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VQiPS: GUC Questionnaire

Guide to Defining Video Quality Requirements

| Getting Started | Use Cases | Use Classes | GUC Aspects | GUC Questionnaire | GUC Example | Video System Tasks | Video System Functions | Recommendations Tool | Acknowledgments |

VQiPS: Use Classes

Generalized Use Class Questionnaire

Apply the Generalized Use Class Questionnaire to each use case you defined to translate them into generalized use classes where two or more use cases constitute a given use class.

Your agency or organization might have more than one use case associated with its mission. Carefully define and analyze each of your use cases to determine the overall most restrictive use class. For example, if police and fire departments are sharing a video system, officers might need to recognize individuals with high-level detail, while firefighters might only need to recognize the presence of smoke. In this case, the police department has a more restrictive use case. Click on Generalized Use Class Questionnaire to download this one-page PDF form file.

  1. Print a copy of the form for each of your use cases.
  2. For a given use case, consider each generalized use class aspect listed on the left side of the questionnaire, and check just one box for each.
  3. Repeat step 2 for each use case.
  4. Group use case forms for which the same boxes are checked.  Each group represents a generalized use class.
  5. For a given use class, get recommendations for video requirements by inputting checkbox answers in the Recommendations Tool for Video Requirements.
  6. Repeat step 5 for each use class.
  7. Use the Recommendations Tool to guide your video requirements decisions.

Using the questionnaire below, click on a generalized use class aspect for more information.

Usage Timeframe - Use Characteristics
Consider: In what timeframe will the video be used?  As in, will the video be used real-time or will it be recorded?

Use TimeframeCharacteristicExample
The video will be viewed at the same time it is being shot[ ] Live or real-timeSecurity monitor being viewed by security personnel
The video will be saved and capable of being played back[ ] RecordedForensic video

Discrimination Level - Use Characteristics
Consider: What level of discrimination do you need to recognize a target of interest?

Use Discrimination LevelCharacteristicExample
High-level description of actions that took place[ ] General Elements of the ActionPeople or person present
Large-scale recognition[ ] Target Class RecognitionCar vs Van
Medium-scale detail recognition[ ] Target CharacteristicsGender, markings, smaller actions
Enough detail to make a positive recognition[ ] Target Positive IDFace, object, alpha-numeric

Target Size - Scene Content
Consider: What is the size of the object of interest with respect to the field of view?

Scene Target SizeContent
[ ] LargeThe target occupies a large percentage of the frame
[ ] SmallThe target occupies a smaller percentage of the frame

Motion - Scene Content
Consider: What level of motion do you anticipate in a scene of interest?

Scene MotionContent
[ ] HighA high-complexity video contains a lot of motion or edges
[ ] LowA low-complexity video contains little motion or few edges

Lighting Level - Scene Content
Consider: What level of lighting do you anticipate in a scene of interest?

Scene Lighting LevelContent
[ ] Constant Lighting - BrightAt a comparatively bright level
[ ] Constant Lighting - DimAt a comparatively dim level
[ ] VariableRanges from bright to dim

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Created September 30, 2016, Updated October 19, 2016