Digital Image Processing, 3nd Ed, Gonzalez & Woods.

Simplified Approach to Image Processing, Crane.

Point Process

Area Process

Geometric Process

Frame Process

Geometric Process

Basic Geometric Process

Forward and Reverse Mapping

Minification only Techniques (Median and Average)

Scaling (Zoom-in and Zoom-out)

Rotation (270, 180, 90 degree)

Translation

Mirroring (Horizontal and Vertical)

Geometric process modify

the arrangement of pixels

based on some geometric

transformation.

Scale

Rotation

Translation

Median Representation

Average Representation

Replaces a block of pixels

with its median values.

Represents a block of pixels

with an average of all of the

pixels.

a. Original image

b. Median

c. Average

Image must often be sized to

certain dimensions.

Zoom-in

Zoom-out

for (int x = 0; x < image1.Width; x++)

{

for (int y = 0; y < image1.Height; y++)

{

pixelcolor = image1.GetPixel(x, y);

image2.SetPixel(2 * x, 2 * y, pixelcolor);

image2.SetPixel((2 * x) + 1, 2 * y, pixelcolor);

image2.SetPixel(2 * x, (2 * y) + 1, pixelcolor);

image2.SetPixel((2 * x) + 1, (2 * y) + 1, pixelcolor);

}

}

for (int x = 0; x <= Convert.ToInt32(Math.Round(widthBaru)) ; x++)

{

for (int y = 0; y <= Convert.ToInt32(Math.Round(heightBaru)); y++)

{

//i[0] – i[8]

//averaging

nRed = Convert.ToInt32((pixelR[0] + pixelR[1] + pixelR[2] +

pixelR[3] + pixelR[4] + pixelR[5] + pixelR[6] + pixelR[7] + pixelR[8]) / 9);

nGreen = Convert.ToInt32((pixelG[0] + pixelG[1] + pixelG[2] +

pixelG[3] + pixelG[4] + pixelG[5] + pixelG[6] + pixelG[7] + pixelG[8]) / 9);

nBlue = Convert.ToInt32((pixelB[0] + pixelB[1] + pixelB[2] +

pixelB[3] + pixelB[4] + pixelB[5] + pixelB[6] + pixelB[7] + pixelB[8]) / 9);

if (nRed > 255)

nRed = 255;

else if (nRed < 0)

nRed = 0;

if (nGreen > 255)

nGreen = 255;

else if (nGreen < 0)

nGreen = 0;

if (nBlue > 255)

nBlue = 255;

else if (nBlue < 0)

nBlue = 0;

Color newpixelcolor = Color.FromArgb(nRed, nGreen, nBlue);

image2.SetPixel(x, y, newpixelcolor);

}

}

Rotates an image about its

center pixel through any

given angle.

270 degree

180 degree

90 degree

Rota 270

for (int x = 0; x < image1.Width; x++) { for (int y = 0; y < image1.Height; y++) { pixelcolor = image1.GetPixel(x, y);

image2.SetPixel(y, image2.Height - 1 - x, pixelcolor); } }

Rota 180

for (int x = 0; x < image1.Width; x++) { for (int y = 0; y < image1.Height; y++) { pixelcolor = image1.GetPixel(x, y);

image2.SetPixel(image2.Width - 1 - x, image2.Height - 1 - y, pixelcolor); } }

Rota 90

for (int x = 0; x < image1.Width; x++) { for (int y = 0; y < image1.Height; y++) { pixelcolor = image1.GetPixel(x, y);

image2.SetPixel(image2.Width - 1 - y, x, pixelcolor); } }

Translation is consists of

moving a section of the

image to another location

image. for (int x = 0; x < image1.Width; x++)

{

for (int y = 0; y < image1.Height; y++)

{

if(((x+transX)>=0)&&((x+transX)<image1.Width)&&

((y+transY)>=0)&&((y+transY)<image1.Height))

{

pixelcolor = image1.GetPixel(x, y);

int nX = x + transX;

int nY = y + transY;

image2.SetPixel(nX, nY, pixelcolor);

}

}

}

To mirror an image is to simpl

flip it about the x or y axis.

Horizontal

Vertical

Horizontal mirroring flips an

image about the y-axis.

for (y=0; y<rows; y++)

for (x=0; x<cols; x++)

DestImage[y*cos+x] =

SourceImage[y*cols+(cols-1-x)];

Vertical mirroring flips an

image about the x-axis.

for (y=0; y<rows; y++)

for (x=0; x<cols; x++)

DestImage[y*cos+x] =

SourceImage[(rows-1-y)*cols+x)];

Point Process

Area Process

Geometric Process

Frame Process