Dark/Bright detection

[auduno]

Dark/Bright detection

[auduno]

You can use getWhitebalance-function in whitebalance.js for checking the "average luminance"-level in the canvas. It will return a value between 0 and 255, where 0 is pitch black and 255 is all white. So for video, you could copy the video to a canvas and check that the value is above or below a threshold:

var grayLevel = headtrackr.getWhitebalance(canvas);
if (grayLevel < 30) {
  // too dark
} else if (grayLevel > 220) {
  // too bright
} else {
  // ok!
  // do something....
}

The choice of thresholds here was a bit arbitrary, 30 is probably too dark and 220 too bright... :)

[rafaelfaria]

Great! thanks! :)

On Wed, Oct 17, 2012 at 10:02 AM, Audun Mathias Øygard <
[email protected]> wrote:

You can use getWhitebalance-function in whitebalance.js for checking the
"average luminance"-level in the canvas. It will return a value between 0
and 255, where 0 is pitch black and 255 is all white. So for video, you
could copy the video to a canvas and check that the value is above or below
a threshold:

var grayLevel = headtrackr.getWhitebalance(canvas);
if (grayLevel < 30) {
// too dark
} else if (grayLevel > 220) {
// too bright
} else {
// ok!
// do something....
}

The choice of thresholds here was a bit arbitrary, 30 is probably too dark
and 220 too bright... :)

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