Thanks, Christian, for the link, but I managed to get the necessary math implemented in my panohead using a lookup table and some fix point aritmethics :-)
You set the angle between the shots on the horizon and it will automatically calculate the reduced numer of shots needed when looking up/down a certain angle, i.e. setting the starting angle to 45° it will nicely produce the above pattern. The software will also reduce the angle between the shots to an angle wich the FOV can be divided through without rest. For example setting the start angle to 45° on a 360x180 will work fine, giving exactly 8 positions, but looking up/down a certain angle, the calculated angle between shots could be something like 163, so you need 3 images to get all 360° covered, now my routine uses the number of shots needed to calculate a proper angle, in this case 360/3 = 120°. So I always have a nice regular pattern like you can see above. The nice thing is that this also optimizes panoramas with another FOV, so shooting something with a FOV of 80° will automatically use 40° steps, without the need to chamge the setting.
That was a lot of head scratching and generating big excel tables with many formulas to get it reduced enough to get it in this small AVR ATMega8 controller :-)
I even reduced the back lash of my gears, so the noise level was reduced a lot and I was able to drive the motors a little faster, so bracket shooting a 360x180 at +-5EV is done now in about 5 minutes, resulting in an image set consisting of 102 images :-)
So, good night for today!!!
vklaffehn wrote:Thanks a lot!
the challenge is not to find or calculate optimal shooting patterns (although it's not THAT easy...), but to get the two small microcontrollers to calculate them. The 2 stepper motors are driven by an Atmel Tiny2313 with only 2 KB ROM, which usage jumped from 68% to 77% just by adding some arithmetics which adds an addiditonal step for the motors every 99th step (turn 1° needs 33,33333 steps, 360° are 12000 steps), and the main ÂµC is an ATMega8 with 8KB ROM, there are still 4KB left :-) Jut got some ideas to optimize it a bit more, and to get it more flexible.
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