processing and supply 
* some sort of output image, no matter how corrupted. 
*/ 

METHODDEF(boolean) 
fill_input_buffer (j_decompress_ptr cinfo) 
{ 
    my_src_ptr src = (my_src_ptr) cinfo->src; 

    WARNMS(cinfo, JWRN_JPEG_EOF); 

    /* Create a fake EOI marker */ 
    src->eoi_buffer[0] = (JOCTET) 0xFF; 
    src->eoi_buffer[1] = (JOCTET) JPEG_EOI; 
    src->pub.next_input_byte = src->eoi_buffer; 
    src->pub.bytes_in_buffer = 2; 

    return TRUE; 
} 


/* 
* Skip data --- used to skip over a potentially large amount of 
* uninteresting data (such as an APPn marker). 
* 
* If we overrun the end of the buffer, we let fill_input_buffer deal with 
* it. An extremely large skip could cause some time-wasting here, but 
* it really isn't supposed to happen ... and the decompressor will never 
* skip more than 64K anyway. 
*/ 

METHODDEF(void) 
skip_input_data (j_decompress_ptr cinfo, long num_bytes) 
{ 
    my_src_ptr src = (my_src_ptr) cinfo->src; 

    if (num_bytes > 0) { 
    while (num_bytes > (long) src->pub.bytes_in_buffer) { 
     num_bytes -= (long) src->pub.bytes_in_buffer; 
     (void) fill_input_buffer(cinfo); 
     /* note we assume that fill_input_buffer will never return FALSE, 
     * so suspension need not be handled. 
     */ 
    } 
    src->pub.next_input_byte += (size_t) num_bytes; 
    src->pub.bytes_in_buffer -= (size_t) num_bytes; 
    } 
} 


/* 
* An additional method that can be provided by data source modules is the 
* resync_to_restart method for error recovery in the presence of RST markers. 
* For the moment, this source module just uses the default resync method 
* provided by the JPEG library. That method assumes that no backtracking 
* is possible. 
*/ 


/* 
* Terminate source --- called by jpeg_finish_decompress 
* after all data has been read. Often a no-op. 
* 
* NB: *not* called by jpeg_abort or jpeg_destroy; surrounding 
* application must deal with any cleanup that should happen even 
* for error exit. 
*/ 

METHODDEF(void) 
term_source (j_decompress_ptr cinfo) 
{ 
    /* no work necessary here */ 
} 


/* 
* Prepare for input from a memory buffer. 
*/ 

GLOBAL(void) 
jpeg_memory_src (j_decompress_ptr cinfo, const JOCTET * buffer, size_t bufsize) 
{ 
    my_src_ptr src; 

    /* The source object is made permanent so that a series of JPEG images 
    * can be read from a single buffer by calling jpeg_memory_src 
    * only before the first one. 
    * This makes it unsafe to use this manager and a different source 
    * manager serially with the same JPEG object. Caveat programmer. 
    */ 
    if (cinfo->src == NULL) { /* first time for this JPEG object? */ 
    cinfo->src = (struct jpeg_source_mgr *) 
     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT, 
        SIZEOF(my_source_mgr)); 
    } 

    src = (my_src_ptr) cinfo->src; 
    src->pub.init_source = init_source; 
    src->pub.fill_input_buffer = fill_input_buffer; 
    src->pub.skip_input_data = skip_input_data; 
    src->pub.resync_to_restart = jpeg_resync_to_restart; /* use default method */ 
    src->pub.term_source = term_source; 

    src->pub.next_input_byte = buffer; 
    src->pub.bytes_in_buffer = bufsize; 
} 

Ensuite, l'utilisation est assez simple. Vous devrez peut-être remplacer SIZEOF() par sizeof(). Trouver un exemple de décompression standard. Remplacez simplement "jpeg_stdio_src" par "jpeg_memory_src". J'espère que cela pourra aider!