Robot Vision

In the 2012 FIRST^® robotics game, Rebound Rumble™ robots could aim their basketball shooters with the help of a webcam and retro-reflective vision target. Retro-reflective materials reflect light directly back at the light source. Safety reflectors and road signs are an example of retro-reflective material where the light from car headlights is reflected directly back at the driver instead of reflecting the light off at another angle like mirrors do. Using this property of reflection a ring of LEDs were mounted around the webcam lens to illuminate the vision targets.

LEDs Mounted on webcam

There are two ways for the robot to search the picture from the webcam to try and find the rectangular vision targets, one is to look for bright rectangles, the other is to look for rectangles that are a specific color. Looking for a rectangle based on brightness is straight forward, however, the computer can be confused by other bright objects in the picture such as the sunlight coming in through windows. Looking for a specific color eliminates the confusion caused by the sunlight because the computer looks for a bright green target instead of just a bright target.

Bright green vision targets

The bright green rectangles pop off the image and standout from the surrounding background.

This is what the robot sees

Each rectangle the robot sees is displayed as a red rectangle on a black background to indicate to the operators what exactly the robot is seeing. Green numbers displayed next to each rectangle indicate the position of each rectangle. Using the location of the rectangles and some trigonometry allows the robot to calculate how far away the target is and if the robot is lined up with the target. Taking the calculated distance from the target the robot and the left and right measurements the robot can automatically aim and adjust the power used to shoot the basketball. Using the computer on the robot to assist the drivers in aiming and shooting the basketballs reduced the workload for the drivers and improved accuracy.

Automotive robots and package sorting systems are examples of robots that use the same basic vision system teams used in Rebound Rumble. Automotive robots use vision systems to see where parts need to be placed and welded; package sorting systems use cameras to read barcodes and other identifying features to send packages to their proper destinations.

Watch the Rebound Rumble game animation on YouTube.
Learn more about FIRST Robotics at www.usfirst.org/frc.

Countdown to Kickoff

The SWAT Team has been hard at work preparing for the upcoming 2011 FIRST Robotics season. We have been teaching the students how to use the tools in the shop, solder electrical components, program using LabView, and create business documents. Along with training the students we also hosted a fundraiser with the local Pizza Hut raising $340. This year is the 20th anniversary of the FIRST Robotics Competition; with only 10 days until kickoff, the team is anxiously awaiting the start of the 2011 season.

Championship Atlanta, GA

The S.W.A.T. team attended the 2009 FIRST championship in Atlanta, GA along with more than 380 other teams.

After Qualification matches S.W.A.T. was ranked 2nd on Curie field. There are 4 fields with teams playing on them inside the Georgia Dome with each field being named after a scientists. S.W.A.T., 1806, picked teams 2039 and 668.

In the quarter finals 1806, 2039, and 668 were defeated after two rounds by the alliance that would eventually win Curie field and take second on Einstein field; the field where the winners from each field play against each other.

S.W.A.T. team outside of Georgia Dome

The S.W.A.T. team was ranked 9th overall out of the about 380 teams. The team’s record is 31 wins and 10 losses.

Greater Kansas City Regional winning alliance

After the second day of the Greater Kansas City regional the SWAT team is ranked third out of 61 teams. SWAT has 5 wins and no losses. On the third day SWAT had won 7 with no losses and advanced to the number 1 rank.

"SWAT was one of eight teams that picked two other teams to join their alliance. The eight alliances then went through an elimination to determine the winning alliance. SWAT team #1806 chose team #931 and team #1208.

In the elimination you have to win two games in order to advance to the next round. The SWAT alliance lost the first match, tied the next match, and then finally won two games to continue. In the semifinals the SWAT alliance lost the first match and them came back to win the two games required. In the finals the SWAT alliance started off with a win and then another to finish and become the winning alliance of the Greater Kansas City Regional.

 
Picture of the winning alliance left Team #1208, Team
#1806, and Team #931

Ship day

Monday night the S.W.A.T. Robotics team packed up the robot to ship to the Kansas city Regional. This marks the end of the six week build season that started January third. Next week the team will uncrate the robot down at Hale Arena along with 61 other teams. All FIRST Robotics Competition teams were given six weeks to design, build, program, and test their robot.

After the Kansas city Regional the robot will be shipped to the regional in St. Louis for the fourth week of competition.

SWAT team tests robot

Tuesday the SWAT team took the 2009 robot down to Liberty High School to test-drive the robot on a practice FIRST Lunacy field. The 2009 robot was able to pickup the orbit balls and throw them into the trailer towed by the 2008 robot. Driving the new robot on the slick surface was not a problem and using the turret to aim at the opposing trailer helped score the orbit balls.