OrbbecSDK_v2

Depth with C

This is a depth guide to get depth stream and depth image by using the Orbbec SDK C API.

Overview

Knowledge

Pipeline is a pipeline for processing data streams, providing multi-channel stream configuration, switching, frame aggregation, and frame synchronization functions.

Frameset is a combination of different types of Frames.

Depth_frame is one of the frames in frameset, it contains the frames’s esolution information and depth data.

Code Overview

1. Create instances

Create the pipeline instance using the default configuration and create a config instance to enable or disable the streams.

// Used to return SDK interface error information.
ob_error *error = NULL;

// Create a pipeline object to manage the streams.
ob_pipeline *pipeline = ob_create_pipeline(&error);
check_ob_error(&error);

// Crete a config object to configure the pipeline streams.
ob_config *config = ob_create_config(&error);
check_ob_error(&error);

2. Start pipeline

enable the depth stream, and then start the pipeline.

// enable depth stream with default stream profile.
ob_config_enable_stream(config, OB_STREAM_DEPTH, &error);
check_ob_error(&error);

// Start Pipeline with the configured streams.
ob_pipeline_start_with_config(pipeline, config, &error);
check_ob_error(&error);

3. Get depth stream

Get the frameset from pipeline, and get the depth frame from frameset.

// Wait for a frameset, timeout after 1000 milliseconds.
const ob_frame *frameset = ob_pipeline_wait_for_frameset(pipeline, 1000, &error);
check_ob_error(&error);

// If no frameset is available with in the timeout, continue waiting.
if(frameset == NULL) {
    continue;
}

// Get the depth frame from frameset。
const ob_frame *depth_frame = ob_frameset_get_depth_frame(frameset, &error);
check_ob_error(&error);

4. Print the distance of the center pixel

Print the distance of the center pixel every 30 frames to reduce output.

if(index % 30 == 0) {
    // Get the width of the depth frame.
    uint32_t width = ob_video_frame_get_width(depth_frame, &error);
    check_ob_error(&error);

    // Get the height of the depth frame.
    uint32_t height = ob_video_frame_get_height(depth_frame, &error);
    check_ob_error(&error);

    // Get the scale of the depth frame.
    float scale = ob_depth_frame_get_value_scale(depth_frame, &error);
    check_ob_error(&error);

    // Get the data of the depth frame, cast to uint16_t* to access the pixels directly for Y16 format.
    uint16_t *data = (uint16_t *)ob_frame_get_data(depth_frame, &error);
    check_ob_error(&error);

    // pixel value multiplied by scale is the actual distance value in millimeters
    float center_distance = data[width * height / 2 + width / 2] * scale;

    // attention: if the distance is 0, it means that the depth camera cannot detect the object（may be out of detection range）
    printf("Facing an object at a distance of %.3f mm away.\n", center_distance);
}

5. Stop pipeline

ob_pipeline_stop(pipeline, &error);

Run Sample

If you are on Windows, you can switch to the directory OrbbecSDK-dev/build/win_XX/bin to find the ob_depth_c.exe.

If you are on linux, you can switch to the directory OrbbecSDK-dev/build/linux_XX/bin to find the ob_depth_c.

Key introduction

Press ‘ESC’ key to stop the pipeline and exit the program.

Result

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