Fast Optic Flow Sensor

[aleonard]

Version: 2
Status: Public release
License: Custom Licence
Download: /files/project_builds/VisionChip_Interface.zip

Centeye is a microelectronics firm in Washington DC that specializes in vision chip or visual microsensor technology for a variety of machine vision applications. Our technology allows the implementation of complete machine vision systems sufficiently light for usage on small robotic platforms.

We started looking into XMOS processors late last year due to interest from our user community. We have found them to be highly flexible and powerful and the 100MHz per thread clock speed allows us to do faster image acquisition than is possible with our other microcontroller based sensors. We have designed a daughter sensor board that can interface with existing XMOS development boards.
We have focused our firmware development on the XC-2 Ethernet board, as the ethernet link provides easy and fast communication with a PC. The firmware implements a simple UDP communication scheme to send raw image and optic flow data via the ethernet link. A basic firmware application captures raw image data at multiple resolutions and computes two dimensional optic flow. The optic flow output is a 2D array of optic flow values that can track multiple different optic flow rates across the image, as opposed to one average value.
The board contains external SRAM (23K256 from Microchip, SPI Interface), flash memory (M25PE20 from Numonyx, 2MB), a 12Bit ADC (AD7276 from Analog Devices), additional power regulation and the Centeye Vision Sensor (exposed Vision Sensor without lens shown in pictures).
I posted a short video clip of the sensor in action: A raw image stream (64x128 res) and 2D optic flow captured by the sensor are displayed on our UI. The top optic flow box is X direction (left-right) and the lower box is Y direction (up-down). Red represents positive direction and Blue represents negative direction. For both dimensions, each bin represents optic flow from a column of dimension 8x64pixels.
Video:

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[nassim]

hi aleonard, this is a great project, any video for how it's work and thanks for sharing

[jason]

As you know I have been chatting with you guys for a while now after discovering all this optical flow stuff and I am most happy we now have our first XMOS project based around this! I am sure RP181 will be excited too :-) I cant wait to see how people may use this tech in the future :-) Do keep us updated and say hi to Geoffrey for me!

[rp181]

I am indeed excited! Looks very easy to use with the Dev board!