VX6953CB datasheet(69/107 Pages) STMICROELECTRONICS

69 / 107 page

8209023 Rev 5

69/107

VX6953CB

EDOF control

The VX6953CB module uses a fixed focused lens with optical aberrations that the EDoF

reconstruction engine is designed for so as to recover the resolution and increase the depth

of field in the range of 15 cm to infinity. The focus is tuned for far distances > 2m but for

closer distances where a standard fixed focus camera would show a blur image, the EDoF

correction is capable of recovering significantly the resolution.

Figure 29. What is sharp?

Some optics facts:

•

The depth of focus narrows with reduction in object distance or with aperture increase.

•

If the lens is focussed at the hyper-focal distance, the sharpness will be the same from

hyperfocal/2 to infinity.

•

The Depth of field is defined by the range of scene distances that appears acceptably

sharp in the image.

•

The size of a pixel (1.4um) can be defined as a blurred spot. A blurred spot smaller

than 1.4um is registered as sharp. Above that value the spot will look blurred (refer to

circle of confusion graph).

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.

VX6953CB Datasheet(PDF) 69 Page - STMicroelectronics