Basler A400K Manual do Utilizador descarregar pdf (Página 103)

AW00118501000 Features

Basler racer Camera Link 95

Creating a "Usershading" File for Gain Shading Correction

To create a "usershading" file for gain shading correction, perform the following steps:

1. Adjust the lighting, optics, line rate, exposure time control mode, exposure time, gain, and

camera temperature as you would for normal operation.

2. Place a uniform white target in the field of view of the camera.

3. Set the camera’s X Offset and Width parameters so that the entire width of the sensor lines will

be used during line acquisition.

4. Perform several line acquisitions and examine the pixel values returned from the camera. The

pixel values for the brightest pixels in each line should be about 90 to 95 % of maximum (i.e., if

the camera is set for 8 bit output, the pixels should be from 90 to 95 % of 255).

a. If the values for the brightest pixels are at 90 to 95 % of maximum, go on to step 5.

b. If the values for the brightest pixels are not at 90 to 95 % of the maximum, adjust your

lighting and/or lens aperture to achieve 90 to 95 %

5. Perform several line acquisitions and examine the pixel values returned from the camera. In

each line, the values for the darkest pixels must be greater than 1/4 of the values for the

brightest pixels. (If the values for the darkest pixels are less than 1/4 of the values for the

brightest, the camera will not be able to fully correct for shading variations.)

a. If the values for the darkest pixels are greater than 1/4 of the values for the brightest, go on

to step 6.

b. If the values for the darkest pixels are less than 1/4 of the values for the brightest pixels, it

usually indicates extreme variations in lighting or poor quality optics. Make corrections as

required.

6. If you use Basler pylon, select Gain Shading in the Basler pylon Viewer or via the Basler pylon

API.

7. If you use Basler pylon, select "usershading" file in the Basler pylon Viewer or via the Basler

pylon API.

If you use direct register access, set the value of the Gain Shading Set Selector register to the

desired user set, e.g. User Shading Set 1

8. If you use Basler pylon, go to the Create enumeration in the Basler pylon Viewer and select

Once or send a create command via the Basler pylon API.

If you use direct register access, set the value of the Gain Shading Create register to OnePush

9. Perform at least 128 line acquisitions.

Creating a "usershading" file for gain shading correction will overwrite any

"usershading" file for gain shading correction that is already in the camera’s

memory.

If you want to preserve the previous "usershading" file save it to your PC before

creating the new "usershading" file.

For information about saving a "usershading" file to the PC, see Section 8.8.3.2

on page 96.

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Basler A400K Manual do Utilizador Página 103