Computer Vision for Robots - Robot Vision and Preception - Lecture Slides, Slides of Computer Science

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Image Processing

and Computer

Vision for Robots

Convolution Application

in Robot Vision

• What is convolution
  • Different filters formed with Convolution
• Convolution application examples

First few examples what can be

achieved with convolution

Binary Image Creation Popularly used in industrial robotics Docsity.com

Bit per Pixel

Convolution Kernel

• New Pixel Value Computed

from Neighboring Pixel

Values

• Convolution of an N x N

Matrix (Kernel) with the

Image

Convolution kernel

• W

i

• F (f(x,y))

• Function of one variable F can be nonlinear, realized in a lookup

table

• F(f(x

,y

), f(x

,y

),…,f(x

,y

) ) can be highly

complicated and nonlinear function

Example of a More general Convolution

m i,j is individual mask elements

p

ij

is individual image elements in row i and column j

m1,1 m2,1 m3,

m1,2 m2,2 m3,

m1,3 m2,1 m3,

Original Image Mask p1,1 p1,2 p1,3 p1,4 p1,5 p1, p2,1 p2,2 p2,3 p2,4 p2,5 p2, p3,1 p3,2 p3,3 p3,4 p3,5 p (^3) , 6 p4,1 p4,2 p4,3 p4,4 p4,5 p4, p5,1 p5,2 p5,3 p5,4 p5,5 p5, p6,1 p6,2 p6,3 p6,4 p6,5 p6,

More general Convolution (continued) At the heart of convolution operation is the convolution mask or kernel , shown as M(ask) or W(indow) in next figures The quotient is known as the weight of the mask ∑ ∑ ∑ ∑ = = = = × = n j ij m i n j ij ij m i m p m Cxy 1 1 1 1 Example of a More general Convolution

Requires

division, too

bad

Filtering by convolution Algorithm

**1. Reads the DN of each pixel in array

2. Multiplies DN by appropriate weight
3. Sums the products of (DN x weight) for the nine pixels, and divides sum by 9
4. Derived value applied to center cell of** **array
5. Filter moves one pixel to right, and operation is repeated, pixel by pixel, line by line**

No. 3 Docsity.com