computer vision – overview
DESCRIPTION
Computer Vision – Overview. Hanyang University Jong-Il Park. Digital Image Processing. Sampling & Quantization Image Enhancement Image Restoration Image Coding( or Image Data Compression) Image Understanding( or Computer Vision). Image formation. Sampling & Quantization. - PowerPoint PPT PresentationTRANSCRIPT
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Computer Vision – Computer Vision – OverviewOverview
Hanyang University
Jong-Il Park
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Department of Computer Science and Engineering, Hanyang University
Digital Image ProcessingDigital Image Processing
Sampling & Quantization
Image Enhancement
Image Restoration
Image Coding( or Image Data Compression)
Image Understanding( or Computer Vision)
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Department of Computer Science and Engineering, Hanyang University
Image formationImage formation
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Department of Computer Science and Engineering, Hanyang University
Sampling & QuantizationSampling & Quantization
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Department of Computer Science and Engineering, Hanyang University
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Department of Computer Science and Engineering, Hanyang University
Subsampling & aliasingSubsampling & aliasing
aliasing
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Department of Computer Science and Engineering, Hanyang University
Sub-Nyquist samplingSub-Nyquist sampling
H ½, v ½ Org.
Circular Zone Plate
aliasing
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Department of Computer Science and Engineering, Hanyang University
Image EnhancementImage Enhancement
Goal to accentuate certain image features for subsequent
analysis or for image display
Input : image Output : image
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Department of Computer Science and Engineering, Hanyang University
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Department of Computer Science and Engineering, Hanyang University
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Department of Computer Science and Engineering, Hanyang University
Image EnhancementImage Enhancement
Techniques contrast/edge enhancement histogram equalization pseudo coloring noise filtering edge sharpening smoothing
Applications processing of remote-sensed image via satellite radar, SAR, Ultrasonic image processing
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Department of Computer Science and Engineering, Hanyang University
Image RestorationImage Restoration
Goal to remove or minimize known/unknown degradations in
image
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Department of Computer Science and Engineering, Hanyang University
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Department of Computer Science and Engineering, Hanyang University
Blur modelBlur model
estimate or recover f(x,y) from g(x,y)
deconvolution problem
modeldiscrete;or
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Department of Computer Science and Engineering, Hanyang University
Enhancement by integrationEnhancement by integration
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Department of Computer Science and Engineering, Hanyang University
Image RestorationImage Restoration
Techniques deblurring noise filtering correction of geometric distortion inverse filtering Least mean square(Wiener) filtering
Applications remote-sensed image processing noise cancellation
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Department of Computer Science and Engineering, Hanyang University
Image Data CompressionImage Data Compression Goal
to reduce the amount of data required to represent images
Input : image Output : bit-stream data
“010100101100110101001 . . . .”
moving image:1,0001,0008(bits/sample)330 frame/sec = 72107 bit/sec
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Department of Computer Science and Engineering, Hanyang University
2-2-D Image Compression, JPEGD Image Compression, JPEG
(a) 27.9 dB at 0.125 bpp (b) 31.5 dB at 0.25 bpp (c) 34.8 dB at 0.5 bpp
Image quality by JPEG
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Department of Computer Science and Engineering, Hanyang University
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Department of Computer Science and Engineering, Hanyang University
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Department of Computer Science and Engineering, Hanyang University
33D Mesh CompressionD Mesh Compression
Original ‘Bunny’
12 bpc 8 bpc10 bpc
Model # of Vertex
# of Triangle
Original (byte)
Compressed (byte)
12 bpc 10 bpc 8 bpc
Bunny 34835 69473 2,879,786 57,952 37,642 24,842
Compression ratio 50 : 1 77 : 1 116 : 1
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Department of Computer Science and Engineering, Hanyang University
Image Data CompressionImage Data Compression Techniques
Error-free coding( or lossless coding) Lossy compression Image Compression Standard
JPEG, H.261, H.263, MPEG-1,2,4 etc Applications
Transmission teleconferencing ,TV system, remote sensing via
satellite Storage
VOD(video on demand), Video CD, DVD(digital video disk), medical imaging, educational and business documents
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Department of Computer Science and Engineering, Hanyang University
Standard Application Bit rate
JPEG Still-image Variable
H.261 Visual telephony and video conferencing p64 kbps
H.263 < 64 kbps
MPEG-1 Full motion video on digital storage media 1.5 Mbps
MPEG-2 Higher resolution video than MPEG-1 2 Mbps
HDTV Terrestrial broad cast 20 Mbps
Image Coding StandardsImage Coding Standards
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Department of Computer Science and Engineering, Hanyang University
MPEGMPEG
MPEG-1 1992 Video CD Includes Audio Layer III (MP3)
MPEG-4 Part 1: 1998 Part 2: 1999 (addition still under development) Audio visual object Mobile telephony (IMT-2000) Interactivity Content –Based Interactivity
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Department of Computer Science and Engineering, Hanyang University
MPEG-7 2001 (addition still under development) Content Description Interface Metadata language and schemes for search & retrieval
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Department of Computer Science and Engineering, Hanyang University
Content-based Image RetrievalContent-based Image Retrieval
Image retrieval
Find similar images from
image database
Used features
Color
Texture
Shape
Query
Retrieved
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Department of Computer Science and Engineering, Hanyang University
Query Image
Image Data List
Retrieval Results
Texture Option
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Department of Computer Science and Engineering, Hanyang University
Video retrieval Scene change detection and key frame extraction Extracted key frame from a movie clip
Content-based Video RetrievalContent-based Video Retrieval
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Department of Computer Science and Engineering, Hanyang University
Video retrieval Automatic indexing Index from a news sequence
Content-based Video RetrievalContent-based Video Retrieval
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Department of Computer Science and Engineering, Hanyang University
Media Framework Tech.Media Framework Tech.
MPEG-21 All electronic creation, delivery and trade of digital
multimedia content Transparent usage of various content types on various
devices connected through various network
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Department of Computer Science and Engineering, Hanyang University
WatermarkingWatermarking
the process of embedding information into a host signal without changing perceived characteristics of the host
WatermarkEmbedding
Image/Document
* Filtering* Lossy Compression* Forgery* Cropping & Scaling* Geometric Distortion
WatermarkInformation
WatermarkGeneration
Key
WatermarkDetection
* Copy Protection* Fingerprinting* Authentification
Key
DecodedWatermark
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Department of Computer Science and Engineering, Hanyang University
Image UnderstandingImage Understanding
Goal to interpret or describe the meaning contained in the
image
Input : image Output : interpretation(description)
““KAISION”KAISION”
““circle”circle”
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Department of Computer Science and Engineering, Hanyang University
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Department of Computer Science and Engineering, Hanyang University
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Department of Computer Science and Engineering, Hanyang University
Stereo Vision (disparity map)Stereo Vision (disparity map)
기준 영상 ( 좌 ) 기준 영상 ( 우 )
변위 참 값 ( 붉은색 : 가리워짐 )
구한 변위 지도 ( 검은색 : 가리워짐 )
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Department of Computer Science and Engineering, Hanyang University
ModelModel image
Input scene
Scene matching result
Scene Matching (1)Scene Matching (1)
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Department of Computer Science and Engineering, Hanyang University
Model
Input image Edge image
Scene matching result
Scene Matching (2)Scene Matching (2)
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Department of Computer Science and Engineering, Hanyang University
– 크기 , 반지름
Fruit ClassifierFruit Classifier
Apple Orange Water Mellon
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Department of Computer Science and Engineering, Hanyang University
– color
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Department of Computer Science and Engineering, Hanyang University
Edge Detection
256)(256 Image Original Lena (a) 10) high 5, low 2,(Operator Canny (b)
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Department of Computer Science and Engineering, Hanyang University
Segmentation
(a) Aerial Original Image (b) Segmented Image
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Department of Computer Science and Engineering, Hanyang University
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Department of Computer Science and Engineering, Hanyang University
There are a lot of interesting topics to explore in image processing and computer vision.