ALLIED Vision Technologies Pike F-1600 - Manual (Page 154)

Description of the data path
PIKE Technical Manual V5.1.2
154
• The shading image can be stored in the camera itself.
The following pictures describe the process of automatic generation of correc-
tion data (PIKE F-032C). Surface plots and histograms were created using the
ImageJ program.
• On the left you see the source image with non-uniform illumination.
• The surface plot on the right clearly shows a gradient of the brightness (0:
brightest  255: darkest pixels).
• The histogram shows a wide band of gray values.
By defocusing the lens, high-frequency image data is removed from the source
image, therefore its not included in the shading image.
Figure 77: Shading correction: Source image with non-uniform illumination
surface plot
histogram
255.0
0.0
48
0.0
p
ix
els
640.
0 pix
els
256 0
Count: 307200 Min: 79
Mean: 135.337 Max. 19
StdDev. 30.497 Mode: 88 (4200)