SlideShare a Scribd company logo
William Ribarsky
(modified by Amos Johnson)
1
Aliasing & Anti-aliasing
William Ribarsky
(modified by Amos Johnson)
2
Aliasing
Aliasing is cause by the discrete nature of pixels (Sampling Error).
Approximation of lines and circles with discrete points often gives a staircase
appearance or "Jaggies".
Desired line
Aliased rendering of the line
William Ribarsky
(modified by Amos Johnson)
3
Anti-aliasing - Solutions
Aliasing can be smoothed out by using higher addressability.
If addressability is fixed but intensity is variable, use the intensity to control the
address of a "virtual pixel". Two adjacent pixels can be be used to give the
impression of a point part way between them. The perceived location of the
point is dependent upon the ratio of the intensities used at each. The
impression of a pixel located halfway between two addressable points can be
given by having two adjacent pixels at half intensity.
An antialiased line has a series of virtual pixels each located at the proper address.
William Ribarsky
(modified by Amos Johnson)
4
Anti-aliased Line Algorithm
Line drawing algorithms can easily be modified to implement virtual pixels. We use the
distance ( e ) value to determine pixel intensities.
Two possible cases which may occur for simple anti-aliased line algorithm:
B
C
D
e
A = max(e+0.5,1) - 1
B = 1 - abs(e-0.5)
C = 1 - min(e+0.5,1)
D = 0
0 <= e <=1.5 0 > e >= -1.5
A
B
C
D
e
A = 0
B = 1 + max(e-0.5, -1)
C = 1 - abs(e+0.5)
D = -min(e-0.5, -1) - 1
A
When color is used
rather than a grey
scale, the red, green
and blue components
are interpolated
separately to
determine each one's
proper intensity.
William Ribarsky
(modified by Amos Johnson)
5
Anti-aliased Circle Algorithm
Circle drawing algorithms can also be easily modified to implement virtual pixels.
Once again, we use the distance ( e ) value to determine pixel intensities.
Two possible cases which may occur for simple anti-aliased circle algorithm:
B
e
B = 1 - abs(e-0.5)
A = 1 - min(e+0.5,1)
0 <= e <= 1/2 0 > e >= -1/2
A
A = 1 - abs(e+0.5)
B = 1 + max(e-0.5, -1)
When color is used
rather than a grey
scale, the red, green
and blue components
are interpolated
separately to
determine each one's
proper intensity.
B
e
A

More Related Content

Similar to aliasing.ppt

Antialiasing
Antialiasing  Antialiasing
Antialiasing
Misha Ali
 
Lect14 lines+circles
Lect14 lines+circlesLect14 lines+circles
Lect14 lines+circles
Siddharth Maloo
 
A MEDIAN BASED DIRECTIONAL CASCADED WITH MASK FILTER FOR REMOVAL OF RVIN
A MEDIAN BASED DIRECTIONAL CASCADED WITH MASK FILTER FOR REMOVAL OF RVINA MEDIAN BASED DIRECTIONAL CASCADED WITH MASK FILTER FOR REMOVAL OF RVIN
A MEDIAN BASED DIRECTIONAL CASCADED WITH MASK FILTER FOR REMOVAL OF RVIN
ijistjournal
 
A MEDIAN BASED DIRECTIONAL CASCADED WITH MASK FILTER FOR REMOVAL OF RVIN
A MEDIAN BASED DIRECTIONAL CASCADED WITH MASK FILTER FOR REMOVAL OF RVINA MEDIAN BASED DIRECTIONAL CASCADED WITH MASK FILTER FOR REMOVAL OF RVIN
A MEDIAN BASED DIRECTIONAL CASCADED WITH MASK FILTER FOR REMOVAL OF RVIN
ijistjournal
 
Notes on image processing
Notes on image processingNotes on image processing
Notes on image processing
Mohammed Kamel
 
47549379 paper-on-image-processing
47549379 paper-on-image-processing47549379 paper-on-image-processing
47549379 paper-on-image-processing
maisali4
 
Image Restoration UsingNonlocally Centralized Sparse Representation and histo...
Image Restoration UsingNonlocally Centralized Sparse Representation and histo...Image Restoration UsingNonlocally Centralized Sparse Representation and histo...
Image Restoration UsingNonlocally Centralized Sparse Representation and histo...
IJERA Editor
 
channel_mzhazbay.pdf
channel_mzhazbay.pdfchannel_mzhazbay.pdf
channel_mzhazbay.pdf
Maksat Zhazbayev
 
Bw31494497
Bw31494497Bw31494497
Bw31494497
IJERA Editor
 
Optimization of Aberrated Coherent Optical Systems
Optimization of Aberrated Coherent Optical SystemsOptimization of Aberrated Coherent Optical Systems
Optimization of Aberrated Coherent Optical Systems
IOSR Journals
 
Advance image processing
Advance image processingAdvance image processing
Advance image processing
AAKANKSHA JAIN
 
Image Interpolation Techniques with Optical and Digital Zoom Concepts -semina...
Image Interpolation Techniques with Optical and Digital Zoom Concepts -semina...Image Interpolation Techniques with Optical and Digital Zoom Concepts -semina...
Image Interpolation Techniques with Optical and Digital Zoom Concepts -semina...
mmjalbiaty
 
Image segmentation
Image segmentationImage segmentation
Image segmentation
Rania H
 
A Novel Approach for Edge Detection using Modified ACIES Filtering
A Novel Approach for Edge Detection using Modified ACIES FilteringA Novel Approach for Edge Detection using Modified ACIES Filtering
A Novel Approach for Edge Detection using Modified ACIES Filtering
idescitation
 
Image Processing
Image ProcessingImage Processing
Image Processing
Tuyen Pham
 
Effective Pixel Interpolation for Image Super Resolution
Effective Pixel Interpolation for Image Super ResolutionEffective Pixel Interpolation for Image Super Resolution
Effective Pixel Interpolation for Image Super Resolution
IOSR Journals
 
Effective Pixel Interpolation for Image Super Resolution
Effective Pixel Interpolation for Image Super ResolutionEffective Pixel Interpolation for Image Super Resolution
Effective Pixel Interpolation for Image Super Resolution
IOSR Journals
 
Linear Image Processing
Linear Image Processing Linear Image Processing
Linear Image Processing
Avinash Rohra
 
M.sc. m hassan
M.sc. m hassanM.sc. m hassan
M.sc. m hassan
Ashraf Aboshosha
 
Lecture 5
Lecture 5Lecture 5
Lecture 5
Wael Sharba
 

Similar to aliasing.ppt (20)

Antialiasing
Antialiasing  Antialiasing
Antialiasing
 
Lect14 lines+circles
Lect14 lines+circlesLect14 lines+circles
Lect14 lines+circles
 
A MEDIAN BASED DIRECTIONAL CASCADED WITH MASK FILTER FOR REMOVAL OF RVIN
A MEDIAN BASED DIRECTIONAL CASCADED WITH MASK FILTER FOR REMOVAL OF RVINA MEDIAN BASED DIRECTIONAL CASCADED WITH MASK FILTER FOR REMOVAL OF RVIN
A MEDIAN BASED DIRECTIONAL CASCADED WITH MASK FILTER FOR REMOVAL OF RVIN
 
A MEDIAN BASED DIRECTIONAL CASCADED WITH MASK FILTER FOR REMOVAL OF RVIN
A MEDIAN BASED DIRECTIONAL CASCADED WITH MASK FILTER FOR REMOVAL OF RVINA MEDIAN BASED DIRECTIONAL CASCADED WITH MASK FILTER FOR REMOVAL OF RVIN
A MEDIAN BASED DIRECTIONAL CASCADED WITH MASK FILTER FOR REMOVAL OF RVIN
 
Notes on image processing
Notes on image processingNotes on image processing
Notes on image processing
 
47549379 paper-on-image-processing
47549379 paper-on-image-processing47549379 paper-on-image-processing
47549379 paper-on-image-processing
 
Image Restoration UsingNonlocally Centralized Sparse Representation and histo...
Image Restoration UsingNonlocally Centralized Sparse Representation and histo...Image Restoration UsingNonlocally Centralized Sparse Representation and histo...
Image Restoration UsingNonlocally Centralized Sparse Representation and histo...
 
channel_mzhazbay.pdf
channel_mzhazbay.pdfchannel_mzhazbay.pdf
channel_mzhazbay.pdf
 
Bw31494497
Bw31494497Bw31494497
Bw31494497
 
Optimization of Aberrated Coherent Optical Systems
Optimization of Aberrated Coherent Optical SystemsOptimization of Aberrated Coherent Optical Systems
Optimization of Aberrated Coherent Optical Systems
 
Advance image processing
Advance image processingAdvance image processing
Advance image processing
 
Image Interpolation Techniques with Optical and Digital Zoom Concepts -semina...
Image Interpolation Techniques with Optical and Digital Zoom Concepts -semina...Image Interpolation Techniques with Optical and Digital Zoom Concepts -semina...
Image Interpolation Techniques with Optical and Digital Zoom Concepts -semina...
 
Image segmentation
Image segmentationImage segmentation
Image segmentation
 
A Novel Approach for Edge Detection using Modified ACIES Filtering
A Novel Approach for Edge Detection using Modified ACIES FilteringA Novel Approach for Edge Detection using Modified ACIES Filtering
A Novel Approach for Edge Detection using Modified ACIES Filtering
 
Image Processing
Image ProcessingImage Processing
Image Processing
 
Effective Pixel Interpolation for Image Super Resolution
Effective Pixel Interpolation for Image Super ResolutionEffective Pixel Interpolation for Image Super Resolution
Effective Pixel Interpolation for Image Super Resolution
 
Effective Pixel Interpolation for Image Super Resolution
Effective Pixel Interpolation for Image Super ResolutionEffective Pixel Interpolation for Image Super Resolution
Effective Pixel Interpolation for Image Super Resolution
 
Linear Image Processing
Linear Image Processing Linear Image Processing
Linear Image Processing
 
M.sc. m hassan
M.sc. m hassanM.sc. m hassan
M.sc. m hassan
 
Lecture 5
Lecture 5Lecture 5
Lecture 5
 

More from AbdullahOmar64

Digital communcation for engineerings.pdf
Digital communcation for engineerings.pdfDigital communcation for engineerings.pdf
Digital communcation for engineerings.pdf
AbdullahOmar64
 
digital anlage c converter for digital .ppt
digital anlage c converter for digital .pptdigital anlage c converter for digital .ppt
digital anlage c converter for digital .ppt
AbdullahOmar64
 
LineCoding_ADCS.ppt
LineCoding_ADCS.pptLineCoding_ADCS.ppt
LineCoding_ADCS.ppt
AbdullahOmar64
 
companding.ppt
companding.pptcompanding.ppt
companding.ppt
AbdullahOmar64
 
The_Role_of_Raised_Cosine.pdf
The_Role_of_Raised_Cosine.pdfThe_Role_of_Raised_Cosine.pdf
The_Role_of_Raised_Cosine.pdf
AbdullahOmar64
 
09-SpreadSpectrum.ppt
09-SpreadSpectrum.ppt09-SpreadSpectrum.ppt
09-SpreadSpectrum.ppt
AbdullahOmar64
 
3-Matched-Filter.ppt
3-Matched-Filter.ppt3-Matched-Filter.ppt
3-Matched-Filter.ppt
AbdullahOmar64
 
mod.pptx
mod.pptxmod.pptx
mod.pptx
AbdullahOmar64
 
waveforms.ppt
waveforms.pptwaveforms.ppt
waveforms.ppt
AbdullahOmar64
 
Lecture_4_Data_Gathering_and_Analysis.pdf
Lecture_4_Data_Gathering_and_Analysis.pdfLecture_4_Data_Gathering_and_Analysis.pdf
Lecture_4_Data_Gathering_and_Analysis.pdf
AbdullahOmar64
 
INI_800_Lecture_1_Introduction.pdf
INI_800_Lecture_1_Introduction.pdfINI_800_Lecture_1_Introduction.pdf
INI_800_Lecture_1_Introduction.pdf
AbdullahOmar64
 
books-library.online-02011910Vr3Z0.pdf
books-library.online-02011910Vr3Z0.pdfbooks-library.online-02011910Vr3Z0.pdf
books-library.online-02011910Vr3Z0.pdf
AbdullahOmar64
 
نظم-العد.pdf
نظم-العد.pdfنظم-العد.pdf
نظم-العد.pdf
AbdullahOmar64
 
convert number.pdf
convert number.pdfconvert number.pdf
convert number.pdf
AbdullahOmar64
 
Guide latex.
Guide latex.Guide latex.
Guide latex.
AbdullahOmar64
 

More from AbdullahOmar64 (15)

Digital communcation for engineerings.pdf
Digital communcation for engineerings.pdfDigital communcation for engineerings.pdf
Digital communcation for engineerings.pdf
 
digital anlage c converter for digital .ppt
digital anlage c converter for digital .pptdigital anlage c converter for digital .ppt
digital anlage c converter for digital .ppt
 
LineCoding_ADCS.ppt
LineCoding_ADCS.pptLineCoding_ADCS.ppt
LineCoding_ADCS.ppt
 
companding.ppt
companding.pptcompanding.ppt
companding.ppt
 
The_Role_of_Raised_Cosine.pdf
The_Role_of_Raised_Cosine.pdfThe_Role_of_Raised_Cosine.pdf
The_Role_of_Raised_Cosine.pdf
 
09-SpreadSpectrum.ppt
09-SpreadSpectrum.ppt09-SpreadSpectrum.ppt
09-SpreadSpectrum.ppt
 
3-Matched-Filter.ppt
3-Matched-Filter.ppt3-Matched-Filter.ppt
3-Matched-Filter.ppt
 
mod.pptx
mod.pptxmod.pptx
mod.pptx
 
waveforms.ppt
waveforms.pptwaveforms.ppt
waveforms.ppt
 
Lecture_4_Data_Gathering_and_Analysis.pdf
Lecture_4_Data_Gathering_and_Analysis.pdfLecture_4_Data_Gathering_and_Analysis.pdf
Lecture_4_Data_Gathering_and_Analysis.pdf
 
INI_800_Lecture_1_Introduction.pdf
INI_800_Lecture_1_Introduction.pdfINI_800_Lecture_1_Introduction.pdf
INI_800_Lecture_1_Introduction.pdf
 
books-library.online-02011910Vr3Z0.pdf
books-library.online-02011910Vr3Z0.pdfbooks-library.online-02011910Vr3Z0.pdf
books-library.online-02011910Vr3Z0.pdf
 
نظم-العد.pdf
نظم-العد.pdfنظم-العد.pdf
نظم-العد.pdf
 
convert number.pdf
convert number.pdfconvert number.pdf
convert number.pdf
 
Guide latex.
Guide latex.Guide latex.
Guide latex.
 

Recently uploaded

Top EPC companies in India - Best EPC Contractor
Top EPC companies in India - Best EPC  ContractorTop EPC companies in India - Best EPC  Contractor
Top EPC companies in India - Best EPC Contractor
MangeshK6
 
Introduction And Differences Between File System And Dbms.pptx
Introduction And Differences Between File System And Dbms.pptxIntroduction And Differences Between File System And Dbms.pptx
Introduction And Differences Between File System And Dbms.pptx
SerendipityYoon
 
Online toll plaza booking system project report.doc.pdf
Online toll plaza booking system project report.doc.pdfOnline toll plaza booking system project report.doc.pdf
Online toll plaza booking system project report.doc.pdf
Kamal Acharya
 
21EC63_Module1B.pptx VLSI design 21ec63 MOS TRANSISTOR THEORY
21EC63_Module1B.pptx VLSI design 21ec63 MOS TRANSISTOR THEORY21EC63_Module1B.pptx VLSI design 21ec63 MOS TRANSISTOR THEORY
21EC63_Module1B.pptx VLSI design 21ec63 MOS TRANSISTOR THEORY
PradeepKumarSK3
 
Adv. Digital Signal Processing LAB MANUAL.pdf
Adv. Digital Signal Processing LAB MANUAL.pdfAdv. Digital Signal Processing LAB MANUAL.pdf
Adv. Digital Signal Processing LAB MANUAL.pdf
T.D. Shashikala
 
PPT_grt.pptx engineering criteria grt for accrediation
PPT_grt.pptx engineering criteria  grt for accrediationPPT_grt.pptx engineering criteria  grt for accrediation
PPT_grt.pptx engineering criteria grt for accrediation
SHALINIRAJAN20
 
Red Hat Enterprise Linux Administration 9.0 RH124 pdf
Red Hat Enterprise Linux Administration 9.0 RH124 pdfRed Hat Enterprise Linux Administration 9.0 RH124 pdf
Red Hat Enterprise Linux Administration 9.0 RH124 pdf
mdfkobir
 
RECENT DEVELOPMENTS IN RING SPINNING.pptx
RECENT DEVELOPMENTS IN RING SPINNING.pptxRECENT DEVELOPMENTS IN RING SPINNING.pptx
RECENT DEVELOPMENTS IN RING SPINNING.pptx
peacesoul123
 
Online airline reservation system project report.pdf
Online airline reservation system project report.pdfOnline airline reservation system project report.pdf
Online airline reservation system project report.pdf
Kamal Acharya
 
Quadcopter Dynamics, Stability and Control
Quadcopter Dynamics, Stability and ControlQuadcopter Dynamics, Stability and Control
Quadcopter Dynamics, Stability and Control
Blesson Easo Varghese
 
CONFINED SPACE ENTRY TRAINING FOR OIL INDUSTRY ppt
CONFINED SPACE ENTRY TRAINING FOR OIL INDUSTRY pptCONFINED SPACE ENTRY TRAINING FOR OIL INDUSTRY ppt
CONFINED SPACE ENTRY TRAINING FOR OIL INDUSTRY ppt
ASHOK KUMAR SINGH
 
Tutorial on MySQl and its basic concepts
Tutorial on MySQl and its basic conceptsTutorial on MySQl and its basic concepts
Tutorial on MySQl and its basic concepts
anishacotta2
 
ANATOMY OF SOA - Thomas Erl - Service Oriented Architecture
ANATOMY OF SOA - Thomas Erl - Service Oriented ArchitectureANATOMY OF SOA - Thomas Erl - Service Oriented Architecture
ANATOMY OF SOA - Thomas Erl - Service Oriented Architecture
Divya Rajasekar
 
CGR-Unit-1 Basics of Computer Graphics.pdf
CGR-Unit-1 Basics of Computer Graphics.pdfCGR-Unit-1 Basics of Computer Graphics.pdf
CGR-Unit-1 Basics of Computer Graphics.pdf
Rugved Collection
 
Girls Call Chennai 000XX00000 Provide Best And Top Girl Service And No1 in City
Girls Call Chennai 000XX00000 Provide Best And Top Girl Service And No1 in CityGirls Call Chennai 000XX00000 Provide Best And Top Girl Service And No1 in City
Girls Call Chennai 000XX00000 Provide Best And Top Girl Service And No1 in City
sunnuchadda
 
printing of ic circuits.pdf
printing       of        ic     circuits.pdfprinting       of        ic     circuits.pdf
printing of ic circuits.pdf
chidambaramnatarajar
 
Presentation slide on DESIGN AND FABRICATION OF MOBILE CONTROLLED DRAINAGE.pptx
Presentation slide on DESIGN AND FABRICATION OF MOBILE CONTROLLED DRAINAGE.pptxPresentation slide on DESIGN AND FABRICATION OF MOBILE CONTROLLED DRAINAGE.pptx
Presentation slide on DESIGN AND FABRICATION OF MOBILE CONTROLLED DRAINAGE.pptx
Er. Kushal Ghimire
 
李易峰祝绪丹做爱视频流出【网芷:ht28.co】可爱学生妹>>>[网趾:ht28.co】]<<<
李易峰祝绪丹做爱视频流出【网芷:ht28.co】可爱学生妹>>>[网趾:ht28.co】]<<<李易峰祝绪丹做爱视频流出【网芷:ht28.co】可爱学生妹>>>[网趾:ht28.co】]<<<
李易峰祝绪丹做爱视频流出【网芷:ht28.co】可爱学生妹>>>[网趾:ht28.co】]<<<
amzhoxvzidbke
 
d2d entrance exam imp ppt DDCET PHY sics
d2d entrance exam imp ppt DDCET PHY sicsd2d entrance exam imp ppt DDCET PHY sics
d2d entrance exam imp ppt DDCET PHY sics
UrvashiModashiya
 
Gas Turbine Principle and its Major Components.pdf
Gas Turbine Principle and its Major Components.pdfGas Turbine Principle and its Major Components.pdf
Gas Turbine Principle and its Major Components.pdf
Enrique Zuppelli
 

Recently uploaded (20)

Top EPC companies in India - Best EPC Contractor
Top EPC companies in India - Best EPC  ContractorTop EPC companies in India - Best EPC  Contractor
Top EPC companies in India - Best EPC Contractor
 
Introduction And Differences Between File System And Dbms.pptx
Introduction And Differences Between File System And Dbms.pptxIntroduction And Differences Between File System And Dbms.pptx
Introduction And Differences Between File System And Dbms.pptx
 
Online toll plaza booking system project report.doc.pdf
Online toll plaza booking system project report.doc.pdfOnline toll plaza booking system project report.doc.pdf
Online toll plaza booking system project report.doc.pdf
 
21EC63_Module1B.pptx VLSI design 21ec63 MOS TRANSISTOR THEORY
21EC63_Module1B.pptx VLSI design 21ec63 MOS TRANSISTOR THEORY21EC63_Module1B.pptx VLSI design 21ec63 MOS TRANSISTOR THEORY
21EC63_Module1B.pptx VLSI design 21ec63 MOS TRANSISTOR THEORY
 
Adv. Digital Signal Processing LAB MANUAL.pdf
Adv. Digital Signal Processing LAB MANUAL.pdfAdv. Digital Signal Processing LAB MANUAL.pdf
Adv. Digital Signal Processing LAB MANUAL.pdf
 
PPT_grt.pptx engineering criteria grt for accrediation
PPT_grt.pptx engineering criteria  grt for accrediationPPT_grt.pptx engineering criteria  grt for accrediation
PPT_grt.pptx engineering criteria grt for accrediation
 
Red Hat Enterprise Linux Administration 9.0 RH124 pdf
Red Hat Enterprise Linux Administration 9.0 RH124 pdfRed Hat Enterprise Linux Administration 9.0 RH124 pdf
Red Hat Enterprise Linux Administration 9.0 RH124 pdf
 
RECENT DEVELOPMENTS IN RING SPINNING.pptx
RECENT DEVELOPMENTS IN RING SPINNING.pptxRECENT DEVELOPMENTS IN RING SPINNING.pptx
RECENT DEVELOPMENTS IN RING SPINNING.pptx
 
Online airline reservation system project report.pdf
Online airline reservation system project report.pdfOnline airline reservation system project report.pdf
Online airline reservation system project report.pdf
 
Quadcopter Dynamics, Stability and Control
Quadcopter Dynamics, Stability and ControlQuadcopter Dynamics, Stability and Control
Quadcopter Dynamics, Stability and Control
 
CONFINED SPACE ENTRY TRAINING FOR OIL INDUSTRY ppt
CONFINED SPACE ENTRY TRAINING FOR OIL INDUSTRY pptCONFINED SPACE ENTRY TRAINING FOR OIL INDUSTRY ppt
CONFINED SPACE ENTRY TRAINING FOR OIL INDUSTRY ppt
 
Tutorial on MySQl and its basic concepts
Tutorial on MySQl and its basic conceptsTutorial on MySQl and its basic concepts
Tutorial on MySQl and its basic concepts
 
ANATOMY OF SOA - Thomas Erl - Service Oriented Architecture
ANATOMY OF SOA - Thomas Erl - Service Oriented ArchitectureANATOMY OF SOA - Thomas Erl - Service Oriented Architecture
ANATOMY OF SOA - Thomas Erl - Service Oriented Architecture
 
CGR-Unit-1 Basics of Computer Graphics.pdf
CGR-Unit-1 Basics of Computer Graphics.pdfCGR-Unit-1 Basics of Computer Graphics.pdf
CGR-Unit-1 Basics of Computer Graphics.pdf
 
Girls Call Chennai 000XX00000 Provide Best And Top Girl Service And No1 in City
Girls Call Chennai 000XX00000 Provide Best And Top Girl Service And No1 in CityGirls Call Chennai 000XX00000 Provide Best And Top Girl Service And No1 in City
Girls Call Chennai 000XX00000 Provide Best And Top Girl Service And No1 in City
 
printing of ic circuits.pdf
printing       of        ic     circuits.pdfprinting       of        ic     circuits.pdf
printing of ic circuits.pdf
 
Presentation slide on DESIGN AND FABRICATION OF MOBILE CONTROLLED DRAINAGE.pptx
Presentation slide on DESIGN AND FABRICATION OF MOBILE CONTROLLED DRAINAGE.pptxPresentation slide on DESIGN AND FABRICATION OF MOBILE CONTROLLED DRAINAGE.pptx
Presentation slide on DESIGN AND FABRICATION OF MOBILE CONTROLLED DRAINAGE.pptx
 
李易峰祝绪丹做爱视频流出【网芷:ht28.co】可爱学生妹>>>[网趾:ht28.co】]<<<
李易峰祝绪丹做爱视频流出【网芷:ht28.co】可爱学生妹>>>[网趾:ht28.co】]<<<李易峰祝绪丹做爱视频流出【网芷:ht28.co】可爱学生妹>>>[网趾:ht28.co】]<<<
李易峰祝绪丹做爱视频流出【网芷:ht28.co】可爱学生妹>>>[网趾:ht28.co】]<<<
 
d2d entrance exam imp ppt DDCET PHY sics
d2d entrance exam imp ppt DDCET PHY sicsd2d entrance exam imp ppt DDCET PHY sics
d2d entrance exam imp ppt DDCET PHY sics
 
Gas Turbine Principle and its Major Components.pdf
Gas Turbine Principle and its Major Components.pdfGas Turbine Principle and its Major Components.pdf
Gas Turbine Principle and its Major Components.pdf
 

aliasing.ppt

  • 1. William Ribarsky (modified by Amos Johnson) 1 Aliasing & Anti-aliasing
  • 2. William Ribarsky (modified by Amos Johnson) 2 Aliasing Aliasing is cause by the discrete nature of pixels (Sampling Error). Approximation of lines and circles with discrete points often gives a staircase appearance or "Jaggies". Desired line Aliased rendering of the line
  • 3. William Ribarsky (modified by Amos Johnson) 3 Anti-aliasing - Solutions Aliasing can be smoothed out by using higher addressability. If addressability is fixed but intensity is variable, use the intensity to control the address of a "virtual pixel". Two adjacent pixels can be be used to give the impression of a point part way between them. The perceived location of the point is dependent upon the ratio of the intensities used at each. The impression of a pixel located halfway between two addressable points can be given by having two adjacent pixels at half intensity. An antialiased line has a series of virtual pixels each located at the proper address.
  • 4. William Ribarsky (modified by Amos Johnson) 4 Anti-aliased Line Algorithm Line drawing algorithms can easily be modified to implement virtual pixels. We use the distance ( e ) value to determine pixel intensities. Two possible cases which may occur for simple anti-aliased line algorithm: B C D e A = max(e+0.5,1) - 1 B = 1 - abs(e-0.5) C = 1 - min(e+0.5,1) D = 0 0 <= e <=1.5 0 > e >= -1.5 A B C D e A = 0 B = 1 + max(e-0.5, -1) C = 1 - abs(e+0.5) D = -min(e-0.5, -1) - 1 A When color is used rather than a grey scale, the red, green and blue components are interpolated separately to determine each one's proper intensity.
  • 5. William Ribarsky (modified by Amos Johnson) 5 Anti-aliased Circle Algorithm Circle drawing algorithms can also be easily modified to implement virtual pixels. Once again, we use the distance ( e ) value to determine pixel intensities. Two possible cases which may occur for simple anti-aliased circle algorithm: B e B = 1 - abs(e-0.5) A = 1 - min(e+0.5,1) 0 <= e <= 1/2 0 > e >= -1/2 A A = 1 - abs(e+0.5) B = 1 + max(e-0.5, -1) When color is used rather than a grey scale, the red, green and blue components are interpolated separately to determine each one's proper intensity. B e A