Patent ID: 8537428
Filing Date: 2013-09-17
Classification: H04N

Abstract:
1. An image reading apparatus comprising: a white reference member; an exposure lamp configured to expose an original document and the white reference member; a CCD sensor including a plurality of linear sensors connected in series, configured to receive reflected light from the original document or the white reference member, and output an image signal with a voltage level corresponding to the amount of received light; a plurality of gain amplifiers configured to amplify the outputs of the linear sensors, respectively; an analog-to-digital converter configured to convert the output signals of the gain amplifiers in an analog-to-digital conversion manner and output the converted signals as image data of the linear sensors; a first control section configured to configured to expose the white reference member by the use of the exposure lamp at the time of starting up the apparatus; a selection section configured to select one linear sensor with the maximum output among the linear sensors at the time of starting up the apparatus; a first processing section configured to adjust the gain of the gain amplifier corresponding to the selected linear sensor so that the maximum value of the image data corresponding to one line of the selected linear sensor is equal to a predetermined value and detect the image data at both ends from the image data corresponding to one line of the selected linear sensor after the adjustment; a first determination section configured to determine whether another linear sensor exists to the left side of the selected linear sensor; a second processing section configured to adjust the gain of the gain amplifier corresponding to the linear sensor existing to the left side so that the image data at the right end of the left linear sensor is equal to the image data at the left end of the linear sensor adjacent thereto on the right and detect the image data at the left end from the image data corresponding to one line of the left linear sensor after the adjustment, when the first determination section determines that another linear sensor exists to the left side of the selected linear sensor; a second determination section configured to determine whether another linear sensor exists to the left side of the left linear sensor after the second processing section detects the image data; a second control section configured to repeat the adjustment and the detection of the second processing section when the second determination section determines that another linear sensor exists to the left side of the left linear sensor; a third determination section configured to determine whether another linear sensor exists to the right side of the selected linear sensor, when the first determination section determines that another linear sensor does not exist to the left side of the selected linear sensor and when the second determination section determines that another linear sensor does not exist to the left side of the left linear sensor; a third processing section configured to adjust the gain of the gain amplifier corresponding to the linear sensor existing to the right side so that the image data at the left end of the right linear sensor is equal to the image data at the right end of the linear sensor adjacent thereto on the left and detect the image data at the right end from the image data corresponding to one line of the right linear sensor after the adjustment, when the third determination section determines that another linear sensor exists to the right side of the selected linear sensor; a fourth determination section configured to determine whether another linear sensor exists to the right side of the right linear sensor after the third processing section detects the image data; and a third control section configured to repeat the adjustment and the detection of the third processing section when the fourth determination section determines that another linear sensor exists to the right side of the right linear sensor, and end the adjustment and the detection of the third processing section when the fourth determination section determines that another linear sensor does not exist to the right side of the right linear sensor.