Category: Grady

Utilizing the scripts outlined in previous blog posts by Grady and I, we were able to create an optimization function to solve for the groove distance and orientation of the diffraction gratings on our holographic glitter sheet. 

Using the data gathered from the plot, pictured above, we were able to get the angles needed for our diffraction grating formula

With the left half of the equation solved using the angles we got from our graph, and the wavelength solved using the method outlined in last week’s blog post about wavelengths, we were able to create an optimization function to solve for our missing information: the distance between the grooves and the orientation of the grooves.

However, there seems to be multiple combinations of orientations and groove distances that can produce the same angle combinations, therefore we need to use more information for our optimization function.

We decided to use all of the lines from a lit square on the monitor to one glitter board to see if acquiring more data to run our optimization on would provide more specific results.

However, there are still multiple combinations of distance and orientation for the grooves that result in near-zero values for the error value. To combat this, we are looking for more parameters for our optimization function that would add constraints to the answers we receive, such as a minimum or maximum value for the groove distance. We have begun working on a script that will look at all pixels and their angles to light squares on the monitor, rather than just one pixels’. Hopefully this large amount of data will produce more specific results from our optimization function.

Grady and I have been working on a script that takes in a large set of pictures of a sheet of holographic glitter, where a picture is taken at every location of a small white box moving along a monitor across from the glitter sheet. The graph we created shows the color of a single glitter pixel when the white box is at that location on the monitor. From this data, I combined the graph with the script I wrote a few weeks ago and created a graph that shows the same thing, just displaying the closest monochromatic wavelength to the RGB value shown and recording that value.

Any photo where the pixel we selected was not lit was not used for this process, as well as any photo where the pixel was fully saturated, or not saturated to at least 15%.

We plan to use these lines to compute a various set of angles that we need, along with the wavelength, to determine the groove spacing of the diffraction grating on our specific holographic glitter sheet.