View Full Version : How to rotate video output using propeller backpack board

12-23-2009, 02:42 AM
Hello, I am using the propeller backpack with a mini camera video feed to display environment information coming from a my robot. However when i need to have the robot move the camera around(looking up or down, etc.) the video output is obviously disoriented. I was hoping someone could point me in the right direction as to how I can control video output orientation.

For example, if my robot has the camera upside down I would like to resample my video output at 180 degree. If i could actually rotate my video output at 1 degree granularity it would be awesome but 90 degree intervals seems like the practical solution. If you have ideas thank you in advance. http://forums.parallax.com/images/smilies/turn.gif

Post Edited (Francisco) : 12/22/2009 7:48:32 PM GMT

Phil Pilgrim (PhiPi)
12-23-2009, 03:11 AM

In a normal video overlay situation, the incoming video is gated on and off by the overlay information but is otherwise unprocessed. To rotate an image, you would need to store each entire frame in the Prop's memory, then output the pixels in a different order. Unfortunately, there's not enough RAM available in the Prop chip to store an entire frame. So image rotation — especially in real time — is outside the realm of possibility.


12-23-2009, 03:32 AM
Thanks for your quick response.

What about if we consider this: I know there are LCD monitors that allow you to manually rotate the video output, including composite video. Do you know if these particular screens have enough memory for this function, or maybe it is all done with analog conversion? For example, perhaps we can transpose the scan lines the video signal is sending out? I'm not really familiar with analog video properties but could this be a less elegant way to get this working? Thanks.

12-23-2009, 04:04 AM
How about a mechanical solution? Attach the camera to a servo that can do at least 180 degrees and then adjust the picture by rotating the servo. The plus side is you can adjust to whatever angle you want. If you already have Pan and Tilt, then just add a Yaw. http://forums.parallax.com/images/smilies/smile.gif

12-23-2009, 04:13 AM
I was trying to do less hardware and more software now, but that may be a good solution. Thanks.