1. A helicopter alert system comprising: a first camera; a second camera; and one or more processors configured to: acquire a first image from the first camera, acquire a second image from the second camera, determine a depth value of a first object based on a disparity between a location of the first object in the first image and a location of the first object in the second image; determine a depth value of a second object based on a disparity between a location of the second object in the first image and a location of the second object in the second image; determine a difference between the depth value of the first object and the depth value of the second object, wherein the difference between the depth value of the first object and the depth value of the second object comprises a depth variance; and in response to the difference between the depth value of the first object and the depth value of the second object exceeding a depth variance threshold value, generate an alert.