MT9P001 Datasheet, PDF (30/48 Pages) ON Semiconductor – CMOS Digital Image Sensor

MT9P001: 1/2.5-Inch 5Mp Digital Image Sensor
Features
Image Acquisition Modes
The MT9P001 supports two image acquisition modes (Shutter Types) (see “Operating
Modes” on page 31), electronic rolling shutter and global reset release.
Electronic Rolling Shutter
The ERS modes take pictures by scanning the rows of the sensor twice in the order
described in “Full-Array Readout” on page 22. On the first scan, each row is released
from reset, starting the exposure. On the second scan, the row is sampled, processed,
and returned to the reset state. The exposure for any row is therefore the time between
the first and second scans. Each row is exposed for the same duration, but at slightly
different point in time, which can cause a shear in moving subjects.
Whenever the mode is changed to an ERS mode (even from another ERS mode), and
before the first frame following reset, there is an anti-blooming sequence where all rows
are placed in reset. This sequence must complete before continuous readout begins.
This delay is:
t_{ALLRESET = 16 × 2004 ×} t_ACLK
Global Reset Release
The GRR modes attempt to address the shearing effect by starting all rows' exposures at
the same time. Instead of the first scan used in ERS mode, the reset to each row is
released simultaneously. The second scan occurs as normal, so the exposure time for
each row would different. Typically, an external mechanical shutter would be used to
stop the exposure of all rows simultaneously.
In GRR modes, there is a startup overhead before each frame as all rows are initially
placed in the reset state (^tALLRESET). Unlike ERS mode, this delay always occurs before
each frame. However, it occurs as soon as possible after the preceding frame, so typically
the time from trigger to the start of exposure does not include this delay. To ensure that
this is the case, the first trigger must occur no sooner than ^tALLRESET after the previous
frame is read out.
Exposure
The nominal exposure time, ^tEXP, is the effective shutter time in ERS modes, and is
defined by the shutter width, SW, and the shutter overhead, SO, which includes the effect
of Shutter_Delay. Exposure time for other modes is defined relative to this time.
Increasing Shutter_Delay (SD) decreases the exposure time. Exposure times are typically
specified in units of row time, although it is possible to fine-tune exposures in units of
t_{ACLKs (where} t_{ACLK is 2 *} t_PIXCLK).
t_{EXP = SW ×} t_{ROW – SO × 2 ×} t_PIXCLK
where:
SW = max(1, (2 * 16 × Shutter_Width_Upper) + Shutter_Width_Lower)
SO = 208 × (Row_Bin + 1) + 98 + min(SD, SDmax) – 94
SD = Shutter_Delay + 1
SDmax = 1232; if SW < 3
1504, otherwise
MT9P001_DS Rev. L 4/15 EN
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©Semiconductor Components Industries, LLC,2015.