# Low stability in qvio due to low number of features

Source: https://forum.modalai.com/topic/1989/low-stability-in-qvio-due-to-low-number-of-features
Category: Flight Core and Legacy VOXL (https://forum.modalai.com/category/9/flight-core-and-legacy-voxl)
Tags: voxl-cam
Posted: 2023-03-23 08:58:35 UTC by Erez Nehama
Replies: 6 · Views: 2154

## Erez Nehama · 2023-03-23 08:58:35 UTC

Currently, I'm using the voxl-cam for vio only. It's mounted on my self-made drone without px-4 (I only want to receive the qvio data).
During flight, the vio resets due to a low number of features (and then it takes time to initialize again). I'm adding some images of the qvio overlay, with cases where the image seems fine and the drone is stable (by the way it can happen on the ground as well), but not enough features were found
![image (2).png](https://forum.modalai.com/assets/uploads/files/1679561724937-image-2.png) ![image (3).png](https://forum.modalai.com/assets/uploads/files/1679561724954-image-3.png) ![image (4).png](https://forum.modalai.com/assets/uploads/files/1679561724959-image-4.png) 

Is there a way to increase the number of valid "good" features? Or maybe another way to increase the stability of the algorithm?

## Reply by Chad Sweet (ModalAI staff) · 2023-03-23 13:56:41 UTC

White walls are very tough for any computer vision algorithm, so those may not ever work well

The images look darker than I would expect. Have you tweaked the exposure settings at all? you could try increasing the ae_desired_msv which is configured in voxl-camera-server and see if that helps add contrast

## Reply by Erez Nehama · 2023-03-30 20:14:40 UTC

Thank you very much! it seems to work a lot better. I've increased ae_desired_msv from 60 to 80.

## Reply by Joshua Ermias · 2024-05-24 17:53:51 UTC (in reply to Erez Nehama)

@Erez-Nehama What command did you type in to increase the "ae_desired_msv"? I've tried using voxel-camer-server and voxel-send-command but neither let me change that value directly @Chad-Sweet

## Reply by tom (ModalAI staff) · 2024-05-24 18:40:52 UTC (in reply to Joshua Ermias)

@Joshua-Ermias It can be set in `/etc/modalai/voxl-camera-server.conf`

## Reply by Joshua Ermias · 2024-05-24 19:39:23 UTC (in reply to tom)

@tom would you recommend using a text editor like Vim and restarting the service or is there a better way to do it?

## Reply by tom (ModalAI staff) · 2024-05-24 19:47:10 UTC (in reply to Joshua Ermias)

@Joshua-Ermias yes that would be the easiest way. You can either restart the service with `systemctl restart voxl-camera-server` or just power cycle your VOXL