Image Filters

Interaction:

1. Initial run: program renders initial image with brushStrokes
2. TAB: fast-forward brushStrokes animation and progress into filter program with menu
   1. Filter menu: 7 thumbnails of different filters
3. MOUSE-CLICK on filter menu: applies filter to central image, cycling through levels of intensity or options where available on repeated clicks
4. BACKSPACE: load a new image 
5. ENTER/RETURN: save image in centre position
6. P: run brushStrokes animation over current central image (could be filtered)

Filters:

1. RGB filtering
   1. Preserve only R/G/B channel
   2. Interaction: cycle through R/G/B filtering
2. Basic toon shade: posterize + edge detection
   1. Simple attempt at a toon shader. 
   2. I blur the posterized image to create a softer look, and ever so slightly blur the edge so that random/anomalous edges don’t stick out too much.
   3. Then I add the pixel color values of these two images to create the toon look.
   4. Interaction: cycle through posterize levels
3. Edge detection
   1. Laplacian function with 8 neighbors
4. Threshold (single or multi level)
   1. For single, use threshold to set pixels with brightnesses below to black and above to white
   2. For multi, use multiple thresholds to set to black, white (as above) and shades of gray for values in between
   3. Interaction: cycle through single-threshold levels then end and stay on multithreshold
5. Halftoning
   1. Used above multi thresholding algorithm to render patterns of 2x2 pixels
   2. In order to do this, I doubled my ‘working space’ with the image, recorded my halftoned patterns into an output image of that double-size as well
   3. Then, I returned the output image sized down
6. Grayscale with intensity 
   1. Divide color value by intensity
   2. Interaction: cycle through intensity
7. Invert
   1. Subtract RGB channels from 255.0

Additional/helper filters:

1. Posterize with levels
   1. Reduce color depth by constraining RGB channels via given level

Code repository: https://github.com/SengulC/img_filters