find_camera_mtx.md

-# Finding Camera Matrix
+# Finding Camera Matrix And Distortion Coefficients
 ---
-We are looking for a Camera Matrix **K** described as:
+Camera calibration is based on [OpenCV2 calibration](http://docs.opencv.org/2.4/doc/tutorials/calib3d/camera_calibration/camera_calibration.html).
+
+We are looking for the Camera Matrix **K** and Distortion Coefficients **D** described as:
 
 ![alt text](http://mathurl.com/gu7suza.png) , 
+![alt text](http://mathurl.com/gujy9u2.png) , 
+
+
+where ![alt text](http://mathurl.com/zbyrpbe.png) are camera focal lengths, ![alt text](http://mathurl.com/jchq2he.png) are optical centers, *p* and *k* are distortion coefficients. 
+
+### Calibration object
+As the calibration object we chose classic black-white chessboard pattern with 8 rows, 7 columns and square's size approximately 35x35mm (Exact dimensions are specified in source code).
+
+### Calibration pictures
+We must take pictures with calibration object in the camera's Field of View in many different positions and cover entire picture with as many points as we can. However, We must respect that, the whole chessboard must be visible.
+
+### Finding chessboards
+We use OpenCV function `findChessboarCorners(gray,(rows,column),params=None)->ret,corners` for finding the chessboard in pictures, where gray is intensity image and corners are chessboard's corners in pixel coordinate system (u,v). After the chessboard is found the position is made more precise and the corners are found with sub-pixel precision `cornerSubPixel(gray,corners,winSize,zeroZone,criteria)->None`. You can read more about this on the page listed above.
+
+### Camera Matrix and Distortion Coefficients
+When we know the position of chessboards in pictures (imagePoints) and correct size of squares and its positions (objectPoints), we can now estimate the Camera Matrix and Distortion Coefficients with OpenCV function `calibrateCamera(objectPoints,imagePoints,imageShape,None,None)->ret,cam_mtx,dist,rvect,tvect`, where `cam_mtx` is wanted the Camera Matrix and `dist` are Distortion coefficients.
+
+
+
+
 
-where *f* is camera focal length, and *c* is optical center for axis *x* and *y*.
+   
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