panoramic viewfinder

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panoramic viewfinder

• patrick baudisch
• desney tan, drew steedly,eric rudolph, matt
  uyttendaele,chris pal, and richard szeliski
• microsoft research
• OZCHI 2005

Preview overall area covered so far
Cropping frame this area will survive cropping
Viewfinder what the camera sees right now
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summary
ultra portable PC web cam
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stitching photos intoa panorama
from photos Teodosio Bender, 1993 from video
Irani and Anandan, 1998
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stitching allows taking wide-angle pictures
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... getting hi-res photos
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but sometimesit goes wrong
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but sometimesit goes wrong

• missing content (65 respondents)
• tricky because of perspective projections
• ghosting (88 respondents)
• hard to detect
• stitching failed (38 respondents)
• lack of overlap, of texture, of focus
• when users notice flaws it is too late

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• panoramicviewfinder

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user interface
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walkthrough goal
building 114
building 115
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walkthrough
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post-processing

• restitching
• upload photo to PC
• restitch using our high-quality offline stitcher
• ? maximum image quality

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post-processing

• auto cropping to rectangular shape
• all desired content is preserved
• ? cropping frame guarantees this
• or manual cropping

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live demo
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(No Transcript)
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dealing with stitching failure

• if user moves camera too quickly (or lack of
  texture)
• viewfinder remains stationary
• but continues to update
• turns red, error sound
• to fix the problem
• pan camera back halfways inside panorama
• and take an additional shot
• or zoom out
• alert ends when next match is found

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• the real-timecropping frame...

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is the key component

• cropping frame tells users when they are done ?
  it is the focus of the users attention
• (traditional viewfinder is focus of attention)

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interaction

• requirements
• goal make sure we have enough content
• too much content is ok
• resulting design control cropping frame
  indirectly by adding content
• no resize handles!
• users can focus on pointing camera
• interaction transfers to consumer camera

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what it does not do

• for artistic reasons, user may want to crop
• cannot crop panorama while shooting
• crop offline, with all other photos

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• related work

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related work

• stitch arbitrary order and arrangement Szeliski
  Shum 97
• real-time Peleg and Herman, 1997

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our focus

• user interface
• preview to help users create successful panorama
• match the interaction model of existing digital
  cameras ? allow port to existing camera
  interaction mechanisms

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stitch assist
canon powershot S230? only horizontal
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related work on interaction
tiltable interfacesRekimoto 1996
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• implementation

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computing panorama

• written in C, frontend GDI and DirectX9
• feature-based stitching Brown et al 92
• uses same libraries as off-line stitcher
• extracting multi-scale oriented patches
• matching with previous image
• estimating camera orientation
• warping image
• Difference keep existing panorama unchanged
• benefit faster ( constant time)
• drawback more accumulation error

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capture modes

• video mode
• accumulates calibration error (Sawney et al. 98)
• auto mode
• snap picture only when necessary
• manual mode
• best control, avoid motion blur

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computing cropping frame

• naive O(n4), but we do it in O(n2)
• step 1 downsample image by factor 4
• step 2 for each pixel
• compute hor and vert spans
• step 3 for each pixel
• upper bound hor span x vert span
• if (upper bound lt current max) move on
• else traverse down

length of horizontalspan starting at this pixel
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• future work conclusion

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future user study...

• as soon as we have a more reliable stitcher
• consider mocking-up stitcher to simulate 100
  reliability

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• Losing track ? breaks the flow
• Even with perfect stitcher there will be
  stitching failures
• We need to be able to lose track without breaking
  the flow

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code editing

1. Batch compiler
2. Forced syntax
3. Curly underlines

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Last frame added to the panorama
Panorama largest sub panorama created so far
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Viewfinder what thecamera sees right now
Burst buffer pictures taken, but not processed
Recycle buffer of frames not yet matched
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future form factor
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future

• start thinking about using cameras in mobile
  phones as pointing devices

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conclusions

• one step closer to makingprocess of taking
  panoramic picturessimilar toprocess of taking
  normal photos

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read more try out
patrickbaudisch.com/projects
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• END