PYTHON25K Datasheet, PDF (31/87 Pages) ON Semiconductor – PYTHON 25K/16K/12K/10K Global Shutter CMOS Image Sensors

NOIP1SN025KA, NOIP1SN016KA, NOIP1SN012KA, NOIP1SN010KA
read pointer (ys) is indicated by a red line crossing the image
array. For this position of the read pointer, three windows
need to be read out. The initial start position for the x−kernel
pointer is the x−start configuration of ROI1. Kernels are
scanned up to the ROI3 x−end position. From there, the
x−pointer jumps to the next window, which is ROI4 in this
illustration. When reaching ROI4’s x−end position, the read
pointer is incremented to the next line and xs is reinitialized
to the starting position of ROI1.
Notes:
• The starting point for the readout pointer at the start of
a frame is the y−start position of the first active
window.
• The read pointer is not necessarily incremented by one,
but depending on the configuration, it can jump in
y−direction. In Figure 28, this is the case when reaching
the end of ROI0 where the read pointer jumps to the
y−start position of ROI1
• The x−pointer starting position is equal to the x−start
configuration of the first active window on the current
line addressed. This window is not necessarily window
#0.
• The x−pointer is not necessarily incremented by one
each cycle. At the end of a window it can jump to the
start of the next window.
• Each window can be activated separately. There is no
restriction on which window and how many of the 8
windows are active.
ROI 2
ROI 4
ROI 3
ys
ROI 1
Subsampling and Binning
Pixel binning and subsampling methods are used as a way
of decimating the image. The number of pixel samples is
reduced by a factor of four, while the optical area is
maintained.
Pixel Binning
Pixel binning is a technique in which different pixels
belonging to a rectangular bin are averaged in the analog
domain. Two-by-two pixel binning is implemented in the
PYTHON XK sensor. This implies that two adjacent pixels
are averaged both in column and row. Binning is
configurable using a register setting. Pixel binning is not
supported on PYTHON XK color option.
Notes:
1. Binning can be activated for the x and y direction
independently by means of the binning_mode
register. Refer to the registermap for more
information.
2. Binning in the y−direction is not supported in
conjunction with Zero ROT mode.
Subsampling
Subsampling is obtained by adapting the readout
sequence. In subsampling mode, both lines and pixels are
read in a read-N-skip-N mode. This reduces the number of
lines in a frame and the number of pixels in a line. Overall
frame time is reduced by a factor 4.
Subsampling can be configured for the x and y direction
independently by means of the subsampling_mode register.
The monochrome sensor is read out in a
read-one-skip-one pattern for both the rows and the
columns, while the color version supports a
read-two-skip-two subsampling scheme. This mode is
selectable through register configuration. Figure 29 shows
which pixels are read and which ones are skipped for
monochrome and color sensors respectively. Readout
direction is indicated as an x and y arrow.
ROI 0
Figure 28. Scanning the Image Array with Five
Windows
www.onsemi.com
31