# Vignetting and Dark Current Correction.

**URL:** <https://community.pix4d.com/t/vignetting-and-dark-current-correction/2784>\
**Category:** PIX4Dmapper Questions/Troubleshooting\
**Created:** [December 30, 2016, 11:51am UTC](https://community.pix4d.com/t/vignetting-and-dark-current-correction/2784 "2016-12-30T11:51:29Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Ghazanfar\_Abbas](https://avatars.discourse-cdn.com/v4/letter/g/3d9bf3/32.png) [@Ghazanfar\_Abbas](https://community.pix4d.com/u/Ghazanfar_Abbas)\
**Post date:** [December 30, 2016, 11:51am UTC](https://community.pix4d.com/t/vignetting-and-dark-current-correction/2784/1 "2016-12-30T11:51:29Z")

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Hi,

I am using Parrot Sequoia (Firmware v1.2.1). for computing NDVI. I am trying to understand the process through which the final images are acquired from the sensor. &nbsp;Specifically, I want to know whether Sequoia compensates for [**Vignetting**](https://en.wikipedia.org/wiki/Vignetting)and [**Dark Current**](https://en.wikipedia.org/wiki/Dark_current_(physics)) effects inside the firmware or do these corrections have to be applied manually in the software?

&nbsp;

If they have to be corrected manually, then:

- How can we utilize the captured images’ **EXIF** information to correct vignetting?
- Does the exif tag **BlackCurrent&nbsp;** correspond to the dark current suppression? How can we use it to correct the dark current effect?

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**Author:** ![Muzq\_Shah](https://sea2.discourse-cdn.com/pix4d/user_avatar/community.pix4d.com/muzq_shah/32/341_2.png) [@Muzq\_Shah](https://community.pix4d.com/u/Muzq_Shah)\
**Post date:** [February 6, 2017, 12:41pm UTC](https://community.pix4d.com/t/vignetting-and-dark-current-correction/2784/2 "2017-02-06T12:41:16Z")

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Hi guys, I am also having the exact same issue. Somebody please reply.

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**Author:** ![Marc\_Desgroseilliers](https://sea2.discourse-cdn.com/pix4d/user_avatar/community.pix4d.com/marc_desgroseilliers/32/187_2.png) [@Marc\_Desgroseilliers](https://community.pix4d.com/u/Marc_Desgroseilliers)\
**Post date:** [March 31, 2017, 3:01pm UTC](https://community.pix4d.com/t/vignetting-and-dark-current-correction/2784/3 "2017-03-31T15:01:57Z")

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Hello,

The vignetting and black current corrections are not applied directly on the images. The necessary information is stored in the exif metadata, and the corrections are applied during the computation of the reflectance maps in Pix4D software. These corrections do not need to be corrected manually (it is recommended to leave the software do it).&nbsp;

Best regards,