Image Processing
1 Lab Project
1.1 Lab Submission
Lego’s Life of George is a game where an image is displayed on the screen for a number of seconds before being blanked. The player of the game then has to construct the shape from Lego blocks from memory. The player photographs the finished blocks and their computer automatically compares the brick pattern to the original image. Similar problems are found in many image processing applications, for example the colour segmentation of real world objects; colour data matrix reading. A colour data matrix has the advantage over conventional blank and white versions in that more information can be stored for a given pattern. An example is shown in figure 1.
Figure 1: An example colour data matrix
For your project you will write software that automatically reads a colour pattern image from hard-disc and returns an array representing the colour pattern. An example image is shown in figure 2. Note the location of the black circles. These are for finding the edge of the image should you need to use them. There is no correct orientation - so your results may be flipped.
The images we become progressively more difficult, and you may not be able to solve them all. Ideally, the process should be fully automatic (for full marks) but this is not easy, so some manual intervention is allowed if you need to. Some images maybe impossible, if you cannot solve them please explain why.
1.2 The image files
There are two sets of images on Canvas
Figure 2: The Project colour matrix example
• images1 .zip and
• Photos .zip are a set of real photographs. Do not attempt to solve these, but comment on each one in your report.
1.3 What to do
• Write a function called findColours(filename) that given the string filename, loads an image and returns an array representing the colours found in the matrix. Please break this down into the following steps:
– findColours will call the following functions:
– A function image=loadImage(filename) that given the string filename, loads an image and returns the image as type double.
– A function, circleCoordinates = findCircles(image) the locates and returns the coordinates of the four black circles.
– A function the correctly un-distorts the images: correctImage(circleCoordinates , image). Note, images maybe flipped since there is no correct orientation.
– A function colours=getColours(image) the takes the double image array, image, and returns an array with the result of the colours. For now this will only use the undistorted images (org_X .png and noise_X .png) The colours used are red, green, yellow, blue and white.
In Matlab this is a 4 × 4 cell array that is holding char strings
Include in your main text what percentage of the images are correctly solved.
• Write in your report the percentage that are correct.
• You may of course write other helper functions to achieve this task, and a main script that calls the findColours function.
• In your report, discuss the real images. You do not need to run your program on them, but discuss any problems that might occur.
• In your report you should include a table of results for all the images. It should have the form.
Table 1: Results Table
1.4 Report
• Each of the above functions should have a separate section, describing how they work and discuss and design decisions that you made. The report should include an assess-ment of the performance of the functions, and suggest improvements that could be made.
• The length of the report should not exceed 1000 words, plus an appendix containing the results tables and a full code with listings of your code. Your code (i.e., the .m files) should be commented and also included so that I can run it. The report and the code should be submitted in a single ZIP file.
• The report format should be a PDF file only. Please do not submit Word files. I’m marking this on a Linux machine with no Word installed so submitting Word documents might will get corrupted and will certainly make me grumpy.
• This is to be submitted on-line. Seeyour timetable for the exact date and time.
• You should not submit copies of Matlab’s own functions or toolbox functions, though your code can call such functions freely.
• Code sections taken from the Internet must be cited in the comments.
• Programs that find accurate matches are, of course, likely to do well. However, the quality of the code and report will be important factors regardless of performance, and originality and ingenuity will betaken into account if you can’t solve all the images.
You can use any approach you wish – though if you want to try something that seems very different to the techniques described in the course it would be sensible to talk to me first. You are free to use any Matlab function or to download any addition Matlab library as long as it is fully referenced.
1.5 Marks
The breakdown of the marks:
The marks breakdown is given in the table 2.
Your code will be run against an unseen data set to get the results score. It is therefore very important to follow the instructions above about the function name and what they return. See Canvas for the exact specifications and examples.
Table 2: Marks breakdown