Segmentation fault (core dumped) with BODY_FORMAT::BODY_34

Software C++
1

Hi, I wrote a pretty simple little program that takes the body masks from my ZED2, fuses them into one Mat and streams it via NDI. Everything is working fine, unless I change to BODY_FORMAT::BODY_34. In that case it immediately gives me a Segmentation fault (core dumped) error. Using the 18 or 38 point models causes no issue. What might be the reason for this particular problem with Body_34?

2

Hi,

Can you share a snippet of code that reproduces the issue please?

What ZED SDK version are you using?

Thanks.

Stereolabs Support

3

SDK 4.1.3 and CUDA V11.4.315 on a ZED Box

It’s basically the body detection sample code with activated segmentation, I grab the mask, convert it into a four channel cv::Mat and stream it via NDI. I figured out that the problem happens at

memcpy(p_frame_buffers1[frame_idx & 1], cv_image_4ch.data, resX * resY * 4);

where I buffer the converted 4 channel mask for the NDI part. So I’m not sure if it is even a StereoLabs SDK problem since conversion to CV Mat beore that step seems to work fine. But something must be different with the data since only Body_34 causes the issue?

Mat fused;
Bodies objects;
cv::Mat cv_image_4ch;

returned_state = zed.grab();

if (returned_state == ERROR_CODE::SUCCESS) {
returned_state = zed.retrieveBodies(objects, detection_parameters_rt);

sl::uchar1 pixel_value = 0;
fused.setTo(pixel_value);

if (!objects.body_list.empty()) {
for (const auto& obj : objects.body_list) {
Mat mask_data = obj.mask;
vectorsl::uint2 bbox_2d = obj.bounding_box_2d;
Vector2 origin = bbox_2d[0];
auto height = mask_data.getHeight();
auto width = mask_data.getWidth();

  	for (unsigned long y = 0; y < height; y++) {
  		for (unsigned long x = 0; x < width; x++) {
                returned_state = mask_data.getValue(x, y, &pixel_value, MEM::CPU); 
  			if (returned_state == ERROR_CODE::SUCCESS) {
  				if (pixel_value > 0) {
  					int fused_x = static_cast<int>(origin[0]) + x;
  					int fused_y = static_cast<int>(origin[1]) + y;
  					if (fused_x >= 0 && fused_x < fused.getWidth() &&
  						fused_y >= 0 && fused_y < fused.getHeight()) {
  						fused.setValue(fused_x, fused_y, pixel_value, MEM::CPU);
  					}
  				}
                }
            }
  	}
  	cv::Mat cv_image = slMat2cvMat(fused);
  	cv::cvtColor(cv_image, cv_image_4ch, cv::COLOR_GRAY2BGRA);
  }

}

 // <- CORE DUMPED AFTER THIS LINE ->

memcpy(p_frame_buffers1[frame_idx & 1], cv_image_4ch.data, resX * resY * 4);

NDI_video_frame1.p_data = (uint8_t*)p_frame_buffers1[frame_idx & 1];

NDIlib_send_send_video_v2(pNDI_send1, &NDI_video_frame1);
frame_idx++;
}

4

Hi,

There is nothing different between the body34 format and the other ones regarding the segmentation mask, that’s why I’m a bit confused with your issue.

I tried to reproduce your setup but I don’t have any crash on my side.

Does it happen all the time? At the first frame of detection?

Stereolabs Support

5

I’m just as confused. It reliably happens as soon as the first object is detected and I start processing its mask. I’ll compile it on my notebook later to check if I can reproduce the issue there.

For the project I’ll likely opt for the 38 model so it’s not a problem for now, just really weird.