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Синтез изображений по изображениям
Синтез изображений по изображениям
Сегодня на лекции
Сегодня на лекции
Traditional Rendering
Traditional Rendering
Image-Based Rendering
Image-Based Rendering
Image-Based Rendering
Image-Based Rendering
Traditional vs
Traditional vs
Simplest IBR methods
Simplest IBR methods
Simplest IBR methods
Simplest IBR methods
Simplest IBR methods
Simplest IBR methods
3D model rendering distortions
3D model rendering distortions
Sprites with Depth
Sprites with Depth
Warping
Warping
Planar pinhole camera
Planar pinhole camera
Orthographic camera
Orthographic camera
3D point position from a pinhole camera
3D point position from a pinhole camera
From two cameras
From two cameras
Warping example
Warping example
Schematic view
Schematic view
Relief textures
Relief textures
Schematic view
Schematic view
New warping function
New warping function
New warping function (2)
New warping function (2)
Two stage warping example
Two stage warping example
Two stage warping example (2)
Two stage warping example (2)
Filling holes
Filling holes
Two classes of holes
Two classes of holes
Resampling
Resampling
Resampling methods
Resampling methods
Splatting
Splatting
Interpolation
Interpolation
Interpolation (2)
Interpolation (2)
Пример
Пример

Презентация: «Синтез изображений по изображениям». Автор: 02a_ign. Файл: «Синтез изображений по изображениям.ppt». Размер zip-архива: 1837 КБ.

Синтез изображений по изображениям

содержание презентации «Синтез изображений по изображениям.ppt»
СлайдТекст
1 Синтез изображений по изображениям

Синтез изображений по изображениям

Рельефные текстуры

2 Сегодня на лекции

Сегодня на лекции

Введение в Синтез Изображений по Изображениям (Image-Based Rendering) Простейшие методы IBR Рельефные текстуры (relief textures)

3 Traditional Rendering

Traditional Rendering

For photorealism Modeling is hard Rendering is slow

User input texture maps, survey data

Modeling

Geometry Textures Light sources

Rendering

Images

4 Image-Based Rendering

Image-Based Rendering

Основные идеи: Использование изображений (фотографий) в качестве исходных данных Использование методов обработки изображений для визуализации.

5 Image-Based Rendering

Image-Based Rendering

For photorealism Fast modeling Complexity independent rendering

Images user input range scanners

Modeling

Images & depth maps

Rendering

Images

6 Traditional vs

Traditional vs

Image-based

Image based computer graphics has three main advantages Photorealism of produced images The speed Simple modeling

7 Simplest IBR methods

Simplest IBR methods

Texture

Texture - is the simplest of IBR methods.

8 Simplest IBR methods

Simplest IBR methods

Sprites

Texture + simple planar geometry = Sprite Sprites are taken from certain camera position (sprite camera)

9 Simplest IBR methods

Simplest IBR methods

Sprites

No geometry information and... Sprites are looking good from view-points close to the sprite camera, but awful from others

10 3D model rendering distortions

3D model rendering distortions

What are we missing? The effect of 3-dimensionality on the screen is a combination of two effects: perspective distortion and parallax Sprites are capable of producing perspective distortions but they are unable to produce correct parallax effect

11 Sprites with Depth

Sprites with Depth

Combine depth and color: Color texel now is a 3D sample.

12 Warping

Warping

Using the samples z-values, image can be transformed (or warped), to enchance the image descriptive power (realism)

13 Planar pinhole camera

Planar pinhole camera

14 Orthographic camera

Orthographic camera

15 3D point position from a pinhole camera

3D point position from a pinhole camera

One image is not enough to determine location of a point in 3D.

16 From two cameras

From two cameras

If we have two cameras, Camera1 and Camera2 with different parameters, capturing the same scene from different locations, a point can be expressed as

17 Warping example

Warping example

18 Schematic view

Schematic view

Warping x’ = warp(x)

Depth map

Final view

Parallax, perspective projection, translation

19 Relief textures

Relief textures

Most of modern 3D accelerators can ultimately fast render textured triangles => We can use this capability to speed up and simplify Image-Based Rendering Such an algorithm is called Relief Textures

20 Schematic view

Schematic view

Software Hardware

Pre-warping

Texture mapping

Relief textures

Warped textures

Final view

Parallax

Perspective projection, translation

21 New warping function

New warping function

x’ = warp(x) = g(h(x), Poly), where g(y, Poly) is texture-mapping function and usually done in hardware h(x) is pre-warpring function

22 New warping function (2)

New warping function (2)

Prewarping function h(x) after some optimizations looks like following: u2 = (u1+mu[d])*nu[d]; v2 = (v1+mv[d])*nv[d]; Extremely simple, isn’t it?

23 Two stage warping example

Two stage warping example

24 Two stage warping example (2)

Two stage warping example (2)

25 Filling holes

Filling holes

This sprite with depth was warped to the new viewpoint Look how many empty spaces on the women face and hair at the picture Let’s call them holes

26 Two classes of holes

Two classes of holes

All the holes fall into two classes by its nature Resampling problem Missing information

27 Resampling

Resampling

Before warping After warping

28 Resampling methods

Resampling methods

Methods to fill the holes Inverse warping Meshing Splatting Interpolation

29 Splatting

Splatting

Draw a little cloud (splat) instead of a pixel in desired image. This cloud has to be opaque in its center becoming more and more transparent to its sides Features Relatively small computation cost Not all the holes are filled

30 Interpolation

Interpolation

Use the fact that u and v are independent from each other after pre-warping (two-pass algorithm) and linearly interpolate depth and color in the intermediate and final images

31 Interpolation (2)

Interpolation (2)

32 Пример

Пример

Пример 1

Пример 2

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