The visual quality of images resulting from Super Resolution (SR) techniques is predicted with blind image quality assessment (BIQA) models trained on a database(s) of human rated distorted images and associated human subjective opinion scores. Such opinion-aware (OA) methods need a large amount of training samples with associated human subjective scores, which are scarce in the field of SR. By contrast, opinion distortion unaware (ODU) methods do not need human subjective scores for training. This paper presents an opinion-unaware BIQA measure of super resolved images based on optimally extracted perceptual features. This set of features was selected using a floating forward search whose objective function is the correlation with human judgment. The proposed BIQA method does not need any distorted images nor subjective quality scores for training, yet the experiments demonstrate its superior quality-prediction performance relative to state-of-the-art opinion-unaware BIQA methods, and that it is competitive to state-of-the-art opinion-aware BIQA methods.