US 12,363,247 B2 · Image sensor having black level correction

Abstract

An image sensor includes a pixel array including at least one light-shielded area where no light enters and an imaging area where light enters, wherein each pixel includes a photoelectric conversion element, a black level processing unit that corrects an output of each pixel in the imaging area, and a memory that stores a predetermined black level reference for each pixel in the imaging area. The processing unit calculates a Slope, which is determined by an average output value at imaging of pixels in the at least one light-shielded area taken during imaging and a reference average output value of pixels in the at least one light-shielded area under certain conditions taken prior to imaging, and correct an output of each pixel in the imaging area using the predetermined black level reference and the Slope.

Claims16

Dependent claims

An image sensor comprising:

a pixel array including at least one light-shielded area where light does not enter and an imaging area where light enters, wherein each pixel of the pixel array includes a photoelectric conversion element;
a black level processing unit for correcting an output of each pixel in the imaging area of the pixel array;
and
a memory for storing a predetermined black level reference for each pixel in the imaging area of the pixel array;
wherein the black level processing unit is configured to:
calculate a Slope, which is determined by an average output value at imaging of pixels in the at least one light-shielded area of the pixel array taken during imaging and a reference average output value of pixels in the at least one light-shielded area of the pixel array under certain conditions taken prior to imaging;
and
correct the output of each pixel in the imaging area using the predetermined black level reference and the Slope.

5 more elements

A method for correcting an output of a pixel of a pixel array of an image sensor, wherein the pixel array comprises an imaging area and two light-shielded areas across the imaging area and the pixel is in the imaging area, using following equation:

OUT
(
x
,
y
)
=
{
IN
(
x
,
y
)
-
A
⁢
V
⁢
G
⁡
(
R
⁢
1
,
R
⁢
2
)
}
+
{
LUT
⁡
(
x
,
y
)
-
A
⁢
VG
⁡
(
R
⁢
1
⁢
ref
,
R
⁢
2
⁢
ref
)
}
*
Slope
+
C
;
wherein:
OUT(x,y) is an output of the pixel at a coordinate (x,y);
IN(x,y) is an output before correction of the pixel at the coordinate (x,y);
AVG(R1,R2) is an average output value at imaging of pixels in the two light-shielded areas taken during imaging;
LUT(x,y) is a predetermined black level reference of the pixel at the coordinate (x,y);
AVG(R1ref,R2ref) is a reference average output value of pixels in the two light-shielded areas under certain conditions taken prior to imaging;
Slope is determined by average output values at imaging of pixels in the two light-shielded areas, respectively, taken during imaging and reference average output values of pixels in the two light-shielded areas under certain conditions, respectively, taken prior to imaging;
and
C is a constant.

70 more elements

OUT
(
x
,
y
)
=
IN
(
x
,
y
)
-
A
⁢
V
⁢
G
⁡
(
R
⁢
1
,
R2
)
-
{
LUT
⁡
(
x
,
y
)
-
A
⁢
VG
⁡
(
R
⁢
1
⁢
ref
,
R
⁢
2
⁢
ref
)
}
*
Slope
+
C
;
wherein:
OUT(x,y) is an output of a pixel at a coordinate (x,y);
IN(x,y) is an output before correction of the pixel at the coordinate (x,y);
AVG(R1,R2) is an average output value at imaging of pixels in the two light-shielded areas taken during imaging;
LUT(x,y) is a predetermined black level reference of the pixel at the coordinate (x,y);
AVG(R1ref,R2ref) is a reference average output value of pixels in the two light-shielded areas under certain conditions taken prior to imaging;
Slope is determined by average output values at imaging of pixels in the two light-shielded areas, respectively, taken during imaging and reference average output values of pixels in the two light-shielded areas under certain conditions, respectively, taken prior to imaging;
and
C is a constant.

66 more elements

Dependencies are inferred from the claim text.

Image sensor having black level correction

Life of this patent

Image sensor having black level correction

Life of this patent

Abstract

Claims16