So far, feeding back the max intensity in the SPGD algorithm has resulted in crap. Basically the intensity just fluctuates randomly around the initial value no matter how many iterations or perturbations. Either the gradient isn't being identified correctly or the measure of the max intensity doesn't provide sufficient information for controlling it.
Irritatingly, even though the intensity isn't maximized the wavefront variance (which is just measured, not used for control), is reduced as if it were the objective. This suggests that the algorithm might be, in both cases, just pushing all the actuators to their maximum value, which happens to result in a relatively low WFS variance.
Tomorrow I'll test both cases using the first mode only. Doing the same with the PI controller should indicate what the optimal value is, and it definitely shouldn't be at the maximum value. If the SPGD algorithm surpasses that value in steady state I'll know that something's wrong.
I spotted some lady with a book on "Medieval Drama" today in Taco Bell. It was thicker than my adaptive filtering book.
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On the edge of incompetence
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