mirror of
https://github.com/jackyzha0/quartz.git
synced 2026-03-24 15:05:42 -05:00
39 lines
1.1 KiB
Markdown
39 lines
1.1 KiB
Markdown
---
|
|
title: "06-homographies"
|
|
tags:
|
|
- lecture
|
|
- cosc342
|
|
---
|
|
|
|
Homographies and mosaics
|
|
- A homography* is:
|
|
- A linear map between two planes (or views of a plane)
|
|
- A 3 x 3 matrix, up to a scale
|
|
- Two images of a scene are related by a homography
|
|
- If the scene is planar, or
|
|
- If the camera only rotates
|
|
- 
|
|
|
|
Homographies for planar scenes
|
|
- Take a line in one view
|
|
- This projects to a plane
|
|
- That intersects the scene (another plane) at a line
|
|
- That projects to a line in the other image
|
|
- So lines are preserved
|
|
- 
|
|
|
|
> [!INFO] can create a "straight" view of a picture!
|
|
|
|
[|300](https://i.imgur.com/BEjOoFL.png)
|
|
|
|
> [!INFO] homography: maps points from one image to another
|
|
|
|
> [!INFO] rephotography, mathing old photographs onto the current view of the user
|
|
|
|
|
|
|
|
homography for rotating camera
|
|
|
|
|
|
|
|
> [!INFO] K matric describe parameters of camera. R matric describes rotation of camera. T is zero because the camera is only rotating. H is the homograhy matrix |