AS0260CSSC28SUD20 datasheet(28/83 Pages) ONSEMI

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AS0260 DS Rev. G Pub. 5/15 EN

©Semiconductor Components Industries, LLC, 2015.

AS0260: 1/6-Inch 1080P High-Definition (HD) System-On-A-Chip (SOC) Digi-

tal Image Sensor

Gamma Correction

The gamma correction curve (as shown in Figure 22) is implemented as a piecewise

linear function with 19 knee points, taking 12-bit arguments and mapping them to 8-bit

output. The abscissas of the knee points are fixed at 0, 64, 128, 256, 512, 768, 1024, 1280,

1536, 1792, 2048, 2304, 2560, 2816, 3072, 3328, 3584, 3840, and 4096. The 8-bit ordinates

are programmable through variables.

The AS0260 IFP includes a block for gamma correction that has the capability to adjust

its shape, based on brightness, to enhance the performance under certain lighting

conditions.

Two custom gamma correction tables may be uploaded, one corresponding to a contrast

curve for brighter lighting conditions, the other one corresponding to a noise reduction

curve for lower lighting conditions. Also included in this block is a Fade-to Black curve

which sets all knee points to zero and causes the image to go black in extreme low light

conditions.

The AS0260 has the ability to calculate the 19 point knee points based on a small number

of variable inputs from the host, another option is for the host to program one or both of

the 19 knee point curves. The diagram below shows how the gamma feature interacts in

AS0260.

Figure 22:

Gamma Interaction

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