PCI Express camera - xiB line¶
1. Are 12bit already transmitted in packed mode or 16bit?¶
At the moment XIMEA test results are:
CB120 model gives 86 FPS at 12bit
CB200 model gives 33 FPS at 12bit
Currently in CB200 model data is transferred in packed mode to consume as low bandwidth as possible.
In the future we can provide other packed/unpacked modes.
2. Does 10 bit and 8 bit proportionally change the speed?¶
For CB200 model, this is not applicable – the sensor supports only 12bit mode.
Data truncation can be implemented inside the FPGA – it would decrease required bandwidth, but it won’t increase speed.
CB120 model has 8, 10 and 12 bit modes and the speed will vary accordingly.
Here is the frame rate speed for different modes:
8 bits - 130 Fps,
10 bits - 103 Fps,
12 bits - 86 Fps
3. Is ROI function just vertical?¶
Horizontal ROI is not supported by the CMOSIS sensors, meaning that reducing horizontal part of the resolution will not increase the speed.
However, XIMEA has implemented horizontal ROI cropping inside CB200 model – it does not increase fps, but it reduces the required PCIe bandwidth during readout.
4. Will binning be available and will it increase the frame rate?¶
CB200 model does not have binning modes.
CB120 model has binning modes specified in the Sensor Performance Calculator
In theory with CB120 model, the frame rate is not a problem – the bottleneck is the PCIe transfer.
The peak sensor readout of CMOSIS CMV12000 is 2400 MB/s whereas the PCIe x4 Gen2 goes reliably up to 1700 MB/s
5. Is the camera API the same as other XIMEA camera families?¶
First units of CB200 model were using custom API (inspired by GenTL) which was successfully applied.
Recently new SDK architecture was designed, which allowed to incorporate CB200 and CB120 models into standard XIMEA API.
You can have a look on the latest Software package HERE
6. What do you need to connect the PCI Express camera?¶
To connect the camera to the PC you need a PCIe Cable (either copper or fiber optic) and PCIe Host Adapter card that you insert into your PC PCIe slot.
The particular options are listed on the main support page.
7. On some pictures the camera is equipped with a simple thread for the lens which is a bayonet mount, but XIMEA claims Canon EF mount. Will the camera be delivered with a custom bayonet adapter or are they available from someone else? How do I mount a Canon EF lens to the camera?¶
There are small mounting holes on the front mechanical part to which a standard 31mm Canon extension tube can be mounted during assembly, like THIS
That provides standard Cannon EF mount lens interface with active lens control pins.
The extension tube can also be omitted during the assembly and then you would have a simple thread to which you can mount your own custom lens adapter.
We have not tested that yet, but theoretically, Thunderbolt has standard PCIe inside, so it could work.
There are also similar gadgets like THIS
9. What is the DC power input?¶
DC power input is 12-24V.
10. What are the environmental specifications of the camera: temperature range, dust/water ingress protection, shock, vibration, etc.?¶
We don't have a full set of certified measurements yet.
Several pilot customers use the camera on the roof of cars hence the shock and vibration aspects are very well covered in the design.
Dust/water protection - this is limited by the PCIe connector which is not IP67, but it is reasonably protected for common applications. In the Molex Cable/Connector datasheet it is stated - WaterProof/Dustproof: Yes
You could compare this with the USB3.0 connector, but basically, you cannot submerge the camera under water - this would have to be a totally different design/project.
Note: Molex does offer special circular IP67 PCIe cables.
11. How can I count fps/speed change with ROI set resolution?¶
You can use Sensor Performance Calculator
For CMV12000 model at 1080p can be counted like this:
Since the sensor does not support vertical ROI – it is clipped inside FPGA manually – the entire row has to be read out
480MHz*16ch/8bit/12*8/1080/5120 = 115fps for CMV20000 in 1080p ROI (12bit mode)
600MHz*32ch/8bit/12*8/1080/4096 = 361fps for CMV12000 in 1080p ROI (12bit)
600MHz*32ch/8bit/10*8/1080/4096 = 434fps for CMV12000 in 1080p ROI (10bit)
600MHz*32ch/8bit/8*8/1080/4096 = 542fps for CMV12000 in 1080p ROI (8bit)
12. What is the shutter speed or exposure time of both models ?¶
The minimum exposure time is approximately 94us to 1s for CMV20000 and approximately 20us for CMV12000.
It can be further decreased to 10us and even less, but the image quality will suffer.
Maximum exposure can be calculated for CMV20000 by setting exposure time register to maximum in which case you will get 1.05s
The exposure time is dependent on frequency, so if you run sensor on the lowest frequency – 120MHz – you’ll get 4.2s
For CMV12000 it is 30us and on lowest frequency 1s.
13. Can the camera run on PCIe 2.0 single lane?
What about using only 1 or 2 PCIe lanes instead of currently specified 4 ?¶
Yes, it is possible to run this camera over a single lane PCIe Gen2.
PCIe is backwards compatible: both PCIe Gen1 and Gen2 modes work.
Lane number is down scale-able: PCIe x1, x2 and x4 work.
This of course implies significantly reduced frame rates.
14. Would this PCIe camera need CPU processing power to acquire images and yes, what would be the CPU utilization ?¶
The image data are transferred to the PC via DMA (direct memory access) so no CPU resources are needed for that.
Some camera controlling / fetching buffers etc. requires CPU, but this is usually almost negligible.
15. Does the PCIe camera support hot plugging ?¶
We have not specifically investigated or developed hot-plug capability, so officially it is not supported and disconnecting/connecting the camera while running might end up with a blue screen.
However, we have noticed that on some new PCs when the camera is plugged during start-up and is enumerated properly, it can later on be unplugged and plugged back again and work properly.
16. Does API provide some HDR mode, in order to increase the maximum dynamic range when you change the gain during exposition ?¶
+In connection to this - can you set the exposition for the next two to three consecutive captures with different expositions to process HDR image later in software?
The CMV20000 CMOS sensor has this option known as "Multiple High Dynamic Range mode".
It could be set/adjusted by setting corresponding sensor registers on the low level.
However, we have not yet prepared any "white paper" or "application note" on this subject.
It is possible to update exposure values during the acquisition - so you should be able to implement such a sequencer in software.
17. Can camera work on lower frequency than 480MHz ?¶
Yes. It is possible to set lower frequency by application.
Example of setting of 250MHz:
xiSetParamInt(handle, XI_PRM_SENSOR_CLOCK_FREQ_HZ, 250*1000000);
As default behavior - the xiAPI measures the maximum data-throughput of the camera connection on xiOpenDevice for 8 bit transport mode.
Based on this measurement the XI_PRM_LIMIT_BANDWIDTH is set and thatchanges the sensor clock to value for delivery of maximum data.
18. How to automatically update sensor clock after changing of sensor/output bit depth or packing ?¶
Changing of some parameters (SENSOR_OUTPUT_CHANNEL_COUNT, SENSOR_DATA_BIT_DEPTH, OUTPUT_DATA_BIT_DEPTH, OUTPUT_DATA_PACKING) might lead to too high data rate to be delivered over PCIe.
When data-throughput is lower then needs to be delivered - frame lost might occur.
In order to keep data delivered by sensor to computer without lost frames - the sensor clock needs to be adjusted to fit data within channel data-throughput limits.
This can be performed after changing some of parameters by calling of
xiSetParamInt(handle, XI_PRM_LIMIT_BANDWIDTH, last_limit_value);
19. Can the camera be triggered by outside signal and generate strobe signal?¶
The camera offers 2 opto-coupled inputs and 2 outputs as well as 4 non-coupled bidirectional IOs.
The levels are described HERE