Image data processing circuit and image data processing method
First Claim
1. An image data processing circuit of a solid state image pickup device from which a dark current component signal and a pixel signal are sequentially output on a line unit basis, comprising:
- a first holding circuit for holding the dark current component signal in a reference line as a reference dark current component signal;
a first subtraction circuit to which the dark current component signal and the pixel signal are sequentially entered on the line unit basis;
a differential circuit for obtaining, as a dark current change amount, a change amount with respect to the reference dark current component signal, of the dark current component signal included in a preceding line output from the solid state image pickup device prior to the line entered to the first subtraction circuit;
a second subtraction circuit to which the dark current component signal and the pixel signal as analog signals output from the solid state image pickup device are entered;
a first selector to which an output of the solid state image pickup device and an output of the second subtraction circuit are entered;
an AD converter provided on a connection path between the first selector and the first subtraction circuit and converting an analog output of the first selector to a digital output; and
a second selector to which an output of the first subtraction circuit and an output of the AD converter are entered,wherein the first subtraction circuit subtracts the dark current change amount from the dark current component signal and the pixel signal which are entered,wherein in the case where a subtracting process of subtracting the dark current change amount from the dark current component signal and the pixel signal is performed in the first subtraction circuit, the first selector selects an output of the solid state image pickup device and the second selector selects an output of the first subtraction circuit, andwherein in the case where the subtracting process is performed in the second subtraction circuit, the first selector selects an output of the second subtraction circuit and the second selector selects an output of the AD converter.
4 Assignments
0 Petitions
Accused Products
Abstract
An object of the present invention is to provide an image data processing circuit and an image data processing method capable of determining a reference signal level corresponding to black in an image with high precision by suppressing occurrence of line dependency and the like in a dark current component signal included in image data output from a solid state image pickup device. A reference dark current component data holding unit selects a reference line from a solid state image pickup device and holds a dark current component of the reference line as a head line average value. To a subtraction circuit, dark current component data and effective pixel data is sequentially input on the line unit basis. A differential circuit obtains, as a detection value, a change amount with respect to the head line average value, of the dark current component data included in a preceding line. The subtraction circuit subtracts the detection value from the dark current component data and the effective pixel data entered.
8 Citations
10 Claims
-
1. An image data processing circuit of a solid state image pickup device from which a dark current component signal and a pixel signal are sequentially output on a line unit basis, comprising:
-
a first holding circuit for holding the dark current component signal in a reference line as a reference dark current component signal; a first subtraction circuit to which the dark current component signal and the pixel signal are sequentially entered on the line unit basis; a differential circuit for obtaining, as a dark current change amount, a change amount with respect to the reference dark current component signal, of the dark current component signal included in a preceding line output from the solid state image pickup device prior to the line entered to the first subtraction circuit; a second subtraction circuit to which the dark current component signal and the pixel signal as analog signals output from the solid state image pickup device are entered; a first selector to which an output of the solid state image pickup device and an output of the second subtraction circuit are entered; an AD converter provided on a connection path between the first selector and the first subtraction circuit and converting an analog output of the first selector to a digital output; and a second selector to which an output of the first subtraction circuit and an output of the AD converter are entered, wherein the first subtraction circuit subtracts the dark current change amount from the dark current component signal and the pixel signal which are entered, wherein in the case where a subtracting process of subtracting the dark current change amount from the dark current component signal and the pixel signal is performed in the first subtraction circuit, the first selector selects an output of the solid state image pickup device and the second selector selects an output of the first subtraction circuit, and wherein in the case where the subtracting process is performed in the second subtraction circuit, the first selector selects an output of the second subtraction circuit and the second selector selects an output of the AD converter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. An image data processing method of a solid state image pickup device from which a dark current component signal and a pixel signal are sequentially output on a line unit basis, comprising:
-
holding the dark current component signal in a reference line as a reference dark current component signal; entering the dark current component signal and the pixel signal sequentially on the line unit basis to a first circuit; obtaining, as a dark current change amount, a change amount with respect to the reference dark current component signal, of the dark current component signal included in a preceding line output from the solid state image pickup device prior to the line entered to the first circuit; entering the dark current component signal and the pixel signal as analog signals output from the solid state image pickup device to a second circuit; entering an output of the solid state image pickup device and an output of the second circuit to a first selector; AD-converting an analog output of the first selector to a digital output; entering the digital output by the AD-converting to the first circuit; entering an output of the first circuit and the digital output by the AD-converting to a second selector; and subtracting the dark current change amount from the dark current component signal and the pixel signal by the first circuit; in the case where a subtracting process of subtracting the dark current change amount from the dark current component signal and the pixel signal is performed in the first circuit; selecting an output of the solid state image pickup device by the first selector; and selecting an output of the first circuit by the second selector; in the case where the subtracting process performed in the second circuit; selecting an output of the second circuit by the first selector; and selecting the digital output by the AD-converting by the second selector.
-
Specification