Introduction

The CMOS visible + SWIR wideband sensor module (IMX991) incorporates the following features:

resolution to 656 x 520 gray scale
supports window AOI mode with faster readout
global shutter
programmable readout timing with free capture windows and partial scan
many trigger modes (free-running, hardware-triggered)

Details of operation

The sensor uses a global shutter, i.e. light exposure takes place on all pixels in parallel, although subsequent readout is sequential.

Free running mode

In free running mode, the sensor reaches its maximum frame rate. This is done by exposure and readout phase. The sensor timing in free running mode is fixed, so there is no control when to start an acquisition. This mode is used with trigger mode Continuous.

Note: When working in "Device Sensor Throughput" mode, the sensor will work with an additional overlapping erase phase. In this case, it is possible that the black level of some lines can be changed and the lines can become brighter. For this reason, it is recommended to use the "Device Link Throughput".

To calculate the maximum frames per second (FPS_max) in free running mode you will need following formula:

Name	Value
InternalLineLength	555
VerticalBlankLines	38
SensorInClock	74.1 (@74.25 MHz Pixel clock)

                 InternalLineLength            ImageHeight + VerticalBlankLines 
FrameTime =  ------------------------------ * ----------------------------------
                   SensorInClock                            1000

                 1
FPS_max =  --------------
            ExposureTime + FrameTime

Frame rate calculator

Note: The calculator returns the max. frame rate supported by the sensor. Please keep in mind that it will depend on the interface and the used image format if this frame rate can be transferred.

Note: The exposure time step width is limited to the sensor's row time of 7.48 us and therefore
- auto exposure with very low exposure times will perform with relatively large increments and
- exposure mode = TriggerWidth (if available) will perform with a jitter corresponding to the row time

The following trigger modes are available:

Setting ("GenICam")	Mode / Setting ("Device Specific")	Description
`"TriggerSelector = FrameStart"` `"TriggerMode = Off"`	Continuous	Free running, no external trigger signal needed.
`"TriggerSelector = FrameStart"` `"TriggerMode = On"` `"TriggerSource = Software"` `"ExposureMode = Timed"` To trigger one frame execute the TriggerSoftware@i command then.	OnDemand	Image acquisition triggered by command (software trigger).
`"TriggerSelector = AcquisitionActive"` `"TriggerMode = On"` `"TriggerSource = <desired Line>"` `"TriggerActivation = LevelLow"` `"ExposureMode = Timed"`	OnLowLevel	Start an exposure of a frame as long as the trigger input is below the trigger threshold. (No FrameTrigger!)
`"TriggerSelector = AcquisitionActive"` `"TriggerMode = On"` `"TriggerSource = <desired Line>"` `"TriggerActivation = LevelHigh"` `"ExposureMode = Timed"`	OnHighLevel	Start an exposure of a frame as long as the trigger input is above the trigger threshold. (No FrameTrigger!)
`"TriggerSelector = FrameStart"` `"TriggerMode = On"` `"TriggerSource = <desired Line>"` `"TriggerActivation = FallingEdge"` `"ExposureMode = Timed"`	OnFallingEdge	Each falling edge of trigger signal acquires one image.
`"TriggerSelector = FrameStart"` `"TriggerMode = On"` `"TriggerSource = <desired Line>"` `"TriggerActivation = RisingEdge"` `"ExposureMode = Timed"`	OnRisingEdge	Each rising edge of trigger signal acquires one image.
`"TriggerSelector = FrameStart"` `"TriggerMode = On"` `"TriggerSource = <desired Line>"` `"TriggerActivation = AnyEdge"` `"ExposureMode = Timed"`	OnAnyEdge	Start the exposure of a frame when the trigger input level changes from high to low or from low to high.

Line Mapping (TriggerSource Impact Acquire -> TriggerSource GenICam (valid values for <desired Line>)):

TriggerSource Impact Acquire	TriggerSource GenICam(BCX)
GP-IN0	Line4
GP-IN1	Line5

Sensor Data

Device Structure

CMOS image sensor (Type 1/4")
Number of effective pixels: 656 (H) x 520 (V)
Unit cell size: 5um (H) x 5um (V)

Characteristics

Gray scale version

Device Feature And Property List

Frame rate calculator
Mode:	Exposure and readout
Product:	BVS CA-GX0
Output image bit depth:	10 bit 12 bit
Pixel clock:	74.25 MHz
Image width:	pixels
Image height:	pixels
Exposure time:	us
Device throughput:	Device Sensor Throughput Device Link Throughput
Link speed:	Single-GigE
	Extended block ID (GEV 2.x)
Network MTU (max. value of the device with the smallest MTU):
Frame rate (max):	1/s
	ExposureTime > FrameTime → FPS = 1 / ExposureTime + Readout