In this paper, we propose a system to automatically design image filters, for manufacturers of image capture devices to maintain desired image quality. The proposed system is based on measuring the Spatial Frequency Response (SFR) of the device using the slanted edge technique. This includes an automatic approach to crop the slanted edges and perform the measurements. Based on the measured SFR, an equalizing filter is automatically designed for the device to standardize its SFR to meet a certain goal, for example, to provide unity gain for low and middle frequency ranges while attenuating higher frequencies. In this way, different devices can share an equivalent frequency response and thus offer consistent image quality. A set of device-independent filters may then be cascaded with the equalizing filter of each device. These device-independent filters are designed once, while the numerous individual device-dependent filters are designed automatically. This procedure saves significant effort designing a large collection of individual filters, while improving the consistency of image quality across different image capture devices. To accommodate SFR variation after manufacturing, an end user could apply this approach, if embedded within the device.
Ahmed H. Eid, Michael J. Phelps, Brian E. Cooper, "A Filter Design Approach for Consistent Image Quality" in Proc. IS&T Int’l. Symp. on Electronic Imaging: Image Quality and System Performance XIII, 2016, https://doi.org/10.2352/ISSN.2470-1173.2016.13.IQSP-010