Zone Parameter Explanations

Zone Parameter Explanations

• Note: This area is complex and needs alot of work. Please help in any way that you can!

Name

Each Zone can be named for reference purposes. Choose a name that helps you identify your zones.

Type

• Active

  This is the zone type you'll use most often, and which will be set for your default zone. This means that this zone will trigger an alarm on any events that occur within it that meet the selection criteria.

• Inclusive

  This zone type can be used for any zones that you want to trigger an alarm only if at least one other Active zone has already triggered one. This might be for example to cover an area of the image like a plant or tree which moves a lot and which would trigger lots of alarms. Perhaps this is behind an area you'd like to monitor though, in this case you'd create an active zone covering the non-moving parts and an inclusive zone covering the tree perhaps with less sensitive detection settings also. If something triggered an alarm in the Active zone and also in the Inclusive zone they would both be registered and the resulting alarm would be that much bigger than if you had blanked it out altogether.

• Exclusive

  The next zone Type is Exclusive. This means that alarms will only be triggered in this zone if no alarms have already been triggered in Active zones. This is the most specialised of the zone types and you may never use it but in its place it is very useful. For instance in the camera covering my garden I keep watch for a hedgehog that visits most nights and scoffs the food out of my cats bowls. By creating a sensitive Exclusive zone in that area I can ensure that a hedgehog alarm will only trigger if there is activity in that small area. If something much bigger occurs, like someone walking by it will trigger a regular alarm and not one from the Exclusive zone. Thus I can ensure I get alarms for big events and also special small events but not the noise in between.

• Preclusive

  This zone type is relatively recent. It is called a Preclusive zone because if it is triggered it actually precludes an alarm being generated for that image frame. So motion or other changes that occur in a Preclusive zone will have the effect of ensuring that no alarm occurs at all. The application for this zone type is primarily as a shortcut for detecting general large-scale lighting or other changes. Generally this may be achieved by limiting the maximum number of alarm pixels or other measure in an Active zone. However in some cases that zone may cover an area where the area of variable illumination occurs in different places as the sun and/or shadows move and it thus may be difficult to come up with general values. Additionally, if the sun comes out rapidly then although the initial change may be ignored in this way as the reference image catches up an alarm may ultimately be triggered as the image becomes less different. Using one or more Preclusive zones offers a different approach. Preclusive zones are designed to be fairly small, even just a few pixels across, with quite low alarm thresholds. They should be situated in areas of the image that are less likely to have motion occur such as high on a wall or in a corner. Should a general illumination change occur they would be triggered at least as early as any Active zones and prevent any other zones from generating an alarm. Obviously careful placement is required to ensure that they do not cancel any genuine alarms or that they are not so close together that any motion just hops from one Preclusive zone to another. As always, the best way is to experiment a little and see what works for you.

• Inactive

  This final zone type is the opposite of Active. In this zone type no alarms will ever be reported. You can create an Inactive zone to cover any areas in which nothing notable will ever happen or where you get constant false alarms that don't relate to what you are trying to monitor. An Inactive zone can overlay other zone types and will be processed first.

Units

• Pixels - Selecting this option will allow many of the following values to be entered (or viewed) in units of pixels.

• Percentage - Selecting this option will allow may of the following values to be entered (orviewed) as a percentage.

Minimum X - Minimum Y - Maximum X - Maximum Y

Use these parameters to define the X,Y coordinates of the corners of the zone that is to be defined.

Alarm Colour

These parameters can be used to indvidually colorize the zone overlay pattern. By default, red is the active zone and green is the ??? zone.

Alarm Check Method

• Alarmed Pixels -

Choosing this Check Method will grey out many of the available parameters. This can simplify the tuning process, and could possibly be a better starting point for learning to adjust the many advanced parameters that are enabled with the other options. Its recommended that you start with this method.

• Filtered Pixels -

Choosing this Check Method opens up the Filtered parameters for adjustment in addition to the Alarmed Pixels above. This should give more accuracy, once you know how to adjust the various parameters and assist with eliminating false alarms and triggering on desired conditions.

• Blob Pixels -

Choosing this Check Methos opens up all of the available parameters. Enabling Blobs provides one more analysis for determination of what is a valid alarm and what is not.

Minimum Pixel Threshold

These setting are used to define limits for the difference in value between a pixel and its predecessor in the reference image.

This value (and the Maximum value as well) defines the amount of change that a single pixel must undergo, from the prior image (the reference image) and the current image, in order for the pixel to have been considered to have changed.

Small abberations in lighting or auto exposure camera adjustments may cause the explicit value of a pixel to vary by small amounts from image to image. This parameter allows you to set the limits of what will be considered a "changed pixel". For example, if your camera points to a blank white wall, and you raise a black colored item into view, then the change in any one pixel will be great, indeed, extreme. If however, you raise a white piece of paper, then the change that an individual pixes sees will be more subtle. Setting this minimum value too high, may allow a white cat to walk undetected across the view of the white wall.

Maximum Pixel Threshold

See the Minimum Pixel Threshold (above) for some explanation.

The default value for this parameter is 0% or 0 (zero) pixels, which disables the check. In other words, a pixel that changes from extreme white to extreme black will always be considered to be changed. This value is probably best left at a value of 0 (zero).

Minimum Alarmed Area

This setting controls the minimum amount of alarmed pixels (read above) needed to trigger an alarm. Depending on the size of the object you are trying to capture, a value too low may cause false alarms, while a value too high might not detect small objects. You will probably need to experiment to find a value that doesn't trigger many false alarms but still able to detect small objects such as dogs or cats.

Maximum Alarmed Area

This setting controls the maximm amount of alarmed pixels (read above) needed to trigger an alarm. The default value for this setting is 0, which disables the check and is probably best to leave it that way.

Filter Width and Filter Height (pixels)

This parameter is always specified in Pixels, even when Percentages are the selected units.

This parameter defines a group of pixels and should always be an odd number.

3 x 3 is the default value, and 5 x 5 is also suggested as another valid option. It is suggested that these numbers be small in number.

Minimum Filtered Area

• This value should always be equal to or less than the Minimum Alarmed Area

Maximum Filtered Area

• This value should always be equal to or less than the Maximum Alarmed Area

Minimum Blob Area

• The following Blob parameters are only available if you have selected "Blobs" as the "Alarm Check Method" above.

When two or more Filtered areas touch or share a boundary, they probably should be evaluated as one contiguous area and not as separate entities. A Blob is the coalesced or consolodated area of multiple filtered areas.

The Minimum blob area the smallest area that would be considered to be a blob.

Maximum Blob Area

This parameter is probably best left at the default value of 0 (zero) or disabled.

Minimum Blobs

Normally, you would want any single blob to trigger an event, so the default value of 1 (one) should suffice. In some circumstances, it may benefit to have only one blob NOT trigger an event, in which case, setting this value to 2 or higher may serve some special purpose.

Maximum Blobs

I believe that the usefulness of this parameter is negligible. Normally set to 0 (zero), it is probably best left at that value.