MT9M114_16 Datasheet, PDF (33/62 Pages) ON Semiconductor – High-Definition (HD) System-On- A-Chip (SOC) Digital Image Sensor

MT9M114: 1/6-Inch 720p High-Definition (HD) System-On-A-Chip (SOC) Dig-
ital Image Sensor
VPC is performed using a mixture of scale and crop, the variables that control this are:
Variable
Name
Function
VAR(0x12,0x005E)
or (R0xC85E)
cam_scale_vertical_tc_mode
When set, the vertical stretching factor is
applied to the centre of the image, so
top/bottom lines are cropped. When
clear, the crop occurs in the top or
bottom of the scene dependent on the
percentage value
(cam_scale_vertical_tc_percentage).
VAR(0x12,0x0060)
or (R0xC860)
cam_scale_vertical_tc_percentage
The amount of tilt (perspective)
correction to be applied. If negative, this
value represents % of FOV reduction with
the bottom line unaffected. If positive,
this value represents % of FOV reduction
with the top line unaffected.
VAR(0x12,0x0062) cam_scale_vertical_tc_stretch_fact Ratio of vertical stretching against the
or (R0xC862)
or
percentage applied. Vertical stretching =
stretch factor x percentage/2.
The effect of using cam_scale_vertical_tc_percentage can be seen below.
90% w
Uncorrected
image
w
w
Uncorrected
image
Case1: CAM_SCALE_VERTICAL_TC_PERCENTAGE = 10%
Vertical plane is tilted-away from
the camera – therefore the bottom
row of image represents the
nearest point. The nearest point
appears bigger in the uncorrected
image, therefore top/bottom ratio
will be greater than 1.0
Case2: CAM_SCALE_VERTICAL_TC_PERCENTAGE = -10%
Vertical plane is tilted-towards the
camera – therefore the top row of
image represents the nearest point.
The nearest point appears bigger in
the uncorrected image, therefore
the top/bottom ratio with be less
than 1.0
90% w
Cam_scale_vertical_tc_percentage defines how much tilt needs to be corrected for in
percentage terms.
MT9M114/D Rev. 11, 2/16 EN
33
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