CSCI 5280 Project 3

Contrast Preserving Decolorization

Xiong Yuanjun

SID: 1155018814

2013.3.26

# 1 Project Files

Matlab
Code

Test Images

Output Images

# 2 Project Description

Decolorization - the process to transform a color image to a grayscale
one - is a basic tool in digital printing, stylized black-and-white
photography, and in many single channel

image processing applications

### Model

The decolorization
function is defined as g = f(c), which is a mapping from color image c to gray
image g.

The mapping function is further expressed
as

where {m} is the set of monomial basis and {w} is the corresponding
coefficients.

With the weak color order assumption, the
energy function w.r.t parameter {w} can be finally written as

### Algorithm

The overall algorithm is like this

# 3 Implementation

The implementation is using MATLAB with the
skeleton code provided. The main acceleration skill is to use 2D filter [1,-1]
and [1;-1] to get the difference between neighbors.

# 4 Experiments

### Test Images

Here we got 10 test images, with different
contents. They are

Image
1 Image
2 Image
3 Image
4 Image
5

Image
6 Image
7 Image
8 Image
9 Image
10

### Parameters

In this program, there is one only one
parameter we need to set. That is the variation of Gaussian functions, .

Here I use the

### Experiment Results

Then we get 10 output image, listed below.
Their original image are shown next to each image.

### Numeric
Evaluation

Using the function ccpr(), we get the following
ccpr value:

We can set that the CCPR significantly
improved the contrast of decolorized picture.

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