Koninklijke Philips Corporation N.v.

Ipg Electronics 503 Limited

Cornelis Antonie Maria Jaspers

The present invention relates to digital image sensors and in particular to contour filters (ZSB, 7) preventing green non-uniformity in the contour signal of the RGB Bayer image sensors. A set of rules is specified for designing the filter coefficients in the filter, whereby green non-uniformity is prevented.

Preventing green non-uniformity in image sensors

The present invention relates to interpolating a missing color value of a given pixel in an array of pixels. The missing color value is determined from color values of neighboring pixels using a median-based technique in which the median is taken of the four pixels values of the horizontally and vertically neighboring pixels (G1-G4) having a same color as the missing color value, and color information from at least one other color (R/B) at the given pixel.

Green reconstruction for image sensors

A reconstruction method based on a white-compensated luminance reconstruction and using filter weights referred to as smartgreen-parameters is proposed. An aliasing free luminance signal, even at the multiples of the sample frequency and in case of a camera without optical low pass filter is achieved. Moreover this white-compensated luminance-signal is free of signal distortion. The proposed method allows a suitable low pass filter to be added or combined and a is particular well suited to implement a variety of abasing free color- and contour-filters. The RGB color signals are reconstructed using filter weights which can be chosen as a function of the heaviness of the sensor matrix and of the optical transfer of the camera.

Method and apparatus for processing a sensor signal having a plurality of pixels from an image sensor, computer program product, computing system and camera

The present invention relates to digital image sensors and in particular to an aliasing free contour filter for RGB Bayer sensors. The filter (ZSB,) prevents an amplification of back folded aliasing artefacts and further eliminates green-green differences caused in the green color of the image sensor.

Contour filter for image sensor output signals

A method for processing analog color signals includes analog preprocessing sensor output signals to obtain analog preprocessed signals that cause a reduced amount of digital quantizatlon errors; converting the analog preprocessed signals into digital signals; reconstructing a first basic color signal, a second basic color signal, and a third basic color signal from the digital signals, and correcting the basic color signals, in which a three color signal matrix containing the first, second and third basic color signals is multiplied by a correction matrix containing coefficients that depend on the analog preprocessing. The analog preprocessing may include a white balance adjustment or the horizontal sum values of the correction matrix are adjusted to one for horizontal sum values larger than one, with the analog preprocessing comprising a corresponding multiplication in the analog preprocessing. A color camera includes an RGB Bayer sensor for generating the sensor output signals, and the above-mentioned processing device.

Processing of color signals in a color camera

A digital image enhancing system for processing pixel contour data comprises a contour filter, means for edge processing and for local noise reduction to reduce the amount of noise in a pixel luminance or color signal (Sin), means to apply a control signal (Ghpf) indicating the gain of a contour signal, and means to apply a control signal (Gcntr) indicating the gain of the contour as a function of local noise in a picture. The means for edge processing and local noise reduction are arranged such that an output signal (Sout) is supplied in response to said input signal (Sin), to a low pass filtered input signal (Slpf) derived therefrom, and to the contour filter output signal (contour) and the above control signals according to the relation:out=cntr*(in&#x2212;)+if&#x3c;1, andout=in+(cntr&#x2212;1)*contour else.

Digital image enhancing system

A signal processing device for a sensor output signal from a sensor covered by a color mask pattern having a plurality of colors, the signal processing device comprising a reconstruction unit () for generating a plurality of color signal values (R, G, B) for each pixel from the sensor output signal; and a clipping device () for clipping the sensor output signal or the plurality of color signal values (R, G, B). Preferably, the signal processing device further comprises: a conversion unit () for generating luminance signals (Y) and chrominance signals (U, V) from the plurality of color signal values (R, G, B), and an adjustment unit () for selectively setting the chrominance signals (U, V) to a zero color difference when clipping is performed (). Advantageously, the clipping device () is arranged between the sensor () and the reconstruction unit (), and the signal processing device further comprises a single bit white clip delay unit () for generating a switch signal for the adjustment unit (), the switch signal comprising an at least 2&#xd7;2 bit array from, or at least in response to, a signal (SS) from the clipping device () indicating that clipping has occurred.

Processing a sensor output signal including a clip

The present invention relates to interpolating a missing color value of a given pixel in an array of pixels. The missing color value is determined from color values of neighboring pixels using a median-based technique in which the median is taken of the four pixels values of the horizontally and vertically neighboring pixels (G1&#x2013;G4) having a same color as the missing color value, and color information from at least one other color (R/B) at the given pixel.

The present invention relates to digital image sensors and in particular to contour filters (ZSB,) preventing green non-uniformity in the contour signal of the RGB Bayer image sensors. A set of rules is specified for designing the filter coefficients in the filter, whereby green non-uniformity is prevented.

A color camera comprises a light sensitive area () comprising light sensitive elements, and a color filter layer () associated with the sensitive elements comprising Red, Green and Blue (R-G-B) filter layer elements. The color filter layer () comprises a repetitive sub-pattern of eight adjacent lines or columns, which sub-pattern comprises color filter elements in the following sequence:

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Eindhoven, Netherlands

Cornelis Antonie Maria Jaspers