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C Sample Point Cloud
Orbbec Gemini 330 Series Documentation

C Sample Point Cloud

Update on 2025-07-25 06:21:27

Function description: Connect the device to open the stream, generate a deep point cloud or RGBD point cloud and save it as a ply format file, and exit the program through the ESC_KEY key

| This example is based on the C++High Level API for demonstration

Create a point cloud and save it as a ply file function. The detailed description of the ply file format can be viewed on the network

//Save point cloud data to ply
void save_points_to_ply( ob_frame* frame, const char* fileName ) {
    int pointsSize = ob_frame_data_size( frame, &error ) / sizeof( ob_point );
    check_error( error );

    FILE* fp = fopen( fileName, "wb+" );
    fprintf( fp, "ply\n" );
    fprintf( fp, "format ascii 1.0\n" );
    fprintf( fp, "element vertex %d\n", pointsSize );
    fprintf( fp, "property float x\n" );
    fprintf( fp, "property float y\n" );
    fprintf( fp, "property float z\n" );
    fprintf( fp, "end_header\n" );

    ob_point* point = ( ob_point* )ob_frame_data( frame, &error );
    check_error( error );
    for ( int i = 0; i < pointsSize; i++ ) {
        fprintf( fp, "%.3f %.3f %.3f\n", point->x, point->y, point->z );
        point++;
    }

    fflush( fp );
    fclose( fp );
}

// Save color point cloud data to ply
void save_rgb_points_to_ply( ob_frame* frame, const char* fileName ) {
    int pointsSize = ob_frame_data_size( frame, &error ) / sizeof( ob_color_point );
    check_error( error );

    FILE* fp = fopen( fileName, "wb+" );
    fprintf( fp, "ply\n" );
    fprintf( fp, "format ascii 1.0\n" );
    fprintf( fp, "element vertex %d\n", pointsSize );
    fprintf( fp, "property float x\n" );
    fprintf( fp, "property float y\n" );
    fprintf( fp, "property float z\n" );
    fprintf( fp, "property uchar red\n" );
    fprintf( fp, "property uchar green\n" );
    fprintf( fp, "property uchar blue\n" );
    fprintf( fp, "end_header\n" );

    ob_color_point* point = ( ob_color_point* )ob_frame_data( frame, &error );
    check_error( error );

    for ( int i = 0; i < pointsSize; i++ ) {
        fprintf( fp, "%.3f %.3f %.3f %d %d %d\n", point->x, point->y, point->z, ( int )point->r, ( int )point->g, ( int )point->b );
        point++;
    }

    fflush( fp );
    fclose( fp );
}

Create Pipeline and stream Configuration

//Create a pipeline to open the Color and Depth streams after connecting devices
pipeline = ob_create_pipeline( &error );
//Create a config to configure the resolution, frame rate, and format of the Color and Depth streams
ob_config* config = ob_create_config( &error );

//Configure Color Stream
ob_stream_profile_list *colorProfiles = ob_pipeline_get_stream_profile_list(pipeline, OB_SENSOR_COLOR, &error);
if(error) {
    printf("Current device is not support color sensor!\n");
    ob_delete_error(error);
    error = NULL;
    // Turn on D2C alignment, which needs to be turned on when generating RGBD point clouds
    ob_config_set_align_mode(config, ALIGN_DISABLE, &error);
    check_error(error);
}
// Open the default profile of Color Sensor, which can be configured through the configuration file
if(colorProfiles) {
    color_profile = ob_stream_profile_list_get_profile(colorProfiles, OB_PROFILE_DEFAULT, &error);
}

    //Configure Depth Stream
if(color_profile) {
    // Try find supported depth to color align hardware mode profile
    depthProfiles = ob_get_d2c_depth_profile_list(pipeline, color_profile, ALIGN_D2C_HW_MODE, &error);
    check_error(error);
    int d2cCount = ob_stream_profile_list_count(depthProfiles, &error);
    check_error(error);
    if(d2cCount > 0) {
        align_mode = ALIGN_D2C_HW_MODE;
    }
    else {
        // Try find supported depth to color align software mode profile
        depthProfiles = ob_get_d2c_depth_profile_list(pipeline, color_profile, ALIGN_D2C_SW_MODE, &error);
        check_error(error);
        d2cCount = ob_stream_profile_list_count(depthProfiles, &error);
        check_error(error);
        if(d2cCount > 0) {
            align_mode = ALIGN_D2C_SW_MODE;
        }
    }
}
else {
    depthProfiles = ob_pipeline_get_stream_profile_list(pipeline, OB_SENSOR_DEPTH, &error);
    check_error(error);
}

Turn on device D2C function

// Turn on D2C alignment, which needs to be turned on when generating RGBD point clouds
ob_config_set_align_mode(config, align_mode, &error);

Enable Steaming

ob_pipeline_start_with_config(pipeline, config, &error);

Create a point cloud filter after opening the stream. Point cloud filters are used to convert depth and color frame data into point cloud data. The purpose of creating a point cloud filter after streaming is to enable the SDK to automatically set camera parameters based on the current streaming configuration. Of course, you can also set it up yourself.

// Create a point cloud Filter object (device parameters will be obtained inside the Pipeline when the point cloud filter is created, so try to configure
// the device before creating the filter)
ob_filter *point_cloud = ob_create_pointcloud_filter(&error);
check_error(error);

// Get the current open-stream camera parameters from the pipeline and pass them to the point cloud filter
ob_camera_param camera_param = ob_pipeline_get_camera_param(pipeline, &error);
check_error(error);
ob_pointcloud_filter_set_camera_param(point_cloud, camera_param, &error);
check_error(error);

Start the main loop, which calls the point cloud filter based on user keys to generate deep point cloud or RGBD point cloud data, and save it as a ply file.

;

    // point position value multiply depth value scale to convert uint to millimeter (for some devices, the default depth value uint is not
    // millimeter)
    ob_pointcloud_filter_set_position_data_scale(point_cloud, depth_value_scale, &error);
    check_error(error);

    ob_pointcloud_filter_set_point_format(point_cloud, OB_FORMAT_RGB_POINT, &error);
    check_error(error);
    ob_frame *pointsFrame = ob_filter_process(point_cloud, frameset, &error);
    check_error(error);
    if(pointsFrame != NULL) {
        save_rgb_points_to_ply(pointsFrame, "rgb_points.ply");
        printf("rgb_points.ply Saved\n");
        ob_delete_frame(pointsFrame, &error);
        check_error(error);
        points_created = true;
    }
    ob_delete_frame(frameset, &error);  // Destroy frameSet to reclaim memory
    check_error(error);
    if(points_created) {
        break;
    }
}

After the main loop exits, stop the stream and destroy the recycled resources

// stop pipeline
ob_pipeline_stop(pipeline, &error);
check_error(error);

// destroy pipeline
ob_delete_pipeline(pipeline, &error);
check_error(error);

// destroy config
ob_delete_config(config, &error);
check_error(error);

// destroy profile
ob_delete_stream_profile(depth_profile, &error);
check_error(error);

// destroy profile
ob_delete_stream_profile(color_profile, &error);
check_error(error);

// destroy profile list
ob_delete_stream_profile_list(colorProfiles, &error);
check_error(error);

ob_delete_stream_profile_list(depthProfiles, &error);
check_error(error);

Expected Output

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