Tuesday, June 10, 2014

PROS and CONS of JPEG Image Compression

JPEG format is one of the most commonly used formats for storing images and photographs. JPEG is an abbreviation of Joint Photographic Expert Group. There are two major categories of JPEG format, one is used by digital cameras to capture and store photographs, called JPEG/Exif format. The other category of JPEG format is JPEG/JFIF format which is mostly used for image transferring and image storing.

Advantages of JPEG Image Format
There are several advantages of JPEG image format.
  • JPEG format has been in use since long time and is extremely portable.
  • JPEG format is compatible with almost every image processing application.
  • JPEG format is compatible with most of the hardware devices e.g printers etc; therefore it is very easy to print the images in JPEG format.
  • JPEG format can be used to store high resolution fast moving images which would be blur in other image formats because owing to their small size, JPEG images can be stored quickly from a camera to storage device.
  • Size of JPEG images can be reduced and compressed which makes this file format suitable for transferring images over the internet because it consumes less bandwidth. A JPEG image can be compressed down to 5% of its original size.
There are plenty of advantages of JPEG Image format; however there are certain disadvantages and drawbacks of these images as well which are of major concern for the photographers and computer scientist which cannot be neglected.
Disadvantages of JPEG Image Format
  • JPEG compression technique is a lossy compression. Lossy compression means that after image is compressed in JPEG format, it loses certain actual contents of the image.
  • Quality of Image is reduced after JPEG compression owing to the loss of actual content of the image.
  • JPEG image compression is not suitable for images with sharp edges and lines. JPEG image format is not capable of handling animated graphic images.
  • JPEG images do not support layered images. Graphic designer need to work on layered images in order to manipulate and edit graphic images which is not possible with JPEG Images.
  • Only 8 bit images are supported by JPEG format. On the other hand, modern high resolution digital cameras support 10, 12, 14 or 16 bit images. If these images are stored in JPEG format, extra information is discarded, resulting in decreased image quality.
JPEG Compression for Barcodes and Facial Images
Barcode in JPEG format reading by BarCode Reader
As discussed, JPEG compression results in loss of data. JPEG compression should not be used to store barcodes. Storing barcodes in JPEG format can result in distorted barcode pattern and can add noise to the barcode image which makes it very difficult for barcode scanners to decode the actual contents of the barcode. Similarly JPEG compression is not suitable for storing facial. It can make it difficult for face recognition softwares to recognize facial images compressed with JPEG compression technique.
It can be concluded from aforementioned facts that JPEG images should only be used in case you want small sized, portable images with smooth edges and color contrast, irrespective of the image quality; however if you want high resolution editable images with sharp contrast, using JPEG image is not a good choice and other image formats such PNG and GIF should be considered which are based on lossless compression algorithms.

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