Lossless compression: maximize frame rates and exceed GigE bandwidth limitations

In situations where getting the most detail from moving objects is critical, system developers are constantly looking for ways to increase frame rates without compromising image quality, preferably at minimal or no additional cost.

Lossless compression: maximize frame rates and exceed GigE bandwidth limitations

In situations where getting the most detail from moving objects is critical, system developers are constantly looking for ways to increase frame rates without compromising image quality, preferably at minimal or no additional cost.

Introduced lossless compression

Frame rate can be increased by up to 70%.Due to the reduced image size, the overall throughput of the camera is reduced, and the maximum frame rate of the GigE camera is increased, exceeding the GigE interface bandwidth limit of around 120MB/s

Increase the number of cameras on a single bus. Due to the reduced overall data transfer on the link, users can install more cameras on a single bus without additional host adapters without degrading the image quality or frame rate of other cameras on the same bus/connection, thereby reducing cost.

Minimize disk space usage; images can now be saved in a compressed format, reducing disk footprint on the host system and reducing the time required to write images to disk.

• 100% image data retention; no packet loss

• free!no extra cost

working principle

Lossless compression, a feature of some Teledyne FLIR GigE machine vision cameras, uses our proprietary algorithm to compress image data. Compression is performed on the camera before transmitting data to the host; this allows our camera to transmit data at a higher maximum frame rate, allowing for data transfer at a lower bandwidth while retaining 100% of the image data . After the data is transferred to the host, it can be decompressed or saved in a smaller compressed format to reduce disk space usage.

When to use lossless compression

Vision systems deployed in ITS (Intelligent Transportation Systems), factory automation, inspection, robotics, motion analysis, and other high-speed and/or high-resolution applications are constrained by Gigabit Ethernet bandwidth. This limitation is especially evident in applications where multiple GigE cameras are connected to a single switch. System designers for these use cases often use multiple host adapters; creating more cost and points of failure, or needing to reduce the resolution and/or frame rate of each camera to continue using a single host adapter.

Lossless compression reduces the amount of data transmitted from the camera for such applications, thereby reducing bandwidth usage and/or increasing the maximum frame rate without compromising image quality. That is to say, the camera bandwidth can break through the interface bandwidth limit while guaranteeing 100% image data.

Example of using multiple GigE cameras

To demonstrate the value of lossless compression, an example application is a conveyor system that requires three 5-megapixel cameras at various locations along the line. Two of the cameras need to run at 20FPS and the other at 30FPS in order for the system to provide accurate output. Also, in this case, both the industrial environment and the required cable length require Gigabit Ethernet.

Lossless compression: maximize frame rates and exceed GigE bandwidth limitations
Figure 1: Three standard BFS-PGE-50S5C cameras connected to a host PC.

Such systems are typically set up as shown in Figure 1 above. The PC host is connected to three Gigabit NICs (Network Interface Cards), one for each BFS-PGE-50S5 camera. Cameras cannot share network interface cards due to the bandwidth limitations of the Gigabit interface (ie each camera’s data transfer requirement approaches the bandwidth limit of one NIC). The third camera, due to its higher frame rate requirements, also had to compromise on resolution to stay within the available bandwidth of the 1GigE NIC. In addition to the more expensive setup with 3 GigE NICs, the vision system designer had to sacrifice image detail from the third camera – less than ideal for this use case.

Lossless compression: maximize frame rates and exceed GigE bandwidth limitations
Figure 2: Lossless compression is employed; “greyed out” GigE NICs are no longer required.

With lossless compression enabled (assuming a compression ratio of 1 to 1.8), the same system can now run the first two cameras on a single interface card, eliminating an entire NIC in the previous setup, saving space and reducing glitches point and reduce the design cost. The third camera is also able to achieve the desired 30 FPS frame rate at full 5MP resolution while using less bandwidth than the previous setting, saving CPU resources.

In summary, enabling lossless compression increases the camera’s maximum frame rate (up to the speed of the sensor) without reducing the camera’s resolution. In addition, this reduces data on the link, thereby reducing peripherals and CPU usage. These unique features reduce system cost, enable higher frame rates, reduce points of failure, and preserve 100% of image data without incurring any additional cost.

Supported camera models

Lossless compression is available on our most popular Blackfly S GigE cameras:

Camera model

megapixels

FPS LLC Disabled

FPS LLC enabled

Percentage increase in FPS

BFS-PGE-04S2

0.4

291

349.7

20%

BFS-PGE-14Y3

1.4

92

150

63%

BFS-PGE-16S2

1.6

78

112

44%

BFS-PGE-19S4

1.9

60

79.9

33%

BFS-PGE-23S3

2.3

53

80

51%

BFS-PGE-31S4

3.1

35

51

46%

BFS-PGE-50S5

5

twenty two

33.4

52%

BFS-PGE-70S7

7

17.4

24.9

43%

BFS-PGE-88S6

8.8

13.9

19.6

41%

BFS-PGE-122S6

12.2

10

14.4

44%

BFS-PGE-161S7

16.1

7.5

12

60%

BFS-PGE-200S6

20

5.1

5.9

16%

This feature will also be available on all upcoming Teledyne FLIR GigE cameras with Sony Pregius S sensors, including Blackfly S GigE and Oryx series cameras.

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