Color video camera with a solid state image sensing device

• US 5,552,827 A
• Filed: 08/30/1994
• Issued: 09/03/1996
• Est. Priority Date: 08/31/1993
• Status: Expired due to Term

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Maenaka, Akihiro, Murata, Haruhiko, Mori, Yukio, Ide, Hirokazu, Okada, Hidefumi
• Primary Examiner(s): Metjahic, Safet
• Assistant Examiner(s): WEST, NINA NHYCHON
• Application Number:
  US08/298,548
• Time in Patent Office: 735 Days
• Field of Search: 348/266, 348/222, 348/240, 348/239, 348/704, 348/241, 348/273, 348/29, 348/30, 348/32, 348/649, 348/242
• US Class Current: 348/266
• CPC Class Codes: H04N 2209/046 Colour interpolation to calculate the missing colour values
• CPC Class Codes: H04N 23/843 Demosaicing, e.g. interpolating colour pixel values
• CPC Class Codes: H04N 25/134 based on three different wavelength filter elements

Abstract

A color video camera includes a CCD, and digital signals of 4 lines produced on the basis of an outputs from the CCD are applied to a selection circuit which selectively outputs digital signals of 3 lines. A horizontal interpolation circuit and a vertical interpolation circuit perform interpolation calculation on the basis of the digital signals, and outputs a plurality of horizontal color signals and a plurality of vertical color signals, respectively. A horizontal correlation detection circuit and a vertical correlation detection circuit evaluate a horizontal correlation value and a vertical correlation value of a specific pixel with respect to pixels around the specific pixel. Horizontal and vertical weighing coefficients are calculated by a coefficient calculation circuit in accordance with the correlation values, and the coefficients are applied to a weighted addition circuit which adds the horizontal color signals and the vertical color signals to each other for each color in accordance with the coefficients, and outputs the color signals of the specific pixel.

Claims

1. A color video camera, comprising:

a solid-state image sensing device having a large number of pixels arranged in a matrix fashion and color filters arranged in a mosaic fashion;

an interpolation processing circuit which performs an interpolation calculation on the basis of color signals of a specific pixel and a plurality of pixels around the specific pixel outputted from the solid-state image sensing device, and outputs a plurality of color signals of said specific pixels; and

an interpolation control circuit which controls said interpolation processing circuit in accordance with a correlation of said specific pixel with respect to said plurality of pixels,

wherein said interpolation processing circuit includes a horizontal interpolation circuit which performs an interpolation calculation in a horizontal direction on the basis of the color signals from said specific pixel and said plurality of pixels and outputs a plurality of horizontal color signals, a vertical interpolation circuit which performs an interpolation calculation in a vertical direction on the basis of the color signals from said specific pixel and said plurality of pixels and outputs a plurality of vertical color signals, and a weighted addition circuit for adding said horizontal color signals and said vertical color signals to each other for each color, said interpolation control circuit includes a coefficient output circuit which outputs at least one of a weighing coefficient for said horizontal color signals and a weighing coefficient for said vertical color signals, said at least one of weighing coefficients being applied to said weighted addition circuit.

2. A color video camera according to claim 1, wherein said coefficient output circuit outputs at least one of the horizontal weighing coefficient and the vertical weighing coefficient on the basis of at least one of a horizontal correlation of said specific pixel with respect to said plurality of pixels and a vertical correlation of said specific pixel with respect to said plurality of pixels.

3. A color video camera according to claim 2, wherein said coefficient output circuit includes a horizontal correlation detection circuit which calculates a horizontal correlation value of said specific pixel with respect to said plurality of pixels on the basis of the color signals from said specific pixel and said plurality of pixels, a vertical correlation detection circuit which calculates a vertical correlation value of said specific pixel with respect to said plurality of pixels on the basis of the color signals from said specific pixel and said plurality of pixels, and a coefficient calculation circuit which calculates at least one of said horizontal weighing coefficient and said vertical weighing coefficient on the basis of at least one of said horizontal correlation value and said vertical correlation value.

4. A color video camera according to claim 3, wherein said horizontal correlation detection circuit includes a first horizontal correlation circuit which calculates a first horizontal correlation value on the basis of the color signals of a specific color, and a second horizontal correlation circuit which calculates a second horizontal correlation value on the basis of all the color signals, and said coefficient output circuit includes a color level detection circuit which detects a color level on the basis of the signal from said solid-state image sensing device, and a horizontal weighted addition circuit which performs a weighted addition of said first horizontal correlation value and said second horizontal correlation value according to said color level and outputs said horizontal weighing coefficient.

5. A color video camera according to claim 4, wherein said vertical weighted addition circuit includes a first coefficient calculation circuit which outputs a coefficient for said second vertical correlation value on the basis of said color level, a vertical multiplication circuit which performs a multiplication of said second vertical correlation value and said coefficient from said first coefficient calculation circuit, and a first addition circuit which performs an addition of an output of said vertical multiplication circuit and said first vertical correlation value.

6. A color video camera according to claim 4, wherein said horizontal weighted addition circuit includes a first coefficient calculation circuit which outputs a coefficient for said second horizontal correlation value on the basis of said color level, a horizontal multiplication circuit which performs a multiplication of said second horizontal correlation value and said coefficient from said first coefficient calculation circuit, and a first addition circuit which performs an addition of an output of said horizontal multiplication circuit and said first horizontal correlation value.

7. A color video camera according to claim 3, wherein said vertical correlation detection circuit includes a first vertical correlation circuit which calculates a first vertical correlation value on the basis of the color signals of a specific color, and a second vertical correlation circuit which calculates a second vertical correlation value on the basis of all the color signals, and said coefficient output circuit includes a color level detection circuit which detects a color level on the basis of the signal from said solid-state image sensing device, and a vertical weighted addition circuit which performs a weighted addition of said first vertical correlation value and said second vertical correlation value according to said color level and outputs said vertical weighing coefficient.

8. A color video camera according to claim 2, wherein said coefficient output circuit includes a filter which outputs at least one of said horizontal weighing coefficient and said vertical weighing coefficient on the basis of a high-frequency component of the color signal of said specific pixel and the color signals of said plurality of pixels.

9. A color video camera according to claim 8, wherein said filter includes a filter circuit which outputs said horizontal weighing coefficient and said vertical weighing coefficient on the basis of a vertical high-frequency component of the color signal of said specific pixel and the color signals of said plurality of pixels.

10. A color video camera according to claim 8, wherein said filter includes a filter circuit which outputs said horizontal weighing coefficient and said vertical weighing coefficient on the basis of a horizontal high-frequency component of the color signal of said specific pixel and the color signals of said plurality of pixels.

11. A color video camera according to claim 8, wherein said filter includes a first filter circuit which outputs said horizontal weighing coefficient oil the basis of a horizontal high-frequency component of the color signal of said specific pixel and the color signals of said plurality of pixels, and a second filter circuit which outputs said vertical weighing coefficient on the basis of a vertical high-frequency component of the color signal of said specific pixel and the color signals of said plurality of pixels.