rimgtool-vignette

Source: vignettes/rimgtool-vignette.Rmd

Introduction to rimgtool

This package provides three functions: - sharpen - compress - crop

As the name suggests, we aim to providing some tools for easy image processing. To use this package, follow the installation guide on README and install this package. Then, import the package.

Team Members

Name Github
Ruidan Ni rita-ni
Frank Lu Frank Lu
Kexin Zhao Margaret8521

Package Overview

rimgtool is a R package that is intended to allow users to compress, sharpen and crop an input image. Our package only allows the input image to be a 3D numpy array and output the manipulated image as a 3D numpy array. It contains three functions: compress(), sharpen(), and crop().

Feature Description

  • compress:
    • This function quantizes an image by restricting each pixel to only take on one of the desired colour values and return a version of the image (the same size as the original) where each pixel’s original colour is replaced with the nearest prototype colour.
  • sharpen:
    • This function enhances the edges in the image and returns a sharper-looking image. At this moment, this function is restricted to gray-scale images only
  • crop:
    • A function that removes border pixels for image croping until the desired width and height are reached.

Installation

You can install the development version from GitHub with:

# install.packages("devtools")
devtools::install_github("UBC-MDS/rimgtool")
#> Downloading GitHub repo UBC-MDS/rimgtool@master
#>   
   checking for file ‘/tmp/RtmpI2yYIv/remotes5ee65f5e5eb5/UBC-MDS-rimgtool-c70d854/DESCRIPTION’ ...
  
✓  checking for file ‘/tmp/RtmpI2yYIv/remotes5ee65f5e5eb5/UBC-MDS-rimgtool-c70d854/DESCRIPTION’
#> 
  
─  preparing ‘rimgtool’:
#>    checking DESCRIPTION meta-information ...
  
✓  checking DESCRIPTION meta-information
#> 
  
─  checking for LF line-endings in source and make files and shell scripts
#> 
  
─  checking for empty or unneeded directories
#> 
  
─  building ‘rimgtool_0.0.0.9000.tar.gz’
#> 
  
   
#> 
#> Installing package into '/tmp/RtmpZF4Lpy/temp_libpath5087cace86a'
#> (as 'lib' is unspecified)

Then, import this package in R console:

library(rimgtool)

Shrpen function

The purpose of this function is to detect and enhance the edges in a grey-scale image using a 2-D convolution so that the details can stand out. Displayed BELOW, the photo on the left-hand side is before sharpening, and the photo on the right-hand side is after sharpening. As the details are enhanced by our sharpening function, the center portion of the flower look more focused.

Apply sharpen function: sharpen(img)

# install.packages('jpeg')
library(jpeg)
img <- jpeg::readJPEG("img/free-wallpaper.jpg")
jpeg::writeJPEG(sharpen(img), target = 'img/sharpened.jpeg')

Compress function

We are going to use butterfly.jpg image which is in the img folder of this repository for illustration.

We can apply the compress function: compress(image, 4)

library(jpeg) # install.packages('jpeg')
library(OpenImageR) # install.packages('OpenImageR')
img <- jpeg::readJPEG("img/butterfly.jpg")
jpeg::writeJPEG(compress(img, 4L), target = 'img/compress.jpeg')

Crop function

We can also apply the crop function:

crop(img, 400, 400)

jpeg::writeJPEG(crop(img, 400, 400), target = 'img/crop.jpeg')