Canon filed a patent for a variable optical lowpass filter for the AE sensor in the viewfinder. It will help to provide better subject tracking by reducing “false colors”.
An excerpt from the patent literature:
An imaging device which is provided with the following and characterized by changing a spatial frequency limit effect of the aforementioned low pass filter according to an output of the aforementioned thermometer.
A finder optical system for observing an object image formed because object light flux which passed a taking lens (102) images on a focusing screen (108) arranged on a primary image formation face.
A photometry device (110) which measures the strength of the light by making a different optical path from an optical path of the aforementioned finder image secondarily the aforementioned object image formed on the aforementioned focusing screen.
A photometry sensor (117) which outputs a plurality of photometry information which the aforementioned photometry device divides into two or more regions light flux of the aforementioned object image formed on the aforementioned focusing screen, and is related with luminance of the aforementioned object image.
A light measurement lens (115) which makes the aforementioned photometry sensor image the aforementioned object image formed on the aforementioned focusing screen, an object recognition means to perform a color and shape recognition of an object using an output of the aforementioned photometry sensor, a low pass filter (116) with a spatial frequency limit effect strange, good, and a thermometer.
Patent Publication No. 2016-173437
– Published 2016.9.29
– Filing date 2015.3.17
– Performing object recognition using an image sensor AE sensor
– Using a variable OLPF for false color reduction
– Image quality decreases when focus deviation occurs is generated by the temperature, is detected object recognition is erroneous
– It suppresses the effect of the variable OLPF according to the temperature, suppressing the influence of the deterioration in image quality.