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Efficient Algorithms for Destroyed Document Reconstruction
Stereo images rectification and disparity: which algorithms?Which algorithms are usable for heatmaps and what are their pros and consEfficient flood filling (seed filling)How to test image segmentation algorithms?Viewing images that compressed using lossless algorithmsSources on dictionary learning and related algorithmsHigh Dimensional Spaces for ImagesImage registration algorithms for images with varying distancesAlgorithms to correct misspelled word?More Efficient Feature Method Than Haar-Feature For Face Detection
$begingroup$
I am not certain this is the proper site for this question however I am mainly looking for resources on this topic (perhaps code). I was watching TV and one of the characters had a lawyer who destroyed his documents using a paper shredder. A lab tech said that the shredder was special.
I am not familiar with this area of computer science/ mathematics but I am looking for information on efficient algorithms to reconstruct destroyed documents. I can come up with a naive approach that is brute force fairly easily I imagine but just going through all the pieces and looking for edges that are the same but this doesn't sound feasible as the number of combinations will explode.
Note: By destroyed documents I am talking about taking a document (printed out) and then shredding it into small pieces and reassembling it by determining which pieces fit together.
image-processing
asked 3 hours ago
ShogunShogun
1085
New contributor
Shogun is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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$endgroup$
add a comment |
$begingroup$
I am not certain this is the proper site for this question however I am mainly looking for resources on this topic (perhaps code). I was watching TV and one of the characters had a lawyer who destroyed his documents using a paper shredder. A lab tech said that the shredder was special.
I am not familiar with this area of computer science/ mathematics but I am looking for information on efficient algorithms to reconstruct destroyed documents. I can come up with a naive approach that is brute force fairly easily I imagine but just going through all the pieces and looking for edges that are the same but this doesn't sound feasible as the number of combinations will explode.
Note: By destroyed documents I am talking about taking a document (printed out) and then shredding it into small pieces and reassembling it by determining which pieces fit together.
image-processing
asked 3 hours ago
ShogunShogun
1085
New contributor
Shogun is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
1
$begingroup$
Can you edit your question to define "destroyed documents"?
$endgroup$
– lox
2 hours ago
1
$begingroup$
You should look at the methods used to recover the Stasi (East German secret police) archives that were shredded or mostly -- oops all the shredders are broken from over use -- torn up after the fall of the Berlin Wall. The BBC has a very high-level summary.
$endgroup$
– David Richerby
2 hours ago
add a comment |
$begingroup$
I am not certain this is the proper site for this question however I am mainly looking for resources on this topic (perhaps code). I was watching TV and one of the characters had a lawyer who destroyed his documents using a paper shredder. A lab tech said that the shredder was special.
I am not familiar with this area of computer science/ mathematics but I am looking for information on efficient algorithms to reconstruct destroyed documents. I can come up with a naive approach that is brute force fairly easily I imagine but just going through all the pieces and looking for edges that are the same but this doesn't sound feasible as the number of combinations will explode.
Note: By destroyed documents I am talking about taking a document (printed out) and then shredding it into small pieces and reassembling it by determining which pieces fit together.
image-processing
asked 3 hours ago
ShogunShogun
1085
New contributor
Shogun is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
I am not certain this is the proper site for this question however I am mainly looking for resources on this topic (perhaps code). I was watching TV and one of the characters had a lawyer who destroyed his documents using a paper shredder. A lab tech said that the shredder was special.
I am not familiar with this area of computer science/ mathematics but I am looking for information on efficient algorithms to reconstruct destroyed documents. I can come up with a naive approach that is brute force fairly easily I imagine but just going through all the pieces and looking for edges that are the same but this doesn't sound feasible as the number of combinations will explode.
Note: By destroyed documents I am talking about taking a document (printed out) and then shredding it into small pieces and reassembling it by determining which pieces fit together.
image-processing
image-processing
asked 3 hours ago
ShogunShogun
1085
New contributor
Shogun is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 3 hours ago
ShogunShogun
1085
New contributor
Shogun is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 2 hours ago
Shogun
asked 3 hours ago
ShogunShogun
1085
New contributor
Shogun is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 3 hours ago
ShogunShogun
1085
asked 3 hours ago
ShogunShogun
1085
1085
New contributor
Shogun is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Shogun is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
1
$begingroup$
Can you edit your question to define "destroyed documents"?
$endgroup$
– lox
2 hours ago
1
$begingroup$
You should look at the methods used to recover the Stasi (East German secret police) archives that were shredded or mostly -- oops all the shredders are broken from over use -- torn up after the fall of the Berlin Wall. The BBC has a very high-level summary.
$endgroup$
– David Richerby
2 hours ago
add a comment |
1
$begingroup$
Can you edit your question to define "destroyed documents"?
$endgroup$
– lox
2 hours ago
1
$begingroup$
You should look at the methods used to recover the Stasi (East German secret police) archives that were shredded or mostly -- oops all the shredders are broken from over use -- torn up after the fall of the Berlin Wall. The BBC has a very high-level summary.
$endgroup$
– David Richerby
2 hours ago
1
1
$begingroup$
Can you edit your question to define "destroyed documents"?
$endgroup$
– lox
2 hours ago
$begingroup$
Can you edit your question to define "destroyed documents"?
$endgroup$
– lox
2 hours ago
1
1
$begingroup$
You should look at the methods used to recover the Stasi (East German secret police) archives that were shredded or mostly -- oops all the shredders are broken from over use -- torn up after the fall of the Berlin Wall. The BBC has a very high-level summary.
$endgroup$
– David Richerby
2 hours ago
$begingroup$
You should look at the methods used to recover the Stasi (East German secret police) archives that were shredded or mostly -- oops all the shredders are broken from over use -- torn up after the fall of the Berlin Wall. The BBC has a very high-level summary.
$endgroup$
– David Richerby
2 hours ago
add a comment |
1 Answer
1
active
oldest
votes
$begingroup$
Your problem is NP-Complete, even for strips (n strips yields (2n)!) used, so people use heuristics, transforms like Hough and morphological filters (to match continuity of text, but this heavily increases complexity for matching) or any kind of genetic / NN search, Ants Colony Optimization.
For summary of consecutive steps and various algorithm I recommend An Investigation into Automated Shredded Document Reconstruction using Heuristic Search Algorithms.
The problem itself may end up in nasty cases, when document is not fully sharp (blurred, printed with low resolution) and strips width is small and cut by physical cutter with dulled edges, because standard merging methods like panorama photo sticher gets lost and yield improper results. This is due to lost information by missing small strips, otherwise if you have full digital image cut into pieces, it is as hard as Jigsaw puzzle, non-digital image falls into approximate search.
To make algorithm automatic another problem is pieces feeding, rarely you can give axis aligned strips, so to start process it is nice to input all stripes as one picture with pieces lay by hand, this imposes another problem (this one is easy) to detect blobs and rotate them.
By special shredder instead of stripes yield very small rectangles. For comparison, P-1 class shredder gives stripes 6-12mm wide of any length (about 1800mm^2), class P-7 gives rectangles with area less than 5mm^2. When you get rectangles instead of stripes, problem yields (4n)! permutations, assuming one one-sided document, if there are lots of shreds from unrelated documents (no pictures, text only) in one bag, problem is not really tractable.
answered 2 hours ago
EvilEvil
8,47742447
$endgroup$
$begingroup$
There may be (2n)! arrangements of the shredded strips, but does that still determine the time complexity? Whenever you find "matches" you can "group" them together, behaving as a "thick strip", where only the first and last edge matter for the sake of comparison against other strips. This "clumping" should reduce the search space hugely, but IDK if it will still beO(n!)
$endgroup$
– Alexander
14 mins ago
add a comment |
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$begingroup$
Your problem is NP-Complete, even for strips (n strips yields (2n)!) used, so people use heuristics, transforms like Hough and morphological filters (to match continuity of text, but this heavily increases complexity for matching) or any kind of genetic / NN search, Ants Colony Optimization.
For summary of consecutive steps and various algorithm I recommend An Investigation into Automated Shredded Document Reconstruction using Heuristic Search Algorithms.
The problem itself may end up in nasty cases, when document is not fully sharp (blurred, printed with low resolution) and strips width is small and cut by physical cutter with dulled edges, because standard merging methods like panorama photo sticher gets lost and yield improper results. This is due to lost information by missing small strips, otherwise if you have full digital image cut into pieces, it is as hard as Jigsaw puzzle, non-digital image falls into approximate search.
To make algorithm automatic another problem is pieces feeding, rarely you can give axis aligned strips, so to start process it is nice to input all stripes as one picture with pieces lay by hand, this imposes another problem (this one is easy) to detect blobs and rotate them.
By special shredder instead of stripes yield very small rectangles. For comparison, P-1 class shredder gives stripes 6-12mm wide of any length (about 1800mm^2), class P-7 gives rectangles with area less than 5mm^2. When you get rectangles instead of stripes, problem yields (4n)! permutations, assuming one one-sided document, if there are lots of shreds from unrelated documents (no pictures, text only) in one bag, problem is not really tractable.
answered 2 hours ago
EvilEvil
8,47742447
$endgroup$
$begingroup$
There may be (2n)! arrangements of the shredded strips, but does that still determine the time complexity? Whenever you find "matches" you can "group" them together, behaving as a "thick strip", where only the first and last edge matter for the sake of comparison against other strips. This "clumping" should reduce the search space hugely, but IDK if it will still beO(n!)
$endgroup$
– Alexander
14 mins ago
add a comment |
$begingroup$
Your problem is NP-Complete, even for strips (n strips yields (2n)!) used, so people use heuristics, transforms like Hough and morphological filters (to match continuity of text, but this heavily increases complexity for matching) or any kind of genetic / NN search, Ants Colony Optimization.
For summary of consecutive steps and various algorithm I recommend An Investigation into Automated Shredded Document Reconstruction using Heuristic Search Algorithms.
The problem itself may end up in nasty cases, when document is not fully sharp (blurred, printed with low resolution) and strips width is small and cut by physical cutter with dulled edges, because standard merging methods like panorama photo sticher gets lost and yield improper results. This is due to lost information by missing small strips, otherwise if you have full digital image cut into pieces, it is as hard as Jigsaw puzzle, non-digital image falls into approximate search.
To make algorithm automatic another problem is pieces feeding, rarely you can give axis aligned strips, so to start process it is nice to input all stripes as one picture with pieces lay by hand, this imposes another problem (this one is easy) to detect blobs and rotate them.
By special shredder instead of stripes yield very small rectangles. For comparison, P-1 class shredder gives stripes 6-12mm wide of any length (about 1800mm^2), class P-7 gives rectangles with area less than 5mm^2. When you get rectangles instead of stripes, problem yields (4n)! permutations, assuming one one-sided document, if there are lots of shreds from unrelated documents (no pictures, text only) in one bag, problem is not really tractable.
answered 2 hours ago
EvilEvil
8,47742447
$endgroup$
$begingroup$
There may be (2n)! arrangements of the shredded strips, but does that still determine the time complexity? Whenever you find "matches" you can "group" them together, behaving as a "thick strip", where only the first and last edge matter for the sake of comparison against other strips. This "clumping" should reduce the search space hugely, but IDK if it will still beO(n!)
$endgroup$
– Alexander
14 mins ago
add a comment |
$begingroup$
Your problem is NP-Complete, even for strips (n strips yields (2n)!) used, so people use heuristics, transforms like Hough and morphological filters (to match continuity of text, but this heavily increases complexity for matching) or any kind of genetic / NN search, Ants Colony Optimization.
For summary of consecutive steps and various algorithm I recommend An Investigation into Automated Shredded Document Reconstruction using Heuristic Search Algorithms.
The problem itself may end up in nasty cases, when document is not fully sharp (blurred, printed with low resolution) and strips width is small and cut by physical cutter with dulled edges, because standard merging methods like panorama photo sticher gets lost and yield improper results. This is due to lost information by missing small strips, otherwise if you have full digital image cut into pieces, it is as hard as Jigsaw puzzle, non-digital image falls into approximate search.
To make algorithm automatic another problem is pieces feeding, rarely you can give axis aligned strips, so to start process it is nice to input all stripes as one picture with pieces lay by hand, this imposes another problem (this one is easy) to detect blobs and rotate them.
By special shredder instead of stripes yield very small rectangles. For comparison, P-1 class shredder gives stripes 6-12mm wide of any length (about 1800mm^2), class P-7 gives rectangles with area less than 5mm^2. When you get rectangles instead of stripes, problem yields (4n)! permutations, assuming one one-sided document, if there are lots of shreds from unrelated documents (no pictures, text only) in one bag, problem is not really tractable.
answered 2 hours ago
EvilEvil
8,47742447
$endgroup$
Your problem is NP-Complete, even for strips (n strips yields (2n)!) used, so people use heuristics, transforms like Hough and morphological filters (to match continuity of text, but this heavily increases complexity for matching) or any kind of genetic / NN search, Ants Colony Optimization.
For summary of consecutive steps and various algorithm I recommend An Investigation into Automated Shredded Document Reconstruction using Heuristic Search Algorithms.
The problem itself may end up in nasty cases, when document is not fully sharp (blurred, printed with low resolution) and strips width is small and cut by physical cutter with dulled edges, because standard merging methods like panorama photo sticher gets lost and yield improper results. This is due to lost information by missing small strips, otherwise if you have full digital image cut into pieces, it is as hard as Jigsaw puzzle, non-digital image falls into approximate search.
To make algorithm automatic another problem is pieces feeding, rarely you can give axis aligned strips, so to start process it is nice to input all stripes as one picture with pieces lay by hand, this imposes another problem (this one is easy) to detect blobs and rotate them.
By special shredder instead of stripes yield very small rectangles. For comparison, P-1 class shredder gives stripes 6-12mm wide of any length (about 1800mm^2), class P-7 gives rectangles with area less than 5mm^2. When you get rectangles instead of stripes, problem yields (4n)! permutations, assuming one one-sided document, if there are lots of shreds from unrelated documents (no pictures, text only) in one bag, problem is not really tractable.
answered 2 hours ago
EvilEvil
8,47742447
answered 2 hours ago
EvilEvil
8,47742447
answered 2 hours ago
EvilEvil
8,47742447
answered 2 hours ago
EvilEvil
8,47742447
8,47742447
$begingroup$
There may be (2n)! arrangements of the shredded strips, but does that still determine the time complexity? Whenever you find "matches" you can "group" them together, behaving as a "thick strip", where only the first and last edge matter for the sake of comparison against other strips. This "clumping" should reduce the search space hugely, but IDK if it will still beO(n!)
$endgroup$
– Alexander
14 mins ago
add a comment |
$begingroup$
There may be (2n)! arrangements of the shredded strips, but does that still determine the time complexity? Whenever you find "matches" you can "group" them together, behaving as a "thick strip", where only the first and last edge matter for the sake of comparison against other strips. This "clumping" should reduce the search space hugely, but IDK if it will still beO(n!)
$endgroup$
– Alexander
14 mins ago
$begingroup$
There may be (2n)! arrangements of the shredded strips, but does that still determine the time complexity? Whenever you find "matches" you can "group" them together, behaving as a "thick strip", where only the first and last edge matter for the sake of comparison against other strips. This "clumping" should reduce the search space hugely, but IDK if it will still be
O(n!)$endgroup$
– Alexander
14 mins ago
$begingroup$
There may be (2n)! arrangements of the shredded strips, but does that still determine the time complexity? Whenever you find "matches" you can "group" them together, behaving as a "thick strip", where only the first and last edge matter for the sake of comparison against other strips. This "clumping" should reduce the search space hugely, but IDK if it will still be
O(n!)$endgroup$
– Alexander
14 mins ago
add a comment |
Shogun is a new contributor. Be nice, and check out our Code of Conduct.
Shogun is a new contributor. Be nice, and check out our Code of Conduct.
Shogun is a new contributor. Be nice, and check out our Code of Conduct.
Shogun is a new contributor. Be nice, and check out our Code of Conduct.
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$begingroup$
Can you edit your question to define "destroyed documents"?
$endgroup$
– lox
2 hours ago
1
$begingroup$
You should look at the methods used to recover the Stasi (East German secret police) archives that were shredded or mostly -- oops all the shredders are broken from over use -- torn up after the fall of the Berlin Wall. The BBC has a very high-level summary.
$endgroup$
– David Richerby
2 hours ago