US 5,402,249 A · Integrated circuit with exterior gain control adjustment

Abstract

An integrated circuit for processing an analog image signal obtained from a CCD, etc. and converting the processed image signal to a digital image signal. The integrated circuit includes a circuit for adjusting an offset voltage included in the analog image signal, a circuit for sampling/holding the image signal from the adjusting circuit, a variable amplifier for varying an amplitude of the image signal output from the sampling/holding circuit, an analog/digital converter for converting the image signal from the variable amplifier to a digital signal, and a circuit for detecting a DC component included in the digital image signal and providing the detection result to the adjusting circuit. Correction of a DC voltage component of the analog image signal and amplitude adjustment of the analog image signal can be performed by using a single LSI, and the LSI can be connected to various types of CCDs without using an additional circuit.

Claims16

Dependent claims

A device for processing an analog image signal supplied from a CCD sensor, comprising:

1) an integrated semiconductor device including:
(a) sample-and-hold means for executing a sample-and-hold operation on the analog image signal;
(b) amplifying means for adjusting the gain of an output from the sample-and-hold means;
(c) converting means for executing an analog-to-digital conversion on an output from the amplifying means and outputting a digital image signal;
(d) peak detecting means for detecting a peak value of said digital image signal output from the converting means;
and
2) look up table means for generating the optimal gain of said amplifying means in response to the peak value detected by said peak detecting means, and setting the gain of said amplifying means by using the generated optimal gain.

4 more elements

A apparatus for processing an analog image signal supplied from a CCD sensor, comprising:

an integrated semiconductor device including as components thereof:
(a) sample-and-hold means for executing a sample-and-hold operation on the analog image signal;
(b) amplifying means for adjusting the gain of an output from the sample-and-hold means;
(c) converting means for executing an analog-to-digital conversion on an output from the amplifying means and outputting a digital image signal;
and
(d) peak detecting means for detecting a peak value of said digital image signals output from the converting means;
and
adjusting means external to the integrated semiconductor device, for adjusting the amplifying means in accordance with the peak value detected by the peak detecting means, the adjusting means having means for determining an optimal gain of the amplifying means on the basis of the peak value detected by the peak value detecting means and means for setting the gain of the amplifying means on the basis of the optimal gain determined by the determining means.

5 more elements

An image reading apparatus comprising:

means for reading an image of an original document, said reading means including a CCD sensor for supplying an analog image signal corresponding to the image of the original document;
an integrated semiconductor device including as components thereof:
(a) sample-and-hold means for executing a sample-and-hold operation on the analog image signal;
(b) amplifying means for adjusting the gain of an output from the sample-and-hold means;
(c) converting means for executing an analog-to-digital conversion on an output from the amplifying means and outputting a digital image signal;
and
(d) peak detecting means for detecting a peak value of said digital image signal output from the converting means;
and
adjusting means external to the semiconductor device for adjusting the amplifying means in accordance with the peak value detected by the peak means, the adjusting means having means for determining the optimal gain of the amplifying means on the basis of the peak value detected by the peak detecting means, and means for setting the gain of the amplifying means on the basis of the optimal gain determined by the determining means.

6 more elements

An image forming apparatus for forming an image on an image bearing member, comprising:

means for reading an image of an original document, said reading means including a CCD sensor for supplying an analog image signal corresponding to the image of the original document;
an integrated semiconductor device having components therein including:
(a) sample-and-hold means for executing a sample-and-hold operation on the analog image signal;
(b) amplifying means for adjusting the gain of an output from the sample-and-hold means;
(c) converting means for executing an analog-to-digital conversion on an output from the amplifying means and outputting a digital image signal;
and
(d) peak detecting means for detecting a peak value of said digital image signal output from the converting means;
and
adjusting means external to the semiconductor device, for adjusting the amplifying means in accordance with the peak value detected by the peak value detecting means, the adjusting means having means for determining an optimal gain of the amplifying means on the basis of the peak value detected by the detecting means, and means for setting the gain of the amplifying means on the basis of the optimal gain determined by the determining means;
and
forming means for forming an image on the image bearing member based on the digital image signal converted by the converting means.

8 more elements

Dependencies are inferred from the claim text.

Integrated circuit with exterior gain control adjustment

Life of this patent

Integrated circuit with exterior gain control adjustment

Life of this patent

Abstract

Claims16