초록 ▼

An image reading apparatus includes a photoelectric conversion element which has a plurality of cells, the plurality of cells including shielded cells which are optically shielded so that each shielded cell outputs only the dark signal, a dark signal data generating system for generating dark signal

An image reading apparatus includes a photoelectric conversion element which has a plurality of cells, the plurality of cells including shielded cells which are optically shielded so that each shielded cell outputs only the dark signal, a dark signal data generating system for generating dark signal data for each cell of the photoelectric conversion element, the dark signal data corresponding to a ratio of an image signal output from each cell under a no-exposure condition to a first reference dark signal which is obtained based on the dark signals output from the shielded cells under the no-exposure condition, a dark signal data memory for storing the dark signal data for each cell, a dark signal component generating system for generating a dark signal component for each cell, the dark signal component corresponding to a product of the dark signal data for each cell multiplied by a second reference dark signal which is obtained based on the dark signals output from the shielded cells under the exposure condition, and a subtracter for subtracting the dark signal component from an image signal obtained for each corresponding cell under the exposure condition.

대표청구항 ▼

An image reading apparatus comprising: a photoelectric conversion element which has a plurality of cells, each cell generating an image signal including a photoelectric conversion signal corresponding to an amount of light incident thereto and a dark signal based on a dark current generated therein,

An image reading apparatus comprising: a photoelectric conversion element which has a plurality of cells, each cell generating an image signal including a photoelectric conversion signal corresponding to an amount of light incident thereto and a dark signal based on a dark current generated therein, said plurality of cells including shielded cells which are optically shielded so that each shielded cell outputs an image signal including only a dark signal; dark signal data generating means for generating dark signal data for each cell of said photoelectric conversion element under a no-exposure condition in which there is no light incident to said photoelectric conversion element, said dark signal data corresponding to a ratio of a pixel data signal output from each cell under the no-exposure condition to a first reference dark signal which is obtained based on dark signals output from the shielded cells under the no-exposure condition; dark signal data storage means, coupled to said dark signal dark generating means, for storing the dark signal data for each cell of said photoelectric conversion element; dark signal component generating means for generating a dark signal component for each cell of said photoelectric conversion element under an exposure condition in which a light is incident to said photoelectric conversion element, said dark signal component corresponding to a product of said dark signal data stored for each cell in said dark signal data storage means multiplied by a second reference dark signal which is obtained based on the dark signals output from the shielded cells under the exposure condition; and dark signal removing means, coupled to said dark signal component generating means, for removing the dark signal component generated for each cell by said dark signal component generating means from an image signal obtained for each corresponding cell of said photoelectric conversion element under the exposure condition, wherein said image reading apparatus outputs the image signal from which the dark signal component is removed for each cell of said photoelectric conversion element.