Image reading apparatus having a D/A converter with a controllab

Details Image reading apparatus having a D/A converter with a controllab Image reading apparatus having a D/A converter with a controllab

1990-03-28

1992-09-29

Coles, Sr., Edward L.

Facsimile and static presentation processing

Facsimile

Specific signal processing circuitry

358463, 358475, H04N 140

Patent

active

051517965

ABSTRACT:
Image reading apparatus having a D/A converter with a controllable output includes a light source for illuminating an original image. A reading device is provided for photoelectrically reading the original image illuminated by the light source and generating an analog image signal. A D/A converter is provided having a digital input terminal, an analog output terminal, and a reference terminal. The analog image signal generated from the reading device is applied to the reference terminal. The D/A converter attenuates the level of the analog image signal applied to the reference terminal based on a damping factor corresponding to the digital data applied to the digital input terminal. The thus-attenuated analog image signal is then output to the analog output terminal. An amplifier is provided for amplifying the attenuated analog image signal output from the analog output terminal of the D/A converter. An A/D converter is provided for converting the amplified analog image signal output from the amplifier into a digital image signal. Control circuitry is provided for controlling the digital data applied to the digital input terminal of the D/A converter to cause the analog image signal supplied to the A/D converter to have a predetermined level. This provides an analog image signal having a constant signal level even when the brightness of the light source, (e.g., a fluorescent lamp) varies widely.

REFERENCES:
patent: 4408231 (1983-10-01), Bushaw et al.

Affiliated with

Also associated with

Rating

Image reading apparatus having a D/A converter with a controllab does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Image reading apparatus having a D/A converter with a controllab, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Image reading apparatus having a D/A converter with a controllab will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1972891