Imaging apparatus having dark current correcting unit

An imaging apparatus comprising:

• a solid-state imaging device in which a plurality of pixel columns, each including a plurality of pixels arrayed in a column direction on a semiconductor substrate, are arrayed in a row direction perpendicular to the column direction on the semiconductor substrate, wherein
• the solid-state imaging device comprises charge transfer sections provided corresponding to the respective pixel columns,
• each charge transfer section transfers electric charges, which are generated in the pixel column corresponding to each charge transfer section, in the column direction, and
• the plurality of pixels of each pixel column comprise
• a plurality of first pixels for acquisition of dark current level, disposed at an end portion of the corresponding charge transfer section on an upstream side in a charge transfer direction,
• a plurality of second pixels for acquisition of dark current level, disposed at an end portion of the charger transfer section on a downstream side in the charge transfer direction, and
• a plurality of light receiving pixels disposed between the first pixels and the second pixels;
• a dark current correcting unit that performs dark current correction based on a second linear function that expresses a level of a dark current using a position coordinate of each light receiving pixel as a variable, wherein the dark current correction subtracts the dark current from a signal corresponding to an electric charge which is generated in each light receiving pixel by imaging, the dark current being a signal corresponding to a dark charge superimposed on the electric charge generated in each light receiving pixel when the electric charge is transferred through the corresponding charge transfer section;
• a storage unit, wherein
• dark current acquisition drive for driving the solid-state imaging device is performed in advance of the imaging and separately from the imaging,
• the storage unit stores a first linear function in association with at least a first average of the first pixels, which is an average of signals corresponding to the respective first pixels among signals acquired by performing the dark current acquisition drive from the charge transfer section corresponding to each pixel column, and
• each first linear function expresses a level of a dark current superimposed on a signal corresponding to the light receiving pixel, using a position coordinate of the light receiving pixel as a variable;
• a second average calculating unit that calculates at least a second average of the first pixels that is an average of signals acquired from the plurality of first pixels of each pixel column by the imaging;
• and
• a second linear function generating unit that generates a second linear function by multiplying respective terms of each first linear function stored in the storage unit by a ratio of the second average to the first average corresponding to each first linear function.

An imaging apparatus comprising:

• a solid-state imaging device in which at least one pixel column including a plurality of pixels arrayed in a column direction on a semiconductor substrate, is arrayed in a row direction perpendicular to the column direction on the semiconductor substrate, wherein
• the solid-state imaging device comprises a charge transfer section provided corresponding to the pixel column, and
• the charge transfer section transfers electric charges, which are generated in the pixel column corresponding to the charge transfer section, in the column direction;
• a dark current correcting unit that performs dark current correction based on a second linear function that expresses a level of a dark current using a position coordinate of each light receiving pixel as a variable, wherein the dark current correction subtracts the dark current from a signal corresponding to an electric charge which is generated in each light receiving pixel by imaging, the dark current being a signal corresponding to a dark charge superimposed on the electric charge generated in each light receiving pixel when the electric charge is transferred through the charge transfer section;
• a temperature detecting unit that detects a temperature around the solid-state imaging device;
• a storage unit, wherein
• dark current acquisition drive for driving the solid-state imaging device is performed in advance of the imaging and separately from the imaging,
• the storage unit stores a first linear function in association with temperature information around the solid-state imaging device which is detected by the temperature detecting unit during the dark current acquisition drive, and
• the first linear function expresses a level of a dark current superimposed on a signal corresponding to each light receiving pixel, using a position coordinate of each light receiving pixel as a variable;
• and
• a second linear function generating unit that generates the second linear function by multiplying respective terms of the first linear function stored in the storage unit by a ratio of temperature information detected by the temperature detecting unit during the imaging to the temperature information corresponding to the first linear function.

A signal processing method for processing signals acquired from a solid-state imaging device in which a plurality of pixel columns, each including a plurality of pixels arrayed in a column direction on a semiconductor substrate, are arrayed in a row direction perpendicular to the column direction on the semiconductor substrate, wherein

• the solid-state imaging device comprises charge transfer sections provided corresponding to the respective pixel columns,
• each charge transfer section transfers electric charges, which are generated in the pixel column corresponding to each charge transfer section, in the column direction, and
• the plurality of pixels of each pixel column comprise
• a plurality of first pixels for acquisition of dark current level, disposed at an end portion of the corresponding charge transfer section on an upstream side in a charge transfer direction,
• a plurality of second pixels for acquisition of dark current level, disposed at an end portion of the charger transfer section on a downstream side in the charge transfer direction, and
• a plurality of light receiving pixels disposed between the first pixels and the second pixels,
• the method comprising:
• performing dark current correction based on a linear function for correction that expresses a level of a dark current using a position coordinate of each light receiving pixel as a variable, wherein the dark current correction subtracts the dark current from a signal corresponding to an electric charge which is generated in each light receiving pixel by imaging, the dark current being a signal corresponding to a dark charge superimposed on the electric charge generated in each light receiving pixel when the electric charge is transferred through the corresponding charge transfer section;
• calculating an average of first-pixel signals, which are acquired from the respective first pixels of each pixel column by the imaging;
• calculating an average of second-pixel signals, which are acquired from the respective second pixels of each pixel column by the imaging;
• setting the average of the first-pixel signals of each pixel column to a level of a dark current superimposed on a signal corresponding to an electric charge, which is generated in a light receiving pixel adjacent to the first pixels of each pixel column by the imaging;
• setting the average of the second-pixels signals of each pixel column to a level of a dark current superimposed on a signal corresponding to an electric charge, which is generated in a light receiving pixel adjacent to the second pixels of each pixel column by the imaging;
• and
• generating the linear function for correction using the average of the first-pixel signals of each pixel column, the average of the second-pixel signals of each pixel column, and number of the light receiving pixels of each pixel column.

A signal processing method for processing signals acquired from a solid-state imaging device in which a plurality of pixel columns, each including a plurality of pixels arrayed in a column direction on a semiconductor substrate, are arrayed in a row direction perpendicular to the column direction on the semiconductor substrate, wherein

• the solid-state imaging device comprises charge transfer sections provided corresponding to the respective pixel columns,
• each charge transfer section transfers electric charges, which are generated in the pixel column corresponding to each charge transfer section, in the column direction, and
• the plurality of pixels of each pixel column comprise
• a plurality of first pixels for acquisition of dark current level, disposed at an end portion of the corresponding charge transfer section on an upstream side in a charge transfer direction,
• a plurality of second pixels for acquisition of dark current level, disposed at an end portion of the charger transfer section on a downstream side in the charge transfer direction, and
• a plurality of light receiving pixels disposed between the first pixels and the second pixels,
• the method comprising:
• performing dark current correction based on a second linear function that expresses a level of a dark current using a position coordinate of each light receiving pixel as a variable, wherein:
• the dark current correction subtracts the dark current from a signal corresponding to an electric charge which is generated in each light receiving pixel by imaging, the dark current being a signal corresponding to a dark charge superimposed on the electric charge generated in each light receiving pixel when the electric charge is transferred through the corresponding charge transfer section, and
• dark current acquisition drive for driving the solid-state imaging device is performed in advance of the imaging and separately from the imaging;
• storing, in a storage unit, a first linear function in association with at least a first average of the first pixels, which is an average of signals corresponding to the respective first pixels among signals acquired by performing the dark current acquisition drive from the charge transfer section corresponding to each pixel column, wherein each first linear function expresses a level of a dark current superimposed on a signal corresponding to the light receiving pixel, using a position coordinate of the light receiving pixel as a variable;
• calculating at least a second average of the first pixels that is an average of signals acquired from the plurality of first pixels of each pixel column by the imaging;
• and
• generating a second linear function by multiplying respective terms of each stored first linear function by a ratio of the second average to the first average corresponding to each first linear function.

A signal processing method for processing signals acquired from a solid-state imaging device in which at least one pixel column including a plurality of pixels arrayed in a column direction on a semiconductor substrate, is arrayed in a row direction perpendicular to the column direction on the semiconductor substrate, wherein

• the solid-state imaging device comprises a charge transfer section provided corresponding to the pixel column, and
• the charge transfer section transfers electric charges, which are generated in the pixel column corresponding to the charge transfer section, in the column direction,
• the method comprising:
• performing dark current correction based on a second linear function that expresses a level of a dark current using a position coordinate of each light receiving pixel as a variable, wherein the dark current correction subtracts the dark current from a signal corresponding to an electric charge which is generated in each light receiving pixel by imaging, the dark current being a signal corresponding to a dark charge superimposed on the electric charge generated in each light receiving pixel when the electric charge is transferred through the charge transfer section;
• detecting a temperature around the solid-state imaging device, wherein:
• dark current acquisition drive for driving the solid-state imaging device is performed in advance of the imaging and separately from the imaging,
• a first linear function is stored in a storage unit in association with temperature information around the solid-state imaging device, which is detected during the dark current acquisition drive, and
• the first linear function expresses a level of a dark current superimposed on a signal corresponding to each light receiving pixel, using a position coordinate of each light receiving pixel as a variable;
• and
• generating the second linear function by multiplying respective terms of the first linear function stored in the storage unit by a ratio of temperature information, which is detected during the imaging, to the temperature information corresponding to the first linear function.