The DMPAC supports the following main features:
- Input image resolution up to 2 MPix with maximum
horizontal resolution of up to 2048 pixels and maximum vertical resolution of up
to 1024 pixels
- Input pixel format of 12-bit
fully packed luminance data, and other formats using the integrated Format
Conversion (FOCO) module
- Pixel level output packed in
16bpp and 32bpp formats for stereo disparity estimates and optical flow
estimates, respectively
- Simultaneous operation of SDE and
DOF, each processing inputs of up to 1 MPix image resolution (1 MPix = 1280 ×
720 pixels)
- Resolution vs. frame rate
scalability (higher frame rate at lower resolution)
- A Dense Optical Flow (DOF) engine: The DOF engine
implements Texas Instruments' proprietary algorithm for estimation/calculation
of the optical flow between the input image pair. The algorithm uses
hierarchical coarse-to-fine block search strategy leveraging image pyramids in
which proprietary binary pixel descriptors are used for pixel correspondence
determination. In the scheme accuracy and smoothness of the flow map is enforced
using optical flow estimates of the causal neighbors of a pixel in the given and
higher (lower resolution) pyramid level (pixels are processed in raster scan
order in a pyramid level to refine existing optical flow estimates). The DOF
engine supports:
- Optical flow vector lengths up to +/- 191 pixels in
horizontal direction and +/- 62 pixels in vertical direction for each
input pixel
- Dense flow vector map for each input pixel
- Optical flow vector precision of 1/16th of
inter pixel distance
- Post filtering of the optical flow estimates using 2D
median filtering
- 16 level confidence score for every output flow
vector
- A Stereo Disparity Engine (SDE): The SDE
implements Texas Instruments' proprietary algorithm in order to find the
disparity map between the input image pair. The SDE supports:
- Disparity search range (SR) of 64/128/192. It can
support either "0 to SR-1" or "-3 to SR-4"
- 1/16th pixel accurate sub-pixel level
disparity estimate
- Disparity estimate post processing using 2D median
filtering
- 8 level confidence score for each disparity output
- Common top level infrastructure:
- Shared Level 2 (SL2)
memory sub-system, which serves both DOF and SDE blocks, along with the
FOCO modules when required as an intermediate storage exchange data
across sub-modules (FOCO to DOF/SDE) and from DDR/System Memory
- A Unified Transfer
Controller (UTC), which serves as a DMA engine
- Messaging and control
mechanism via a Hardware Thread Scheduler (HTS) block
- A Counter, Timer and
System Event Trace (CTSET) module, which provides event tracing
capability for the SDE and DOF hardware threads
The DMPAC does not support (but relies on other
HWAs/processors on the SoC to perform these tasks):
- Epipolar rectification of the stereo input
images
- Image pyramid generation for the optical flow
input images