Using this function, raster images can be extracted to your hard drive. Print2CAD summarizes all raster images from the PDF to a common image at a 300 dpi resolution.
The threshold is a very important factor with which scanned drawings can be cleaned up. It is also a crucial factor for the success or failure of a vectorization.
The vectorization is always carried out based on a Black / White raster image. Based on the threshold value, the program decides what is black and what is white.
For black/white vectorizations, the threshold value for the color black associates the color black to all pixels that are darker than the threshold. The remaining pixels are white.
The threshold for colored vectorizations must be split into a separate value for black and a separate value for white. Between the two values, the colors are unchanged.