A visible-near-infrared (VIS-NIR) hyperspectral imaging sensor is proposed for online nondestructive monitoring of polymer film blends produced by extrusion blowing. Such a sensor provides a much higher spatial resolution of analysis compared to probes or probe arrays, which should help in detecting smaller localized defects inducing poor film quality (mechanical, optical, barrier properties) at a macroscopic scale. Multiresolutional miultivariate image analysis (MR-MIA) was used to extract those spectral and textural features from images that are the most highly correlated to film composition distribution and mechanical properties. When applied to a low-density polyethylene/polystyrene (LDPE/PS) blend produced under various operating conditions, the imaging sensor was able to monitor the two dominant effects on mechanical properties: (1) the effect of film composition (raw materials) and (2) the stretching effect caused by postextrusion conditions (process).