images.c

This example can be found in examples\c\images\images.c.

This example shows how to enable image transfer on the PST Tracker and how to use the PST SDK to retrieve images. Images are 8 bit grayscale and are stored as an unsigned char* without memory alignment or padding.

When compiling and running this example, please make sure that the required dependencies can be found by the executable (e.g. by copying the Redist directory into the build directory. When the PST SDK has been installed through the PST Software Suite installer the Redist folder can be found in the Development folder.).

 
#ifdef WIN32
#include <windows.h>
#else
#include <unistd.h>
#endif
 
/*
* Define handler functions required to ensure a clean shutdown of the PST Tracker when the
* application is terminated.
*/
 
static void Exithandler(int sig);
 
#ifdef WIN32
BOOL WINAPI ConsoleHandler(DWORD CEvent)
{
    Exithandler(CEvent);
    return TRUE;
}
#endif
 
/* End of handler functions */
 
#include "pstsdk_c.h"
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <signal.h>
 
/* Control variable for main loop */
static sig_atomic_t running = 1;
 
/* Number of data points to grab before application termination */
static const uint32_t numberOfSamplesToGrab = 1000;
 
/*
* Implementation of a tracker callback function.
* The OnTrackerData() callback function receives the data as soon as it becomes
* available.
*/
void OnTrackerData(const PstTrackerData* tracker_data, EPstErrorStatus status)
{
    static uint32_t samplesGrabbed = 0;
    if (samplesGrabbed++ >= numberOfSamplesToGrab)
        running = 0;
 
    // Do something with the received data.
}
 
/*
* Implement the exit handler to shut-down the PST Tracker connection on application termination.
*/
static void Exithandler(int sig)
{
    pst_sdk_shutdown();
    exit(0);
}
 
// Print the last error message.
void PrintLastErrorMessage()
{
    char* last_error_message = NULL;
    EPstErrorStatus error_status = pst_alloc_and_get_last_error_message(&last_error_message);
    if (error_status != PST_ERROR_STATUS_OK)
    {
        last_error_message = "Failed to allocate memory error.";
    }
    printf("last error message: %s \n", last_error_message);
    pst_free(last_error_message);
}
 
// Check error status and shutdown tracker upon error.
void CheckErrorCode(EPstErrorStatus status)
{
    if (status != PST_ERROR_STATUS_OK)
    {
        PrintLastErrorMessage();
        pst_sdk_shutdown();
        exit(status);
    }
}
 
int main(int argc, char *argv[])
{
    // Register the exit handler with the application
#ifdef WIN32
    SetConsoleCtrlHandler((PHANDLER_ROUTINE)ConsoleHandler, TRUE);
#else
    signal(SIGTERM, Exithandler);
    signal(SIGKILL, Exithandler);
    signal(SIGQUIT, Exithandler);
    signal(SIGINT, Exithandler);
#endif
 
    PstTracker ctracker;
 
#ifdef WIN32
    // Create an instance of the Tracker object using the default configuration path and file names.
    CheckErrorCode(pst_tracker_init(&ctracker));
#else
    // On Linux, specify the type of grabber that needs to be used as the last parameter:
    // "basler_ace" for PST HD or "basler_dart" for PST Pico
    CheckErrorCode(pst_tracker_init4(&ctracker, "", "config.cfg", "models.db", argv[1]));
#endif
 
    char* version_string;
    CheckErrorCode(pst_tracker_alloc_and_get_version_info(&ctracker, &version_string));
    // Print version number of the tracker server being used.
    printf("Running PST Server version %s \n", version_string);
    pst_free(version_string);
 
    // Register the OnTrackerData callback function to the tracker server.
    CheckErrorCode(pst_tracker_add_tracker_data_callback(&ctracker, OnTrackerData));
 
    // Start the tracker server.
    CheckErrorCode(pst_tracker_start(&ctracker));
 
    // Perform a system check to see if the tracker server is running OK and print the result.
    printf("System check: %i \n\n", (int)pst_tracker_system_check(&ctracker));
    printf("***************************\n\n");
 
    // Set the frame rate to 60 Hz.
    CheckErrorCode(pst_tracker_set_framerate(&ctracker, 60.0));
    double fps;
    CheckErrorCode(pst_tracker_get_framerate(&ctracker, &fps));
    printf("Current frame rate: %f Hz\n\n", fps);
 
    // In order to start receiving images, enable image transfer. When image transfer is disabled,
    // the vector of images returned by GetImage will be empty.
    pst_tracker_enable_image_transfer(&ctracker);
 
    // The standard PST trackers will run at a reduced frame rate of 30 Hz when image transfer is enabled.
    // However, since this frame rate is temporary for as long as image transfer is enabled, that frame rate
    // will not be reported as the current frame rate.
    CheckErrorCode(pst_tracker_get_framerate(&ctracker, &fps));
    printf("Enabled image transfer. Current frame rate: %f Hz\n\n", fps);
    printf("***************************\n\n");
 
    // Try to capture 100 images.
    for (int i = 0; i < 100; ++i)
    {
        //Make sure to initialize the PstImage with ::pst_image_init before using pst_tracker_get_pst_image function.
        PstImage images;
        pst_image_init(&images);
 
        // Get a reference to the last grabbed image in the PstImage struct.
        // Note that enabling image transfer takes some time. While image transfer is being enabled,
        // the images vector in the PstImage struct will be empty.
        CheckErrorCode(pst_tracker_get_pst_image(&ctracker, &images));
        printf("Retrieval operation successful!\n");
        printf("Retrieved %zu image(s) of size: %zu X %zu \n\n", images.number_of_images, images.width, images.height);
        // Do something with the image.
 
        // Make sure to destroy PstImage after using it.
        pst_image_destroy(&images);
        // Don't request images too fast, wait for around 1/60 seconds
#ifdef WIN32
        Sleep(17);
#else
        usleep(17000);
#endif
    }
    // Wait for 5 seconds, since this is > 4 seconds, image transfer will be disabled automatically.
    printf("Waiting 5 seconds for image transfer to be automatically disabled...\n\n");
#ifdef WIN32
    Sleep(5000);
#else
    sleep(5);
#endif
 
    // Try to grab one image. Since image retrieval timed out, it should return an empty image vector.
    PstImage images;
    pst_image_init(&images);
    CheckErrorCode(pst_tracker_get_pst_image(&ctracker, &images));
    printf("Retrieval operation successful!\n");
    printf("Retrieved %zu image(s) of size: %zu X %zu \n\n", images.number_of_images, images.width, images.height);
 
    // Main loop, wait for auto-termination.
    while (running == 1)
    {
#ifdef WIN32
        Sleep(100);
#else
        usleep(100000);
#endif
    }
 
    // Make sure that the connection to the PST Tracker is shut down properly.
    pst_tracker_destroy(&ctracker);
 
    // Pause command line to see results.
    printf("Press enter to continue...\n");
    getchar();
 
    return 0;
}