Unit 4 DIP Questions and Answers
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Below we've given Unit 4 Image Segmentation of DIP | Share it to your friends .
Get all possible questions for EC2029 Digital Image Processing (DIP) of Anna University students,here in StudentsIdea.
You may need to know:
* Unit 1 Two Marks & Answers
* Unit 2 Two Marks & Answers
* Unit 3 Two Marks & Answers
* 16 Marks for All 5 Units
Students,if you have any queries please feel free to post it via comments.Also share your ideas,suggestions,to us here : studentshell@gmail.com
Below we've given Unit 4 Image Segmentation of DIP | Share it to your friends .
UNIT IV IMAGE SEGMENTATION
1. What is image compression?
Image compression refers to the process of redundancy amount of data required to
represent the given quantity of information for digital image. The basis of reduction
process is removal of redundant data.
2. What is Data Compression?
Data compression requires the identification and extraction of source redundancy.
In other words, data compression seeks to reduce the number of bits used to store or transmit information.
3. What are two main types of Data compression?
Lossless compression can recover the exact original data after compression. It is
used mainly for compressing database records, spreadsheets or word processing
files, where exact replication of the original is essential.
Lossy compression will result in a certain loss of accuracy in exchange for a
substantial increase in compression. Lossy compression is more effective when
used to compress graphic images and digitised voice where losses outside visual
or aural perception can be tolerated.
4. What is the need for Compression?
In terms of storage, the capacity of a storage device can be effectively increased with methods that compress a body of data on its way to a storage device and decompresses it when it is retrieved.
In terms of communications, the bandwidth of a digital communication link can be
effectively increased by compressing data at the sending end and decompressing data at the receiving end.
At any given time, the ability of the Internet to transfer data is fixed. Thus, if data can effectively be compressed wherever possible, significant improvements of data
throughput can be achieved. Many files can be combined into one compressed document making sending easier.
5. What are different Compression Methods?
Run Length Encoding (RLE)
Arithmetic coding
Huffman coding and
Transform coding
6. Define is coding redundancy?
If the gray level of an image is coded in a way that uses more code words than
necessary to represent each gray level, then the resulting image is said to contain coding redundancy.
7. Define interpixel redundancy?
The value of any given pixel can be predicted from the values of its neighbors.
The information carried by is small. Therefore the visual contribution of a single pixel to an image is redundant. Otherwise called as spatial redundant geometric redundant or
8. What is run length coding?
Run-length Encoding, or RLE is a technique used to reduce the size of a repeating
string of characters. This repeating string is called a run; typically RLE encodes a run of symbols into two bytes, a count and a symbol. RLE can compress any type of data regardless of its information content, but the content of data to be compressed affects the compression ratio. Compression is normally measured with the compression ratio:
9. Define compression ratio.
Compression Ratio = original size / compressed size: 1
10. Define psycho visual redundancy?
In normal visual processing certain information has less importance than other
information. So this information is said to be psycho visual redundant.
11. Define encoder
Source encoder is responsible for removing the coding and interpixel redundancy
and psycho visual redundancy.
There are two components
A) Source Encoder
B) Channel Encoder
12. Define source encoder
Source encoder performs three operations
1) Mapper -this transforms the input data into non-visual format. It reduces the
interpixel redundancy.
2) Quantizer - It reduces the psycho visual redundancy of the input images .This
step is omitted if the system is error free.
3) Symbol encoder- This reduces the coding redundancy .This is the final stage of
encoding process.
13. Define channel encoder
The channel encoder reduces reduces the impact of the channel noise by inserting
DEPARTMENT OF ECE, ADHIPARASAKTHI COLLEGE OF ENGINEERING, KALAVAI.
EC2029 DIGITAL IMAGE PROCESSING
redundant bits into the source encoded data.
Eg: Hamming code
14. What are the types of decoder?
Source decoder- has two components
a) Symbol decoder- This performs inverse operation of symbol encoder.
b) Inverse mapping- This performs inverse operation of mapper.
Channel decoder-this is omitted if the system is error free.
15. What are the operations performed by error free compression?
1) Devising an alternative representation of the image in which its interpixel
redundant are reduced.
2) Coding the representation to eliminate coding redundancy
16. What is Variable Length Coding?
Variable Length Coding is the simplest approach to error free compression. It
reduces only the coding redundancy. It assigns the shortest possible codeword to the most probable gray levels.
17. Define Huffman coding
Huffman coding is a popular technique for removing coding redundancy.
When coding the symbols of an information source the Huffman code
yields the smallest possible number of code words, code symbols per
source symbol.
18. Define Block code
Each source symbol is mapped into fixed sequence of code symbols or code
words. So it is called as block code.
19. Define instantaneous code
A code word that is not a prefix of any other code word is called instantaneous or
prefix codeword.
20. Define uniquely decodable code
A code word that is not a combination of any other codeword is said to be
uniquely decodable code.
21. Define B2 code
Each code word is made up of continuation bit c and information bit which are
binary numbers. This is called B2 code or B code. This is called B2 code because two information bits are used for continuation bits
22. Define the procedure for Huffman shift
List all the source symbols along with its probabilities in descending order.
Divide the total number of symbols into block of equal size. Sum the probabilities of all the source symbols outside the reference block. Now apply the procedure for
reference block, including the prefix source symbol. The code words for the remaining symbols can be constructed by means of one or more prefix code followed by the reference block as in the case of binary shift code.
23. Define arithmetic coding
In arithmetic coding one to one corresponds between source symbols and code
word doesn’t exist where as the single arithmetic code word assigned for a sequence of source symbols. A code word defines an interval of number between 0 and 1.
24. What is bit plane Decomposition?
An effective technique for reducing an image’s interpixel redundancies is to
process the image’s bit plane individually. This technique is based on the concept of
decomposing multilevel images into a series of binary images and compressing each binary image via one of several well-known binary compression methods.
25. What are three categories of constant area coding?
The three categories of constant area coding are
All white
All black
Mixed intensity.
The most probable or frequency occurring is assign a 1 bit code ‘0’, other two
categories area assigned as 2 bit code ‘10’ and ‘11’
27. How effectiveness of quantization can be improved?
Introducing an enlarged quantization interval around zero, called a dead
zero.
Adapting the size of the quantization intervals from scale to scale. In
either case, the selected quantization intervals must be transmitted to the
decoder with the encoded image bit stream.
28. What are the coding systems in JPEG?
1. A lossy baseline coding system, which is based on the DCT and is
adequate for most compression application.
2. An extended coding system for greater compression, higher
precision or progressive reconstruction applications.
3. a lossless independent coding system for reversible compression.
29. What is JPEG?
The acronym is expanded as "Joint Photographic Expert Group". It is an
international standard in 1992. It perfectly Works with color and grayscale images, Many applications e.g., satellite, medical,...
30. What are the basic steps in JPEG?
The Major Steps in JPEG Coding involve:
_ DCT (Discrete Cosine Transformation)
_ Quantization
_ Zigzag Scan
DEPARTMENT OF ECE, ADHIPARASAKTHI COLLEGE OF ENGINEERING, KALAVAI.
EC2029 DIGITAL IMAGE PROCESSING
_ DPCM on DC component
_ RLE on AC Components
_ Entropy Coding
31. What is MPEG?
The acronym is expanded as "Moving Picture Expert Group". It is an international
standard in 1992. It perfectly Works with video and also used in teleconferencing
Input image Wavelet transform Quantizer Symbol
encoder
Symbol
decoder
Inverse wavelet
transform
Compressed
image
Compressed image
Decompressed
Image
32. Draw the JPEG Encoder.
33. Draw the JPEG Decoder.
34. What is zig zag sequence?
The purpose of the Zig-zag Scan:
_ To group low frequency coefficients in top of vector.
_ Maps 8 x 8 to a 1 x 64 vector
35. Define I-frame
I-frame is Intraframe or Independent frame. An I-frame is compressed
independently of all frames. It resembles a JPEG encoded image. It is the reference point for the motion estimation needed to generate subsequent P and P-frame.
36. Define P-frame
P-frame is called predictive frame. A P-frame is the compressed difference
between the current frame and a prediction of it based on the previous I or P-frame
37. Define B-frame
B-frame is the bidirectional frame. A B-frame is the compressed difference
between the current frame and a prediction of it based on the previous I or P-frame or next P-frame. Accordingly the decoder must have access to both past and future reference frames.
1. What is image compression?
Image compression refers to the process of redundancy amount of data required to
represent the given quantity of information for digital image. The basis of reduction
process is removal of redundant data.
2. What is Data Compression?
Data compression requires the identification and extraction of source redundancy.
In other words, data compression seeks to reduce the number of bits used to store or transmit information.
3. What are two main types of Data compression?
Lossless compression can recover the exact original data after compression. It is
used mainly for compressing database records, spreadsheets or word processing
files, where exact replication of the original is essential.
Lossy compression will result in a certain loss of accuracy in exchange for a
substantial increase in compression. Lossy compression is more effective when
used to compress graphic images and digitised voice where losses outside visual
or aural perception can be tolerated.
4. What is the need for Compression?
In terms of storage, the capacity of a storage device can be effectively increased with methods that compress a body of data on its way to a storage device and decompresses it when it is retrieved.
In terms of communications, the bandwidth of a digital communication link can be
effectively increased by compressing data at the sending end and decompressing data at the receiving end.
At any given time, the ability of the Internet to transfer data is fixed. Thus, if data can effectively be compressed wherever possible, significant improvements of data
throughput can be achieved. Many files can be combined into one compressed document making sending easier.
5. What are different Compression Methods?
Run Length Encoding (RLE)
Arithmetic coding
Huffman coding and
Transform coding
6. Define is coding redundancy?
If the gray level of an image is coded in a way that uses more code words than
necessary to represent each gray level, then the resulting image is said to contain coding redundancy.
7. Define interpixel redundancy?
The value of any given pixel can be predicted from the values of its neighbors.
The information carried by is small. Therefore the visual contribution of a single pixel to an image is redundant. Otherwise called as spatial redundant geometric redundant or
8. What is run length coding?
Run-length Encoding, or RLE is a technique used to reduce the size of a repeating
string of characters. This repeating string is called a run; typically RLE encodes a run of symbols into two bytes, a count and a symbol. RLE can compress any type of data regardless of its information content, but the content of data to be compressed affects the compression ratio. Compression is normally measured with the compression ratio:
9. Define compression ratio.
Compression Ratio = original size / compressed size: 1
10. Define psycho visual redundancy?
In normal visual processing certain information has less importance than other
information. So this information is said to be psycho visual redundant.
11. Define encoder
Source encoder is responsible for removing the coding and interpixel redundancy
and psycho visual redundancy.
There are two components
A) Source Encoder
B) Channel Encoder
12. Define source encoder
Source encoder performs three operations
1) Mapper -this transforms the input data into non-visual format. It reduces the
interpixel redundancy.
2) Quantizer - It reduces the psycho visual redundancy of the input images .This
step is omitted if the system is error free.
3) Symbol encoder- This reduces the coding redundancy .This is the final stage of
encoding process.
13. Define channel encoder
The channel encoder reduces reduces the impact of the channel noise by inserting
DEPARTMENT OF ECE, ADHIPARASAKTHI COLLEGE OF ENGINEERING, KALAVAI.
EC2029 DIGITAL IMAGE PROCESSING
redundant bits into the source encoded data.
Eg: Hamming code
14. What are the types of decoder?
Source decoder- has two components
a) Symbol decoder- This performs inverse operation of symbol encoder.
b) Inverse mapping- This performs inverse operation of mapper.
Channel decoder-this is omitted if the system is error free.
15. What are the operations performed by error free compression?
1) Devising an alternative representation of the image in which its interpixel
redundant are reduced.
2) Coding the representation to eliminate coding redundancy
16. What is Variable Length Coding?
Variable Length Coding is the simplest approach to error free compression. It
reduces only the coding redundancy. It assigns the shortest possible codeword to the most probable gray levels.
17. Define Huffman coding
Huffman coding is a popular technique for removing coding redundancy.
When coding the symbols of an information source the Huffman code
yields the smallest possible number of code words, code symbols per
source symbol.
18. Define Block code
Each source symbol is mapped into fixed sequence of code symbols or code
words. So it is called as block code.
19. Define instantaneous code
A code word that is not a prefix of any other code word is called instantaneous or
prefix codeword.
20. Define uniquely decodable code
A code word that is not a combination of any other codeword is said to be
uniquely decodable code.
21. Define B2 code
Each code word is made up of continuation bit c and information bit which are
binary numbers. This is called B2 code or B code. This is called B2 code because two information bits are used for continuation bits
22. Define the procedure for Huffman shift
List all the source symbols along with its probabilities in descending order.
Divide the total number of symbols into block of equal size. Sum the probabilities of all the source symbols outside the reference block. Now apply the procedure for
reference block, including the prefix source symbol. The code words for the remaining symbols can be constructed by means of one or more prefix code followed by the reference block as in the case of binary shift code.
23. Define arithmetic coding
In arithmetic coding one to one corresponds between source symbols and code
word doesn’t exist where as the single arithmetic code word assigned for a sequence of source symbols. A code word defines an interval of number between 0 and 1.
24. What is bit plane Decomposition?
An effective technique for reducing an image’s interpixel redundancies is to
process the image’s bit plane individually. This technique is based on the concept of
decomposing multilevel images into a series of binary images and compressing each binary image via one of several well-known binary compression methods.
25. What are three categories of constant area coding?
The three categories of constant area coding are
All white
All black
Mixed intensity.
The most probable or frequency occurring is assign a 1 bit code ‘0’, other two
categories area assigned as 2 bit code ‘10’ and ‘11’
27. How effectiveness of quantization can be improved?
Introducing an enlarged quantization interval around zero, called a dead
zero.
Adapting the size of the quantization intervals from scale to scale. In
either case, the selected quantization intervals must be transmitted to the
decoder with the encoded image bit stream.
28. What are the coding systems in JPEG?
1. A lossy baseline coding system, which is based on the DCT and is
adequate for most compression application.
2. An extended coding system for greater compression, higher
precision or progressive reconstruction applications.
3. a lossless independent coding system for reversible compression.
29. What is JPEG?
The acronym is expanded as "Joint Photographic Expert Group". It is an
international standard in 1992. It perfectly Works with color and grayscale images, Many applications e.g., satellite, medical,...
30. What are the basic steps in JPEG?
The Major Steps in JPEG Coding involve:
_ DCT (Discrete Cosine Transformation)
_ Quantization
_ Zigzag Scan
DEPARTMENT OF ECE, ADHIPARASAKTHI COLLEGE OF ENGINEERING, KALAVAI.
EC2029 DIGITAL IMAGE PROCESSING
_ DPCM on DC component
_ RLE on AC Components
_ Entropy Coding
31. What is MPEG?
The acronym is expanded as "Moving Picture Expert Group". It is an international
standard in 1992. It perfectly Works with video and also used in teleconferencing
Input image Wavelet transform Quantizer Symbol
encoder
Symbol
decoder
Inverse wavelet
transform
Compressed
image
Compressed image
Decompressed
Image
32. Draw the JPEG Encoder.
33. Draw the JPEG Decoder.
34. What is zig zag sequence?
The purpose of the Zig-zag Scan:
_ To group low frequency coefficients in top of vector.
_ Maps 8 x 8 to a 1 x 64 vector
35. Define I-frame
I-frame is Intraframe or Independent frame. An I-frame is compressed
independently of all frames. It resembles a JPEG encoded image. It is the reference point for the motion estimation needed to generate subsequent P and P-frame.
36. Define P-frame
P-frame is called predictive frame. A P-frame is the compressed difference
between the current frame and a prediction of it based on the previous I or P-frame
37. Define B-frame
B-frame is the bidirectional frame. A B-frame is the compressed difference
between the current frame and a prediction of it based on the previous I or P-frame or next P-frame. Accordingly the decoder must have access to both past and future reference frames.
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