These are the 2 steps to set the correct CAM_FOV for your camera
Step 1 – Set a default CAM_FOV
The first step is to set one of these default CAM_FOV values for your camera:
|Model name||ELP-USBFHD01M-L180||ELP-USBFHD01M-BL180||Leorover Fisheye USB Camera with Waterproof case||ELP-USBFHD01M-L170||SainSmart Wide Angle FOV160° 5-Megapixel Camera Module - for Raspberry Pi||Generic no-fisheye webcam||Generic smartphone/tablet||ASTAR CaliCam® Fisheye Stereo Camera||ASTAR CaliCam® Fisheye Stereo Camera|
|CAM_FOV value||120 or 130||120 or 130||120 or 130||70||100||0||0||120||90|
Step 2 – Check the default CAM_FOV
The second step is to check the result provided with the default CAM_FOV shown in the table above and adjust the CAM_FOV accordingly if needed.
To do so:
- Click on the Save Config and Restart button inside the Configuration page.
- Click on the Main tab.
- Click on Start Positioning.
Now you can check if the default CAM_FOV value is correct. A CAM_FOV value is correct when 2 conditions are met:
- 1st CONDITION – the black arcs inside the Video Preview do not cover too much of the frame.
- If there are no black arcs in any of the 4 sides then it means that the selected CAM_FOV is too low – please increase it of 20° and repeat the test.
- If the black arcs are on all the 4 sides and fill a considerable area of the frame then it means that the selected CAM_FOV is too high – lower it of 20° and repeat the test.
- If the black arcs are slightly seen up and down then the selected CAM_FOV is correct.
- 2nd CONDITION – the lines/shapes that are straight in the real life are also straight inside the Video Preview.
Please send us the image of the Video Preview and your calibration file and we will let you know right away if the CAM_FOV value is correct.
There are some cameras for which the output image is cropped when the resolution is set to a value lower than the maximum resolution and thus the FOV is different than the maximum FOV shown in the specifications. In this situations the CAM_FOV shown in the table above is not good and needs to be reduced.
The FOV of the ELP-USBFHD01M-L170 camera (when the CAM_IMAGE_WIDTH is set to 640 and the CAM_IMAGE_HEIGHT is set to 480) is NOT 170° (as when the camera is used at 1920 X 1080). So, setting a CAM_FOV of 120° makes the image too cropped (and black arcs would cover a big part of the image). This is why the right CAM_FOV in a situation like this one is 70°.