Agisoft Metashape

Agisoft Metashape => Bug Reports => Topic started by: howcanoewang on December 04, 2021, 08:32:06 AM

Title: Duplicate image file names override each other when build dense cloud [Solved]
Post by: howcanoewang on December 04, 2021, 08:32:06 AM

Apologize, it is caused by the poor amount of tie points (4549 by high - fail;  46646 by highest - success), not caused by the duplicate image names.

Please archive or delete this post if necessary.

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I am using "Foldio 360" rotation platform to take object images for 3D reconstruction,  it will rotate 10 degrees (horizontally) each time and take 36 images, and always name as follows: [01.jpg, 02.jpg, 03.jpg, ... , 36.jpg]

(https://user-images.githubusercontent.com/19968935/144697718-ae47ec70-14f5-4a48-8e65-bda6fd121124.png)

The camera position is always fixed, but scanned object is flipped for 45 degrees (vertically), and finally got 8 image groups:

Quote

/root/
|- rotation 0/
|   |- 01.jpg
|   |- 02.jpg
|   |- ...
|   |- 36.jpg
|- rotation 45/
|   |- 01.jpg
|   |- ...
|   |- 36.jpg
|- rotation 90/
|- rotation 135/
|- ...
|- rotation 315/

(please note, for each folder, the subimages have the same image name)

Then, I added all these images in one chunk, and grouped them by camera groups, and make masks for each image to remove the static backgrounds.

(https://user-images.githubusercontent.com/19968935/144698016-bc3725e6-05d2-4c3e-b2f4-20bdc6dcb8f9.png)

Successfully aligned photos by [highest accuracy, generic preselection, sequential reference preselection, apply mask to key points, exclude stationary tie points and adaptive camera model fitting], got expected tie points (left subimg). But build dense cloud, it produces point cloud with a missing part (right subimg), which is almost the same result from only 36 images from "rotation 90" folder.

(https://user-images.githubusercontent.com/19968935/144698188-94954b68-bfff-455b-98db-96b6463ce8ca.png)

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Then I copied and rename the project folder like this, given unique image names:

Quote

/root/
|- rotation 0/
|   |- c0_01.jpg
|   |- c0_02.jpg
|   |- ...
|   |- c0_36.jpg
|- rotation 45/
|   |- c45_01.jpg
|   |- ...
|   |- c45_36.jpg
|- rotation 90/
|- rotation 135/
|- ...
|- rotation 315/

Doing the same thing like before (except ranaming image.label c0_01 -> 01 for sequential reference preselection by script in Metashape project, otherwise unable to align all images at all), and got expected dense cloud:

(https://user-images.githubusercontent.com/19968935/144698438-b9097ac4-f75e-4d0c-88b1-f51000976ef6.png)

The only difference between two projects, is whether image names are unique or not. I personally guess it is caused by a bug in the MVS steps of building dense cloud, the duplicate image name override previous calculation results. A simple compairson:

(https://user-images.githubusercontent.com/19968935/144698584-2fedfa74-0e9e-440e-8672-9462bcbbbdc3.png)