PRELIMINARY
MT9M111
SOC MEGAPIXEL DIGITAL IMAGE SENSOR
Architecture Overview
The MT9M111 consists of a sensor core, the color-
processing pipeline, and a measurement and control-
logic block (the camera controller). The following is a
brief overview of the architecture.
adjustments can be made both by the user and the
auto exposure unit (for dynamic saturation reduction
in high or low-lighting situations).
Resize
Sensor Core
The sensor core is taken from the MT9M011 stand-
alone sensor and includes a number of features specif-
ically targeting the mobile market. Of primary interest
is support for low-power preview/viewfinding with
hardware-accelerated switching to full-resolution for
snapshots. This switch can be achieved without
adversely affecting exposure or color balance. This
enables taking single-frame and Xenon flash snap-
shots while minimizing snapshot lag. LED snapshots
are discussed below; they also benefit significantly
from this feature.
The IFP can resize to virtually any output resolution
through digitally filtered sub-sampling. Output resolu-
tions include, but are not limited to, VGA, QVGA, CIF,
and QCIF. When the output resolution is smaller than
the sensor-generated image, smooth, continuous
zoom and pan become available. The user simply
defines the zoom window, pan offset, and output reso-
lution, and the resizer calculates all other parameters
for the resize function.
Camera Control
The camera controller continuously accumulates
image brightness and color statistics. Two units use
these measurements to adjust the sensor and color-
pipe settings. The auto exposure unit adjusts gain and
shutter width to maintain a user-defined luma target.
The image measurement region can be modified to
permit, for example, backlight compensation. The user
can also control the speed and sensitivity of the algo-
rithm from highly responsive (for LED flash and view-
finding) to somewhat dampened (for video). Finally,
the unit can detect 50Hz or 60Hz rolling flicker bars
(due to ambient illumination) and adjusts exposure
appropriately to eliminate this adverse effect on image
quality.
The AWB module adjusts gains and the CCM to
compensate for the effects of changing scene illumina-
tion on the quality of the color rendition. The user has
control over the region of the scene to be analyzed as
well as the responsivity of the algorithm to illuminant
changes.
Lens-Shading Correction and Black
Level Conditioning
The stream of raw data from the sensor enters the
pipeline and undergoes several transformations.
Image stream processing starts with conditioning the
black level and applying a digital gain.
The lens-shading block compensates for spatially
varying signal loss caused by the lens. The block is pro-
grammable and implements separate correction func-
tions for R,G, and B independently.
Defect Correction
Following lens correction, the data stream is ana-
lyzed for the presence of defects. A two-dimensional
digital filter calculates suitable replacement values.
Edge sensitivity minimizes false detections, helping to
preserve image sharpness.
Interpolation, Aperture, and Color Cor-
rection
The Bayer pixel pattern data is interpolated to
recover missing color components for each pixel fol-
lowing defect correction. Configurable aperture cor-
rection sharpens the image and to avoid amplifying
noise, can be programmed to be less aggressive in low-
light conditions.
The resulting interpolated RGB data passes through
the current color correction matrix (CCM), gamma,
and color saturation corrections.
The CCM can be manually loaded or dynamically
configured by the AWB unit. The gamma correction
unit is fully user-programmable, and color saturation
Camera Interface and Test Patterns
The MT9M111 outputs processed video as a stan-
dard ITU-R BT.656 stream, an RGB stream, or as pro-
cessed or unprocessed Bayer data. The ITU-R BT.656
stream contains YCbCr 4:2:2 data with optional
embedded synchronization codes. This output is typi-
cally suitable for subsequent display by standard (pro-
gressive scan) video equipment, or JPEG/MPEG
compression. RGB functionality provides support for
LCD devices.
The MT9M111 can be configured to output 16-bit
RGB (RGB565), 15-bit RGB (RGB555), and two types of
12-bit RGB (RGB444). The user can configure internal
09005aef8136743e pdf/09005aef8136761e zip
MT9M111__SOC1310__2.fm - Rev. C 10/04 EN
12
Micron Technology, Inc., reserves the right to change products or specifications without notice.
©2004 Micron Technology, Inc. All rights reserved.
MICRON [ MICRON TECHNOLOGY ]
