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Mechanical and Electrical
4.5Image Bus
4
The image data read by the CCD goes through
CCD
PWB-A
PWB-BB
Shading correction
The CCD (Charge Coupled Device) reads the data on the Film.
The elemental output signals are evened out in compensation for uneven illuminance of the Projection Lamp and sensitivity variations among CCD cells and Projection Lens.
Shading Correction
If the CCD were to read the reflected light from an original having a uniform density, the outputs along the length of that CCD may vary individually due to uneven light distribution along the length of the Lamp and varying sensitivities of different CCD chips. These variations are corrected through shading correction.
White Black
| Image |
White |
|
| CCD output |
Black |
|
White | After Shading Correction |
|
Black
A/D conversion
Line memory
The analog image signals output from the CCD are converted to digital image signals.
The pixel signals from the five CCD chips are output serially in the order of CCD1, CCD2, CCD3, CCD4, and CCD5.
Density conversion
A
The data read by the CCD is proportionate to the intensity of the light that has passed through the film. A conversion formula is used to convert the data read by the CCD into the image density data which has a characteristic linear to the film density.
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