InfoVis:Wiki - User contributions [en]

Greenberg, Saul

2009-06-24T15:53:05Z

UE-InfoVis09-01:

== Saul Greenberg ==

[[Image:Greenberg.gif|thumb|Saul Greenberg]]

Saul Greenberg is a Professor in the Department of Computer Science at the University of Calgary, holding the NSERC/iCORE/Smart Technologies Industrial Chair in Interactive Technologies. He concentrates on probing the cross-discipline aspects of Human-Computer Interaction and CSCW. Research led to a variety of projects and publications, such as the development of toolkits which enable a rapid prototyping of groupware and physical user interfaces. Furthermore, Greenberg is well known for his refinement of evaluation methods, to name only a few of his works which all handle the main problem of situative interaction.

Beside his work as a teacher, Greenberg is an editorial board member for the International Journal of Human Computer Studies and the CSCW Journal and is extensively affiliated with ACM (SIGCHI/CSCW).

Greenberg, being a prolific author, was granted the CHCCS Achievement award in May 2007, previously, he was elected to the ACM CHI Academy in April 2005. He is listed as the 5th most frequent author in HCI Bibliography.

== Curriculum Vitae ==

Before his spell at the [http://www.ucalgary.ca ''University of Calgary''], he graduated from [http://www.mcgill.ca ''McGill University''] as a B.Sc. in 1976. The M.Sc. degree in Computer Science was followed by his Ph.D. thesis on tools in command-driven interfaces [http://grouplab.cpsc.ucalgary.ca/Publications/1988-GreenbergPhDThesis] in 1989.

His recent work includes without limitation the introduction of a Footprints Scrollbar or visualization techniques such as [[Exploring Video Streams using Slit-Tear Visualizations | slit-tear exploration of video streams]].

== External Links ==
*[http://pages.cpsc.ucalgary.ca/~saul/wiki/pmwiki.php/Main/SaulGreenberg ''Personal web page'']
*[http://grouplab.cpsc.ucalgary.ca/ ''Laboratory for HCI, CSCW and UbiComp at the University of Calgary'']

[[category: persons]]

Exploring Video Streams using Slit-Tear Visualizations

2009-05-27T11:05:54Z

UE-InfoVis09-01:

== Authors ==
*[[Tang, Anthony | Anthony Tang]]
*[[Greenberg, Saul | Saul Greenberg]]
*[[Fels, Sidney | Sidney Fels]]

== Short description ==
{{Quotation|Video slicing — a variant of slit scanning in photography — extracts a scan line from a video frame and successively adds that line to a composite image over time. The composite image becomes a time line, where its visual patterns reflect changes in a particular area of the video stream. We extend this idea of video slicing by allowing users to draw marks anywhere on the source video to capture areas of interest. These marks, which we call slit-tears, are used in place of a scan line, and the resulting composite timeline image provides a much richer visualization of the video data. Depending on how tears are placed, they can accentuate motion, small changes, directional movement, and relational patterns.| [Tang et al., 2008]}}

== Suitable Datatypes ==

This method can be applied to live video as well as captured AVI files where each frame is either computed seperately or completely in advance, together with its successors. The latter is only relevant to non-live video.

== Figures ==
'''Composition of a slit-tear visualization'''

For each video frame, the pictures under each slit are captured and aligned into a vertical column which is appended to the right side of the visualization. The bottom of the image represents a number of video frames that capture a top-down view of a room with three blue doorways. Herein, four slits have been manually defined. The actual slit-tear visualization above shows the occurence of events. In frame two, a person walks towards to the bottom door, crossing slit number 2. This intrusion is captured and can be seen as yellow trace in successive frames for the corresponding slit. [[Image:Slit image.jpeg|thumb|How slit-tears create a visualization]]

'''Pattern-level analysis'''

This image shows how events can be visualized spatially which allows for a discovery of patterns and for an effective correlation of events. Frames t1 to t5 capture a traffic intersection at particular moments in time according to the three slits, drawn by the observer. The interaction of cars and pedestrians is visualized by setting up a timeline for each pre-defined slit where the movement of the objects is depicted by strokes of different length, based on their orientation to each slit. [[Image:Intersection.jpeg|thumb|Traffic intersection]]

== Important citations ==

{{Quotation|More generally, events of interest can be problematic to see in conventional replay of video when the image quality may be poor, events may be very brief or spatially small, and patterns over time may be hard to detect. Slit-tears are a technique that helps to overcome these difficulties.| [Tang et al., 2008]}}

{{Quotation|The interactivity of slit-tear placement at any time (inclding clearing old slit-tears) means that people can use it as a tool for ongoing generation and provisional testing of hypothesis about the video data.| [Tang et al., 2008]}}

{{Quotation|...our slit-tear tool conceptualizes the analysis space in a readily understood ''camera'' and ''pixel'' space. The timeline simply takes selected areas of the video and translates the time dimension to a spatial dimension. The raw data is still visible in this representation.| [Tang et al., 2008]}}

== Evaluation ==
As per May 2009, there are no evaluations of slit-tear visualizations. Hence, an evaluation of the effectiveness of this tool for novice users in realistic tasks is planned for the near future.

== References ==
[Tang et al., 2008] Anthony Tang, Saul Greenberg and Sidney Fels, 2008. [http://portal.acm.org/citation.cfm?id=1520340.1520516 Exploring Video Streams using Slit-Tear Visualizations.] In Proceedings of the working conference on Advanced Visual Interfaces (AVI 2008). (May 28-30, Napoli, Italy). ACM Press. pp: 191-198.

== Demonstrations ==
[http://grouplab.cpsc.ucalgary.ca/cookbook/index.php/Demos/SlitTears iLab Cookbook - Slit Tears: Visualizing Video over Time.]

[[Category:Techniques]]

Exploring Video Streams using Slit-Tear Visualizations

2009-05-25T12:35:54Z

UE-InfoVis09-01:

== Authors ==
*[[Tang, Anthony | Anthony Tang]]
*[[Greenberg, Saul | Saul Greenberg]]
*[[Fels, Sidney | Sidney Fels]]

== Short description ==
{{Quotation|Video slicing — a variant of slit scanning in photography — extracts a scan line from a video frame and successively adds that line to a composite image over time. The composite image becomes a time line, where its visual patterns reflect changes in a particular area of the video stream. We extend this idea of video slicing by allowing users to draw marks anywhere on the source video to capture areas of interest. These marks, which we call slit-tears, are used in place of a scan line, and the resulting composite timeline image provides a much richer visualization of the video data. Depending on how tears are placed, they can accentuate motion, small changes, directional movement, and relational patterns.| [Tang et al., 2008]}}

== Suitable Datatypes ==

This method can be applied to live video as well as captured AVI files where each frame is either computed seperately or completely in advance, together with its successors. The latter is only relevant to non-live video.

== Figures ==
'''Composition of a slit-tear visualization'''

For each video frame, the pictures under each slit are captured and aligned into a vertical column which is appended to the right side of the visualization. The bottom of the image represents a number of video frames that capture a top-down view of a room with three blue doorways. Herein, four slits have been manually defined. The actual slit-tear visualization above shows the occurence of events. In frame two, a person walks towards to the bottom door, crossing slit number 2. This intrusion is captured and can be seen as yellow trace in successive frames for the corresponding slit. [[Image:Slit image.jpeg|thumb|How slit-tears create a visualization]]

'''Pattern-level analysis'''

This image shows how events can be visualized spatially which allows for a discovery of patterns and for an effective correlation of events. Frames t1 to t5 capture a traffic intersection at particular moments in time according to the three slits, drawn by the observer. The interaction of cars and pedestrians is visualized by setting up a timeline for each pre-defined slit where the movement of the objects is depicted by strokes of different length, based on their orientation to each slit. [[Image:Intersection.jpeg|thumb|Traffic intersection]]

== Important citations ==

{{Quotation|More generally, events of interest can be problematic to see in conventional replay of video when the image quality may be poor, events may be very brief or spatially small, and patterns over time may be hard to detect. Slit-tears are a technique that helps to overcome these difficulties.| [Tang et al., 2008]}}

{{Quotation|The interactivity of slit-tear placement at any time (inclding clearing old slit-tears) means that people can use it as a tool for ongoing generation and provisional testing of hypothesis about the video data.| [Tang, A., Greenberg, S., and Fels, S., 2008]}}

{{Quotation|...our slit-tear tool conceptualizes the analysis space in a readily understood ''camera'' and ''pixel'' space. The timeline simply takes selected areas of the video and translates the time dimension to a spatial dimension. The raw data is still visible in this representation.| [Tang et al., 2008]}}

== Evaluation ==
As per May 2009, there are no evaluations of slit-tear visualizations. Hence, an evaluation of the effectiveness of this tool for novice users in realistic tasks is planned for the near future.

== References ==
[Tang et al., 2008] Anthony Tang, Saul Greenberg and Sidney Fels, 2008. [http://portal.acm.org/citation.cfm?id=1520340.1520516 Exploring Video Streams using Slit-Tear Visualizations.] In Proceedings of the working conference on Advanced Visual Interfaces (AVI 2008). (May 28-30, Napoli, Italy). ACM Press. pp: 191-198.

== Demonstrations ==
[http://grouplab.cpsc.ucalgary.ca/cookbook/index.php/Demos/SlitTears iLab Cookbook - Slit Tears: Visualizing Video over Time.]

[[Category:Techniques]]

Exploring Video Streams using Slit-Tear Visualizations

2009-05-25T12:35:13Z

UE-InfoVis09-01:

== Authors ==
*[[Tang, Anthony | Anthony Tang]]
*[[Greenberg, Saul | Saul Greenberg]]
*[[Fels, Sidney | Sidney Fels]]

== Short description ==
{{Quotation|Video slicing — a variant of slit scanning in photography — extracts a scan line from a video frame and successively adds that line to a composite image over time. The composite image becomes a time line, where its visual patterns reflect changes in a particular area of the video stream. We extend this idea of video slicing by allowing users to draw marks anywhere on the source video to capture areas of interest. These marks, which we call slit-tears, are used in place of a scan line, and the resulting composite timeline image provides a much richer visualization of the video data. Depending on how tears are placed, they can accentuate motion, small changes, directional movement, and relational patterns.| [Tang et al., 2008]}}

== Suitable Datatypes ==

This method can be applied to live video as well as captured AVI files where each frame is either computed seperately or completely in advance, together with its successors. The latter is only relevant to non-live video.

== Figures ==
'''Composition of a slit-tear visualization'''

For each video frame, the pictures under each slit are captured and aligned into a vertical column which is appended to the right side of the visualization. The bottom of the image represents a number of video frames that capture a top-down view of a room with three blue doorways. Herein, four slits have been manually defined. The actual slit-tear visualization above shows the occurence of events. In frame two, a person walks towards to the bottom door, crossing slit number 2. This intrusion is captured and can be seen as yellow trace in successive frames for the corresponding slit.
[[Image:Slit image.jpeg|thumb|How slit-tears create a visualization]]

'''Pattern-level analysis'''

This image shows how events can be visualized spatially which allows for a discovery of patterns and for an effective correlation of events. Frames t1 to t5 capture a traffic intersection at particular moments in time according to the three slits, drawn by the observer. The interaction of cars and pedestrians is visualized by setting up a timeline for each pre-defined slit where the movement of the objects is depicted by strokes of different length, based on their orientation to each slit.
[[Image:Intersection.jpeg|thumb|Traffic intersection]]

== Important citations ==

{{Quotation|More generally, events of interest can be problematic to see in conventional replay of video when the image quality may be poor, events may be very brief or spatially small, and patterns over time may be hard to detect. Slit-tears are a technique that helps to overcome these difficulties.| [Tang et al., 2008]}}

{{Quotation|The interactivity of slit-tear placement at any time (inclding clearing old slit-tears) means that people can use it as a tool for ongoing generation and provisional testing of hypothesis about the video data.| [Tang, A., Greenberg, S., and Fels, S., 2008]}}

{{Quotation|...our slit-tear tool conceptualizes the analysis space in a readily understood ''camera'' and ''pixel'' space. The timeline simply takes selected areas of the video and translates the time dimension to a spatial dimension. The raw data is still visible in this representation.| [Tang et al., 2008]}}

== Evaluation ==
As per May 2009, there are no evaluations of slit-tear visualizations. Hence, an evaluation of the effectiveness of this tool for novice users in realistic tasks is planned for the near future.

== References ==
[Tang et al., 2008] Anthony Tang, Saul Greenberg and Sidney Fels, 2008. [http://portal.acm.org/citation.cfm?id=1520340.1520516 Exploring Video Streams using Slit-Tear Visualizations.] In Proceedings of the working conference on Advanced Visual Interfaces (AVI 2008). (May 28-30, Napoli, Italy). ACM Press. pp: 191-198.

== Demonstrations ==
[http://grouplab.cpsc.ucalgary.ca/cookbook/index.php/Demos/SlitTears iLab Cookbook - Slit Tears: Visualizing Video over Time.]

[[Category:Techniques]]

Exploring Video Streams using Slit-Tear Visualizations

2009-05-25T12:32:50Z

UE-InfoVis09-01:

== Authors ==
*[[Tang, Anthony | Anthony Tang]]
*[[Greenberg, Saul | Saul Greenberg]]
*[[Fels, Sidney | Sidney Fels]]

== Short description ==
{{Quotation|Video slicing — a variant of slit scanning in photography — extracts a scan line from a video frame and successively adds that line to a composite image over time. The composite image becomes a time line, where its visual patterns reflect changes in a particular area of the video stream. We extend this idea of video slicing by allowing users to draw marks anywhere on the source video to capture areas of interest. These marks, which we call slit-tears, are used in place of a scan line, and the resulting composite timeline image provides a much richer visualization of the video data. Depending on how tears are placed, they can accentuate motion, small changes, directional movement, and relational patterns.| [Tang et al., 2008]}}

== Suitable Datatypes ==

This method can be applied to live video as well as captured AVI files where each frame is either computed seperately or completely in advance, together with its successors. The latter is only relevant to non-live video.

== Figures ==
'''Composition of a slit-tear visualization'''
For each video frame, the pictures under each slit are captured and aligned into a vertical column which is appended to the right side of the visualization. The bottom of the image represents a number of video frames that capture a top-down view of a room with three blue doorways. Herein, four slits have been manually defined. The actual slit-tear visualization above shows the occurence of events. In frame two, a person walks towards to the bottom door, crossing slit number 2. This intrusion is captured and can be seen as yellow trace in successive frames for the corresponding slit.
[[Image:Slit image.jpeg|thumb|How slit-tears create a visualization]]
 
'''Pattern-level analysis'''
This image shows how events can be visualized spatially which allows for a discovery of patterns and for an effective correlation of events. Frames t1 to t5 capture a traffic intersection at particular moments in time according to the three slits, drawn by the observer. The interaction of cars and pedestrians is visualized by setting up a timeline for each pre-defined slit where the movement of the objects is depicted by strokes of different length, based on their orientation to each slit.
[[Image:Intersection.jpeg|thumb|Traffic intersection]]
 

== Important citations ==

{{Quotation|More generally, events of interest can be problematic to see in conventional replay of video when the image quality may be poor, events may be very brief or spatially small, and patterns over time may be hard to detect. Slit-tears are a technique that helps to overcome these difficulties.| [Tang et al., 2008]}}

{{Quotation|The interactivity of slit-tear placement at any time (inclding clearing old slit-tears) means that people can use it as a tool for ongoing generation and provisional testing of hypothesis about the video data.| [Tang, A., Greenberg, S., and Fels, S., 2008]}}

{{Quotation|...our slit-tear tool conceptualizes the analysis space in a readily understood ''camera'' and ''pixel'' space. The timeline simply takes selected areas of the video and translates the time dimension to a spatial dimension. The raw data is still visible in this representation.| [Tang et al., 2008]}}

== Evaluation ==
As per May 2009, there are no evaluations of slit-tear visualizations. Hence, an evaluation of the effectiveness of this tool for novice users in realistic tasks is planned for the near future.

== References ==
[Tang et al., 2008] Anthony Tang, Saul Greenberg and Sidney Fels, 2008. [http://portal.acm.org/citation.cfm?id=1520340.1520516 Exploring Video Streams using Slit-Tear Visualizations.] In Proceedings of the working conference on Advanced Visual Interfaces (AVI 2008). (May 28-30, Napoli, Italy). ACM Press. pp: 191-198.

== Demonstrations ==
[http://grouplab.cpsc.ucalgary.ca/cookbook/index.php/Demos/SlitTears iLab Cookbook - Slit Tears: Visualizing Video over Time.]

[[Category:Techniques]]

Exploring Video Streams using Slit-Tear Visualizations

2009-05-25T12:31:46Z

UE-InfoVis09-01:

== Authors ==
*[[Tang, Anthony | Anthony Tang]]
*[[Greenberg, Saul | Saul Greenberg]]
*[[Fels, Sidney | Sidney Fels]]

== Short description ==
{{Quotation|Video slicing — a variant of slit scanning in photography — extracts a scan line from a video frame and successively adds that line to a composite image over time. The composite image becomes a time line, where its visual patterns reflect changes in a particular area of the video stream. We extend this idea of video slicing by allowing users to draw marks anywhere on the source video to capture areas of interest. These marks, which we call slit-tears, are used in place of a scan line, and the resulting composite timeline image provides a much richer visualization of the video data. Depending on how tears are placed, they can accentuate motion, small changes, directional movement, and relational patterns.| [Tang et al., 2008]}}

== Suitable Datatypes ==

This method can be applied to live video as well as captured AVI files where each frame is either computed seperately or completely in advance, together with its successors. The latter is only relevant to non-live video.

== Figures ==
'''Composition of a slit-tear visualization'''
For each video frame, the pictures under each slit are captured and aligned into a vertical column which is appended to the right side of the visualization. The bottom of the image represents a number of video frames that capture a top-down view of a room with three blue doorways. Herein, four slits have been manually defined. The actual slit-tear visualization above shows the occurence of events. In frame two, a person walks towards to the bottom door, crossing slit number 2. This intrusion is captured and can be seen as yellow trace in successive frames for the corresponding slit.
[[Image:Slit_tear.jpeg|thumb|How slit-tears create a visualization]]
 
'''Pattern-level analysis'''
This image shows how events can be visualized spatially which allows for a discovery of patterns and for an effective correlation of events. Frames t1 to t5 capture a traffic intersection at particular moments in time according to the three slits, drawn by the observer. The interaction of cars and pedestrians is visualized by setting up a timeline for each pre-defined slit where the movement of the objects is depicted by strokes of different length, based on their orientation to each slit.
[[Image:Intersection.jpeg|thumb|Traffic intersection]]
 

== Important citations ==

{{Quotation|More generally, events of interest can be problematic to see in conventional replay of video when the image quality may be poor, events may be very brief or spatially small, and patterns over time may be hard to detect. Slit-tears are a technique that helps to overcome these difficulties.| [Tang et al., 2008]}}

{{Quotation|The interactivity of slit-tear placement at any time (inclding clearing old slit-tears) means that people can use it as a tool for ongoing generation and provisional testing of hypothesis about the video data.| [Tang, A., Greenberg, S., and Fels, S., 2008]}}

{{Quotation|...our slit-tear tool conceptualizes the analysis space in a readily understood ''camera'' and ''pixel'' space. The timeline simply takes selected areas of the video and translates the time dimension to a spatial dimension. The raw data is still visible in this representation.| [Tang et al., 2008]}}

== Evaluation ==
As per May 2009, there are no evaluations of slit-tear visualizations. Hence, an evaluation of the effectiveness of this tool for novice users in realistic tasks is planned for the near future.

== References ==
[Tang et al., 2008] Anthony Tang, Saul Greenberg and Sidney Fels, 2008. [http://portal.acm.org/citation.cfm?id=1520340.1520516 Exploring Video Streams using Slit-Tear Visualizations.] In Proceedings of the working conference on Advanced Visual Interfaces (AVI 2008). (May 28-30, Napoli, Italy). ACM Press. pp: 191-198.

== Demonstrations ==
[http://grouplab.cpsc.ucalgary.ca/cookbook/index.php/Demos/SlitTears iLab Cookbook - Slit Tears: Visualizing Video over Time.]

[[Category:Techniques]]

Exploring Video Streams using Slit-Tear Visualizations

2009-05-25T12:18:14Z

UE-InfoVis09-01:

== Authors ==
*[[Tang, Anthony | Anthony Tang]]
*[[Greenberg, Saul | Saul Greenberg]]
*[[Fels, Sidney | Sidney Fels]]

== Short description ==
{{Quotation|Video slicing — a variant of slit scanning in photography — extracts a scan line from a video frame and successively adds that line to a composite image over time. The composite image becomes a time line, where its visual patterns reflect changes in a particular area of the video stream. We extend this idea of video slicing by allowing users to draw marks anywhere on the source video to capture areas of interest. These marks, which we call slit-tears, are used in place of a scan line, and the resulting composite timeline image provides a much richer visualization of the video data. Depending on how tears are placed, they can accentuate motion, small changes, directional movement, and relational patterns.| [Tang et al., 2008]}}

== Suitable Datatypes ==

This method can be applied to live video as well as captured AVI files where each frame is either computed seperately or completely in advance, together with its successors. The latter is only relevant to non-live video.

== Figures ==
'''Pattern-level analysis'''
This image shows how events can be visualized spatially which allows for a discovery of patterns and for an effective correlation of events. Frames t1 to t5 capture a traffic intersection at particular moments in time according to the three slits, drawn by the observer. The interaction of cars and pedestrians is visualized by setting up a timeline for each pre-defined slit where the movement of the objects is depicted by strokes of different length, based on their orientation to each slit.

[[Image:Intersection.jpeg|thumb|Traffic intersection]] 

== Important citations ==

{{Quotation|More generally, events of interest can be problematic to see in conventional replay of video when the image quality may be poor, events may be very brief or spatially small, and patterns over time may be hard to detect. Slit-tears are a technique that helps to overcome these difficulties.| [Tang et al., 2008]}}

{{Quotation|The interactivity of slit-tear placement at any time (inclding clearing old slit-tears) means that people can use it as a tool for ongoing generation and provisional testing of hypothesis about the video data.| [Tang, A., Greenberg, S., and Fels, S., 2008]}}

{{Quotation|...our slit-tear tool conceptualizes the analysis space in a readily understood ''camera'' and ''pixel'' space. The timeline simply takes selected areas of the video and translates the time dimension to a spatial dimension. The raw data is still visible in this representation.| [Tang et al., 2008]}}

== Evaluation ==
As per May 2009, there are no evaluations of slit-tear visualizations. Hence, an evaluation of the effectiveness of this tool for novice users in realistic tasks is planned for the near future.

== References ==
[Tang et al., 2008] Anthony Tang, Saul Greenberg and Sidney Fels, 2008. [http://portal.acm.org/citation.cfm?id=1520340.1520516 Exploring Video Streams using Slit-Tear Visualizations.] In Proceedings of the working conference on Advanced Visual Interfaces (AVI 2008). (May 28-30, Napoli, Italy). ACM Press. pp: 191-198.

== Demonstrations ==
[http://grouplab.cpsc.ucalgary.ca/cookbook/index.php/Demos/SlitTears iLab Cookbook - Slit Tears: Visualizing Video over Time.]

[[Category:Techniques]]

Exploring Video Streams using Slit-Tear Visualizations

2009-05-25T12:17:17Z

UE-InfoVis09-01:

== Authors ==
*[[Tang, Anthony | Anthony Tang]]
*[[Greenberg, Saul | Saul Greenberg]]
*[[Fels, Sidney | Sidney Fels]]

== Short description ==
{{Quotation|Video slicing — a variant of slit scanning in photography — extracts a scan line from a video frame and successively adds that line to a composite image over time. The composite image becomes a time line, where its visual patterns reflect changes in a particular area of the video stream. We extend this idea of video slicing by allowing users to draw marks anywhere on the source video to capture areas of interest. These marks, which we call slit-tears, are used in place of a scan line, and the resulting composite timeline image provides a much richer visualization of the video data. Depending on how tears are placed, they can accentuate motion, small changes, directional movement, and relational patterns.| [Tang et al., 2008]}}

== Suitable Datatypes ==

This method can be applied to live video as well as captured AVI files where each frame is either computed seperately or completely in advance, together with its successors. The latter is only relevant to non-live video.

== Figures ==
'''Pattern-level analysis:'''

This image shows how events can be visualized spatially which allows for a discovery of patterns and for an effective correlation of events. Frames t1 to t5 capture a traffic intersection at particular moments in time according to the three slits, drawn by the observer. The interaction of cars and pedestrians is visualized by setting up a timeline for each pre-defined slit where the movement of the objects is depicted by strokes of different length, based on their orientation to each slit.

[[Image:Intersection.jpeg|thumb|Traffic intersection]]

== Important citations ==

{{Quotation|More generally, events of interest can be problematic to see in conventional replay of video when the image quality may be poor, events may be very brief or spatially small, and patterns over time may be hard to detect. Slit-tears are a technique that helps to overcome these difficulties.| [Tang et al., 2008]}}

{{Quotation|The interactivity of slit-tear placement at any time (inclding clearing old slit-tears) means that people can use it as a tool for ongoing generation and provisional testing of hypothesis about the video data.| [Tang, A., Greenberg, S., and Fels, S., 2008]}}

{{Quotation|...our slit-tear tool conceptualizes the analysis space in a readily understood ''camera'' and ''pixel'' space. The timeline simply takes selected areas of the video and translates the time dimension to a spatial dimension. The raw data is still visible in this representation.| [Tang et al., 2008]}}

== Evaluation ==
As per May 2009, there are no evaluations of slit-tear visualizations. Hence, an evaluation of the effectiveness of this tool for novice users in realistic tasks is planned for the near future.

== References ==
[Tang et al., 2008] Anthony Tang, Saul Greenberg and Sidney Fels, 2008. [http://portal.acm.org/citation.cfm?id=1520340.1520516 Exploring Video Streams using Slit-Tear Visualizations.] In Proceedings of the working conference on Advanced Visual Interfaces (AVI 2008). (May 28-30, Napoli, Italy). ACM Press. pp: 191-198.

== Demonstrations ==
[http://grouplab.cpsc.ucalgary.ca/cookbook/index.php/Demos/SlitTears iLab Cookbook - Slit Tears: Visualizing Video over Time.]

[[Category:Techniques]]

Exploring Video Streams using Slit-Tear Visualizations

2009-05-25T12:16:33Z

UE-InfoVis09-01:

== Authors ==
*[[Tang, Anthony | Anthony Tang]]
*[[Greenberg, Saul | Saul Greenberg]]
*[[Fels, Sidney | Sidney Fels]]

== Short description ==
{{Quotation|Video slicing — a variant of slit scanning in photography — extracts a scan line from a video frame and successively adds that line to a composite image over time. The composite image becomes a time line, where its visual patterns reflect changes in a particular area of the video stream. We extend this idea of video slicing by allowing users to draw marks anywhere on the source video to capture areas of interest. These marks, which we call slit-tears, are used in place of a scan line, and the resulting composite timeline image provides a much richer visualization of the video data. Depending on how tears are placed, they can accentuate motion, small changes, directional movement, and relational patterns.| [Tang et al., 2008]}}

== Suitable Datatypes ==

This method can be applied to live video as well as captured AVI files where each frame is either computed seperately or completely in advance, together with its successors. The latter is only relevant to non-live video.

== Figures ==
'''Pattern-level analysis:'''

This image shows how events can be visualized spatially which allows for a discovery of patterns and for an effective correlation of events. Frames t1 to t5 capture a traffic intersection at particular moments in time according to the three slits, drawn by the observer. The interaction of cars and pedestrians is visualized by setting up a timeline for each pre-defined slit where the movement of the objects is depicted by strokes of different length, based on their orientation to each slit.

[[Image:Intersection.jpeg|thumb|Traffic intersection showing the interaction patterns of cars and pedestrians]]

== Important citations ==

{{Quotation|More generally, events of interest can be problematic to see in conventional replay of video when the image quality may be poor, events may be very brief or spatially small, and patterns over time may be hard to detect. Slit-tears are a technique that helps to overcome these difficulties.| [Tang et al., 2008]}}

{{Quotation|The interactivity of slit-tear placement at any time (inclding clearing old slit-tears) means that people can use it as a tool for ongoing generation and provisional testing of hypothesis about the video data.| [Tang, A., Greenberg, S., and Fels, S., 2008]}}

{{Quotation|...our slit-tear tool conceptualizes the analysis space in a readily understood ''camera'' and ''pixel'' space. The timeline simply takes selected areas of the video and translates the time dimension to a spatial dimension. The raw data is still visible in this representation.| [Tang et al., 2008]}}

== Evaluation ==
As per May 2009, there are no evaluations of slit-tear visualizations. Hence, an evaluation of the effectiveness of this tool for novice users in realistic tasks is planned for the near future.

== References ==
[Tang et al., 2008] Anthony Tang, Saul Greenberg and Sidney Fels, 2008. [http://portal.acm.org/citation.cfm?id=1520340.1520516 Exploring Video Streams using Slit-Tear Visualizations.] In Proceedings of the working conference on Advanced Visual Interfaces (AVI 2008). (May 28-30, Napoli, Italy). ACM Press. pp: 191-198.

== Demonstrations ==
[http://grouplab.cpsc.ucalgary.ca/cookbook/index.php/Demos/SlitTears iLab Cookbook - Slit Tears: Visualizing Video over Time.]

[[Category:Techniques]]

Exploring Video Streams using Slit-Tear Visualizations

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== Authors ==
*[[Tang, Anthony | Anthony Tang]]
*[[Greenberg, Saul | Saul Greenberg]]
*[[Fels, Sidney | Sidney Fels]]

== Short description ==
{{Quotation|Video slicing — a variant of slit scanning in photography — extracts a scan line from a video frame and successively adds that line to a composite image over time. The composite image becomes a time line, where its visual patterns reflect changes in a particular area of the video stream. We extend this idea of video slicing by allowing users to draw marks anywhere on the source video to capture areas of interest. These marks, which we call slit-tears, are used in place of a scan line, and the resulting composite timeline image provides a much richer visualization of the video data. Depending on how tears are placed, they can accentuate motion, small changes, directional movement, and relational patterns.| [Tang et al., 2008]}}

== Suitable Datatypes ==

This method can be applied to live video as well as captured AVI files where each frame is either computed seperately or completely in advance, together with its successors. The latter is only relevant to non-live video.

== Figures ==
'''Social Aspects:'''

This plot is a representation of the students' social activities (i.e. in a discussion board); It allows different views on aspects like date, student or topic. The size of the point describes the intensity and the color the activity a student did (red for start a topic, green for an answer and blue for reading).

[[Image:Sozal_Aspects.jpg|thumb|Social Aspects]]

== Important citations ==

{{Quotation|More generally, events of interest can be problematic to see in conventional replay of video when the image quality may be poor, events may be very brief or spatially small, and patterns over time may be hard to detect. Slit-tears are a technique that helps to overcome these difficulties.| [Tang et al., 2008]}}

{{Quotation|The interactivity of slit-tear placement at any time (inclding clearing old slit-tears) means that people can use it as a tool for ongoing generation and provisional testing of hypothesis about the video data.| [Tang, A., Greenberg, S., and Fels, S., 2008]}}

{{Quotation|...our slit-tear tool conceptualizes the analysis space in a readily understood ''camera'' and ''pixel'' space. The timeline simply takes selected areas of the video and translates the time dimension to a spatial dimension. The raw data is still visible in this representation.| [Tang et al., 2008]}}

== Evaluation ==
As per May 2009, there are no evaluations of slit-tear visualizations. Hence, an evaluation of the effectiveness of this tool for novice users in realistic tasks is planned for the near future.

== References ==
[Tang et al., 2008] Anthony Tang, Saul Greenberg and Sidney Fels, 2008. [http://portal.acm.org/citation.cfm?id=1520340.1520516 Exploring Video Streams using Slit-Tear Visualizations.] In Proceedings of the working conference on Advanced Visual Interfaces (AVI 2008). (May 28-30, Napoli, Italy). ACM Press. pp: 191-198.

== Demonstrations ==
[http://grouplab.cpsc.ucalgary.ca/cookbook/index.php/Demos/SlitTears iLab Cookbook - Slit Tears: Visualizing Video over Time.]

[[Category:Techniques]]

File:Intersection.jpeg

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UE-InfoVis09-01: a traffic intersection showing the interaction patterns of cars and pedestrians, visualized as slit-tears.

== Summary ==
a traffic intersection showing the interaction patterns of cars and pedestrians, visualized as slit-tears.
== Copyright status ==

== Source ==
Tang T., Greenberg S., Fels S., 2008. Exploring Video Streams using Slit-Tear Visualizations

File:Googletalk.jpeg

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UE-InfoVis09-01: online status in google talk, visualized by the slit-tear technique

== Summary ==
online status in google talk, visualized by the slit-tear technique
== Copyright status ==

== Source ==
Tang T., Greenberg S., Fels S., 2008. Exploring Video Streams using Slit-Tear Visualizations

File:Slit image.jpeg

2009-05-25T11:59:16Z

UE-InfoVis09-01: how slit-tears create a visualization

== Summary ==
how slit-tears create a visualization
== Copyright status ==

== Source ==
Tang T., Greenberg S., Fels S., 2008. Exploring Video Streams using Slit-Tear Visualizations

Exploring Video Streams using Slit-Tear Visualizations

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Exploring Video Streams using Slit-Tear Visualizations

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Exploring Video Streams using Slit-Tear Visualizations

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Greenberg, Saul

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UE-InfoVis09-01: Page created

File:Greenberg.gif

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UE-InfoVis09-01: Image of Saul Greenberg.

== Summary ==
Image of Saul Greenberg.
== Copyright status ==

== Source ==
http://www.cs.waikato.ac.nz/~ihw/images/people/saul-greenberg.gif

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Tang, Anthony

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== Anthony Tang ==

[[Image:Tang.jpg|thumb|Anthony Tang]]

Anthony Tang is a PhD candidate at the University of British Columbia with a specialization on Human-Computer Interaction. His thesis investigates the design of interactive collaboration interfaces is currently in progress and expected to be finished in summer 2009.

Having graduated with a B.Sc. degree from Simon Fraser University, Tang then investigated the field of Human-Computer Interaction at the University of Calgary, supervised by Dr. Saul Greenberg, which earned him the M.Sc. degree in 2005.

== Research Projects ==
His research currently focuses on Computer Supported Cooperative Work (CSCW) while his recent publications comprise topics such as ubiquitous computing, novel interaction techniques and ethnomethodology. Along with Saul Greenberg and Sidney Fels, leader of the Human Communication Technologies Laboratory at the University of British Columbia, Tang currently pursues research in the field of information visualization. His recent projects include works on large-scale public interfaces [http://hct.ece.ubc.ca/publications/pdf/tang-etal-chi-2008.pdf] as well as the [[Exploring Video Streams using Slit-Tear Visualizations | exploration of video streams by use of slit-tear visualizations ]].

== External Links ==
*[http://tonytang.wikidot.com/publications ''Publications'']
*[http://tonytang.wikidot.com ''Personal web page'']

[[category: persons]]

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File:Tang.jpg

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UE-InfoVis09-01: Image of Anthony Tang

== Summary ==
Image of Anthony Tang
== Copyright status ==

== Source ==
http://hct.ece.ubc.ca/people/pics/tony-thumb.jpg

Exploring Video Streams using Slit-Tear Visualizations

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UE-InfoVis09-01: Article created