reg:Mapper::grid creates internal Mat of type == input Mat, but always assigns <double>

[rkhamilton]

The example files for the mapper always convert the input images to CV_64FC3. It's fine that this is a required input type, but there is no type checking in the MapperGradProj (and others?) calculate() method. You can execute this code:

    MapperGradProj mapper;
    MapperPyramid mappPyr(mapper);
    Ptr<Map> mapPtr;
    mappPyr.calculate(img1, img2, mapPtr);

and it will have an unhandled exception in mapper:grid() if img1 and img2 are CV_8UC3. Grid creates two internal Mats of fhe same type as the input (e.g. CV_8UC3). However, it later assigns values of type double or type Vec3d to that new Mat. This throws an unhandled error.

I suggest that grid() should either create internal variable that are always of type CV_64FC?. I also suggest that mapper:: calculate() should perform a check that inputs to the overall mapper calculate function are of the expected type.