Consider the following images. The purpose of this homework is to develop software that can distinguish blurry photographs of objects that may appear similar. You can write the programs using any programming language that you want.

You may find the code that changed the relative red/green/blue content of an image a useful starting point for your code. Note: be sure to check how many times you need to run fgets() at the top of the image. Different images may have more or fewer lines before the line that contains the number of columns and rows.

1. (0 points) Download the photographs and convert them from jpeg format to PGM (ascii) grey-scale format.
2. (20 points) Write and submit a program to produce a histogram of grey-scale values for each photograph. Plot and submit the histograms.
3. (10 points) Write and submit a program to implement a thresholding scheme. For pixels with values greater than the threshold value, assign a value of 255, and for pixels with values less than the threshold value, assign a value of zero. Use the histogram from the previous problem to determine a good threshold value. Plot and submit the resulting black and white images.
4. (Optional -- 20 points extra credit) Using one of the masks described in class, write a program to detect and plot the edges of the images.