Introduction of Compression Technology
What is Data Compression?
Data compression uses different techniques to reduce number of bits required to represent an image or video in the form of bits.
it is an art or science of representing information in compressed form.
Applications : Audio
Text
Photography / Image
it is an art or science of representing information in compressed form.
Applications : Audio
Text
Photography / Image
Video
There are 2 compression techniques:
1) Lossy compression
2) Lossless compression
What is lossy compression?
Original Data ≠ Decompressed Data
Loss of Information
Loss of Information
Its compression ratio is > 4:1
Quality of Information is Change
Applications: Audio,Video, Image
In lossy compression data is loss after compression.
Quality of Information is Change
Applications: Audio,Video, Image
In lossy compression data is loss after compression.
What is lossless compression?
Original Data = Decompressed Data
No loss of information
Its compression ratio is 4:1
Quality of Information is not Change
Applications: Text (applicable on text)
In lossless compression data is not loss after compression.
Measures of Performance:
1) Compression Ratio
2) Rate
3) Distortion
4) Space saving / Saving percentage
1.Compression Ratio
Compression ratio is the ratio between number of bits to represent an information in form of bits before compression.
Quality of Information is not Change
Applications: Text (applicable on text)
In lossless compression data is not loss after compression.
Measures of Performance:
1) Compression Ratio
2) Rate
3) Distortion
4) Space saving / Saving percentage
1.Compression Ratio
Compression ratio is the ratio between number of bits to represent an information in form of bits before compression.
Compression Ratio= Bits before compression /bits after compression
2.Rate
Rate is the average number of bits required to represent a single sample of information.
3.Distortion:
It is the difference between the original data & reconstructed data after decompress. It shows the amount of information lost due to compression.
4. Space saving/ Saving Percentage
It is the reduction in size relative to the uncompressed data.
Space saving = 1- (compressed size / uncompressed size)
Rate is the average number of bits required to represent a single sample of information.
3.Distortion:
It is the difference between the original data & reconstructed data after decompress. It shows the amount of information lost due to compression.
4. Space saving/ Saving Percentage
It is the reduction in size relative to the uncompressed data.
Space saving = 1- (compressed size / uncompressed size)
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