VX6854LC datasheet(85/114 Pages) STMICROELECTRONICS

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VX6854LC

EDoF control

102

Considering the above points, EDoF aims to make the blur spot invariant (or change its

reference) over a range of objects distances, thus defeating the obvious geometric optical

effects to enhance the Depth of Field.

The plot below shows the EDoF main principle:

Figure 32. EDoF main principle

10.1

EDoF capabilities

The EDoF reconstruction engine is applied to the image after defect correction. It has

denoising, sharpening, deconvolution algorithms among others that allow recovering the

resolution.

It is advised that the end user does not use the EDoF IP as a sharpness block. EDoF has a

depth of field recovery role. Oversharpening the image using EDoF before the HOST image

processing might alter the final image quality.

The EDoF reconstruction engine can improve the depth of field for a colored image in the

range of 30 cm to infinity and for a monochrome image below 30 cm.

The EDoF block works with ranges of distances in four modes for which the correction

applied will be different:

•

Super macro mode: < 30 cm

•

Macro mode: 30 to 49 cm

•

Portrait: 50 to 119 cm

•

Landscape: 120 cm to infinity

The distance estimation analyzes gradients and relative sharpness among channels.

It first returns a measure of the sharpest channel in the image giving a macro “vote” when

the sharpest channel is the blue one, portrait when it’s the green and landscape when it’s

the red.

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