Here is how this technique works:

The vector-APP coronagraph[1] uses the wavelike nature of light to cancel out the starlight whilst allowing the planet’s light to shine through.

This manipulation is implemented through a complex phase pattern that can only be manufactured using advanced liquid crystal 3D patterning techniques [2]. This technique creates two images of the star, for which dark D-shaped regions are located on opposite sides of each star image. In this way, the whole region around the star can be scrutinized for planets. By combining several layers of liquid crystals, the device can be used over a wide range of wavelengths, including the infrared where the contrast between planet and star is more favorable.

It sounds like a really smart way to at least start narrowing where to focus.  Even by paying close attention to only these regions seems like good common sense!

We hope you like the video below as well highlighting interesting strategy as well.

thanks to The University of Montreal for the great info