Hot pixel correction
Every pixel that exceeds a certain threshold in the black reference image is marked as a hot
pixel. If the hot pixel correction is switched on, the camera replaces the value of a hot pixel by
an average of its neighbour pixels (see Fig. 4.40).
h o t
p i x e l
p
n
p
n - 1
p
n + 1
p
n
= p
n - 1
+ p
n + 1
2
Figure 4.40: Hot pixel interpolation
4.6.3
Gain Correction
The gain correction is based on a grey reference image, which is taken at uniform illumination
to give an image with a mid grey level.
Gain correction is not a trivial feature. The quality of the grey reference image
is crucial for proper gain correction.
Gain correction algorithm
After configuring the camera with a black and grey reference image, the camera is ready to
apply the gain correction:
1.
Determine the average value of the grey reference image.
2.
Subtract the offset correction matrix from the grey reference image.
3.
Divide the average value by the offset corrected grey reference image.
4.
Pixels that have a grey level higher than a certain threshold are marked as hot pixels.
5.
Store the result in the camera as the gain correction matrix.
6.
During image acquisition, multiply the gain correction matrix from the offset-corrected
acquired image and interpolate the hot pixels (see Section 4.6.2).
Gain correction is not a trivial feature. The quality of the grey reference image
is crucial for proper gain correction.
4.6 Image Correction
59
Содержание CameraLink MV1-D1312 series
Страница 1: ...User Manual MV1 D1312 I CameraLink Series CMOS Area Scan Camera MAN041 09 2010 V2 5...
Страница 2: ......
Страница 4: ...2...
Страница 8: ...CONTENTS 6...
Страница 14: ...2 How to get started CameraLink 12...
Страница 24: ...3 Product Specification 22...
Страница 49: ...Figure 4 30 Example of decimation 2 on image of injection needle 4 3 Reduction of Image Size 47...
Страница 72: ...4 Functionality Figure 4 56 Unsharp Mask Examples 70...
Страница 110: ...8 Mechanical and Optical Considerations 108...
Страница 112: ...9 Warranty 110...
Страница 114: ...10 References 112...
Страница 118: ...A Pinouts 116...