Camera Code Update

[Kevin Watson]

I've made a few changes to the camera code and would like to get some feedback before releasing it. If you can think of something you'd like changed or added, please leave a message here. These are the changes do far:

2/11/07 changes made for version 2.2:

Important: after loading the new software, make sure
you "Load default values" and then "Save changes" from
the tracking menu.

terminal.c/.h:
-Fixed benign bug where old_camera_t_packets was not getting updated in Tracking_Info_Terminal().

-Altered code to use Tracking_Config_Data values for center tilt and pan values instead of hardwired values in Tracking_Info_Terminal().

-Altered code to use Get_Camera_T_Packets() function instead of directly accessing camera_t_packets variable.

camera.c/.h:
-Added Poll_Mode() function.

-Added Get_Camera_ACKs() function.

-Added Get_Camera_NCKs() function.

-Added Get_Camera_T_Packets() function.

tracking.c/.h:
-Altered code to use Get_Camera_T_Packets() function instead of directly accessing camera_t_packets variable.

-Changed default CONFIDENCE_THRESHOLD_DEFAULT values to 10 (was 20).

-Greatly simplified search code (same functionality with less code).

-Changed search parameters so that a fixed tilt angle of about 30 degrees is used.

-For finer control, moved camera pan servo to PWM output 15.

-For finer control, Moved camera tilt servo to PWM output 16.

user_routines_fast.c:
-Replaced call to Generate_Pwms() in User_Autonomous_Code() with a call to PWM().

serial_ports_readme.txt:
-Corrected installation instruction #4.

camera_readme.txt:
-Added Virtual_Window() function description.

-Added Poll_Mode() function description.

-Added Get_Camera_ACKs() function description.

-Added Get_Camera_NCKs() function description.

-Added Get_Camera_T_Packets() function description.

pwm.h:
-Using new PWM() software, optimized camera tilt for a range of 0 to 90 degrees.


-Kevin

[Tom Bottiglieri]

After I just finished porting your tracking software to work with WPILib...!!!!

Can't wait to test the new stuff out. I'm particularly excited about the increased servo resolution.

[Kevin Watson]

Originally Posted by Tom Bottiglieri

After I just finished porting your tracking software to work with WPILib...!!!!

Can't wait to test the new stuff out. I'm particularly excited about the increased servo resolution.

This is the new search code:

///////////////////
// //
// search code //
// //
///////////////////
 
// To provide a delay for the camera to lock onto the
// target between position changes, we only step the camera
// to a new position every SEARCH_DELAY times while we're 
// in search mode. SEARCH_DELAY is #define'd in tracking.h
loop_count++;
 
if(loop_count >= Tracking_Config_Data.Search_Delay)
{
// reset the loop counter
loop_count =0;
 
// If we're starting a new search, initialize the pan
// and tilt servos to the search starting point.
// Otherwise, just continue the search pattern from
// where we left off. The variable new_search is reset
// to one each time the tracking code (above) executes.
if(new_search ==1)
{
new_search =0;
temp_pan_servo = Tracking_Config_Data.Pan_Min_PWM;
temp_tilt_servo = Tracking_Config_Data.Tilt_Center_PWM; 
}
else
{
// calculate new pan position based upon the current pan servo position
temp_pan_servo = (int)pan_servo_position;
 
// step the pan servo to its next destination
temp_pan_servo += (int)Tracking_Config_Data.Pan_Search_Step_Size;
 
// is the new pan servo position beyond the end of its travel?
if(temp_pan_servo > (int)Tracking_Config_Data.Pan_Max_PWM)
{
// send the pan servo back to the starting position
temp_pan_servo = (int)Tracking_Config_Data.Pan_Min_PWM;
 
// calculate new tilt position based upon the current pan servo position
temp_tilt_servo = (int)tilt_servo_position;
 
// step the tilt servo to its next destination
temp_tilt_servo += (int)Tracking_Config_Data.Tilt_Search_Step_Size;
 
// is the new tilt servo position beyond the end of its travel?
if(temp_tilt_servo > (int)Tracking_Config_Data.Tilt_Max_PWM)
{
// send the tilt servo back to the starting position
temp_tilt_servo = (int)Tracking_Config_Data.Tilt_Min_PWM;
}
// update the local variable used to store the current tilt servo positions
tilt_servo_position = (unsignedchar)temp_tilt_servo;
}
// update the local variable used to store the current pan servo positions
pan_servo_position = (unsignedchar)temp_pan_servo;
}
 
// update the pan and tilt servo PWM value
Set_Pan_Servo_Position(pan_servo_position);
Set_Tilt_Servo_Position(tilt_servo_position);
}

The increased servo resolution was mentioned towards the end of this thread:

http://www.chiefdelphi.com/forums/sh...ad.php?t=51802

-Kevin

[team 2244]

Thanks for this new version!!!
Our team is having some problems with the CMUCam2.1 version, the tilt and pan is not moving and stuff like this!We`ll try to test this one.
Probably we`ll need to change the PWM`s to other outputs. Am I correct??(we`re newbies, and we need a lot of help!!!)
We hope it works!!!

Bye!

[Greg Marra]

Originally Posted by team 2244

Probably we`ll need to change the PWM`s to other outputs. Am I correct??

Kevin's revised code takes advantage of the ability to use hardware built into the PIC to generate higher-precision PWM signals on PWM 13-16. This allows you finer control over the tilt and pan of the camera for better triangulation.

So, you could modify the code to use the PWMs you were before, but I would recommend moving to PWM 15 and 16 as Kevin has done.

[Goldeye]

Sounds excellent. I think you should release it as soon as possible; time is running short

[team 2244]

What you mean when you say better triangulation??
And where do I add this new search code that Kevin has created??
Probably I will do a lot of questions don`t be mad please
Thanks for your help!

[Alan Anderson]

Originally Posted by team 2244

And where do I add this new search code that Kevin has created??

If you don't already understand the innards of tracking.c, I think you're better off leaving it alone. The 2.1 code does exactly the same thing as this update, just not as elegantly.

[Bharat Nain]

Request: Please release the streamlined version of this too.

[Kevin Watson]

Originally Posted by Bharat Nain

Request: Please release the streamlined version of this too.

Yes, once I'm reasonably happy with the code, I'll quickly port it over to the streamlined version. Unless I need to make some last minute changes, I'll zip-up the bells & whistles code tonight and post a link here.

-Kevin

[Bomberofdoom]

Kevin, PWM outputs 15 and 16 are used for the (left?) motors. If you take those PWM outputs, we won't be able to use the camera to move the robot to the light. But of course, that's not a real issue, since I can change the Servo PWM outputs. But mabye others don't know how do to it and could freak out a bit because some of thier engines are not working.
I don't mind you have changed it, but just thinking about the weaker ones.

Our team will check the code tommorow, tweak it as needed.

Thanks for the update.

[Kevin Watson]

Originally Posted by Alan Anderson

If you don't already understand the innards of tracking.c, I think you're better off leaving it alone. The 2.1 code does exactly the same thing as this update, just not as elegantly.

I'm not sure the new code is elegant, but I am sure the old search code is not elegant .

-Kevin

[Kevin Watson]

Originally Posted by Bomberofdoom

Kevin, PWM outputs 15 and 16 are used for the (left?) motors. If you take those PWM outputs, we won't be able to use the camera to move the robot to the light. But of course, that's not a real issue, since I can change the Servo PWM outputs. But mabye others don't know how do to it and could freak out a bit because some of thier engines are not working.
I don't mind you have changed it, but just thinking about the weaker ones.

Yes, it's a pain, but I need to move the pan and tilt servos to the range 13 through 16 to exploit the new PWM() functionality. You make a good point and I'll make sure it's very clear in the readme_first.txt document that the assignments have changed.

-Kevin

[Bio]

Considering you've got a get, you may very well be including it already, but we would definitely appreciate Reset_Camera_ACKs() and Reset_Camera_NCKs() functions. Not a real big deal, but it would save us a variable.

[Tyr333]

I've noticed that when the camera is in a search, if the camera is resetting its pan for a new sweep:
"if(temp_pan_servo >= PAN_MAX_PWM_DEFAULT)
{
temp_pan_servo = PAN_MIN_PWM_DEFAULT;"

and if the camera sees the light during this motion of resetting the pan to its minimum, when it arrives at this new pan position, the camera tilts down. It continues to search at this lower tilt, reaches the maximum pan, tilts back up, sweeps to its minimum pan, sees the light during this trip, and tilts down again. It continues this loop and never tracks the light. We don't usually have this problem, but at certain distances from the light it becomes impossible to track. What can we do to fix this?