CSC1130 Introduction to Computing Using Java 2021-2022 First Term build an image processing app to process PPM a images.

INSTRUCTIONS TO CANDIDATES

ANSWER ALL QUESTIONS

Java Assignement

Copyright © 2021 CUHK, designed by Yim Pan, CHUI Page 1 of 4

Peacock Figure: adopted from public domain image source -

https://all-free-download.com/free-photos/download/proud_183457.html

CSC1130 Introduction to Computing Using Java 2021-2022 First Term

Department of Computer Science and Engineering, The Chinese University of Hong Kong

 

Expected normal time spent: 8 hours

Photo Kiosk

Aim: - build an image processing app to process PPM a

images.

- practise using existing classes/objects and creating our own methods.

- practise file I/O, String and 1D/2D array processing.

1. Firstly, the program prepares and displays some simple “default” images for your reference.

2. Then, it reads and shows some given PPM files:

3.

4.

5. The program may display some text via System.out for your own debugging purposes. If the user

clicks Close (×) button in any message dialog, act as if the user had clicked OK.

3. Then, it shows a

grayscale version of

“peacock_256.ppm”,

saves as “grayscale.ppm”.

a Portable Pixel Map (PPM) is a simple image file which supports RGB full colour images in ASCII text

format. Reference: https://en.wikipedia.org/wiki/Netpbm_format#PPM_example

4. Lastly, it shows a more

saturated version of

“peacock_256.ppm”, saves

as “saturate.ppm”.

Copyright © 2021 CUHK, designed by Yim Pan, CHUI Page 2 of 4

6. A client class PhotoKiosk is given. You are expected to complete the implementation of another class

PPM.

7. When reading a PPM image file, there may be various kinds of errors and issues such as file not found,

wrong file format, etc. Follow the given sample code to throw an Exception to indicate header

problem. You need NOT consider other kinds of file format issues. You may keep the given

Exception handling (try-catch) blocks.

8. Here is the expected standard PPM file format, free from additional features such as comment:

P3

width height

max_value

R G B R G B R G B...

R G B R G B R G B...

...

R G B R G B R G B...

The first two characters on the first line must be "P3".

Then 3 numbers follow: width and height define the size of the image;

max_value is usually 255 which indicates maximum possible value of a pixel component value.

R, G, B’s are red, green and blue pixel component values defining a full colour image in RGB. All

values shall fall within 0 and max_value, i.e., usually within 0 – 255.

There are height pixel lines run from top to bottom row-by-row. Each pixel line contains width

number of pixels, well, R, G, B triplets.

All numbers are delimited by white-spaces (including space, tab and newline.)

Therefore, Java Scanner class is well suited for reading the PPM file in plain text ASCII format.

The origin of the image and window coordinates system is always at the top-left corner.

9. In order to grayscale or saturate the image, you shall do processing in the YUV color space (a model

used in the PAL video standard) which defines one luminance component (Y) and two chrominance

components, called U (blue projection) and V (red projection); after processing, you convert back to a

RGB color. RGB to/from YUV Conversion b (scaled and offset version) is given by:

Y = (0.257 × R) + (0.504 × G) + (0.098 × B) + 16

U = -(0.148 × R) - (0.291 × G) + (0.439 × B) + 128

V = (0.439 × R) - (0.368 × G) - (0.071 × B) + 128

R = 1.164 × (Y - 16) + 1.596 × (V - 128)

G = 1.164 × (Y - 16) - 0.813 × (V - 128) - 0.391 × (U - 128)

B = 1.164 × (Y - 16) + 2.018 × (U - 128)

In both these cases, you have to clamp the output values to keep them in the [0-255] range, i.e., check

and rectify the resultant values in order to make negative values zero and make over-size values 255.

(0, 0)

row

column

width

height

b

"Video Demystified", Keith Jack (ISBN 1-878707-09-4).

Copyright © 2021 CUHK, designed by Yim Pan, CHUI Page 3 of 4

Procedure (Step-by-Step):

1. Before you code, revise the concepts in OOP, specifically how to define methods and constructors.

You will deal with 2D array of Color c

in this exercise.

2. Create a new NetBeans project PhotoKiosk with a default main class

photokiosk.PhotoKiosk. Copy the given code, Java source files and PPM files from Blackboard

into the proper locations under your project folder.

3. Client class PhotoKiosk is given. You are expected to complete the implementation of another class

PPM.

4. Your class PPM should provide methods to read PPM, write PPM, do color space conversion, as well as

grayscale/saturate the image.

a) To grayscale the image, you shall replace the R, G, B values with the luma component Y on the

current image.

 public PPM grayscale() {

 /*** student's work here to generate a grayscaled image based on Y ***/

 }

Newly generated image should be saved into a file named “grayscale.ppm”, and then go to the

next saturate image step.

b) To saturate the image more, you shall manipulate the two chrominance components U and V with

a simple linear scaling at middle-chroma by:

U’ = (U – 128 ) × S + 128

V’ = (V – 128 ) × S + 128

where U’ and V’ denote the new chrominance components while S is the saturation scale factor, we

assume S = 2 in this assignment. Updated YUV is mapped back to RGB; output values should be

clamped to keep them in the [0-255] range.

 public PPM saturate() {

 /*** student's work here to generate a more saturated image based on U & V ***/

 }

Newly generated image should be saved into a file named “saturate.ppm”, then program exits.

5. The newly saved files should usually reside in your NetBeans application project folder by default, in

the PPM format, again free from additional features such as comment.

6. Zip and Submit your whole NetBeans project folder in an archive file PhotoKiosk.zip via our

Online Assignment Collection Box on Blackboard https://blackboard.cuhk.edu.hk.

c

. java.awt.Color documentation: https://docs.oracle.com/javase/7/docs/api/java/awt/Color.html

Copyright © 2021 CUHK, designed by Yim Pan, CHUI Page 4 of 4

Marking Scheme and Notes:

1. The submitted program should be free of any typing mistakes, compilation errors and warnings.

2. Comment/remark, indentation, style are under assessment in every programming assignments unless

specified otherwise. Variable naming, proper indentation for code blocks and adequate comments are

important. Include also your personal particulars and your academic honesty declaration statement in a

header comment block of each source file.

3. Remember to upload your submission and click Submit before 6:00 p.m. of the due date. No late

submission would be accepted.

4. If you submit multiple times, ONLY the content and timestamp of the latest one would be counted.

You may delete (i.e. take back) your attached file and re-submit. We ONLY take into account the last

submission.

University Guideline for Plagiarism:

Attention is drawn to University policy and regulations on honesty in academic work, and to the

disciplinary guidelines and procedures applicable to breaches of such policy and regulations.

Details may be found at http://www.cuhk.edu.hk/policy/academichonesty/.

With each assignment, students are required to submit a statement that they are aware of these

policies, regulations, guidelines and procedures, in a header comment block.

 

Attachments:

Related Questions

. Introgramming & Unix Fall 2018, CRN 44882, Oakland University Homework Assignment 6 - Using Arrays and Functions in C

DescriptionIn this final assignment, the students will demonstrate their ability to apply two ma

. The standard path finding involves finding the (shortest) path from an origin to a destination, typically on a map. This is an

Path finding involves finding a path from A to B. Typically we want the path to have certain properties,such as being the shortest or to avoid going t

. Develop a program to emulate a purchase transaction at a retail store. This program will have two classes, a LineItem class and a Transaction class. The LineItem class will represent an individual

Develop a program to emulate a purchase transaction at a retail store. Thisprogram will have two classes, a LineItem class and a Transaction class. Th

. SeaPort Project series For this set of projects for the course, we wish to simulate some of the aspects of a number of Sea Ports. Here are the classes and their instance variables we wish to define:

1 Project 1 Introduction - the SeaPort Project series For this set of projects for the course, we wish to simulate some of the aspects of a number of

. Project 2 Introduction - the SeaPort Project series For this set of projects for the course, we wish to simulate some of the aspects of a number of Sea Ports. Here are the classes and their instance variables we wish to define:

1 Project 2 Introduction - the SeaPort Project series For this set of projects for the course, we wish to simulate some of the aspects of a number of