> ## Documentation Index
> Fetch the complete documentation index at: https://support.lumafield.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Beam Hardening Correction

> Use BHC to correct for beam hardening artifacts and reduce streaking artifacts in the Voyager software. 

Beam hardening is a CT artifact that comes from the X-ray source being polychromatic: lower-energy photons are absorbed more than higher-energy ones. The beam’s average energy increases as it passes through material (the beam “hardens”).

Reconstructions that display characteristic **cupping** (center darker than edges) and dark **streaks** between dense objects can benefit from Beam Hardening Correction. In the below image, the edges of the part appear to be higher density than the center, despite the part being monomaterial.

<Frame>
  <img src="https://mintcdn.com/lumafield/UbVLuU7Qf_3Jq5qF/images/BHC_Shell.png?fit=max&auto=format&n=UbVLuU7Qf_3Jq5qF&q=85&s=7382bd0827baf6f5dce088c4b321219d" alt="BHC Shell" width="1193" height="1277" data-path="images/BHC_Shell.png" />
</Frame>

<h2 id="how-to-run-bhc">
  How to run BHC
</h2>

Click on the Correct button in the Toolbar to open the correction workflow.

<Frame>
  <img src="https://mintcdn.com/lumafield/UbVLuU7Qf_3Jq5qF/images/Correct_icon.png?fit=max&auto=format&n=UbVLuU7Qf_3Jq5qF&q=85&s=474b7e06a413c5825aa1f01a3aeb8eb3" alt="Correct Icon" title="Correct Icon" style={{ width:"22%" }} width="380" height="298" data-path="images/Correct_icon.png" />
</Frame>

Ensure the Beam Hardening Correction option is toggled on and click next.

<Frame>
  <img src="https://mintcdn.com/lumafield/UbVLuU7Qf_3Jq5qF/images/BHC_Attributes.png?fit=max&auto=format&n=UbVLuU7Qf_3Jq5qF&q=85&s=78e4ff6dc1fa0f35b26976428fd0d351" alt="BHC Panel" lightAlt="BHC Panel" darkAlt="BHC Panel" width="1440" height="1264" data-path="images/BHC_Attributes.png" />
</Frame>

Adjust the slider so that the line intersects the part in an area of interest (i.e. a darker, more dense region where there is likely to be beam hardening artifacts). Select "Next" and wait for correction images to be generated.

<Frame>
  <img src="https://mintcdn.com/lumafield/qkr1hx2ghaKlpeTJ/images/bhc-2.jpg?fit=max&auto=format&n=qkr1hx2ghaKlpeTJ&q=85&s=bd8d9334f4838f71765a36a69648acee" alt="Bhc 2" width="404" height="505" data-path="images/bhc-2.jpg" />
</Frame>

Once the correction preview images are available, load them and select the BHC setting that makes a single material as consistent a brightness as possible. Click Run Reconstruction and wait for it to generate (this new Reconstruction will show up in the list of other reconstructions in the data tab).

<Frame>
  <img src="https://mintcdn.com/lumafield/qkr1hx2ghaKlpeTJ/images/bhc-3.gif?s=337b150eb49b9e1f019305a02ddd7f75" alt="Bhc 3" width="480" height="288" data-path="images/bhc-3.gif" />
</Frame>

In this animation, you can see that the battery has even grey values across the width of the battery on the second correction factor value.
