8.Features
© 2023 China Daheng Group, Inc. Beijing Image Vision Technology Branch 159
8.5.
Image Transmission
8.5.1.
Maximum Allowable Frame Rate
1)
The maximum allowable frame rate of the network
The maximum allowable frame rate of the network is the camera's maximum transmission frame rate that
the current network supports. The maximum frame rate that the MER-G-P/MER-G series camera network
supports is determined by the camera's resolution, pixel format (Pixel Size), and the valid network
bandwidth. It is can be expressed by the formula:
The maximum allowable frame rate of the network = the valid network bandwidth/ resolution/ Pixel Size
Example 1: The camera resolution is 1628*1236, the pixel format is BayerRG8, packet size is 1500 bytes,
and packet delay is 1000. The current valid network bandwidth is 468Mbps.
The maximum allowable frame rate of the network = 468Mbps / (1628*1236)/8 = 29 fps
The maximum allowable frame rate of the network is 29fps, for MER-200-20GM/C-P camera, it can meet
the front-end sensor’s requirement that the acquisition frame rate is 20fps. In addition to the limitations of
network bandwidth, the maximum working frame rate of the camera is affected by the following two factors:
The camera front-end sensor readout time and the camera internal transfer time is called the camera
acquisition time. The camera acquisition time is affected by the ROI which is set by the user
The camera's exposure time
2)
The calculation of the camera's acquisition time
The camera's acquisition time is related to the OffsetY and the height of the ROI. When the OffsetY and
height of the ROI is changed, it will affect the front-end acquisition frame period of the camera, then affect
the acquisition frame rate.
The specific calculation formulas are as follows:
MER-030-120GM/C(-P)
Row period (unit: μs):
T
row
=
780
48
= 16.25
Camera acquisition time (unit: μs):
T
acq
=( int
(
512-(8)
8
)
+int
(
8
8
)
+(8)-((int
(
8
8
)
-1)×8)+1 )×T
row
MER-031-300GM/C(-P)
（
NIR
）
Row period (unit: μs):
T
row
=
78
+
width / 4
36