Allied Vision Technologies Pike Manual de instrucciones descargar pdf (Pagina 133)

Description of the data path

PIKE Technical Manual V4.0.0

133

Look-up table (LUT) and gamma function

The AVT PIKE camera provides sixteen (0-15) user-defined look-up tables

(LUT). The use of one LUT allows any function (in the form Output = F(Input))

to be stored in the camera's RAM and to be applied on the individual pixels

of an image at run-time.

The address lines of the RAM are connected to the incoming digital data,

these in turn point to the values of functions which are calculated offline,

e.g. with a spreadsheet program.

This function needs to be loaded into the camera's RAM before use.

One example of using an LUT is the gamma LUT:

There are two gamma LUTs (gamma=0.7 and gamma=0.45)

Output = (Input)

0.7

and Output = (Input)

0.45

These two gamma LUTs are used with all PIKE models.

It is known as compensation for the nonlinear brightness response of many

displays e.g. CRT monitors. The look-up table converts the incoming 14 bits

from the digitizer to outgoing up to 14 bits.

Figure 68: LUTs with gamma=0.45, gamma=0.7

Output = f (Input)

2000

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10000

12000

14000

16000

0 2000 4000 6000 8000 10000 12000 14000 16000

Input

Output

Pike, gamma=0.45 Pike, gamma=0.7

1 2 ... 128 129 130 131 132 133 134 135 136 137 138 ... 331 332

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Allied Vision Technologies Pike Manual de instrucciones Pagina 133