The present disclosure relates to methods and apparatuses for monitoring substrates advancing along a converting apparatus in a machine direction. The apparatus may include an analyzer connected with a line scan camera through a communication network. The analyzer may be configured as a field programmable gate array, an application specific integrated circuit, or a graphical processing unit. In addition, the line scan camera may include a linear array of pixel data and define a linear field of view, wherein the line scan camera is arranged such that the linear field of view extends in the machine direction. The apparatus may further include an illumination source that illuminates the linear field of view. In operation, the substrate is advanced in the machine direction such that a portion of the substrate advances through the linear field of view. In turn, the apparatus may be configured to perform various monitoring and/or control functions.