Record 3D image in bag file - several minutes period

[SamConti]

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Required Info
Camera Model	D435
Operating System & Version	Ubuntu 16
Kernel Version (Linux Only)	4.4.38
Platform	Raspberry Pi
Language	python

Issue Description

Hello,

I would like to take a 3D image every 5 minutes and store it in a bag file but I don't know how to do this.
The frame format have to be 1280x720 and Z16 format.

At this point I'm able create the basic :
import pyrealsense2 as rs
pipelne = rs.pipeline()
config = rs.config()
config.enable_stream(rs.stream.depth, 1280, 720, rs.format.z16, 6)
pipeline.start(config)

I think I configure with a frame rate of 6 fps...maybe can I set to 1fps and save an image every 300 images ?
About place the image in bag file, I don't know how to do this...

Thanks,

[dorodnic]

Hi @SamConti

Several ways to go about it.

The easiest approach is just to create a pipeline, start, stop, delete the pipeline, wait 5 minutes, repeat.
Drawback is warm-up time of ~0.5-1 second. Benefit is low power consumption since the camera is off most of the time.

Second approach is to use record.pause method.

auto dev = pipe.start(config).get_device().as<rs2::record>();
while (auto fs = pipe.wait_for_frames())
{
     dev.pause();
     sleep(5000);
     dev.resume();
}

Benefits are fast response and one single recorded BAG file (unlike other methods)

There is another tool that can be useful for your needs:
If you explicitly include rs_export.hpp you would be able to save each individual frameset into its own tiny ROS-bag.
This is not as well tested as the main recorder, but these should successfully capture all the data including relevant extrinsic / intrinsic calibration, and you should be able to open them in the Viewer.

#include <librealsense2/rs.hpp>
#include <librealsense2/rs_export.hpp>

rs2::save_single_frameset saver;
while (auto fs = pipe.wait_for_frames())
{
     saver.process(fs);
     sleep(5000);
}

[SamConti]

Hello,

Thank you for your feedback.
Clearly I need a bag file for each frame, so first method you explains I think.
But, my apologizes I'm newbie with this camera, how to save the image in bag file ?

I can found this kind of code:

frames = pipeline.wait_for_frames()
depth_frame = frames.get_depth_frame()
depth_image = np.asanyarray(depth_frame.get_data())
cv2.imwrite(args.directory + "/" + str(i).zfill(6) + ".png", depth_image)

I see the code wait for a frame and save it as image but how in bag file ?

[dorodnic]

No worries,

int i = 0;
while (true)
{
     { // new scope to force pipeline to be released at the end
           rs2::pipeline p;
           rs2::config cfg;
           std::stringstream ss;
           ss << "file_" << i << ".bag";
           cfg.enable_record_to_file(ss.str());
           p.start(cfg);
           p.wait_for_frames();
           p.stop();
     }
     sleep(5000);
     i++;
}

Check out examples/record-playback for more info

[SamConti]

OK I create the bag file in python, but I have a problem with it.
When I load it in Realsense viewer I have this error

Failed to load file C:\Users\Samuel CONTI\Desktop\BagFile.bag. Reason: Io in rs2_context_add_device(ctx:0000021724F39240, file:C): Failed to create ros reader: Bag unindexed

Is there a way to fix this ?

My code is is simply:

import pyrealsense2 as rs
pipeline = rs.pipeline()
config = rs.config()
config.enable_stream(rs.stream.depth, 1280, 720, rs.format.z16, 6)
config.enable_record_to_file("BagFile.bag")
pipeline.start(config)
frames = pipeline.wait_for_frames()
pipeline.stop()

EDIT: I found the problem, the script have to be closed from the IDE and bag file are correct.

Thank you,

[jkenney9a]

This looks like the same problem we had here #3044. I haven't found any other solution than to close the IDE like you did.

[SamConti]

Hi,

Yes I saw this topic, but solution is for C++ not python. So I get around the problem placing the code to read the camera in a separate *.py file and call it as a thread when needed (not tested as a simple function) = the code is executed, the file is automatically released and the problem doesn't occur.

[SamConti]

Hello,

I up this topic because I have a problem I don't know to get around.
The camera need several seconds (at leaset 6-7s) for stabilization else depth image is not good, then during this time bag file is running and filling itself. He becomes too big in size and I would like just one good image inside. Is there a way to avoid this ?

[lramati]

Try

import pyrealsense2 as rs

pipeline = rs.pipeline()
config = rs.config()
config.enable_stream(rs.stream.depth, 1280, 720, rs.format.z16, 6)
config.enable_record_to_file("BagFile.bag")

auto dev = pipe.start(config).get_device().as<rs2::record>();

# Skip first 10 seconds to allow depth to stabilize
dev.pause()
sleep(10000) 
dev.resume()

# only record a frame every 5 seconds
while (auto fs = pipe.wait_for_frames())
{
     dev.pause();
     sleep(5000);
     dev.resume();
}

[SamConti]

Hello,

There's a syntax error at this line auto dev = pipe.start(config).get_device().as<rs2::record>();

[RealSenseCustomerSupport]

---

Hi SamConti,

For getting a recorder device, you may do something like this:

profile = pipeline.start(config)
recorder = rs.recorder("BAG_FILE_PATH+NAME_TO_RECORD_TO.bag", profile.get_device())
...
recorder.pause()
...
recorder.resume()

Notes: with this, you can skip the line of setting up bag file name "config.enable_record(...)"
Hope this can help clarify.

Thanks!

[SamConti]

Hi,

Just thank you.
I will perform more test but first test seems to be very good :)

Thanks!

[soarwing52]

Hi,
I'm doing the same thing, which is take one frame every few seconds.
but I found that I lost a lot of frames.

my structure is:

    pipeline = rs.pipeline()
    config = rs.config()
    config.enable_stream(rs.stream.depth, 1280, 720, rs.format.z16, 30)
    config.enable_stream(rs.stream.color, 1920, 1080, rs.format.rgb8, 30)
    config.enable_record_to_file(file_name)
    profile = pipeline.start(config)
    device = profile.get_device()
    recorder = device.as_recorder()
    rs.recorder.pause(recorder)

and I have the

    color_sensor = profile.get_device().query_sensors()[1]
    color_sensor.set_option(rs.option.auto_exposure_priority, False)

which to turn off auto exposure priority to record data

and my runtime screen is:

  try:
        while True:
            frames = pipeline.wait_for_frames()
            depth_frame = frames.get_depth_frame()
            color_frame = frames.get_color_frame()
            if not depth_frame or not color_frame:
                continue

and for recording I have:

               rs.recorder.resume(recorder)
                time.sleep(0.01)
                r_frames = pipeline.wait_for_frames()
                r_depth_frame = r_frames.get_depth_frame()
                r_color_frame = r_frames.get_color_frame()
                rs.recorder.pause(recorder)

I'm recording every second one frame on a moving car, road survey.
and my question would be

how can I confirm that I got one frame recorded?
I tried set the sleep longer but I'll get more frames if the exposure is set faster and none when its not ready

i also tried the

if not depth or not color:
continue

didn't work either