Imaging device
View Patent ↗A solid-state imaging element includes photoelectric conversion elements having a complementary or Bayer color filter array. The solid-state imaging element adds together electric charges stored in nine photoelectric conversion elements having color filters of one of multiple colors in each portion of six rows and six columns, to obtain a resulting electric charge, and outputs the resulting electric charge as one pixel. A portion for one of the colors deviates from a portion for each of the other colors by three rows and/or three columns. This pixel-addition operation produces an effect of a spatial low pass filter, thereby reducing signal components exceeding a Nyquist frequency corresponding to a target resolution. Consequently, aliasing noise in an image with the target resolution is reduced, and therefore higher image quality can be achieved, when compared with a conventional resolution reduction technique.
1. An imaging device that produces image data showing an image with a target resolution lower than an original resolution of the imaging device, comprising:
a plurality of photoelectric conversion elements which are arranged in a two-dimensional matrix, each have a color filter of a predetermined color selected from a plurality of colors on a light-receiving surface thereof, each store an electric charge by photoelectric conversion, and in each row and column of the matrix, two of the plurality of colors are arranged alternately;
a charge adding unit operable to, for each portion of L rows and C columns in the matrix, where 6≦L, 6≦C and L and C are even natural numbers, add together electric charges stored in photoelectric conversion elements that have color filters of a same color in the portion, to obtain a resulting electric charge, the charge adding unit adding together the electric charges by repeatedly adding together electric charges in a row direction and transferring a result by two rows and furthermore repeatedly adding together electric charges in a column direction and transferring a result by two columns;
a read unit operable to read resulting electric charges for all portions of L rows and C columns in the matrix;
an image data generating unit operable to generate image data showing an image based on the read resulting electric charges, the image having a tentative resolution which is lower than the original resolution; and
a zoom unit operable to zoom the image with the tentative resolution so as to reduce the tentative resolution to the target resolution and produce the image data showing the image with the target resolution, wherein
a number of the plurality of photoelectric conversion elements is greater than a number of photoelectric conversion elements required for the tentative resolution to be equal to the target resolution.
2. The imaging device of claim 1 , further comprising:
a contour-correction unit operable to correct the image data showing the image with the target resolution to enhance a contour part of the image.
3. The imaging device of claim 1 , wherein
in each portion, the charge adding unit adds together electric charges stored in photoelectric conversion elements having color filters of one of the plurality of colors, and
a portion for one of the plurality of colors deviates from a portion for each of a rest of the colors.
4. The imaging device of claim 3 , wherein
L=4m+2 and C=4n+2, where m and n are natural numbers, and
the portion for one of the colors deviates from the portion for each of the rest of the colors by L/2 rows, by C/2 columns, or L/2 rows and C/2 columns.