Facsimile and static presentation processing – Facsimile – Picture signal generator
Reexamination Certificate
1999-07-14
2003-08-19
Grant, II, Jerome (Department: 2624)
Facsimile and static presentation processing
Facsimile
Picture signal generator
C358S482000
Reexamination Certificate
active
06608706
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a scanning method for performing a low resolution scan, and more particularly, to a scanning method for performing a low resolution scan by using a high resolution scanning module.
2. Description of the Prior Art
Please refer to FIG.
1
.
FIG. 1
is a schematic diagram of the charge coupled device (CCD)
24
of a high resolution scanning module. The main component of the prior art scanning module is a charge coupled device (CCD)
24
. The CCD
24
of the prior art high resolution scanning module comprises a plurality of linearly arranged photo sensors
12
, a shift register
14
, and an output unit
20
. The shift register
14
comprises a plurality of serially connected storage units
16
and an output port
18
. The number of the storage units
16
is equal to the number of the photo sensors
12
and each of the storage units
16
is electrically connected with one correspondent photo sensor
12
. Each photo sensor senses a document and generates the correspondent induced charges, and each storage unit
16
stores the induced charges generated by the connected photo sensor
12
. The induced charges stored in the storage units
16
are able to serially migrate toward the output port
18
where they are sequentially output. The output unit
20
is electrically connected to the output port
18
of the shift register
14
and receives the induced charges outputted from the output port
18
to generate a correspondent induced voltage. Therefore, the induced voltage outputted from the output unit
20
possesses image data. The output unit
20
outputs the induced voltage to an A/D converter
22
electrically connected to the output unit
20
where the induced voltage outputted from the output unit
20
is converted into a digital image signal.
When using the CCD
24
of the high resolution scanning module to perform the highest resolution scan on a document, the scanning method comprises the following steps:
Step 1: activating the photo sensors
12
to sense the light transmitted from the document for a predetermined time period to generate correspondent induced charges;
Step 2: transmitting the induced charges from the photo sensors
12
into corresponding storage units
16
;
Step 3: shifting the induced charges stored in the storage units
16
into the output unit
20
in sequence;
Step 4: outputting the induced voltage of the output unit
20
after induced charges of one storage unit
16
are accumulated in the output unit
20
, and resetting the output unit
20
to continue receiving the induced charges from the output port
18
, and using the A/D converter
22
to convert the induced voltage outputted from the output unit
20
into a digital image signal;
Step 5: repeating the previous step until all the induced charges in the storage units
16
are outputted.
Please refer to FIG.
2
.
FIG. 2
is a schematic diagram of the selection of the image data when performing a low resolution scan according to the prior art. When using the CCD
24
of the high resolution scanning module to perform a low resolution scan, for example, scanning at 600 dpi with the highest possible resolution being 1200 dpi (dots per inch), the difference between the low resolution scan and the high resolution scan is the selection of the image data. As shown in
FIG. 2
, when scanning is performed at 1200 dpi, the induced charges in each of the storage units
16
are transmitted to the output port
18
. When scanning is performed at 600 dpi, the induced charges in every other storage unit
16
are transmitted.
Increases in the speed of transmission of interfaces has led to rapid transmission speeds in current interfaces. The prior art method of discarding part of the image data during low resolution scanning with a high resolution scanning module cannot effectively enhance the scanning speed of the low resolution scan due to exposure time limitations. As a result, the low resolution scan cannot be performed rapidly.
SUMMARY OF THE INVENTION
It is therefore a primary objective of the present invention to provide a scanning method for performing a low resolution scan by using a high resolution scanning module to solve the above mentioned problem.
In a preferred embodiment, the present invention provides a scanning method for performing a low resolution scan by using a high resolution scanning module, the scanning module comprising:
a plurality of linearly arranged photo sensors, each of the photo sensors being capable of sensing light transmitted from a document to generate correspondent induced charges;
a shift register comprising a plurality of serially connected storage units and an output port, the number of the storage units being equal to the number of the photo sensors, each of the storage units being electrically connected with one correspondent photo sensor for storing the induced charges generated by the connected photo sensor, the induced charges stored in the storage units being able to serially migrate toward the output port and sequentially output from the output port; and
an output unit electrically connected to the output port of the shift register for receiving the induced charges output from the output port and generating a correspondent induced voltage; the low resolution scanning method comprising:
activating the photo sensors to sense the light transmitted from the document for a first predetermined time period to generate correspondent induced charges;
transmitting the induced charges from the photo sensors into corresponding storage units;
shifting the induced charges stored in the storage units into the output unit in sequence;
outputting the induced voltage of the output unit after induced charges of a first predetermined number of the storage units are accumulated in the output unit, and resetting the output unit to continue receiving the induced charges from the output port; and
repeating the previous step until all the induced charges in the storage units are output.
It is an advantage of the present invention that the exposure time of the photo sensors is shortened when performing a low resolution scan, so the low resolution scan can be performed rapidly.
REFERENCES:
patent: 3801884 (1974-04-01), Sequin
patent: 3909803 (1975-09-01), Bankowski, Jr.
patent: 5337163 (1994-08-01), Kawamoto
patent: 5416611 (1995-05-01), Tandon
patent: 5986267 (1999-11-01), West
patent: 6153874 (2000-11-01), Monoi
Grant II Jerome
Hsu Winston
Mustek Systems Inc.
Worku Negussie
LandOfFree
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