jstjohnz
Apprentice elf
This is a project that I've been working on for some time, and I'm happy to announce that the TLS3001, a 12-bit RGB pixel, is now fully supported on the Sandevices E680/E681 series of RGB pixel controllers. Why is this important? Even though DMX channels are only 8-bits, having a total of 4,096 intensities available allows those 256 DMX values to be mapped to specific values in the 0-4095 range to produce a more natural dimming curve.
Those who have worked with LED lights in general, or RGB pixels in particular, have probably noticed that the dimming curve doesn't appear smooth to the eye. That's because our eye's response to light is very non-linear; small intensity changes at the low end are very noticeable, whereas the same intensity change at the high end would go unnoticed. So, to the human eye, a typical LED appears to dim very slowly at first, then abruptly towards the low end. The difference between full off (0 intensity) and an intensity level of 1, is a pretty big jump, but you'd probably never notice the difference between an intensity of 230 (90%) and 255 (full on)
That's where the extra dynamic range of the 12 bit pixels really shines. By implementing a mapping curve, also known as gamma correction, we can make the level changes at the low end be very small, then gradually increasing until they become much larger at the bright end of the curve. Then, to the eye, the dimming response of the pixel becomes much more natural, much more like the dimming we are used to with incandescent bulbs. If you have both incandescent lights and pixels in your display, the LEDs will more closely track the incandescents when dimming.
The second advantage has to do with displaying images, whether still, or motion, on a large array of pixels. The linear dimming curve of an uncorrected LED makes it very difficult to display accurate shades of brightness, so a lot of image detail can be washed out. By employing gamma correction at the pixel level, it allows images to be rendered with much more detail.
Finally, the extra resolution allows you to select a master dimming level at the controller, say 25%, 50%, 75% or 100% of full brightness, either to compensate for changes in ambient lighting, or to reduce power requirements and voltage drop.
Those who have worked with LED lights in general, or RGB pixels in particular, have probably noticed that the dimming curve doesn't appear smooth to the eye. That's because our eye's response to light is very non-linear; small intensity changes at the low end are very noticeable, whereas the same intensity change at the high end would go unnoticed. So, to the human eye, a typical LED appears to dim very slowly at first, then abruptly towards the low end. The difference between full off (0 intensity) and an intensity level of 1, is a pretty big jump, but you'd probably never notice the difference between an intensity of 230 (90%) and 255 (full on)
That's where the extra dynamic range of the 12 bit pixels really shines. By implementing a mapping curve, also known as gamma correction, we can make the level changes at the low end be very small, then gradually increasing until they become much larger at the bright end of the curve. Then, to the eye, the dimming response of the pixel becomes much more natural, much more like the dimming we are used to with incandescent bulbs. If you have both incandescent lights and pixels in your display, the LEDs will more closely track the incandescents when dimming.
The second advantage has to do with displaying images, whether still, or motion, on a large array of pixels. The linear dimming curve of an uncorrected LED makes it very difficult to display accurate shades of brightness, so a lot of image detail can be washed out. By employing gamma correction at the pixel level, it allows images to be rendered with much more detail.
Finally, the extra resolution allows you to select a master dimming level at the controller, say 25%, 50%, 75% or 100% of full brightness, either to compensate for changes in ambient lighting, or to reduce power requirements and voltage drop.