1. An optical navigation device, adapted to control an operation of a pointer on a display apparatus, the optical navigation device comprising: a device body comprising a housing with an opening, the housing having an accommodating space formed therein; a substrate having a lower surface, the substrate horizontally arranged in the accommodating space of the housing, wherein the lower surface of the substrate is parallel to a bottom plane of the device body; a light source disposed on the lower surface of the substrate, operatively generating a light illuminating a navigation surface of the optical navigation device through the opening of the housing; an image sensor disposed on the lower surface of the substrate, operatively capturing a plurality of images responsive to a reflected light reflected from the navigation surface to generate a plurality of frames according to a predetermined frame rate, wherein the image sensor, the light source, and the opening of the housing are arranged along a long axis of the device body or along an axis parallel to the long axis of the device body, the image sensor is oriented tiltly on the lower surface of the substrate at a preset angle with respect to a long axis of the device body, the image sensor is also parallel to the bottom plane of the device body and the image sensor has an active imaging array with a size of M columns of pixels by N rows of pixels, wherein M and N are integers, the M columns of pixels are perpendicular to the N rows of pixels, and each column of the active imaging array has the preset angle with respect to the long axis of the device body; a coordinate converting unit, configured to perform a coordinate transformation to a first displacement vector of the optical mouse computed relative to the navigation surface to generate a second displacement vector using a rotation matrix, wherein the displacement information of the optical mouse is generated according to the second displacement vector, wherein the second displacement vector is determined according to the first displacement vector and the rotation matrix; and a processing module disposed on the lower surface of the substrate and coupled to the light source and the image sensor, the processing module operatively generating a displacement information of the optical navigation device relative to the navigation surface according to at least one of the plurality of frames.