Imaging device and image processing program for estimating fixed pattern noise from partial noise output of available pixel area

• US 20060098888A1
• Filed: 10/13/2005
• Published: 05/11/2006
• Est. Priority Date: 10/22/2004
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Morishita, Akihiko
• Granted Patent: US 8,300,977 B2
• Time in Patent Office: Days
• US Class Current: 382/254
• CPC Class Codes: H04N 25/671 for non-uniformity detection or correction

Abstract

An imaging device of the present invention includes an image capturing unit, a noise obtaining unit, a fixed noise calculating unit, and a noise eliminating unit. The image capturing unit generates image data by photoelectrically converting, pixel by pixel, a subject image formed on an available pixel area of a light-receiving surface. The noise obtaining unit reads a noise output from a partial area of the available pixel area. The fixed noise calculating unit calculates an estimation of fixed pattern noise of the available pixel area based on the noise output read from the partial area. The noise eliminating unit subtracts the fixed pattern noise from the image data.

Claims

1. An imaging device comprising:

an image capturing unit which generates image data by photoelectrically converting, pixel by pixel, a subject image formed on an available pixel area of a light-receiving surface;

a noise obtaining unit reading a noise output from a partial area of said available pixel area;

a fixed noise calculating unit which calculates an estimation of fixed pattern noise of said available pixel area by regularly expanding a noise pattern in said available pixel area, the noise pattern being obtained from said noise output read from the partial area; and

a noise eliminating unit subtracting said fixed pattern noise from said image data.

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

said noise obtaining unit reads the noise output from a predetermined row of said available pixel area; and

said fixed noise calculating unit calculates an estimation of the fixed pattern noise of said available pixel area by expanding, in a column direction of said available pixel area, a noise pattern of the noise output read from said predetermined row.

3. The imaging device according to claim 2, wherein:

a number of the predetermined row from which said noise obtaining unit reads the noise output is plural; and

said fixed noise calculating unit calculates an estimation of the fixed pattern noise of said available pixel area by expanding, in the column direction of said available pixel area, a noise pattern of the noise outputs read from the plural predetermined rows.

4. The imaging device according to claim 1, wherein:

said noise obtaining unit reads the noise output from a predetermined row and a predetermined column of said available pixel area; and

said fixed noise calculating unit calculates an estimation of the fixed pattern noise of an Xth column/a Yth row of said available pixel area based on the noise output of an Xth column of said predetermined row and the noise output of a Yth row of said predetermined column.

5. The imaging device according to claim 4, wherein

said fixed noise calculating unit calculates an estimation of the fixed pattern noise of the Xth column/Yth row of said available pixel area by weighted addition of the noise output of the Xth column of said predetermined row and the noise output of the Yth row of said predetermined column

6. The imaging device according to claim 4, wherein

said fixed noise calculating unit smoothes the noise output of said predetermined column in a column direction, and calculates an estimation of the fixed pattern noise of the Xth column/Yth row of said available pixel area by modulating the noise output of the Xth column of said predetermined row with a smoothed noise output of the Yth row of said predetermined column.

7. The imaging device according to claim 1, further comprising:

a release unit receiving a photographing instruction; and

a shutter unit which opens an optical path to said light-receiving surface according to said photographing instruction to project said subject image onto said light-receiving surface, and causes said image capturing unit to generate said image data, wherein;

said noise obtaining unit obtains said noise output during a light-shielding period from when said release unit receives said photographing instruction to when said shutter unit starts the opening operation;

said fixed noise calculating unit accepts said noise output, and calculates an estimation of the fixed pattern noise of a pixel position at a timing synchronous with the pixel position of said image data read from said image capturing unit; and

said noise eliminating unit subtracts, substantially in real time, the fixed pattern noise from said image data read from said image capturing unit.

8. An imaging device comprising:

an image capturing unit which generates image data by photoelectrically converting, pixel by pixel, a subject image formed on an available pixel area of a light-receiving surface;

a noise obtaining unit reading a noise output from a partial area of said available pixel area; and

a file generating unit generating an image file by appending said noise output as information to said image data.

9. An image processing program for processing an image file generated in the imaging device according to claim 8, the program comprising program codes to cause a computer to function as:

extracting unit reading image data and an noise output from said image file;

a fixed noise calculating unit which calculates an estimation of fixed pattern noise of an available pixel area by regularly expanding, in said available pixel area, a noise pattern obtained from said noise output; and

a noise eliminating unit subtracting said fixed pattern noise from said image data.