Single-camera stereoaerophotogrammetry using UAV sensors

An apparatus of conducting aerial survey, comprising:

• an unmanned aerial vehicle that has a processor and a plurality of sensors;
• wherein the plurality of sensors comprises a camera, gyro, and accelerometer;
• wherein the unmanned aerial vehicle can fly over a target object from a first location to a second location, wherein the second location has a non-zero vertical and horizontal distance from the first location;
• wherein the camera takes a first aerial image at the first location and a second aerial image at the second location;
• wherein the processor first calculates the relative vertical and horizontal distance using a fusion estimation algorithm on the gyro and accelerometer readings, wherein the sensor fusion estimation algorithm comprises:
• collecting real-time sensor readings from the gyro and accelerometer;
• filtering the real-time sensor readings with a pre-processing filter;
• calculating the integration of the filtered accelerometer readings regulated by minimizing the mean squared error between the filtered gyro readings and the gyro readings estimated from the filtered accelerometer readings;
• wherein the processor then solves the pixel depth information of the aerial images by using a stereophotogrammetry algorithm and the calculated relative vertical and horizontal distances;
• wherein the processor then derives the ground sample distance of each pixel from the pixel depth information;
• wherein the processor lastly uses the ground sample distance values to compute a geometric property of the target object.