Getting the right view angle

Image quality, Resolution, Light sensitivity, Signal/noise ratio, etc.
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Bas
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Joined: 02 Aug 2021, 15:01

Getting the right view angle

Post by Bas »

I want to add a camera and a lens to my camera database, but somehow I do not seem to get the correct viewing angles.
I am wondering if I am overlooking something. I added my camera db to this message an xlsx file.

The camera to be modelled is a Bosch dinion 6000 HD, with a varifocal lens 4,1-9 mm, will list a link to the data sheets below.
The angles videocad calculates for me are significantly smaller then provided by the manufacturer.

Camera Bosch Dinion IP Starlight 6000 HD (1080p)
Lens LVF_5005C_S4109
Manufacturer tool www.boschsecurity.com/LensCalculator/ht ... lator.html
Attachments
Camera db.zip
(8.32 KiB) Downloaded 625 times

Support
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Re: Getting the right view angle

Post by Support »

Hello, Bas

Very often I receive similar questions about modeling specific camera models.

Usually, the view angles given in the camera specification do not coincide with the angles calculated using the classic formulas for two reasons:

1. Lens distortion (actual for lens focal length 4-6mm and less)
2. An error in setting the size of the active area of ​​the image sensor.

Errors in camera specifications are also possible but rare.
VideoCAD allows you to take into account both of these reasons. See more: About active area of the image sensor, About Lens distortion

For the camera Bosch dinion 6000 HD, the angles calculated by VideoCAD (without take into account lens distortion) and the angles from the Bosch calculator are almost the same for the focal length of 9mm.

Pay attention to the aspect ratio of the image sensor - 16:9. It is not specified in the specification, only the 1/2.8 "format is indicated. If the aspect ratio of the sensor is not specified, then it has to be selected, usually between 16:9 and 4:3.
Although, if there are 2 view angles in the specification, then it is enough just to enter their values in Real view angles boxes and turn on the distortion modeling.

Image

For the focal length of 4.1mm, the vertical angle is close. The horizontal angle from the calculator is larger (78 deg), the calculator tries to take into account the lens distortion in a simplified way.
You can assign angles from Bosh calculator to the camera in VideoCAD and get exact model.

Image

Image

However this calculator looks very approximate, you should not take it as accurate. The exact values ​​of the view angles are in camera specifications or from your own measurement.

Modeling vary-focal function is also possible, you can specify view angles at max and min lens focal lengths using the List/Range of lens focal lengths.
You can record the values in the camera model database.

Bas
Posts: 5
Joined: 02 Aug 2021, 15:01

Re: Getting the right view angle

Post by Bas »

Thank you very much for the swift and detailed explaination, it helped a lot.
However, with the distortion simulated, changing the camera orientation in 3d view is very slow and laggy, where it was smooth before. I noticed that it became smooth again after disabling image processing. Is this optimizable e.g., by changing settings?

Support
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Re: Getting the right view angle

Post by Support »

Starting from VideoCAD11, distortion modeling in the 3D Video window occurs without loss of quality and with a slight delay. Although the speed depends on the capabilities of your video card.
In previous versions of VideoCAD, modeling distortion leads to slowdown and blurring, but it depends less on the video card.

When image processing is enabled, many camera parameters can be simulated, but the creation of the 3D image is slowed down.
The slowdown with image processing enabled depends on which modeling tools you have enabled. See more

It is recommended to disable image processing in most cases. Enable image processing only while simulating camera parameters and image resolution.

Image processing is not required to simulate lens distortion.

Everything written above refers to VideoCAD11. What version of VideoCAD do you have?
I recommend to upgrade to VideoCAD11. In VideoCAD 11 3D graphic is much faster.

Bas
Posts: 5
Joined: 02 Aug 2021, 15:01

Re: Getting the right view angle

Post by Bas »

A couple of months ago we went from version 8 to 11, there was indeed a significant performance increase.
You say the speeds depend greatly on the capabilities of the videocard, which properties should we look for in a videocard for best results?
Right now we have availability of a "gtx 1050 Ti" and a "quadro p620", however I noticed that the videocard does not exceed 30% load when VideoCAD utilizes it.

When we have image processing enabled, videocad takes approximatly 3-4 seconds to generate the image, even when there are no constructions or models in the view area. Could this be reduced by omitting some camera parameters?

Support
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Re: Getting the right view angle

Post by Support »

Bas wrote:
05 Aug 2021, 08:15
You say the speeds depend greatly on the capabilities of the videocard, which properties should we look for in a videocard for best results?
Right now we have availability of a "gtx 1050 Ti" and a "quadro p620", however I noticed that the videocard does not exceed 30% load when VideoCAD utilizes it.
Sorry, I am not an expert on video card models and have not tested them.
Bas wrote:
05 Aug 2021, 08:15
When we have image processing enabled, videocad takes approximatly 3-4 seconds to generate the image, even when there are no constructions or models in the view area. Could this be reduced by omitting some camera parameters?
This is too long time for a camera with default parameters. You need to look at what tools you have enabled.
Modeling of illumination and light sensitivity, luminaries, exposure time, depth of field, animation most of all affect the time of image creation. If several such tools are enabled, the delays are multiplied.
When you create a camera, these tools are disabled by default. You can turn them on and off both for all cameras and for each camera separately.

Why do you keep image processing turned on all the time? What parameters require constant modeling?

The easiest way to increase 3D permormance is to disable image processing and get the creation of 3D images in a fraction of second. Modeling camera parameters is not fast but it is physical accurate and can be easy turned on and off.

Turn on image processing only for the time of modeling the image quality and camera parameters, this is not necessary all time. Please read it, it's important.

Bas
Posts: 5
Joined: 02 Aug 2021, 15:01

Re: Getting the right view angle

Post by Bas »

Support wrote:
05 Aug 2021, 16:43
Sorry, I am not an expert on video card models and have not tested them.
I also tested on another system, 10th gen i9, maybe that there was a bottleneck or some sort on the primary system. But results looked the same, only 30% utilisation. Also tried an SLI configuration, still 30% utilisation of 1 card.
Some research online suggests that the software might not be able to use multiple cores.
Could it be an idea to move the computational part to the cuda cores since they can do it extremely fast?
Support wrote:
05 Aug 2021, 16:43
Why do you keep image processing turned on all the time? What parameters require constant modeling?
Image processing is not turned on constantly. however, I noticed such a decrease in performance, that I wondered that there might be something wrong.


On a side note, on the other system I also played a bit with driver settings, such as anti aliasing and supersampling, the result (in 3d world for example) is stunning, smooth 60 Hz, crisp models and constructions.

Support
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Re: Getting the right view angle

Post by Support »

Bas wrote:
06 Aug 2021, 09:18
Image processing is not turned on constantly. however, I noticed such a decrease in performance, that I wondered that there might be something wrong.
Image processing (simulation of camera parameters) is done mostly by the CPU and slows down the speed of creating images. This is written in the help system.

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