DIP-Homework 1 Solved

Problem 1: WARM-UP 
(a) The goal of this problem is to get familiar with converting a color image to a grayscale one. Please convert the given color image, sample1.jpg, to a grayscale image named 1_result.jpg.

(b) Please also perform horizontal flipping on sample1.jpg and output the result as 2_result.jpg.

sample1.jpg

Problem 2: IMAGE ENHANCEMENT 
Given gray-level images sample2.jpg, sample3.jpg and sample4.jpg, please follow the instructions below to create several new images.

                             sample2.jpg                                   sample3.jpg         

(a) Decrease the brightness of sample2.jpg by dividing the intensity values by 5 and output the image as 3_result.jpg.

(b)  Increase the brightness of 3_result.jpg by multiplying the intensity values by 5 and output the image as 4_result.jpg.

(c) Plot the histograms of sample2.jpg, 3_result.jpg and 4_result.jpg. What can you observe from these three histograms?  

(d)  Perform global histogram equalization on sample3.jpg and output the results

5_result.jpg.

(e)  Perform local histogram equalization on sample3.jpg and output the results as 6_result.jpg.

(f)  Plot the histograms of 5_result.jpg and 6_result.jpg. What is the main difference between local and global histogram equalization?
sample4.jpg
 
(g)  Please design a transfer function to enhance sample4.jpg as best as you can. Output the result as 7_result.jpg and specify all the parameters.  

Show the resultant image(s) and the corresponding histogram(s). Please provide some discussions on the results as well.

Problem 3: NOISE REMOVAL 
Given an original image named sample5.jpg and two images corrupted by noise as shown in sample6.jpg and sample7.jpg, please follow the instructions below to create some new images.

(a) Design proper filters to remove noise from sample6.jpg and sample7.jpg, and output the resultant images as 8_result.jpg and 9_result.jpg, respectively.  

Please detail the steps of the denoising process and specify all the corresponding parameters. Provide some discussions about the reason why those filters and parameters are chosen.

(b)Compute the PSNR values of 8_result.jpg and 9_result.jpg and provide some discussions.

sample5.jpg
sample6.jpg             

sample7.jpg

Appendix

Problem 1: WARM-UP sample1.jpg            400×560  color

Problem 2: IMAGE ENHANCEMENT 

                sample2.jpg          400×560
gray-scale
                sample3.jpg          400×560
gray-scale
                sample4.jpg          400×560

Problem 3: NOISE REMOVAL 
gray-scale
                sample5.jpg          400×560
gray-scale
                sample6.jpg          400×560
gray-scale
                sample7.jpg          400×560
gray-scale