COMPARATIVE STUDY ON THE IMAGE COMPRESSION OF PHOTO SHARING SITES USING MEAN SQUARE ERROR, PEAK SIGNAL TO NOISE RATIO AND DATA-RATE SAVINGS
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International Journal of Electrical, Electronics and Data Communication, ISSN: 2320-2084 Volume-5, Issue-6, Jun-2017
http://iraj.in
COMPARATIVE STUDY ON THE IMAGE COMPRESSION OF
PHOTO SHARING SITES USING MEAN SQUARE ERROR, PEAK
SIGNAL TO NOISE RATIO AND DATA-RATE SAVINGS
1
GIMA S. BATINGGAL, 2JASMIN D. NIGUIDULA
1
Colegio de San Juan de Letran-Calamba Bucal, Calamba City, Philippines
2
Technological Institute of the Philippines-Manila Manila, Philippines
E-mail: 1gsbatinggal@letran-calamba.edu.ph, 2jasniguidula@yahoo.com
Abstract- Nowadays, lots of people are very enthusiastic when it comes to sharing of photos in social media sites or photo
sharing sites (Madden, Lenhart, Cortesi, Gasser, Duggan, Smith and Beaton, 2013). However, it is observed that when
photos are uploaded the qualities of the pictures were reduced. This study evaluated the image compression of various sites
using mean square error (MSE), peak signal-to-noise ratio (PSNR) and data-rate savings to determine which site will
produce a better quality picture and allocates lesser memory space. The results attained from this study showed that there
are several photo sharing sites that gave out zero noise in image downloading and uses high data-rate saving.
Keywords- Netizens, reconstructed image, noise, dimension, bits per pixel
I. INTRODUCTION specifications as to the graphical formats that can be
used on the Web. All you need is a MIME type, so
According to Merriam Webster, “social media site is that the format is labeled correctly for transfer across
a form of electronic communication”. It was used for the Web.” Moreover, Facebook Help Center only
social networking and micro blogging. Netizens supports certain types of image formats and it
create communities online to share information and recommends using .jpg, .bmp, .png, .gif and .tiff
other contents like pictures and videos. files. However, Hill (2013) stated that “.tiff files are
Consumer psychologist Dr. Leah Tierney (2015) said huge and take forever to upload. That is why
people around the world are indulge in sending uploading .tiff is not worth the effort”.
messages in Tweeter, sharing information and life Furthermore, the study does not discuss how the
experiences on Facebook, current adventures on image compression algorithm works on these sites
Instagram, and uploading and downloading since the developers of the sites did not disclose
numerous videos on Youtube. In line with this, Dr. concrete data about their image compression
Tierner found out five main reasons why people algorithm. Text, audio and video are also not part of
behave the way they do. These includes: (1) to this study due to time constraints.
express one’s identity; (2) to build rapport; (3) for an The result of this study can be used as reference in
incentive; (4) to feel a sense of belonging; and (5) to understanding the level of distortion and data-rate
advocate great content”. saving found in the image compression of various
However, this doesn’t give the people knowledge on photo sharing sites.
which social media sites or photo sharing sites will
provide better quality pictures and will allocates II. LITERATURE REVIEW
lesser memory space. For this reason, the researchers
would like to evaluate the image compression of “Image compression is an application that reduces
various photo sharing sites by means of mean square the size of an image in bytes”. The reduction in file
error (MSE), peak signal-to-noise ratio (PSNR) and size allows extra amount of memory space and
data-rate saving. minimizes the time needed for pictures to be sent or
To identify which site to include in this study, the downloaded from World Wide Web (Bose,
researchers considered the best and most popular Madhulika, & Acharjee, 2014).
photo sharing websites. According to As regards to compression technique or compression
TrendingTopMost.com, AllTop9.com, algorithm, this actually refers to compression and
Techlicious.com and Tomsguide.com, the most reconstruction algorithm. According to Sayood
popular photo sharing sites include Facebook, (2006), “the compression algorithm takes an input X
Instagram, Imgur, Flickr, Photobucket, Shutterfly, and produces a representation Xc”. While the
SmugMug, Zenfolio, GooglePhotos and Tumblr. “reconstruction algorithm operates on the
Concerning image format, the researchers decided to compressed representation Xc to generate the
use JPG, GIF, PNG and BMP. According to reconstruction Y.” Compression algorithm can be
www.w3c.org, “there is no limit in the Web
Comparative Study on the Image Compression of Photo Sharing Sites using Mean Square Error, Peak Signal to Noise Ratio and Data-Rate
Savings
114
International Journal of Electrical, Electronics and Data Communication, ISSN: 2320-2084 Volume-5, Issue-6, Jun-2017
http://iraj.in
classified as lossless or lossy compression. Lossless
compression “guarantees full reconstruction of the
original data without incurring any distortion in the
process”. On the other hand, lossy compression
involves losses of some information from the original
data (Asolkar, Zope, Suralkar, 2013).
On the other hand, according to MathWorks.com,
there are two kinds of quality metrics for image.
These are peak signal to noise ratio or PSNR and
structural similarity or SSIM index. “PSNR is simple Figure 1. Screenshot of a Java Program that Gets the RGB
values of an Image
to calculate but sometimes does not align well with
perceived standard quality” while “SSIM is based on 3.2 Performance Evaluation Parameters
the principle that the human visual system is good 3.2.1 Data-Rate Saving
Data-rate saving metric is a measurement to know
for extracting information based on structure”.
the amount of storage reduced after an image
In addition, Huynh-Thu and Ghanbari (2012) have
compression.
shown that “PSNR can be a valid quality measure if
The equation for data-rate saving is:
the data content and the codec type are not changed”.
Data-rate saving = 100 – (1- B1 / B0)
Table 1 shpows the number of colors in an image
Where
according to the number of bits per pixel based
B0: refers to the file size of the original picture
onTutorialspoint.com.
Table 1. Number of Colors in an Image According B1: refers to the file size of the reconstructed picture
to Bits per Pixel For example:
If B0 = 80.4 KB and B1 = 30.4 KB then
3.2.2 PSNR and MSE
PSNR is a metric for comparing the reconstructed
image of different image compression algorithms.
III. METHODS According to National Instruments (2013), “PSNR
refers to the ratio between the maximum possible
3.1 Data Acquisition value (power) of a signal and the power of distorting
The experiment started with uploading and noise that affects the quality of its representation”.
downloading of 8-bit pictures in the photo sharing Different image compression algorithm can be
sites. The dimension of each downloaded images are compared scientifically using the same test image to
identified to know if the site is qualified for the determine which algorithm produces better results.
experiment. Instagram.com was excluded from this The formula for PSNR is:
study, because the dimension of the original test data PSNR = 20 log10 Maxf /√MSE
or image is not equal to the downloaded image. Where,
The researchers acquired the RGB values in the MAXf refers to the maximum signal value present in
picture using a java program. They used getWidth() the original image. For example, if the test data is an
and getHeight() methods to get the width and height 8-bit image, then Maxf value is 255 since the color
of an image. The values of width and height were for 8-bit image are 0 to 255. Take note that these
used in defining the length of the 2D image. Also, values have its corresponding color representation.
they applied the image.getRGB() method to get the MSE is a measure of level of distortion of the
red, green and blue (RGB) on every elements of the reconstructed image from the original image.
2D image. The equation for MSE is:
m-1 n-1
1 ∑ ∑ || f(i,j) – g(i,j) ||2
MSE = mn
Where 0 0
f is the array of data in the original image;
g is the array of data in the reconstructed image;
i refers to the index of each row in the 2D image;
j is the index of each column in the 2D image;
Comparative Study on the Image Compression of Photo Sharing Sites using Mean Square Error, Peak Signal to Noise Ratio and Data-Rate
Savings
115
International Journal of Electrical, Electronics and Data Communication, ISSN: 2320-2084 Volume-5, Issue-6, Jun-2017
http://iraj.in
m refers to the total number of vertical pixels in the have 0% data-rate savings since its file size does not
2D image and change after reconstruction.
n is the total number of horizontal pixels in the 2D
image.
On the other hand, a sample data were presented
below to show how to compute the PSNR and MSE
using the RGB values in Table 2 and Table 3.
Figure 2. Data-Rate Saving of the Test Data in JPG Format
Figure 3 shows that Facebook.com has the highest
data-rate saving based on its value of 90%. However,
Imgur.com, Flickr.com, Photobucket.com,
SmugMug.com, GooglePhotos.com and Tumblr.com
First, get the summation of difference between the
have 0% data-rate saving since its file size does not
original and reconstructed image.
change after reconstruction. The PNG file is not
supported in Shutterfly.com.
Second, compute the average of mseRed, mseGreen
and mseBlue.
Third, multiply the mseAverage to 1. Then divide
the product to the product of m and n, where m is the
Figure 3. Data-Rate Saving of the Test Data in PNG Format
number of vertical pixels and n is the number of
horizontal pixels.
Figure 4 shows that Facebook.com has the highest
data-rate saving based on its value of 78%. However,
Imgur.com, Flickr.com, Photobucket.com,
SmugMug.com, GooglePhotos.com and Tumblr.com
have 0% data-rate saving since its file size does not
Last, If MAXf is equal to 255 (using 8-bit image) change after reconstruction. The GIF file is not
then supported in Shutterfly.com.
3.3 Interpretation
The interpretation of the result is supported by what
is stated in the literature - the higher the data-rate
saving, the higher the data loss; the higher the mean
square error, the higher the noise or error; and the
higher the PSNR value, the greater the image
compression used.
IV. RESULTS AND DISCUSSIONS
The following figures and table provides the statistics Figure 4. Data-Rate Saving of the Test Data in GIF Format
and comparison of all photo sharing sites according
to data-rate saving, MSE and PSNR values. Figure 5 shows that Facebook.com has the highest
Figure 2 shows that Imgur.com has the highest data- data-rate saving of 93% while GooglePhotos.com has
rate savings based on its value of 66%. However, the lowest data-rate saving of 0%.
Flickr.com, Photobucket.com, Shutterfly.com,
SmugMug.com, GooglePhotos.com and Tumblr.com
Comparative Study on the Image Compression of Photo Sharing Sites using Mean Square Error, Peak Signal to Noise Ratio and Data-Rate
Savings
116
International Journal of Electrical, Electronics and Data Communication, ISSN: 2320-2084 Volume-5, Issue-6, Jun-2017
http://iraj.in
CONCLUSION
The study showed how to compare various photo
sharing sites using the equation of peak signal to
noise ratio and mean square error to determine
which site provides better quality picture. It also
showed how to determine which site has better
compression rate through data-rate saving equation.
Base on the data, there are sites with better image
quality representation based on its MSE value of 0db
Figure 5. Data-Rate Saving of the Test Data in BMP Format
however these sites also have 0% compression rate
Table 4 shows the MSE and PSNR of the base on its data-rate saving value. For these reasons,
reconstructed images from various photo sharing the researchers concluded that the data-rate saving of
sites. Based on its MSE value for JPG format, results a compressed image is directly proportional to the
have shown that apart from Facebook.com and value of MSE. If the data-rate saving of a site is
Imgur.com, the remaining sites did not produce lower than the other site, therefore the MSE value is
noise. also lower than the other site. If the data-rate saving
As for the PNG and GIF files, among the 8 sites only of a site is high then the level of noise in the
the downloaded image from Facebook.com produced reconstructed image is also high. In addition, it was
noise. observed that the photo sharing site with the highest
For the BMP file, the downloaded images from distortion or noise base on its MSE value have low
Photobucket.com and GooglePhotos.com. have zero PSNR value. For these reason, the researchers
MSE value (noise). concluded that MSE is indirectly proportional to the
value of peak signal-to-noise ratio (PSNR). If a site
Table 4 Summary Results of Computed PSNR and MSE using has low MSE value, you can expect that this site has
the downloaded images from various Photo Sharing Sites high PSNR value. Thus, if a site has high MSE
value, therefore the quality of image representation is
low. In summary, no photo sharing site can provide
better quality pictures without sacrificing the time it
takes to upload and download pictures because as
what the researchers concluded earlier, the data-rate
saving is directly proportional to MSE and MSE is
indirectly proportional to PSNR.
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Comparative Study on the Image Compression of Photo Sharing Sites using Mean Square Error, Peak Signal to Noise Ratio and Data-Rate
Savings
117
International Journal of Electrical, Electronics and Data Communication, ISSN: 2320-2084 Volume-5, Issue-6, Jun-2017
http://iraj.in
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