To detect the rotation angle, use the Hough transformation.
For noise reduction, replace any pixel, that does not have a neighbour (north, east, south or west) with the same color (a similar color, using a tolerance threshold), with the average of the neighbours.
Search for vertical white gaps for layout detection. Slice along the vertical gap. For each slice, now search horizontal gaps, and slice. If the slices have the same (a similar) height, you are at line level. Otherwise repeat vertical/horizontal slicing, until you only have lines left. The last step then is again a vertical slicing, giving you the single characters (or ligatures in some cases). Long and narrow or short and wide slices are lines.
Compare the character slices with a character library. If performance is not the main concern, try to find the characters within different font libraries, until you can identify the font used. Then stick with that font for character recognition.
In the original image, replace each character with the background color, which is determined by interpolating pixels that not are part of the character for each pixel of the character. This gives you the background image, if any.
