# Collision prevention depth calculation results in empty image

Source: https://forum.modalai.com/topic/148/collision-prevention-depth-calculation-results-in-empty-image
Category: General Questions (https://forum.modalai.com/category/2/general-questions)
Posted: 2021-03-04 01:09:23 UTC by Lynn Koudsi
Replies: 0 · Views: 449

## Lynn Koudsi · 2021-03-04 01:09:23 UTC

I'm on the latest version of voxl-dfs-server, and I'm attempting to get collision prevention working, but I went through the code and it seems like the disparity computation is resulting in an empty matrix. In result, it's detecting no objects. 

I've also tried placing a board infront of the camera and moved it around, but no luck.

I've attached the dsp image, as well as the input from the stereo cameras. I've calibrated the cameras today.

Thanks!

![disp_raw.png](https://forum.modalai.com/assets/uploads/files/1614819831352-disp_raw.png) 
![img2_resized.png](https://forum.modalai.com/assets/uploads/files/1614819732474-img2_resized.png) 
![img2_rect.png](https://forum.modalai.com/assets/uploads/files/1614819732432-img2_rect.png) 
![img2_blur.png](https://forum.modalai.com/assets/uploads/files/1614819732431-img2_blur.png) 
![img1_resized.png](https://forum.modalai.com/assets/uploads/files/1614819732431-img1_resized.png) 
![img1_rect.png](https://forum.modalai.com/assets/uploads/files/1614819732431-img1_rect.png) 
![img1_blur.png](https://forum.modalai.com/assets/uploads/files/1614819732430-img1_blur.png)