50
In the TC-245 CCD with the anti-blooming function is turned on, the CCD can withstand 100
times the amount of light that would have produced saturation without the anti-blooming function.
As shown in the above figure, the CCD would saturate at 1 lux with Anti-blooming disabled but
would saturate at 100 lux with Anti-blooming enabled.
The effectiveness of the anti-blooming function is defined as the blooming overload ratio.
This is calculated as the following:
Blooming Overload Ratio
Light (in lux) reqd. to saturate the CCD with Antiblooming ON
Light (in lux) reqd. to saturate the CCD with Antiblooming OFF
=
For the above example (see figure above) the Blooming overload Ratio = 100
8.4.9 Can anti-blooming be disabled ?
Yes; the anti-blooming function can be disabled. In some applications, where the light level is
carefully controlled and a larger linear region of operation is required, it is possible to disable
anti-blooming.
If anti-blooming is disabled, any bright spots in the field of view will cause blooming ! Although
this does not damage the CCD, it makes the camera difficult to use in most applications.
Note: this is NOT a user adjustment in the camera. Please call DVC to request more information
on this modification.
8.4.10 What is meant by integration time ?
Integration time is defined as the duration that charge is allowed to accumulate in the charge
sites of the CCD.
8.4.11 What is the integration time in the standard mode of operation ?
The standard mode of operation results in an integration period of 1/60 seconds or 16.66 ms.
This is accomplished by means of a transfer of charge from the Imaging Area (sensitive to light)
to the Storage Area (opaque to light) every 1/60 sec - the process called Frame Transfer. Both
the Imaging Area and the Storage Areas are identical in size (755H X 242V). By transferring the
charge matrix once per field (1/60 sec) and by the process of electronically displacing the
integration area every field (pseudo-interlacing), a full frame of 755H X 484V is obtained.
Non-standard integration periods can be obtained under certain special modes. These are user
selectable by means of logic levels on the Mode select (default High) pins of the DB-37
connector.
Longer exposures are permitted in the integration mode; shorter exposures are permitted in the
integration mode as well as in the shutter modes.
Summary of Contents for DigitEyes Series
Page 14: ...9 Figure 4 3 TC 245 Gate Level Drawing Texas Instruments 1994 ...
Page 61: ...56 12 Appendix D Camera Mechanical Drawings Figure 12 1 Camera Mechanical Drawings ...
Page 63: ...58 Figure 13 2 Camera Noise Spectrum Min Gain Bandwidth 10kHz to 4 2MHz ...
Page 64: ...59 Figure 13 3 Camera Noise Spectrum Max Gain Bandwidth 100kHz to 4 2Mhz ...
Page 65: ...60 Figure 13 4 Camera Noise Spectrum Max Gain Bandwidth 10kHz to full ...