Stereo Camera

Hi,

I have used a similar camera from IDS. The problem is that you will need a camera with a really short focal length to match the Oculus FOV.

The FOV calculations can be made like this:
Horizontal FOV = 2*ARCTAN(SH /(2*FL))
Vertical FOV = 2*ARCTAN(SV /(2*FL))

FL = Focal length of lens
SH = Sensor horizontal (width)
SV = Sensor vertical (height)

The IDS cameras you link use a 1/1.8" sensor which gives the sensor size of 7.176 mm x 5.319 mm

Using the above calculations gives that the needed Focal length will be approx. 2 mm to be able to capture a 120 deg horizontal FOV.

First thanks for your help.

This mean only my sensor and focal length is important for the FOV?

My sensor has the following SV=5.427 and SH=6.784. When i take a focal length of 1.55 my FOV is 2.28°???

Isn't the field Angle important? In our case its 120° or not?
When i want to rebuild the human eye i need 120°?

Soruce: willsteptoe.com/post/67399683294/ar-rift-camera-selection-part-2

"GermanStudent" wrote:

This mean only my sensor and focal length is important for the FOV?

Yes, for the field of view only the sensor size and focal length matter. But you seem to have messed up your calculations.

The camera you linked in your first post have a 1/1.8 sensor, this means that the sensor diagonal is 1/1.84 inch. This gives a sensor size of 7.176 mm horizontal and 5.319 mm vertical (assuming you use the cameras in landscape mode).

If you use a lens with focal length of 1.5 mm you will get the following field of view:

HFOV = 2*ARCTAN(SH /(2*FL)) = 2 * ARCTAN ( 0.007176  / (2 * 0.0015)) = 2,35 radians = 135 degrees
VFOV = 2*ARCTAN(SV /(2*FL)) = 2 * ARCTAN ( 0.005319  / (2 * 0.0015)) = 2,11 radians = 121 degrees

Hi,

"pixelminer" wrote:
Vertical FOV = 2*ARCTAN(SV /(2*FL))

This only works if the lens is rectilinear though, which is most probably not the case at these values.
You would need to know the radial distortion parameters of the lens or the mapping function.

Note that in the general case the sensor "size" value indicated in specs (like 1/1.8" here) is more of a "category" than a physical value. (1" sensors are not 1" in any dimension).

The imaging area is also smaller than the whole sensor, due to dark rows, etc. The product sheet for the linked camera indicates 6.784 mm x 5.427 mm (still unclear if this is the whole pixel array or the usable array).

Another thing to take into account is the crop factor. The lens will project an image circle of a given diameter on the focal plane. Depending on the sensor size, the image rectangle will be entirely or partly inscribed in the circle. This will change the field of view imaged by the sensor. You will only get the full field of view of the lens in all dimensions if you have the entire circle into the image, in which case you won't use all the pixels.

The imaged diagonal field of view will match the lens FOV only if the lens projects a circle that perfectly match the sensor diagonal. M12 lenses usually have a "sensor size" rating that you can use to match your sensor.

"joan" wrote:

This only works if the lens is rectilinear though, which is most probably not the case at these values.
You would need to know the radial distortion parameters of the lens or the mapping function.

You are correct, shorter focal length normally means greater distortions and as we approach fish eye lenses linear formulas have greater errors.

"joan" wrote:
Note that in the general case the sensor "size" value indicated in specs (like 1/1.8" here) is more of a "category" than a physical value. (1" sensors are not 1" in any dimension).

The imaging area is also smaller than the whole sensor, due to dark rows, etc. The product sheet for the linked camera indicates 6.784 mm x 5.427 mm (still unclear if this is the whole pixel array or the usable array).

I missed the specified sensor size in the data sheet. But the specified pixel size (5.3 μm) multiplied with the resolution gives the same values, so it looks as this is the usable array that is specified.

Anyhow... Since this is quite expensive cameras I hope that OP's camera dealer can help him/her with selecting a lens with the desired FOV.

Hi developers, i bought this lens LNESTION BM4018S118 http://www.lensation.de/en/shop/detail/ ... l?sef=hcfp

Now i want to set the videostreams to the oculus. Are there any examples or porjects for that?

"GermanStudent" wrote:
Hi developers, i bought this lens LNESTION BM4018S118 http://www.lensation.de/en/shop/detail/ ... l?sef=hcfp

Now i want to set the videostreams to the oculus. Are there any examples or porjects for that?

This has been discussed in the following threads:
viewtopic.php?f=20&t=15906
viewtopic.php?f=20&t=14893

Hi i took this Programm:
https://github.com/federico-mammano/Loo ... culus-Rift
http://federico-mammano.github.io/Looki ... ulus-Rift/

and its running great but now i have a problem with the resolution. As you can see on the photo: http://www.bilder-upload.eu/upload/3976 ... 694086.png the reolution is way to smal now is there any posibility to change it to the cameraresolution?

I already serached for it since one week in the programm but cant find the parameter.

Since that program uses OpenCV, my guess (without delving deeper into the code) would be that you need to set the camera resolution to the cv::VideoCapture object somewhere.

Something like this:

...
videoCaptureDevice = new cv::VideoCapture(0);
videoCaptureDevice->set(cv::CAP_PROP_FRAME_WIDTH, 1280);
videoCaptureDevice->set(CV_CAP_PROP_FRAME_HEIGHT, 1024);
...

Also make sure that you have connected the cameras to USB3 ports and that the IDS Camera Manager software actually detects that the camera is connected to a USB3 port. I had an issue with one of my IDS cameras, which had a faulty connector. This resulted in that even though that the camera was connected to an USB3 port, the IDS software still reported it as USB2 which put a serious cap on frame rate.

Tanks for your reply. At the moment i use the USB2.0 port but its no problem i know the fps sink next week i have usb3.0 cables.

I tried to set the Video Height and width here but then there is this error

iWidth= (int)Video.set(CV_CAP_PROP_FRAME_WIDTH,1280);
iHeight= (int)Video.set(CV_CAP_PROP_FRAME_HEIGHT,1024);


"Unhandled exception at 0x0102552e in OculusRoomTiny.exe: 0xC0000005: Access violation writing location 0x03a9c102."