2014 Ball HSV Values

Has anybody determined the HSV values of the blue ball? My team received the red ball and I’ve been using the minimum range as (160, 50, 50) and maximum as (180, 200, 200). These values are for OpenCV, so hue is considered form 0 to 180, instead of 0 to 360 as usual. The same for saturation and value, which are 0 to 255 in OpenCV, whereas they’re usually taken from 0 to 100.

Regardless of what works for others, it is probably a good idea to calibrate these values on the field, as they may vary greatly depending on lighting and camera settings.

Yes, it’s very important to calibrate them on the field, but it’s good to have a range with which to work. Also, the hue value won’t change to much. Or so I’ve been told :ahh:

Ideally, hue wouldn’t change too much, but under white lights vs yellow lights etc, I think it would vary some. And auto white balance or auto exposure can really screw with this kind of thresholding.

Anyway, our team has a blue ball. If I get a chance to find a good range, I’ll try to remember to post it here. Can’t promise it would be anytime soon – we have a lot of other things to get working first.

I just did some testing today with OpenCV and one of the JPGs that came with LV of the red and blue ball. This was from a print, not a real blue ball. Calibration on the field is a must!

Here are the Upper and Lower values for HSV I found worked for testing purposes:

UH = 135
LH = 70
US = 186
LS = 25
UV = 227
LV = 100

Hope those help.