# manually calibrating images

**URL:** <https://community.pix4d.com/t/manually-calibrating-images/18286>\
**Category:** PIX4Dmapper\
**Created:** [May 27, 2021, 10:04pm UTC](https://community.pix4d.com/t/manually-calibrating-images/18286 "2021-05-27T22:04:29Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Rio\_Hondo\_GIS\_Progra](https://avatars.discourse-cdn.com/v4/letter/r/ccd318/32.png) [@Rio\_Hondo\_GIS\_Progra](https://community.pix4d.com/u/Rio_Hondo_GIS_Progra)\
**Post date:** [May 27, 2021, 10:04pm UTC](https://community.pix4d.com/t/manually-calibrating-images/18286/1 "2021-05-27T22:04:29Z")

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the images “uncalibrated” in the image are over heavy canopy so I understand that it has some difficulty and perhaps next time capture higher … was captured at~400’. Couple of questions …

1. Are the red ‘x’ indicating attempts to calibrate?
2. If I manually add tie points, what is the minimum tie points?
3. Is there any guide on performing these steps?

Thanks!

 ![uncal](https://global.discourse-cdn.com/pix4d/original/2X/e/e70b5c89eb3009cfc162e39508c57167c17cdc17.jpeg)

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**Author:** ![Rio\_Hondo\_GIS\_Progra](https://avatars.discourse-cdn.com/v4/letter/r/ccd318/32.png) [@Rio\_Hondo\_GIS\_Progra](https://community.pix4d.com/u/Rio_Hondo_GIS_Progra)\
**Post date:** [May 27, 2021, 10:36pm UTC](https://community.pix4d.com/t/manually-calibrating-images/18286/2 "2021-05-27T22:36:02Z")

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here is an example, this isolated uncalibrated tile has many red ‘+’ shown on the right … are these tie points determined or? if not, I assume I need to identify manual tie points in the image and if so, one from each corner and another in the center? I am not interested in this case to have the DSM, only the ortho

 ![uncalibrated](https://global.discourse-cdn.com/pix4d/original/2X/9/98c199a6c218e1b4ba7991ddb16ae71d0868fbf5.jpeg)

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**Author:** ![Daniele\_Lecci](https://sea2.discourse-cdn.com/pix4d/user_avatar/community.pix4d.com/daniele_lecci/32/9493_2.png) [@Daniele\_Lecci](https://community.pix4d.com/u/Daniele_Lecci)\
**Post date:** [May 28, 2021, 3:10pm UTC](https://community.pix4d.com/t/manually-calibrating-images/18286/3 "2021-05-28T15:10:38Z")

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Hi,

Thank you for your message.  
The red crosses refer to automatic keypoints that are not matched with any keypoint of other images.

You can find more information here, you can try to manually calibrate a camera:

> **[How to manually calibrate uncalibrated Cameras in the rayCloud](https://support.pix4d.com/hc/en-us/articles/202560189-How-to-manually-calibrate-uncalibrated-Cameras-in-the-rayCloud)**
>
> When an image is not calibrated during step 1. Initial Processing, it can be manually calibrated using the rayCloud.
> 
>  
> 
> Note: The manual calibration should be done for a small amount of images. Th...

This is a typical issue for a vegetation project, which normally are not easy to reconstruct.

This article might help you for vegetation areas

> **[How to improve the outputs of dense vegetation areas using PIX4Dmapper?](https://support.pix4d.com/hc/en-us/articles/202560159-How-to-improve-the-outputs-of-dense-vegetation-areas-using-Pix4Dmapper)**
>
> Trees, forest and dense vegetation areas have specific properties that require special care. When processing such datasets, different type of issues might occur as described in this article togethe...

I will continue our discussion with the direct support ticket that you opened.

Cheers.