3.4.1

Pattern generation

The pattern generation allows the generation of digital patterns in the output frame for test and debug. It is also

possible to insert a cross bar in the image with configurable position, size, and brightness. The available patterns

are:

•

Solid color

•

Color bars

•

Vertical grayscale

•

Horizontal grayscale

•

Diagonal grayscale

•

Pseudo-random data

Figure 3. Available patterns

3.4.2

Defective pixel correction

Active pixels are automatically corrected by a dynamic algorithm embedded in the sensor ISP, enabling defect-

free images straight out of the sensor without further algorithm development or processing resources.

The advanced correction algorithm can correct singlet and couplet of defects and take into account local spatial

gradients.

The host can program the strength of the correction to find the perfect balance between systematic defect

correction and preserving existing textures/patterns in the image. The correction strength evolves automatically

with exposure time. This mechanism can be deactivated for debugging purposes and for specific use cases such

as structured light.

3.4.3

Dark calibration

The pixel matrix has dedicated lines with shielded pixels that dynamically retrieve the dark level and subtract it

from the active image. Temperature, exposure time, or gain changes are compensated. Temporal smoothing and

fractional bit dithering are applied to avoid a sudden one-code step. This block also embeds a programmable

digital gain control feature with a granularity of 1/256 followed by a configurable pedestal to offset the dark level

along the ISP pipe.

VD66GY

Functional description

DS13838 - Rev 7

page 7/37