Extracting pointer information and displaying it as an image

Question

Hey,
I am using Intel's OpenCV image processing library in LabVIEW.
There's a pointer to a struct IplImage that is passed around in order to run image processing functions.
The struct IplImage is defined as: 
typedef struct _IplImage
int nSize; /* sizeof(IplImage) */
int ID; /* version (=0)*/
int nChannels; /* Most of OpenCV functions support 1,2,3 or 4 channels */
int alphaChannel; /* ignored by OpenCV */
int depth; /* pixel depth in bits: IPL_DEPTH_8U, IPL_DEPTH_8S, IPL_DEPTH_16U,
IPL_DEPTH_16S, IPL_DEPTH_32S, IPL_DEPTH_32F and IPL_DEPTH_64F are supported */
char colorModel[4]; /* ignored by OpenCV */
char channelSeq[4]; /* ditto */
int dataOrder; /* 0 - interleaved color channels, 1 - separate color channels.
cvCreateImage can only create interleaved images */
int origin; /* 0 - top-left origin,
1 - bottom-left origin (Windows bitmaps style) */
int align; /* Alignment of image rows (4 or 8).
OpenCV ignores it and uses widthStep instead */
int width; /* image width in pixels */
int height; /* image height in pixels */
struct _IplROI *roi;/* image ROI. when it is not NULL, this specifies image region to process */
struct _IplImage *maskROI; /* must be NULL in OpenCV */
void *imageId; /* ditto */
struct _IplTileInfo *tileInfo; /* ditto */
int imageSize; /* image data size in bytes
(=image->height*image->widthStep
in case of interleaved data)*/
char *imageData; /* pointer to aligned image data */
int widthStep; /* size of aligned image row in bytes */
int BorderMode[4]; /* border completion mode, ignored by OpenCV */
int BorderConst[4]; /* ditto */
char *imageDataOrigin; /* pointer to a very origin of image data
(not necessarily aligned) -
it is needed for correct image deallocation */
IplImage;
I am having problems with closing OpenCV's GUI window when called from LabVIEW in Linux. A solution to this may be to not use OpenCV's GUI window in LabVIEW for Linux, but rather pass back the pointer to the processed image in LabVIEW. From that pointer, we can send it to a C wrapper to extract some information that we want from the struct in order and pass back those values to LabVIEW. Then LabVIEW will process those values and display the image. What will I need to extract from the pointer (via a C wrapper) in order to display the image onto LabVIEW?
I attached a LabVIEW example that I found. This example loads and displays an image. I am thinking of doing something similar to that. Instead of loading an image from the file dialog, I will pass all of the necessary information to Draw Flattened Pixmap.
Attachments:
Picture4.vi ‏56 KB

Answer 1

My description of my problems with interfacing OpenCV with LabVIEW is contained in this discussion
Basically, the code works in C in Linux, C in Windows, LabVIEW for Windows, but not in LabVIEW for Linux.
We finally were able to get OpenCV to interface with LabVIEW for Linux by doing some complex edition to make install. However, LabVIEW was still having trouble with the function to close all HighGUI windows. Even though it went through the function, it will not close the HighGUI window. Also the HighGUI window freezes and when it eventually closes, it crashes LabVIEW.
When I test it by writing C programs, the function does what it is supposed to do.