Abstract: Single-chip digital cameras use a color filter array and subsequent interpolation strategy to produce full-color images. WHile the design of the interpolation algorithm can be grounded in traditional sampling theory, the fact that the sampled data is distributed among three different color planes adds a level of complexity. Previous ways of treating this problem were based on computationally intensive approaches, such as iteration. Such methods, while effective, cannot be implemented in todays crop of digital cameras due to the limited computing resources of the cameras and the accompanying host computers. These previous methods are usually derived from general numerical methods that do not make many assumptions about the nature of the data. Significant computational economies, without serious losses in image quality, can be achieved if it is recognized that the data is image data and some appropriate image model is assumed. To this end, the design of practical, high- quality color filter array interpolation algorithms based on a simple image model is discussed.

Abstract: A color interpolation technique may use a Bayer matrix or pattern. In one embodiment, a color intensity gradient may be calculated between data from a center pixel in the Bayer pattern and the sensor spaced from the center pixel. A minimum and maximum gradient for a plurality of pixels may then be determined. Minimum and maximum intensity values for a group of pixel data values may be determined and these may be averaged to determine a value which may be utilized for interpolation purposes. The technique can use only a simple shift and does not require large dividers.

Abstract: PROBLEM TO BE SOLVED: To provide a solid-state image pickup device where the resolution can be enhanced through signal processing by the software and the processing time can be reduced, and to provide an image data generating method SOLUTION: A digital still camera 10 uses an A/D converter section 20 to convert an image pickup signal from an image pickup section 18 which includes a color filter CF of a Bayer pattern into digital data, and a luminance data generating section 24a calculates luminance data YH using the obtained data A high-frequency luminance data generating section 24b applies low-pass filter processing to the luminance data YH to apply board frequency processing to the luminance data YH A plane interpolation expansion section 24c generates color data which do not correspond to a pixel, by using the luminance data YH that are broad band processed and each of RGB color data substantially obtained A matrix section 24d generates a luminance signal Y and color difference signals Cr, Cb from the plane data An aperture adjustment section 24e improves a frequency characteristic of a high frequency portion of the luminance signal Y

Abstract: A color filter array for CMOS and CCD image sensor applications, the color filter array having a tiling pattern of cyan, magenta, yellow, and blue pass filters. An imaging device with this color filter array provides signals in a CMYB color space.

Abstract: The ordered color filter arrays (CFA) used in single sensor, color digital still cameras introduce distracting color artifacts. These artifacts are due to the phase shifted, aliased signals introduced by the sparse sampling by the CFAs. This work reports the results of an investigation on the possibility of using random patterns as a CFA for single sensor, digital still cameras. From a single blue noise mask pattern, three mutually exclusive, random CFAs are constructed representing the red, green, and blue color filters. An edge adaptive method consisting of missing-pixel edge detection and boundary sensitive interpolation is employed to reconstruct the entire image. Experiments have shown that the random CFA alleviates the problem of the low-frequency color banding associated with ordered arrays. This method also has the advantage of better preserving color free, sharp neutral edges, and results in less deviation from neutral on high frequency, monochrome information.

Abstract: PROBLEM TO BE SOLVED: To realize a high speed processing without the deterioration of picture quality by realizing the correspondence of an interpolation processing in accordance with the characteristics of plural constitution elements for expressing the color tones and the brightness of the respective picture elements, executing the interpolation processing with an optimum combination and outputting picture data. SOLUTION: The output data of an image pickup element 22 is amplified by an AGC circuit 23 and it is digitally converted by an A/D converter 24. At that time, data is that from which teeth are dropped by an RGB filter covering the image pickup element 22 and therefore an inter-output characteristic emphasis is canceled in a picture processing part. Light reception sensitivity is made flat and the bit map system picture data of three primary color reference is generated. Since JPEG system picture data is required at last, a data system for expressing again data obtained by gradation-expressing it by brightness for the respective colors RBG with luminance and a color difference is converted in a controller 10 for reducing the encoding burden. At that time, the colors themselves do not changed but only a coordinate system is changed. The picture is enlarged for reducing deterioration in JPEG encoding after conversion and JPEG encoding is executed.

Abstract: PROBLEM TO BE SOLVED: To provide a signal processing unit by which an image with higher image quality is obtained by displaying a border of signals smoothly and to provide its signal processing method. SOLUTION: An electronic still camera gives data in a buffer memory section 12a of a signal processing section 12 to a color filter interpolation processing section 12A via a data select section 12b. A color filter interpolation processing section 12A calculates the pixel value at void positions of a color filter G through an arithmetic operation based on a discrimination result, depending on comparison of correlation values in two oblique directions calculated with respect to the void position of the color filter G or comparison between the correlation value and a prescribed level Ths. The color filter interpolation processing section 12A interpolates the voids of a color filter R and/or a color filter B and gives the result to a YC conversion section 12e. The YC conversion section 12e generates a high frequency component YH of the luminance signal in a calculated object pixel, based on only the pixel value of the color filter G with respect to each pixel or on the pixel values of the color filters G, R, B.

Abstract: Advanced complementary color filter technology without dyeing process has been developed to simplify color filter fabrication process and to improve UV-resistance and thermal stability of color filter for CCD image sensors and CMOS image sensors. Using this advanced technology, complementary color filter is able to be fabricated by conventional lithography process with usual TMAH developer. This technology has achieved fine resolution of less than 1.5 micrometers lines and spaces in spite of previous inclusion of complementary colorings within the photo-sensitive polymers. These photo-sensitive polymers are negative type and consist of five key elements. The performance of the color filter characteristics that UV-resistance is more than 30 million lux-hour and thermal stability is more than 250 degree(s)C, has been realized by the advanced technology. Consequently this technology has been applied to 1/4-inch CCD image sensors, the optical color characteristics of the CCD image sensors has been achieved nearly same and good color spectrums as the conventional one.

Abstract: In seconds, a digital camera performs full-color rendering that includes color filter array interpolation, color calibration, anti-aliasing, infrared rejection, and white-point correction. This article describes the design decisions that make this processing possible.