PDF: 4749051511/Source:7788125767
Aptina reserves the right to change products or specifications without notice.
MT9T111_DG - Rev. B 9/10 EN
122
©2007 Aptina Imaging Corporation. All rights reserved.
MT9T111: Developer Guide
Lens Calibration Procedure
Preliminary
Lens Calibration Procedure
This section describes how to calibrate and tune lens shading and generate PGA
(Programmable Gain Adjustment) coefficients for the MT9T111.
Equipment
• JudgeII or SpectralightIII (preferred) lightbox
• Two diffusers with filter holder
• DevWare software
Setup
Place one diffusion filter a few inches in front of the camera lens, place the second diffu-
sion filter directly in front of the camera lens with the illumination source approximately
1 meter away from the glass and camera, as shown in Figure 59. The light field created
from the glass should be uniform and the lens should be focused to infinity and not on
the glass plate. It is important that the lens is focused as it will be used in a real camera
module.
Figure 59:
Lens Calibration Equipment Setup
Note:
Place a black curtain over the camera system or place camera system in a dark box to
prevent light reflections on the back of the diffusion glass
Table 36:
Recommended Equipment and Settings
Equipment
Value
Common Light Sources
Illuminant A, 2850K
TL84 Fluorescent, ~4200K
Daylight, 6500K
Target
Uniform illumination source with de-focused lens
Lens
Matched CRA mini lens with IR cut filter
Gamma Setting
0.45, sRGB
Light Box
Glass Diffuser
Diffuser
Image Sensor