Distance from a moving image capture device to one or more points is determined. An optical flow is calculated from a first image and a second image captured by the moving image capture device. The horizontal component of the optical flow is used to generate a horizontal distance map including horizontal distances and the vertical component of the optical flow is used to generate a vertical distance map including vertical distances. Horizontal weights are applied to the horizontal distance map to generate a modified horizontal distance map where horizontal distances proximate to a vertical line intersecting a focus of expansion are attenuated. Vertical weights are applied to the vertical distance map to generate a modified vertical distance map where vertical distances proximate to a horizontal line intersecting the focus of expansion are attenuated. The modified vertical distance map and the modified horizontal distance map are then summed.