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Agam Shah, IDG News Service

An open-source project aims to give a rudimentary eye to robots with the help of a camera that can detect, identify and track the movement of specific objects.

The Pixy camera sensor board, being developed by Charmed Labs and Carnegie Mellon University, can detect objects based on seven colors, and then report them back to a computer. A Kickstarter campaign was launched on Thursday to fund the $25,000 project, and the organizations are on pace to reach full funding by the end of the day.

Adding the Pixy could be viewed as giving robots basic vision, said Rich LeGrand, founder of Charmed Labs.

“Once you have vision, then you can introduce the idea of tasks,” LeGrand said. “If you want a robot to charge itself, that’s a simple example of a task. This will get you there. If you want to a robot to navigate, this will get you there.”

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The camera can recognize simple items based on color, like a purple dinosaur, or a green ball. Objects are also recognized by specific color markings or codes.

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For example, a power outlet can be recognized by the Pixy when specific color stickers are placed next to each other on the object. Interestingly, the color-coding mechanism is also used in Mumbai as a low-tech way for the “dabbawallas”—or people delivering lunch boxes—to figure out where food needs to be delivered.

The Pixy can also be “taught” what to recognize based on color codes, and algorithms for that can be programmed into the board. A software called PixyMon, which works on Macs and PCs, processes the algorithm and visual information received from the Pixy and reflects the image and objects on a screen.

Some work involved

“If you’re willing to color tags and objects that you’re interested in... this is a great sensor. It’ll find these objects, it’ll find hundreds of them, and it will give you the results back,” LeGrand said.

The robot can deliver the results back to a computer through multiple output mechanisms, giving hobbyists many ways to process information. Pixy has ARM-designed Cortex-M0 and Cortex-M4 cores, a 1280-by-800-pixel sensor, 264KB of cache and 1MB of flash storage. Robots based on the popular Arduino microcontroller can be hooked to the Pixy, LeGrand said.

CharmedLab's and Carnegie Mellon's Pixy open-source camera robotCHARMEDLABS A robot equipped with Pixy

The hardware can process images with a resolution of 640 by 480 pixels at 50 frames per second. It’s possible to track basic images in real time, and the image processing doesn’t bog down the CPU, LeGrand said.

Cameras have been a part of robotics since the 1990s, but expensive to implement, LeGrand said.

His goal with the Kickstarter project is to buy parts and make a cheap camera accessible to the wider robotics and hobbyist communities. The project will also fund the development of future versions of Pixy, and he has the backing of the respected robotics department at Carnegie Mellon.

”I thought hey, try to keep to keep the cost down, keep it robust... and people would use it for different projects,” LeGrand said.

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Comments

  • Admin

    Gentlemen,

    Let's keep this discussion civil please. I do not want to have to close this blog post out.

    Regards,

    TCIII Admin

  • I expected you to defend your picture.... 

  • Developer

    Alex, no need to get personal, in particular when you are out of arguments and do not even justify your verdict. I won't continue the conversation at this point, since there is nothing to gain from it.

  • Lorenz--- you seem like a smart guy, but your pic doesn't show what you think it shows.  

    A couple other things---

    I don't care about the BOM--- I just case about how much it costs me-- pixy is 1/3 the price, which is significant.

    I brought up the M0 core because it's there for you to use and it's a couple hundred more MIPS to throw at image processing.  That's significant also ---- has nothing at all to do with DMA.  

  • Developer

    Alex,

    The speeds you will find in UAV setups are significantly higher than in the video. I also can't concur with your statement that rolling shutter is "unlikely". Because the silicon costs for the additional pixel buffers is higher for a global shutter chip, and because those buffers do consume space on the chip, a global shutter sensor is more expensive and less light sensitive. That's the reason the default sensors in almost all devices are rolling shutter these days.

    Also note that you shouldn't judge the price of the two units without knowing their BOMs. The PX4FLOW BOM is significantly less than the sale price, and if a $25k initial run had been made, it would sell now for less than the Pixy. Also do not forget that you would need to add the ultrasound, which is $25 alone. The Kickstarter backing claims hint that you will receive one for $99, add an ultrasound and the solder work to mount it and you end up give and take at the price of PX4FLOW.

    The fact that you highlight the M0 core as benefit raises the question if you are familiar with DMA. The Pixy will only really be able to leverage the M4 core, and you might be delighted to hear the M4 core on PX4FLOW is not involved in the pixel transfer either. I would consider a Cortex A5 board with 500 MHz more capable, this is essentially the same performance class as PX4FLOW.

    Finally, I have attached a screenshot of the said video, which hints at rolling shutter. To be fair this could also be due to radial distortion, but its certainly not supporting your global shutter theory. I concur with you that only the full datasheet will tell. Note that rolling shutter means that the beams are bent.

    3692808237?profile=original

  • Hey Lorenz, 
    It doesn't look to me like the Pixy is designed for static scenes...  The scenes look dynamic to me.  (check out the video http://www.kickstarter.com/projects/254449872/pixy-cmucam5-a-fast-e...
     
    I'm pretty sure also that progressive scan does not equal rolling shutter.  The datasheet for the Pixy sensor is only available if you sign an NDA.  But rolling shutter pretty unlikely--- I'd be surprised if this sensor has a rolling shutter.  No slant artifacts at all in the Pixy video....  
    Note also, PIXY is about 1/3 the price of PX4FLOW, but looks more capable.  Pixy open source, so it looks like it could run an optical flow algorithm (like PX4FLOW) if you wanted it to, despite the fact that it uses a color sensor (the Pixy processor is dual-core 204Mhz --- one core could handle the pixel stream and the other core could do the higher-level processing...)
  • As a matter of fact I'm close to have 500 MHz ++ Arm Cortex based board. I will post something more very soon.
  • I'll buy one Lorenz, and I totally agree.

    Significant on board pre-processing of video data is really important.

    I want information out, not a bunch of pixels.

  • Developer

    This is clearly designed for static scenes and CMU Cam has an impressive history in tightly embedded vision. I'm not so sure if it will apply well, if at all, to dynamic scenes and aerial robotics:

    Unfortunately not a real improvement over PX4FLOW - its 204 vs 168 Mhz, 192 KB vs 264 KB RAM (PX4FLOW will be shipping soon with 256 KB RAM) and if I didn't read the data sheet wrong it suffers from rolling shutter (bent lines effect) as the sensor is identified as "progressive scan".

    For all interested: The reason that PX4FLOW is monochrome is because it saves a lot of processing time. As a color sensor has a color filter and the process to create a color image from the raw filter image (called de-bayering, as the first filters were produced by a company called Bayer) is quite processing-intense.

    It would be a single component change in assembly to produce a color version - so if there is interest, I'm sure 3DR would respond to customer demand.

    What I really would love to see is an embedded vision board optimized for manufacturing cost, monochrome, global shutter and with a 500 MHz++ Cortex A5 or A9, implementing the USB Video device class (so it would process onboard, but also serve itself as machine vision camera). It could be done for the same costs as the current PX4FLOW, and it  would add many new possibilities.

    That however is not where the CMU Cam team is likely interested in, and so rather a different direction then a shortcoming of their new design - thumbs up for a project with a long history in combining vision with UbiComp.

  • Hi TC3,

    I'm putting together my 2 wheel suspended pendulum robot frame Aluminum and Stainless steel now (two 26" 500 watt brushless bicycle wheels).

    92 lbs lead acid batteries 35ah at 48 volts. Heavy robot.

    APM providing primary IO interface but including HP laptop, laser scanner, PX4 Flow Cam and Kinect for vision duties. Also FPV camera.

    Planning on composite environment sensing interface on brushless gimbal stabilized platform.

    Think you just found my next item.

    Preprocessed visual data is very good.

    Gary

This reply was deleted.