Overview

The following WVGA sensor models are available for the VisionCam XM and the VisionSensor PV/PV2:

Supported WVGA sensors
Sensor	Type	Hardware	eFG_CAMERA_TYPE	Number of pixels	Pixel size	Optical format
MT9V032M	Monochrome	VisionCam XM	FG_CAMERA_TYPE_752_480_IMAGO_VCx_MT9V032M	752 x 480	6 µm x 6 µm	1/3"
MT9V032M	Monochrome	VisionSensor PV	FG_CAMERA_TYPE_736_480_IMAGO_VSx_MT9V032M	736 x 480
MT9V032C	Color	VisionCam XM	FG_CAMERA_TYPE_752_480_IMAGO_VCx_MT9V032C	752 x 480
MT9V032C	Color	VisionSensor PV	FG_CAMERA_TYPE_736_480_IMAGO_VSx_MT9V032C	736 x 480

Features

Global Shutter with simultaneous integration and readout
63 frames per second at full resolution
10-bit ADC with 10 bit or 8 bit image readout
Shutter efficiency > 99%
Companding mode for higher resolution at low light / lower resolution at high light (see special feature Companding)
Hardware Demosaicing support for the VisionCam XM

Supported pixel formats

The supported pixel formats and maximum frame rates are listed below:

Supported pixel types
Sensor	eFG_PIXEL_TYPE	Output format
MT9V032M (Monochrome)	FG_PIXEL_TYPE_Y_8	1 byte per pixel
MT9V032M (Monochrome)	FG_PIXEL_TYPE_Y_16	2 bytes per pixel containing 10 valid bits
MT9V032C (Color)	FG_PIXEL_TYPE_Y_8	Raw bayer, 1 byte per pixel
	FG_PIXEL_TYPE_Y_16	Raw bayer, 2 bytes per pixel containing 10 valid bits
	FG_PIXEL_TYPE_RGB_24	Hardware Demosaicing: 3 bytes per pixel containing 8 bit R/G/B
	FG_PIXEL_TYPE_RGBX_32	Hardware Demosaicing: 4 bytes per pixel containing 8 bit R/G/B/dummy

Note

The VisionSensor PV only supports the pixel type FG_PIXEL_TYPE_Y_8 (no hardware demosaicing or 10 bit support). The usable sensor width is also limited to 736 pixels.
For raw Bayer pixel format, the first line starts with B-G components.
The function FG_set_gain_rgb() is only supported with hardware demosaicing on the VisionCam XM. It can be used to adjust the gain for each color component.

Frame rates

The frame rate can be increased be reducing the AOI size. Some examples are listed in the following table:

Maximum frame rate examples
AOI size	Max. frame rate
752 x 480	63
640 x 480	72
752 x 240	116
320 x 240	138

Special features

The sensor supports the following special features, see also section Configure special features for additional features:

Special features
Property name	Description	FGCamera.so
Companding	Sets companding mode 0: disable companding → linear ADC conversion (default) 1: enable companding → higher resolustion at low light, lower resolution at high light	≥ 1.1.2.0
DigitalTestPattern	Enables test pattern using a constant pixel value: 0 .. 0x3FF → constant pixel value ≥ 0x400 → disable test pattern	≥ 1.0.0.0
ExposureMode	Configures the behavior of FG_set_shutter_time() for compensation of noise artifacts and for using shorter exposure times, see also Using short exposure times. This feature is only available for the VisionSensor PV and requires PRU firmware ≥ 1.1.0.0. 0: Integration time of the sensor equals specified shutter time 1: Integration time of the sensor is increased by 50 µs, the effective exposure time is controlled by the LED / strobe signal (default)	≥ 1.2.0.0
Mirror	Flips the image horizontally and / or vertically 0: no flipping (default) 1: flip horizontally 2: flip vertically 3: flip horizontally and vertically (rotation by 180°) Please note that the order of color components for raw Bayer format doesn't depend on this setting.	≥ 1.2.8.0

RGB Demosaicing

The hardware demosaicing feature of the VisionCam XM is automatically enabled by using the pixel type FG_PIXEL_TYPE_RGB_24 or FG_PIXEL_TYPE_RGBX_32 with FG_set_aoi().

The demosaicing algorithm uses a high quality 5x5 filter, see High-Quality Linear Interpolation for Demosaicing of Bayer-Patterned Color Images for a description.

The function FG_set_gain_rgb() can be used to adjust the gain for each color component.

Using short exposure times

The sensor supports a minimum integration time of 110 µs. The sensor also accumulates more noise at the end of the integration time. This mainly becomes noticeable at short exposure times (e.g. < 150 µs).

To work around both problems, the effective exposure time can be controlled by adjusting the LED strobe timing. The strobe timing can be adjusted down to 1 µs. Using a longer sensor integration time than the selected strobe time helps to avoid light hitting the sensor at the noise sensitive end of the integration period.

VisionCam XM:
The LED strobe timing has to be controlled manually, see example code in section Controlling the LED Strobe unit. Modify the code to use edge trigger mode VIB::Strobe::STROBE_MODE_HARDWARE_EDGE. The desired LED strobe time is then controlled with VIB::Strobe::SetOnTime(). Then, set the integration time of the sensor at least 50 µs longer than the strobe time.
VisionSensor PV:
The special feature ExposureMode (enabled by default) controls the LED strobe timing when setting the exposure time with FG_set_shutter_time(). The integration time is automatically increased by about 50 µs. Additionally, this mode allows shorter and more fine-grained exposure settings. This applies to both the LED and the external strobe signal on digital output OUT0.

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