Super-resolution for mixed-resolution multiview images using a relative frequency response estimation method

In mixed-resolution multiview setups, spatially neighboring high-resolution views can be used to increase the image quality of an intermediate low-resolution camera perspective. By utilizing corresponding depth data, high-frequency information can be projected from the reference perspectives onto the image plane of the low-resolution view, creating the desired super-resolved image. In this context, the high-frequency part is extracted by subtracting an estimated low-resolution image from a high-resolution reference view. Starting from this, an approach is proposed that aims at first estimating the frequency responses of the involved cameras. As a consequence, the low-frequency part of a neighboring view can be adapted to the image characteristics of the intermediate low-resolution camera perspective. Exploiting this knowledge, the approach finally leads to a high-frequency part that better fits the target low-resolution view and thus to a better super-resolution quality. For a downsampling factor of 4, the proposed estimation leads to an average gain of 0.53 dB.