IMAGING DEVICE

• US 20150172618A1
• Filed: 02/07/2014
• Published: 06/18/2015
• Est. Priority Date: 02/21/2013
• Status: Active Grant

• Current Assignee: Clarion Co., Ltd. (Faurecia SA)
• Original Assignee: Clarion Co., Ltd. (Faurecia SA)
• Inventors: Takahashi, Teruki, Kojima, Takahide, Obata, Kouji
• Granted Patent: US 9,906,766 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60R 1/00 Optical viewing arrangements; Real-time viewing arrangements for drivers or passengers using optical image capturing systems, e.g. cameras or video systems specially adapted for use in or on vehicles
• CPC Class Codes: B60R 2300/106 using night vision cameras
• CPC Class Codes: H04N 2209/047 using multispectral pick-up elements
• CPC Class Codes: H04N 23/11 for generating image signals from visible and infrared light wavelengths
• CPC Class Codes: H04N 23/843 Demosaicing, e.g. interpolating colour pixel values
• CPC Class Codes: H04N 25/133 including elements passing panchromatic light, e.g. filters passing white light
• CPC Class Codes: H04N 25/135 based on four or more different wavelength filter elements
• CPC Class Codes: H04N 5/33 Transforming infrared radiation cameras or camera modules for generating image signals from infrared radiation H04N23/20; circuitry of SSIS for transforming infrared radiation into image signals H04N25/20
• CPC Class Codes: H04N 9/646 for image enhancement, e.g. vertical detail restoration, cross-colour elimination, contour correction, chrominance trapping filters
• CPC Class Codes: H04N 9/68 for controlling the amplitude of colour signals, e.g. automatic chroma control circuits H04N9/71, H04N9/73 take precedence; camera processing pipelines for controlling the colour saturation of colour signals H04N23/86
• CPC Class Codes: H04N 9/77 Circuits for processing the brightness signal and the chrominance signal relative to each other, e.g. adjusting the phase of the brightness signal relative to the colour signal, correcting differential gain or differential phase circuits for matrixing H04N9/67

Abstract

An image sensor including a plurality of pixels on which three types of filters which transmit light having different wavelengths and have transmittances equal to each other in a visible light region, and a clear filter in which a transmittance of the visible light region is expressed by a linear sum of the transmittances of the filters and which has a transmittance equal to the transmittances of the filters in a near-infrared light region are arranged, the image sensor outputs a first output signal, an output signal linear-transforming part transforms the first output signal into a second output signal having linearity, a color signal-generating part generates color signals, an infrared-separating part generates infrared-separated color signals, a luminance signal-generating part generates a luminance signal from the first output signal, and a color-luminance-combining part combines the infrared-separated color signals and the luminance signal and generates video signals.

Claims

1. An imaging device comprising:

an image sensor which includes a plurality of pixels on which a plurality of filters are arranged in a predetermined manner, and outputs from each of the pixels a first output signal which varies non-linearly in accordance with luminance of incident light incident to the pixels,

the plurality of filters including;

three types of filters which selectively transmit light of a visible light region different from each other and have spectral transmittances equal to each other in a near-infrared light region, and one type of filter in which a spectral transmittance of a visible light region is expressed by a linear sum of the spectral transmittances of the three types of filters and which has a spectral transmittance equal to the spectral transmittances of the three types of filters in the near-infrared light region;

an output signal linear-transforming part, when assuming that the image sensor outputs a second output signal which varies linearly throughout a luminance range of the incident light, which transforms the first output signal outputted from each of the pixels to the second output signal;

a color signal-generating part, from the second output signal, when assuming that a filter other than the filters of the plurality of filters arranged on the plurality of pixels is arranged, which generates a plurality of color signals which are predicted to be outputted from the plurality of pixels;

an infrared-separating part which generates a plurality of infrared-separated color signals in which a near-infrared light component is separated from the plurality of color signals;

a luminance signal-generating part which generates a luminance signal from the first output signal; and

a color-luminance-combining part which combines the plurality of the infrared-separated color signals and the luminance signal and generates video signals.

2. The imaging device according to claim 1, comprising:

a color saturation-detecting part which detects the color signals are saturated; and

a saturation-suppressing part which performs clipping processing in which values of the color signals which are detected to be saturated are transformed into predetermined values and outputs infrared non-separated color signals,

wherein in the color saturation-detecting part, when saturated color signals are detected, in the color-luminance-combining part, the infrared non-separated color signals and the luminance signal are combined, and the video signals are generated, and in the color saturation-detecting part, when no saturated color signal is detected, in the color-luminance-combining part, infrared-separated color signals outputted from the infrared-separating part and the luminance signal are combined, and the video signals are generated.

3. The imaging device according to claim 2, wherein the infrared-separating part further calculates a near-infrared light component amount remaining after generating the infrared-separated color signals, the saturation-suppressing part determines an output of the color saturation-detecting part or an occurrence of saturated pixel based on the near-infrared light component amount, and when a saturated pixel is detected, performs clipping processing in which a pixel value of the saturated pixel is transformed into a predetermined value, and outputs infrared non-separated color signals, and in the color-luminance-combining part, the infrared non-separated color signals and the luminance signal are combined, and the video signals are generated.

4. The imaging device according to claim 2, wherein the color-luminance-combining part combines normalized signals in which the infrared-separated color signals are normalized by a luminance component calculated from the infrared-separated color signals, or normalized signals in which the infrared non-separated color signals are normalized by a luminance component calculated from the infrared non-separated color signals and the luminance signal by multiplying, and generates the video signals.

5. The imaging device according to claim 3, wherein the color-luminance-combining part combines normalized signals in which the infrared-separated color signals are normalized by a luminance component calculated from the infrared-separated color signals, or normalized signals in which the infrared non-separated color signals are normalized by a luminance component calculated from the infrared non-separated color signals and the luminance signal by multiplying, and generates the video signals.