Korea Aerospace Research Institute | Date: 2014-11-24
Provided are a surface inspection apparatus and a surface inspection method. More particularly, disclosed are a surface inspection apparatus and a surface inspection method to allow for inspection of a foreign material on non-uniformly colored diffusive surfaces containing a metal or polymer material or the like.
Korea Aerospace Research Institute | Date: 2014-06-03
Disclosed is a method for four-path tree structured vector quantization, comprising: (a) placing codebook vectors where magnitudes of vectors are arranged in order at lowermost nodes; (b) configuring upper nodes by averaging vector values of the lowermost adjacent four nodes; (c) calculating mean square errors to paths of the upper nodes (A, B, C, and D) corresponding to four paths from an input vector X; (d) presetting a threshold between 0 and 1 after the (c); (e) calculating thresholds between the input vector X and four paths A, B, C, and D, based on the mean square errors; and (f) comparing the thresholds calculated in the (d) with the preset threshold to select a path having a threshold greater than the preset threshold, in which dynamic four-path tree structured vector quantization is used instead of conventional dynamic two-path tree structured vector quantization, thereby more efficiently and quickly searching a codebook.
Korea Aerospace Research Institute | Date: 2013-12-27
An airfoil of gas turbine engine is provided, which can improve cooling efficiency at a leading edge of the airfoil even when a location of combustion gas stagnation changes, without having to increase cooling air flowrate. The airfoil of gas turbine engine includes a cooling passage formed inside the airfoil to guide cooling air, and one or more cooling slots in elongated form, extending through the leading edge of the airfoil to a direction of the cooling passage and across a lengthwise direction of the leading edge.
Korea Aerospace Research Institute | Date: 2013-07-24
Provided is a three-dimensional rigid ball driving system including: a support frame having a polyhedral shape; a rigid ball positioned at the center of an inner portion of the support frame; a plurality of ball bearings installed at corners of inner sides of the support frame, respectively, and contacting a surface of the rigid ball; and a plurality of electromagnets disposed around the ball bearings and generating magnetic fields to rotate the rigid ball; and a controller controlling the electromagnets to control a rotation direction and a rotation speed of the rigid ball.
Korea Aerospace Research Institute | Date: 2013-11-15
Provided is a method for estimating and calibrating an absolute misalignment between an attitude control sensor of a satellite or a flight vehicle imaging and transmitting ground images having high resolution and an imaging payload.