bit 6

bit 5

bit 4

b

3

b2

b0

b1

bit 7

bit plane

256

128

64

32

16

24-bit RGB Image

8-bit Red Image

8-bit Green Image

8-bit Blue Image

8 Red Bit-Planes

8 Green Bit-Planes

8 Blue Bit-Planes

DLPC300

DLPS023A – JANUARY 2012 – REVISED JULY 2012

www.ti.com

Figure 3. Bit Slices

The length of each bit-plane in the time slot is weighted by the corresponding power of 2 of its binary

representation. This provides a binary pulse-width modulation of the image. For example, a 24-bit RGB input has

three colors with 8-bit depth each. Each color time slot is divided into eight bit-planes, with the sum of all bit

planes in the time slot equal to 256. See Figure 4 for an illustration of this partition of the bits in a frame.

Figure 4. Bit Partition in a Frame for an 8-Bit Color

Therefore, a single video frame is composed of a series of bit-planes. Because the DMD mirrors can be either on

or off, an image is created by turning on the mirrors corresponding to the bit set in a bit-plane. With the binary

pulse-width modulation, the intensity level of the color is reproduced by controlling the amount of time the mirror

is on. For a 24-bit RGB frame image inputted to the DLP300, the DLPC300 creates twenty-four bit planes, stores

them on the mDDR, and sends them to the DLP3000 DMD, one bit-plane at a time. Depending on the bit weight

of the bit-plane, the DLPC300 controls the time this bit-plane is exposed to light, controlling the intensity of the

bit-plane. To improve image quality in video frames, these bit-planes, time slots, and color frames are intertwined

and interleaved with spatial-temporal algorithms by the DLPC300.

For other applications where this image enhancement is not desired, the video processing algorithms can be

bypassed and replaced with a specific set of bit-planes. The bit-depth of the pattern is then allocated into the

corresponding time slots. Futhermore, an output trigger signal is also synchronized with these time slots to

indicate when the image is displayed. For structured light applications this mechanism provides the capability to

display a set of patterns and signal a camera to capture these patterns overlayed on an object.

4

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