Two ways to compress your images!
This R package specializes in reducing the size of images. It contains two main functions :crop(), and compress(). The crop() functions reduce the size of an image by reducing the height and width of an image to the size specified by the user. The compress() function reduces the size of an image by reducing the number of bits used in each colour channel of the image. The package could be used by people to reduce the size of images, which could then be uploaded to social media platforms or other websites and applications that have limits on image size.
crop(img_path, H, W, out_path)
- Description: This function reduces the image to the specified size by removing rows and columns of pixels from the borders.
- Inputs:
| Parameter | Type | Description |
|---|---|---|
img_path |
string |
File path to a png image |
H |
int |
Desired height of the cropped image |
W |
int |
Desired width of the cropped image |
out_path |
string |
File path to where to save the cropped png image |
- Output:
string, file path to cropped image (pngimage with sizeH x W)
compress(image, b, out_path)
- Description: This function compresses the image by reducing the number of bits for each channel based on user input.
- Inputs:
| Parameter | Type | Description |
|---|---|---|
img_path |
string |
File path to a png image |
b |
int |
An integer between 1 and 8; number of bits used for each channel in the compressed image |
out_path |
string |
File path to where to save the compressed png image |
- Output:
string, file path to the compressedpngimage
image_size(image)
- Description: Calculates and returns the size of an image in bytes.
- Input:
string, file path to apngimage
- Output:
int, size of the image in bytes
To install this package, use the following command in the R console:
devtools::install_github("UBC-MDS/image-compression-toolkit--R", build_opts = c("--no-resave-data", "--no-manual"))
| Task | In a Script (after, library(imageCompress)) |
|---|---|
Crop image.png to size 10 X 15 |
crop("../image.png", H = 10L, W = 15L, "..//cropped_image.png") |
Compress an image.png to 5 bits per channel |
compress("..//image.png", b = 5L, "..//compressed_image.png") |
Get the size of image.png |
image_size("..//image.png") |
The following examples use the bigger_test.png image from the data folder, displayed below.
To get the size of the image:
library(imageCompress)
image_size("../data/bigger_test.png")
This returns the size of the image in bytes.
45534
To crop the image:
crop("../data/bigger_test.png", 175L, 200L, "../data/crop_img.png")
This returns the absolute file path to the cropped image, as specified in the
out_pathargument of the function. The cropped image is shown below.
..data/cropped_img.png
To compress the image:
compress("..data/bigger_test.png", 2L, "../data/compressed_img.png")
This returns the absolute file path to the compressed image. The compressed image is shown below.
..data/compressed_img.png
There already are packages for image processing in R and Python:
The existing packages are very comprehensive and provide many functions such as transformations, filters, file conversions and other advanced functions. Our package focuses specifically on image compression and reducing image size using K-means clustering. This package is not a wrapper or an improvement of an existing package. It simply uses an unsupervised learning algorithm (K-means clustering) to reduce the number of bits used to represent an image.