# Voxl 2 DFS Server

Source: https://forum.modalai.com/topic/1676/voxl-2-dfs-server
Category: General Questions (https://forum.modalai.com/category/2/general-questions)
Posted: 2023-01-09 19:51:25 UTC by bendraper
Replies: 6 · Views: 1196

## bendraper · 2023-01-09 19:51:25 UTC

How do you tell the DFS server that you only have one pair of stereo cameras. At no point when you run vox-dfs-configure does it ask you about your setup, and when I go to /etc/modalai/voxl-dfs-server.conf and manually get rid of one pair and change the extrinsics and intrinsics paths and save, running the server just reverts that file to have a "front" and "rear" pair. I've also tried editing this file, running the configurator, and selecting "no" when asking if I want to reset to factory defaults, and it still overwrites my changes in that file... What factors/scripts affect the generation of that conf file?

## Reply by Chad Sweet (ModalAI staff) · 2023-01-10 01:15:09 UTC

If the software thinks the file is corrupted, it will reset to defaults.

1. What are the exact steps you are trying? Are you calling any other configure after you edit the file?
2. What symptom are you trying to fix if two stereo pair are configured? 
3. Do you have two stereo pair plugged in?

## Reply by bendraper · 2023-01-10 14:17:22 UTC

@Chad-Sweet first if I try to run voxl-dfs-server as is, I get the following,
```
=================================================================
min_disparity:   4
max_disparity:   64
min_threshold:   10
cost_threshold:  10
width:           640
height:          480
pc_skip_n_lines: 4
dfs pair #0
    enable:             1
    input_pipe:         stereo_front
    skip_n_frames:      1
    blur_size:          0
    post_median_size:   0
    intrinsics_file:    /data/modalai/opencv_stereo_front_intrinsics.yml
    extrinsics_file:    /data/modalai/opencv_stereo_front_extrinsics.yml
dfs pair #1
    enable:             1
    input_pipe:         stereo_rear
    skip_n_frames:      1
    blur_size:          0
    post_median_size:   0
    intrinsics_file:    /data/modalai/opencv_stereo_rear_intrinsics.yml
    extrinsics_file:    /data/modalai/opencv_stereo_rear_extrinsics.yml
=================================================================
loading calibration files
ERROR: Failed to open calibration file: /data/modalai/opencv_stereo_front_intrinsics.yml
```

And it fails because its looking for "stereo_front" and "stereo_rear" but I only have one pair that in the pipe is just "stereo". So I then go to etc/modalai/voxl-dfs-server.conf which currently looks like this (I'll exclude the comments in this file)

```
{
	"skip_n_frames":	5,
	"n_disparity_levels":	48,
	"sobel_cutoff":	5,
	"first_median_filter_size":	17,
	"en_second_median_filter":	true,
	"second_median_filter_size":	7,
	"min_disparity":	4,
	"max_disparity":	64,
	"min_threshold":	10,
	"cost_threshold":	10,
	"width":	640,
	"height":	480,
	"pc_skip_n_lines":	4,
	"dfs_pair_0":	{
		"enable":	true,
		"input_pipe":	"stereo_front",
		"skip_n_frames":	1,
		"blur_size":	0,
		"post_median_size":	0,
		"intrinsics_file":	"/data/modalai/opencv_stereo_front_intrinsics.yml",
		"extrinsics_file":	"/data/modalai/opencv_stereo_front_extrinsics.yml"
	},
	"dfs_pair_1":	{
		"enable":	true,
		"input_pipe":	"stereo_rear",
		"skip_n_frames":	1,
		"blur_size":	0,
		"post_median_size":	0,
		"intrinsics_file":	"/data/modalai/opencv_stereo_rear_intrinsics.yml",
		"extrinsics_file":	"/data/modalai/opencv_stereo_rear_extrinsics.yml"
	}
}
```

and remove the "rear" stereo and then edit the front stereo to just be "stereo", and save it to looks like the following

```
{
	"skip_n_frames":	5,
	"n_disparity_levels":	48,
	"sobel_cutoff":	5,
	"first_median_filter_size":	17,
	"en_second_median_filter":	true,
	"second_median_filter_size":	7,
	"min_disparity":	4,
	"max_disparity":	64,
	"min_threshold":	10,
	"cost_threshold":	10,
	"width":	640,
	"height":	480,
	"pc_skip_n_lines":	4,
	"dfs_pair_0":	{
		"enable":	true,
		"input_pipe":	"stereo",
		"skip_n_frames":	1,
		"blur_size":	0,
		"post_median_size":	0,
		"intrinsics_file":	"/data/modalai/opencv_stereo_intrinsics.yml",
		"extrinsics_file":	"/data/modalai/opencv_stereo_extrinsics.yml"
	}
}
```
THEN I run voxl-configure-dfs and say NO to reset to defaults, YES to enable the server. If i try to run voxl-dfs-server again, I get the same

 ```
ERROR: Failed to open calibration file: /data/modalai/opencv_stereo_rear_intrinsics.yml
```

And I get this because somehow the voxl-dfs-server.conf file was reset to its factory state

## Reply by Chad Sweet (ModalAI staff) · 2023-01-10 15:32:57 UTC

@bendraper said in [Voxl 2 DFS Server](/post/7776):
> voxl-configure-dfs

OK, thanks. It sounds like a bug.

Instead of running ```voxl-configure-dfs``` the second time, just run ```systemctl enable voxl-dfs-server```

## Reply by bendraper · 2023-01-10 21:53:28 UTC (in reply to Chad Sweet)

@Chad-Sweet said in [Voxl 2 DFS Server](/post/7777):
> systemctl enable voxl-dfs-server

That doesn't seem to fix the issue. I can issue that command after editing the file, but the inspect-services just says its enabled but not running. Then when I run voxl-dfs-server, it repopulates that conf file to have a "stereo_rear" and fails because the path its looking for the extrinsics obviously does not exist. Is the naming convention I'm using when I edit that file correct? if I only have one stereo pair, should it still be "dfs_pair_0" or should it be something else. The naming convention for this file also differs to that of what is shown on the DFS-Server wiki page.

## Reply by Chad Sweet (ModalAI staff) · 2023-01-10 22:06:01 UTC

Looking at the code [here](https://gitlab.com/voxl-public/voxl-sdk/services/qrb5165-dfs-server/-/blob/master/src/main.cpp#L274), maybe you just need to set dfs_pair_1 enable to false instead of deleting it?

## Reply by bendraper · 2023-01-11 14:44:44 UTC (in reply to Chad Sweet)

@Chad-Sweet That seems to have done the trick! Thanks