ACM100
Register Description
0x00 User Tint
Bit Definition
15
0
14
1
13
0
12
0
11
0
10
0
9
1
8
0
7
0
6
0
5
0
4
0
3
1
2
1
1
0
0
0
AB_K
TINT_EN
TINT
The User Tint register is used when manual control of the integration period is required by the application. The bits are defined
as follows:
[15:13] AB_K :
This bit field can be used to slow down the response of the automatic Tint control to changes in the
scene. This may be desirable if smooth changes between camera settings are preferable to rapid
response. New Tint values are calculated based on the assumption that the image average will scale
linearly with the Tint setting. The algorithm works by calculating the difference between the current and
target image average and then based on that difference calculating what change in Tint is required to
attain the desired image average. The algorithm then multiplies the change in Tint by the AB_K value
and then adds the result to the current Tint value. Therefore, smaller values of AB_K will cause the Tint
value to adjust in smaller increments, although the size of the steps will remain proportional to the lighting
change for a fixed AB_K.
The following table shows some examples of how AB_K affects the Tint calculations for a desired image
average of 128. (Calculated Tint = Tint(128/Image Average))
Image
Average
Calculated
Tint
Tint
Difference
Tint
100
100
100
250
250
250
AB_K
1
New Tint
256
50
50
256
256
256
213
213
213
156
156
156
-37
-37
-37
0.5
0.25
1
178
50
139
150
150
150
213
0.5
0.25
231
241
The operation of this field is defined by the following table. Other values are not defined and should not
be used
AB_K
Description
4
3
2
1
Normal Response
75% of Normal Speed
50% of Normal Speed
25% of Normal Speed
Writing a ‘1’ to this bit will enable manual control of the integration period. When enabled, the TINT value
specified in this register will be used and automatic control of the integration period is disabled. Writing
a ‘0’ to this location will disable manual control and enable the automatic control of the integration period.
Changes to this bit will take affect on the next full frame of video.
[12] TINT_EN:
[11:0] TINT:
This field specifies the integration period as a number of rows. The maximum integration is 525 rows.
At a frame rate of 30 fps, writing a value of 0X20D would result in a 33 msec integration period. Changes
to this parameter will take affect on the next full frame of video.
Document Number: 001-05325 Rev. **
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