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The Image sensor size can be specified by any of the following ways:
This traditional way of setting Image sensor size can be unaccurate for modern cameras.
If you enter a format which does not exist in the list, the box turns yellow, and the Image sensor size will be calculated by VideoCAD.
See more: Specifying image sensor size through its diagonal and aspect ratio
See more: Direct specifying image sensor side sizes
You can set the size of the Image sensor by the interval between pixels (Pixel Interval) in microns, for example "17mcm". This is useful for thermal cameras.
After format or length of diagonal, separated by space character, you can specify the aspect ratio of the image sensor in the form of W:H. For example: 1/3" 16:9 or d6 16:9. If the aspect ratio of the image sensor is not specified, it is assumed equal to 4:3. But if the Latin letter "A" is set as the first character in the List of Resolutions and the aspect ratio of the Image sensor is not set explicitly, then the ratio of the sides of the Image sensor will be calculated as the ratio of the maximum number of pixels horizontally and vertically in the List of Resolutions.
See more: Direct specifying active area size of the image sensor
Active area side sizes of the image sensor can be specified in millimeters horizontally and vertically separated by asterisk, in the form of W*H. For example: 4.8*3.6;
See more: Direct specifying active area side sizes of the image sensor See also: Sensor and Lens>Image sensor, Specifying active area size of the image sensor/
When moving the cursor to the image sensor box the information on horizontal and vertical view angles of lens appears.
Changing the Image sensor size, and therefore the calculated values of view angles of camera with enabled modeling lens distortion will lead to detuning parameters of distortion and warping view area form. To correct the mismatch you should set new values of the actual view angles, taking into account the changed values of calculated view angles.
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Focal length can be chosen from the list or typed into this box or duplicate boxes on the Tool bar of the Graphics window and on the 3D Video.
Using the List / Range of the lens focal length you can limit changes of the focal length by the list of the range.
Possible window colors:
Changing the lens focal length and therefore the calculated values of view angles of camera with enabled modeling lens distortion will lead to detuning parameters of distortion and warping view area form. To correct the mismatch you should set new values of the actual view angles, taking into account the changed values of calculated view angles. To accurately simulate lens distortion with different focal lengths, the camera can be assigned a List / Range of lens focal length. In the list, you can specify real view angles for different combinations of Aspect ratio, crop factor, image sensor size and focal length.
To simulate long-range cameras with a large focal length, it is required to expand the Space limits and the Maximum distance of drawing View area. The maximum simulation distance may be limited by the graphics card.
You can change lens focal length of all selected cameras simultaneously. For this purpose:
See also: Sensor and Lens>Lens
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Aspect ratio (of output image)
Separated by space character after the Aspect ratio you can set the crop factor - the ratio of cropping active area size of the image sensor when the active area does not touch the edges of the image sensor. The Crop factor can be set as a vulgar fraction (separated by slash) or a real number. For example 4:3 0.67 or 16:9 720/1080. If the Crop factor is not specified, it is taken to be unity.
See more: Specifying the crop factor
If the Set Aspect ratio from pixels checkbox is checked, the Aspect ratio will be recalculated at any change in the numbers of active pixels, as the ratio of the numbers of pixels horizontally and vertically. If a List of resolution is assigned to the active camera, and in the List of resolution, the Crop factor is assigned to each resolution, then when selecting the number of active pixels included in the List of resolution, the Crop factor assigned to this resolution will be applied.
See more: List of resolution
If the camera has directly assigned active area sizes, then this box shows 'custom' and it becomes unavailable. To make it available, set the size of image sensor by any way except of direct specifying its active area size.
For correct calculation of person detection, identification and license plate reading areas and pixel density, after changing the Aspect ratio it is necessary to check and adjust vertical number of pixels in the Sensitivity and Resolution box and Image size on the Processing tab on the Image parameter panel.
Changing the aspect ratio and therefore the calculated value of vertical view angle of camera with enabled modeling lens distortion will lead to detuning parameters of distortion and warping view area form. To correct the mismatch you should set new values of the actual view angles, taking into account the changed values of calculated view angles. To accurately simulate the lens distortion with different focal lengths, the camera can be assigned a List / Range of lens focal length. In the list, you can specify real view angles for different combinations of Aspect ratio, crop factor, image sensor size and focal length.
See also: Sensor and Lens>Image sensor's active area, Specifying active area size of the image sensor
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As a result of clicking this button, the Sensor and Lens panel will be shown.
On the panel you can set:
In addition to specifying lists, the tools of the panel can improve accuracy of modeling shape of the view area, take into account dependence of the size of active area of the image sensor on the selected resolution, and also take into account effect of lens distortion.
For details, see Sensor and Lens, Specifying active area size of the image sensor
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Height of installation can be chosen from the list or typed. The height of installation influences all calculated parameters.
In multi-level 3D projects, in 3D Video and 3D World, as well as in calculation of shadows, the height of installation, heights of view area lower and upper bounds are calculated relative to the Base height
Height of installation can be negative.
When drawing a camera in the vertical projection of the Graphics window, its height will be equal to the sum of the camera installation height, the base height of the camera and the height in the parameters of the group to which the camera belongs, if the Base heights of cameras in vertical projection checkbox is checked.
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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:
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In the box you can specify the camera rotation angle around its main optical axis, in degrees.
If a camera is rotated by an angle more than 45 degrees, when calculating person detection and identification, license plate reading areas, the parameters: minimum vertical resolution (pixel/meter, pixel/ft), the minimum vertical size of face image ( pixels ), the minimum vertical size of license plate ( pix) are calculated based on the number of pixels along the horizontal, instead of the number of pixels along the vertical, as in this case the vertical side of the field of view is located along the horizontal.
When calculating pixel density, the influence of rotation of the camera around its axis on the position of the vertical and horizontal in the frame is determined using the When rotating camera around its axis or in corridor mode, bind horizontal/ vertical combobox in the Options box.
In the Graphics window, 3D Video and 3D world windows rotation of camera is displayed accurately. However, each passing through a multiple of 45 degrees angle, camera tilt angle is changed so as to keep the values of the View area upper bound height and the View area upper bound distance, taking into account the fact that a view area face appeared on top, becomes the upper bound of the view area.
When you rotate the camera around its axis the view area projection changes its shape, sometimes becomes infinite. To limit the distance of drawing view area, use the Maximum distance of drawing view area.
For a fuller picture of rotated view area projections it is recommended to set the Level 2 in pop up menu of the View area projection bounds and Shadow buttons.
See also: Using camera rotation around its own axis
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The base height affects the position of the camera along the vertical, relative to other cameras and constructions in the 3D Video and 3D World windows, as well as in the calculation of shadows in the Graphics window.
At the time of placing a new camera or pasting copied camera, its base height is automatically set equals to the base height of the active layer .
Height of criteria of person detection and person identification, license plate reading are considered relative to the base height of the camera, which the projections of identification, detection, license plate reading areas belong to.
The base height is calculated relative to the Zero ground and can be negative.
When drawing a camera in the vertical projection of the Graphics window, its height will be equal to the sum of the camera installation height, the base height of the camera and the height in the parameters of the group to which the camera belongs, if the Base heights of cameras in vertical projection checkbox is checked.
See also: Working with layers and multi-level projects, Layers>Height
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The height of view area upper bound can be chosen from the list or typed. In the horizontal projection of the calculated view area the space above the upper bound height is not taken into consideration.
Together with view area upper bound distance it completely determines a camera tilt angle and all calculated parameters through it.
The height of view area upper bound influences the projections of the person detection, identification and the license plate reading areas only through changing the camera tilt angle. The individual values of lower and upper bounds are customized in these projections' calculation criteria. For instance, when identifying a person the default lower bound is 1.5 m and the upper one is 2.2 m.
In multi-level 3D projects, in 3D Video and 3D World, as well as in calculation of shadows, the height of installation, heights of view area lower and upper bounds are calculated relative to the Base height
Height of view area upper bound can be negative.
Height of calculating Pixel density, Shadows and Depth of Field
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The height of view area lower bound can be chosen from the list or typed. In the horizontal projection of the calculated view area the space below the lower bound height is not taken into consideration.
The height of view area lower bound influences the following calculated parameters:
The height of view area lower bound doesn't influence the projections of the person detection, identification and license plate reading areas. The individual values of lower and upper bounds are customized in these projections calculation criteria. For instance, when identifying a person the default lower bound is 1.5 m and the upper one is 2.2 m.
In multi-level 3D projects, in 3D Video and 3D World, as well as in calculation of shadows, the height of installation, heights of view area lower and upper bounds are calculated relative to the Base height
Height of view area lower bound can be negative.
Height of calculating Pixel density, Shadows and Depth of Field
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View area upper bound distance
When the camera is located above the view area upper bound, a view area upper bound distance is the maximal distance of surveillance. The view area upper bound distance is chosen from the list or typed. The view area is calculated up to this distance.
When the camera is located below the view area upper bound, the view area upper bound distance can become the minimal distance of surveillance.
When a camera is located above the view area upper bound, a view area upper bound distance is the maximal distance of surveillance. The view area upper bound distance is chosen from the list or typed. The view areas are calculated up to this distance. Together with the height of view area upper bound, the view area upper bound distance completely determines the camera tilt angle and all the calculated parameters through it.
The view area upper bound distance influences the projections of the person detection, identification and the license plate reading areas only through changing the camera tilt angle. The maximal distances of the person detection, identification and the license plate reading can differ from the lower and upper bounds distance both to a smaller or larger extent.
When you rotate the camera around its axis, each pass through a multiple of 45 degrees angle, the camera tilt angle is changed so that a view area face appearing on top, becomes the view area upper bound.
See also: Maximum distance of drawing view area, Near and far bounds of the View area.
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View area lower bound distance
The view area lower bound distance is a calculated parameter and can not be edited.
When the camera is located above the view area upper bound, the view area lower bound distance is the minimal distance of surveillance (dead zone of surveillance).
When the camera is located below the view area upper bound, in some positions the view area lower bound distance is the minimal distance of surveillance too.
In some positions the view area lower bound distance can be the maximal distance of surveillance.
The view area lower bound distance can be negative.
The view area lower bound distance doesn't influence the person detection, identification and the license plate reading area projections. The minimal distances of the person detection, identification and the license plate reading can differ from the lower and upper bounds' distance both to a smaller or larger extent.
This parameter reflects the correct value only if:
In other cases, the projection of view area has a more complicated form and displayed graphically in the Graphics window.
See also: Near and far bounds of the View area.
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The view area projection length is a calculated parameter and can not be edited.
When there is an actual view area projection, the view area projection length displays the absolute value of difference between the upper and the lower bound distances of view area projection.
When there is no actual view area projection, the parameter doesn't have any sense and is not displayed. The parameter displaying enhances the convenience in use when it is required to obtain the length of view area projection.
This parameter reflects the correct value only if:
In other cases, the projection of view area has a more complicated form and displayed graphically in the Graphics window.
See also: Near and far bounds of the View area.
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Width of view area projection upper bound
The width of view area projection upper bound is a calculated parameter and can not be edited.
According to the "Projection" switcher state the width of view area projection upper bound displays the camera view area width at the point of intersection between the camera view area bound and the view area projection upper bound, or the view area projection edge width between the lower bound and the upper one.
This parameter reflects the correct value only if:
In other cases, the projection of view area has a more complicated form and displayed graphically in the Graphics window.
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Width of view area projection lower bound
The width of view area projection lower bound is a calculated parameter and can not be edited.
According to the "Projection" switcher state the width of view area projection lower bound displays the camera view area width at the intersection point between the camera view area bound and the view area projection lower bound, or the view area projection edge width between the lower bound and the upper one.
This parameter reflects the correct value only if:
In other cases, the projection of view area has a more complicated form and displayed graphically in the Graphics window.
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A "Projection" is a switcher determining a way of calculation:
When the switcher is checked, the view area bound distance and width are calculated according to narrower level of the view area opposite bound. In this case all the points of the calculated view area horizontal projection from the lower bound up to the upper one hit in the camera view area.
When the switcher is not checked, the distance up to the camera view area bound intersection with the upper or lower bounds and the width of this bound are calculated.
When the view area is not narrowing towards the opposite bound, the switcher doesn't have any sense and is not displayed.
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Maximum distance of drawing view area
Value in this combo box limits the distance from the camera beyond which the view area is not drawn in the Graphics window and in the 3D World.
This tool is particularly useful for simulating camera rotation around its axis and lens distortion. The maximum distance defines the scale of view area projection in PDF report.
If the value in this box is less than the maximum of the view area upper bound distance and the view area lower bound distance, the box is colored in pink color.
When the maximum distance of drawing view area is less than the far bound of view area projection or the view area projection is infinite, then the maximum distance plays the role of the far bound of view area projection.
The Maximum distance of drawing view area limits the View area in Dome mode, as well as when simulating FishEye and PTZ cameras.
To simulate long-range cameras with a large focal length, it is required to expand the Space limits. The maximum simulation distance may be limited by the graphics card, at long distance artefacts may occur especially on 3D models.
See also: Show all objects, Near and far bounds of the View area.
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Parameters at view area projection bounds
See also: Near and far bounds of the View area.
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External link: "The principles of CCTV design in VideoCAD. Part I. Camera view area"(*.pdf).