VideoCAD

Definitions

Hide Navigation Pane

Definitions

Previous topic Next topic No directory for this topic Expand/collapse all hidden text  

Definitions

Previous topic Next topic Topic directory requires JavaScript JavaScript is required for expanding text JavaScript is required for the print function Mail us feedback on this topic!  

Camera view area

 

A dimensional figure in shape of a near-pyramid* with vertex abutting the camera lens and bisector, coinciding with the main optical axis of the camera lens.

Any object within the view area will be displayed on the screen, if it is not shaded by other objects on the scene.

 

View area has the form of a regular pyramid only if lens distortion is negligible. The lens distortion complicates the form of the view area.

 

* View area of panoramic cameras occupies half of space.

 

View area projections

 

Horizontal projection of the view area can be displayed as a volume projection (Projection) or in the form of two sections of the view area on two levels (2 levels). Type of displaying for the active camera is selected in the pop up menu of the View area projection bounds button.

 

In the case of the volume projection (Projection):

 

It is displayed as projection to horizontal plane of a view area part, which is residing between the view area upper and lower bounds specified in parameters in the Camera Geometry box.

 

View area horizontal projection is calculated according to the rule:

 

A point on the horizontal projection is considered visible if a vertical segment, formed by this point in the range of heights from the view area lower bound height to the view area upper bound height, is visible wholly.

 

Click to expand
Click to expand

 

In the case of 2 sections (2 levels):

 

Instead of the volume horizontal projection, two sections on the view area upper bound height and on the view area lower bound height are displayed simultaneously.

Click to expand
Click to expand

 

 

Near and far bounds of the View area

 

VideoCAD distinguishes 10 camera positions depending on the combination of view angles, installation height, tilt angle, lower and upper bounds of the view area. In eight out of ten positions, the view area projection exists.

The position of the active camera is shown schematically in the Camera geometry box.

 

Кликните чтобы развернуть

Кликните чтобы развернуть

Кликните чтобы развернуть

Кликните чтобы развернуть

Кликните чтобы развернуть

 

Кликните чтобы развернуть

Кликните чтобы развернуть

Кликните чтобы развернуть

Кликните чтобы развернуть

Кликните чтобы развернуть

 

Depending on the position of the camera:

 

The near (to the camera) bound of the view area projection can be equal to the distance to the view area lower bound or the distance to the view area upper bound.

The far (from the camera) bound of the view area projection can also be equal  to the distance to the view area lower bound or the distance to the view area upper bound. And in some positions of the camera, the view area projection is infinite and the far bound does not exist.

The view area projection is also limited by the Maximum distance of drawing view area. In case of infinite view area projection or when the Maximum distance of drawing view area is less than the far  bound of the view area projection, the far bound is considered the Maximum distance of drawing view area.

 

 

Camera control area

 

A complex dimensional figure inside view area.

Camera control area forms by subtracting shadows of environment objects (uncontrolled areas) from the camera view area.

Any object within the control area will be displayed on the screen.

 

In the Graphics window VideoCAD calculates Horizontal projection of the control area.  In the 3D World window, the Camera control area is represented in 3D by View area faces and Active camera coverage.

 

Click to expand
Click to expand

 

Control area horizontal projection

 

Horizontal projection of the control area can be displayed as a volume projection (Within projection) or in the form of two sections of the view area on two levels (2 levels). Type of displaying for the active camera is selected in the pop up menu of the Shadow button.

 

In the case of the volume projection (Within projection):

 

Projection to horizontal plane of a control area part, which is residing between the view area upper and lower bounds specified in parameters in the Camera Geometry box.

 

Control area horizontal projection is calculated according to the rule:

 

A point on the horizontal projection is considered visible if a vertical segment, formed by this point in the range of heights from the view area lower bound height to the view area upper bound height, is visible wholly.

Click to expand
Click to expand

 

In the case of 2 sections (2 levels):

 

Projection of the control area is displayed by two sections of the view area by the horizontal planes located at the lower and upper bounds of view area.  Shadows from obstructions are deducted from these sections.

 

See also: 3D World> 3D View area, 3D World> Active camera coverage.

Click to expand
Click to expand

 

Projections of person detection area

 

Projections to horizontal and vertical planes of a view area part meeting person detection criteria.

 

 

Projections of person identification area

 

Projections to horizontal and vertical planes of a view area part meeting person identification criteria.

 

 

Projections of license plate reading area

 

Projections to horizontal and vertical planes of a view area part meeting license plate reading criteria.

 

 

Camera Field of View

 

A flat* figure limited by view area bounds and residing in a plane, perpendicular to the main optical axis of camera lens.

 

The field of view has rectangular form only if lens distortion is negligible. The lens distortion complicates the form of the field of view.

 

* Field of view of panoramic cameras is  hemisphere shaped and has a bound in the form of circle.

 

Camera resolution in LPH - lines per picture height

 

Lines per Picture Height (LPH) - is an unit of measuring image resolution. It equals the number of distinct lines in the image (the sum of the black + white lines ) were placed at the size equal to the height of the frame.

 

Analog cameras have limited vertical resolution because of a fixed number of horizontal lines , therefore, the resolution is a number of vertical lines along the horizontal, not over the entire width of the frame but along a part of the width equals to the height of the frame.

In this case, the Lines per Picture Height equal to the television lines (TV - lines ) .

If we assume number of lines across the whole width , the number of lines must be divided by the ratio of the horizontal to the vertical frame size (Aspect Ratio).

 

In VideoCAD camera resolution is determined by the number of lines per picture height (LPH), wherein the contrast of the lines drops to a predetermined portion of  contrast of the widest lines ( 10 %, 20 %, 30 %, 50 %).

In the 3D Video window you can watch the resolution LPH using the Test chart that is set up so that visually displays the resolution in LPH regardless of aspect ratio.

 

Image sensor size and size of active area of the image sensor

 

The Image sensor size in VideoCAD implies the size of the entire light sensitive area of the image sensor, which can form an image with the maximum number of pixels horizontally and vertically.

 

Active area of the image sensor in VideoCAD implies an area of ​​image sensor on which in a given mode of the camera the image is formed. The sizes of the active area may be less than or equal to the image sensor size. Active area can differ in different modes of operation of the same camera.

 

Exactly the active area size and lens focal length determines the angles of view, and through them influences on the results of camera modeling. Accuracy of specifying the active area size greatly affects the accuracy of modeling the camera.

 

Aspect ratio of the active area of image sensor is identical with the aspect ratio of the output image of the camera, but can differ from the aspect ratio of the image sensor.

 

On the figure on the right you can see the image sensor size and the active area of the image sensor in case of the image sensor has aspect ratio of 4:3, but the output image from the camera has aspect ratio of 16:9.

 

See also: Specifying active area size of the image sensor

 

Camera tilt angle

 

Camera tilt angle is a calculated parameter and can not be edited directly. The camera tilt angle is an angle between the main optical axis of camera lens and a horizontal.

 

Camera inclination is defined not by the tilt angle but by the three parameters:

 

 

 

 

Zero ground

 

Zero height level, relative which  the base height of layer, base height of cameras and ground height in the 3D World window are determined.

 

Relative the base height of layer, heights of all constructions on this layer, illuminators and 3D models are determined.

Relative the base height of camera, heights associated with the camera: installation height, view area lower bound and upper bound heights, the height of the criteria of detection, dentification and license plate reading, measurement height of pixel density, height of the test object are determined.

 

Background

 

It is a prepared horizontal site plan in any of the following formats:

 

*.bmp - a bitmap (e.g., the layout scanned from a paper copy);

*.dxf - AutoCAD format  (created in AutoCAD or other program supporting export to *.dxf);

*.dwg - AutoCAD format (created in AutoCAD or other program supporting export to *.dwg);

*.pdf - cross-platform electronic document format from Adobe Systems;

*.jpg, *.png, *.gif, *.tif - the compressed image (e.g., a digital picture of the plan, scanned image);

*.wmf, *.emf, *.emf+ - Windows Metafile (export to *.wmf is supported by the majority of the Windows  graphics applications).

 

Over the background, cameras, constructions and 3D models can be drawn.

 

AutoCAD DXF and DWG formats allows additional possibilities:

lines and polylines from the buckground can be imported to VideoCAD constructions using Import DXF / DWG background tool;
VideoCAD cameras and constructions can be added to the AutoCAD background to special layers;
you can control visibility of layers of such background, hide texts.

 

Compatiability with AutoCAD versions

 

VideoCAD 11.0 can use files of the following CAD formats as a background:

 

*.dxf AutoDesk DXF Release 12, 13, 14 , 2000, 2002, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015.

*.dwg AutoDesk DWG Release 12, 13, 14 , 2000, 2002, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015.

 

Software registration by personal registration code  (applied for all versions except VideoCAD Professional)

 

After installing the program you must enter personal pair of the name and the registration code, which is valid on any computer. USB dongle is not required.

 

If the license provides limited number of workplaces, attempt to run the program on more computers may produce error.

 

Software registration on USB Dongle basis  (applied for VideoCAD Professional)

 

The program is operable on any computers to which port the dongle is connected. So you can carry the program from computer to computer, modernize computer, etc.

 

In the past USB dongle was used for VideoCAD6, VideoCAD 7 Lite, VideoCAD 7 Professional, VideoCAD 8 Professional. Now it is used for VideoCAD 11 Professional only.

 

When you purchase a new license of VideoCAD 11 Professional Kit, one license of VideoCAD 8 Lite can be supplemented free of charge. This minimizes the inconvenience of having to use the USB dongle with VideoCAD Professional.

 

The dongle should be connected to the USB port of you computer.

 

You can get more information on USB dongles in the USB dongle topic.

 

Software protection on HID identifiers basis (not used for new licenses)

 

In the past HID protection was used for VideoCAD1..VideoCAD6, VideoCAD 7 Lite. Now it is not used for new licenses.

 

The registration is realized with the tie to your computer parameters. After computer change, hard disk formatting or other serious upgrade you will need a reserve registration.

 

Although the number of reserve registrations is limited to two, the registration counter cleaning is regularly realized. So you won't lose the purchased program in any case. If you spend all reserve registrations before the registration counter cleaning, you will have to wait for the next registration counter cleaning to continue using the program.

 

You may exchange the variant on the HID protection to the variant with the dongle protection, paying in addition for the cost of the dongle and delivery.