Teledyne PIXIS-XF, System Manual

Page: 49 / 116

Chapter 5 Operation 49
Figure 5-9: Full Frame at Full Resolution
CCD Readout begins with the simultaneous shifting of all pixels one row toward the
shift register, in this case the row at the top. The shift register is a single line of pixels
along one edge of the CCD, not sensitive to light and used for readout only. Typically
the shift register pixels hold twice as much charge as the pixels in the imaging area of
the CCD.
After the first row is moved into the shift register, the charge now in the shift register is
shifted toward the output node, located at one end of the shift register. As each value is
emptied into the output it is digitized. Only after all pixels in the first row are digitized is
the second row moved into the shift register. The order of shifting in our example is
therefore A1, B1, C1, D1, A2, B2, C2, D2, A3, …
After charge is shifted out of each pixel the remaining charge is zero, meaning that the
array is immediately ready for the next exposure.
A subsection of the CCD can be read out at full resolution, sometimes dramatically
increasing the readout rate while retaining the highest resolution in the Region Of
Interest (ROI). Some overhead time is required to shift out and discard unwanted pixels.
5.5.2 Binning
Binning is the process of adding the data from adjacent pixels together to form a single
pixel (sometimes called a super pixel), and it can be accomplished in either hardware or
software. Rectangular groups of pixels of any size may be binned together, subject to
some hardware and software limitations.
4
4
11
-01
12_0
024
A1 B1 C1 D1
A2
A3
A4
A5
A6
B2
B3
B4
B5
B6
C2
C3
C4
C5
C6
D2
D3
D4
D5
D6
A1 B1 C1 D1
A3
A4
A5
A6
B2
B3
B4
B5
B6
C3
C4
C5
C6
D3
D4
D5
D6
A2 C2 D2
A1
B1 C1 D1
A3
A4
A5
A6
B2
B3
B4
B5
B6
C3
C4
C5
C6
D3
D4
D5
D6
A2 C2 D2
B1 C1 D1
A3
A4
A5
A6
B2
B3
B4
B5
B6
C3
C4
C5
C6
D3
D4
D5
D6
A2 C2 D2
1
2
3
4