Notice how there's some outrageous and short-lived tones during sunrise and sunset -- that's the white balance jumping around (Possibly an automatic saturation gain too?)
Then notice how the brightness doesn't peak and fall during the day, instead jumping quickly from darkness to "full" brightness with frequent dramatic shifts far greater than reality would allow. That's because the moving cloud cover is triggering the auto exposure to jump around incessantly.
The ideal fix would be to replace the webcam with a digital camera capable of tethered shooting and fully manual operation. You'd fix the shutter, aperture and ISO values to a level that minimizes clipping, set the white balance to daylight, and point the camera in a direction least likely to be in the sun's path (in the southern hemisphere, that's south).
In order to capture the dynamic range fully, you could allow the camera to automatically choose the shutter speed, then compensate in the algorithm by reading the shutter speed from the EXIF data.
That said, full points for the idea, and for a great web app to visualize the data!
The ones at sunrise are weird (blue throws off the white balance) but the sunset ones are actually accurate-- that's the color of a NY sunset in the summer. Surreal, eh?
I miss New York.
The cheap option that comes to mind would be an old and/or second hand Canon PowerShot capable of running CHDK firmware. Ask friends and family; you'd probably be able to score one free from a dusty cupboard draw.
And it looks like, more than the auto-white balance thing, he's getting washed-out skies from overexposure. This is a very common problem in photography- ever take a photo somewhere with a blue sky dotted with clouds but in the photo the sky comes out solid white or gray? Go back and look at some of your old photos, you will notice it.
There is no easy solution without sacrificing exposure of the lower half (what is usually the subject) however in this case the subject IS the sky, so select a camera that has manual exposure, set it a little lower and you'll be all right.
So you could feel like you were in the best location in the world on the best day of the year. Or just synchronize your work/sleep schedule with some other timezone.
Small versions as nice gifts, big custom versions for the luxury/institutional market. Chumby app. Wall mounted LCD/LED and/or LED dome projection.
Any hardware hackers feel like pairing up? I'm a short flight from Shenzhen. ;)
This would be a great visualization of daylight quantity and quality over the year.
What those do show is:
- The huge variations in day length due to latitude
- How those of us in higher latitudes spend in the gloaming - my favourite time of day
You can plot other variables like this too - temperature, humidity, ...
This would more closely match the progression of time, instead of making rows of squares.
I'm often looking for color inspiration, so will use this. Would be amazing to have this for Colorado skies, especially as the sun sets over the Rockies.
Hope it's helpful.
a bug fix:
`document.body.style.backgroundColor = 'rgb('+rgb.r+','+rgb.b+','+rgb.g+')';`
`document.body.style.backgroundColor = 'rgb('+rgb.r+','+rgb.g+','+rgb.b+')';
If it's auto color balance, it's completely useless.