mvBlueLYNX-M702a (1.3 Mpix [1280 x 1024])

Introduction

The CMOS sensor module (MT9M001) incorporates the following features:

resolution to 1280 x 1024 gray scale
supports window AOI mode with faster readout
dynamic range 61dB
programmable analog gain (0..12dB)
progressive scan sensor (no interlaced problems!)
rolling shutter
programmable readout timing with free capture windows and partial scan
many trigger modes (free-running, hardware-triggered)

Details of operation

The sensor uses following acquisition mode:

rolling shutter (ShutterMode = "ElectronicRollingShutter").

With the rolling shutter the lines are exposed for the same duration, but at a slightly different point in time.

Note: Moving objects together with a rolling shutter can cause a shear in moving objects.

Furthermore, the sensor offers one operating mode:

snapshot mode (which means sequential exposure and readout)

Snapshot mode

In snapshot mode, the image acquisition process consists off several sequential phases:

Trigger

Snapshot mode starts with a trigger. This can be either a hardware or a software signal.

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 = AcquisitionActive"` `"TriggerMode = On"` `"TriggerSource = <desired Line>"` `"TriggerActivation = LevelHigh"` `"ExposureMode = TriggerWidth"`	OnHighExpose	Each rising edge of trigger signal acquires one image, exposure time corresponds to pulse width.
`"TriggerSelector = AcquisitionActive"` `"TriggerMode = On"` `"TriggerSource = <desired Line>"` `"TriggerActivation = LevelLow"` `"ExposureMode = TriggerWidth"`	OnLowExpose	Each falling edge of trigger signal acquires one image, exposure time corresponds to pulse width.
`"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 mvIMPACT Acquire -> TriggerSource GenICam (valid values for <desired Line>)):

TriggerSource mvIMPACT Acquire	TriggerSource GenICam(M7/BCP)
GP-IN0	Line2
GP-IN1	Line3

See also

For detailed description about the trigger modes (https://www.matrix-vision/manuals/ [mvIMPACT Acquire API])

C: TCameraTriggerMode
C++: mvIMPACT::acquire::TCameraTriggerMode

Erase, exposure and readout

After the trigger pulse, the complete sensor array is erased. This takes some time, so there is a fix delay from about 285 us between the trigger pulse on digital input 0 and the start of exposure of the first line.
The exact time of exposure start of each line (except the first line) depends on the exposure time and the position of the line. The exposure of a particular line N is finished when line N is ready for readout. Image data is read out line-by-line and transferred to memory (see: http://www.matrix-vision.com/tl_files/mv11/Glossary/art_rolling_shutter_en.pdf).
Exposure time is adjustable by software and depends on the image width. To calculate the exposure step size you will need following formula:

LineDelay = 0

PixelClkPeriod =    1
                 --------
                 PixelClk

RowTime = ( ImageWidth + 244 + LineDelay ) * PixelClkPeriod

RowTime = MinExposurTime = ExposureStepSize

Image data is then shifted out line-by-line and transferred to memory.

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

FrameTime = (ImageWidth + 244) * ((ImageHeight + 16) / PixelClock)

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

CMOS Timing in Snapshot mode

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.

Sensor Data

Device Structure

Progressive scan CMOS image sensor
Image size: 6.66(H)x5.32(V)mm (Type 1/2")
Number of effective pixels: 1280 (H) x 1024 (V)
Unit cell size: 5.2um (H) x 5.2um (V)

Exposure step size calculator
Image width:	pixels
Exposure step size:	us

Frame rate calculator
Mode:	Sequential exposure and readout (default)
Pixel clock:	40 MHz 27 MHz
Image width:	pixels
Image height:	pixels
Exposure time:	us
Frame rate (max):	1/s
	ExposureTime > FrameTime → FPS = 1 / ExposureTime

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