Facsimile and static presentation processing – Facsimile – Picture signal generator
Reexamination Certificate
1997-12-22
2002-03-19
Grant, II, Jerome (Department: 2624)
Facsimile and static presentation processing
Facsimile
Picture signal generator
C358S506000
Reexamination Certificate
active
06359706
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image reading apparatus, and more particularly to an image reading apparatus capable of reading shading data.
2. Related Background Art
A film scanner for inputting the image of a film into a personal computer is so constructed that in the image reading operation, first scan the image with a low resolution and a high speed (pre-scan) is performed to thereby display the entire image on the personal computer, and then the main scanning operation in a desired range designated on the preview image is performed to thereby send the obtained image data to the personal computer.
The configuration of such film scanner will be explained in the following with reference to
FIG. 28
, in which shown are an illuminating light source
2801
; a film holder
2802
for supporting a film constituting a translucent original and capable of transporting the thin translucent film, supported on the plane of the drawing (Y-Z plane), in a direction Y; an imaging lens system
2803
; and a CCD linear image sensor
2804
(hereinafter simply called linear image sensor). The linear image sensor
2804
is positioned that its longitudinal direction is along a Z-direction in the plane of the drawing. By such arrangement, the main scanning direction, which is the longitudinal direction of the linear image sensor
2804
, becomes perpendicular to the moving direction of the film holder
2802
. In reading the color image on the film, there can be conceived following variations in the combination of the light source
2801
and the linear image sensor
2804
:
Light source
CCD
Image reading
(1) White
three lines
R,G,B simultaneous
reading
(2) Three colors
one line
R,G,B time-shared
(B,G,R)
reading
(3) While +B,G,R
one line
R,G,B time-shared
filters
reading
These methods have respective advantages and disadvantages. In the following description, there will be assumed the combination (1).
In
FIG. 28
, there are shown an analog image processing circuit
2805
for gain setting and clamping of an analog image signal output from the linear image sensor
2804
; an A/D converter
2806
for converting the analog signal into a digital signal; a digital image processing circuit
2807
for effecting image processing and CCD drive pulse removal; an image processing circuit
2807
composed of a gate array and capable of various high-speed processings; a line buffer
2808
for temporarily storing the output image data from the digital image processing circuit
2807
; an interface
2809
for communication with an external equipment
2810
such as a personal computer; a system controller
2811
for releasing control signals based on a stored sequence program of the entire film scanner and adapted to execute various operations according to instruction from the external equipment
2810
; a CPU bus
2812
connecting the digital image processing circuit
2807
, the line buffer
2808
and the interface
2809
and composed of an address bus and a data bus; a sub scanning motor
2813
composed of a stepping motor for displacing the film holder
2802
in the sub scanning direction; a sub scanning motor driver
2814
for driving the sub scanning motor
2813
according to a command from the system controller
2811
; sub scan position detecting unit
2815
composed of a photointerrupter for detecting a projection of the film holder
2802
, for detecting a reference position of the sub scanning; and a light source activation circuit
2816
for activating the illuminating light source
2801
.
The film scanner is constructed as explained in the foregoing, and is adapted to release image data to the external equipment
2810
according to a software of the system controller
2811
(hereinafter called “firmware”) and a software (hereinafter also called driver software) for operating the film scanner from the external equipment such as the personal computer
2810
. The procedure will be explained briefly with reference to FIG.
29
. It is assumed that the film scanner and the external equipment
2810
are powered, that the firmware and the driver software are activated and that the film has been loaded by the user in a predetermined position of the film holder
2802
.
At first, in a step S
2901
, the user enters a preview command from the external equipment
2810
, which in response provides, through the driver software, the firmware with the designated information, including the kind of the film, the reading area (entire image area in this case) and the reading resolution (low resolution).
In a next step S
2902
, the firmware sets the designated information, namely the film kind, the reading area and the reading resolution, on the system controller
2811
, thereby effecting electrical preparation.
In a next step S
2903
, the sub scan position detecting unit
2815
read the information of the sub scanning position, and the system controller so controls the sub scanning motor
2813
as to bring the film to an initial position.
In a next step S
2904
, the system controller
2811
sends a command to turn on the light source to the light source activation circuit
2816
, thereby turning on the light source
2801
.
Then, in a step S
2905
, the system controller
2811
outputs a command for the output of timing pulses (driving pulses for the linear image sensor
2804
, RAM address control pulses etc.) for the reading of a line.
A next step S
2906
reads the image data of each line with a predetermined exposure time and drives the sub scanning motor
2813
with a predetermined speed. Thereafter the digital image processing circuit
2807
executes the image processing, and the image data are output to the external equipment
2810
.
When the scanning of the above-mentioned image reading area is completed in a step S
2907
, the system controller
2811
drives the sub scanning motor
2813
to return the film holder to the initial position. Also the light source
2801
is turned off, and various functions are terminated as soon as all the image data are output from the digital image processing circuit
2807
.
A next step S
2908
terminates the scanning, and the firmware of the system controller
2811
enters a routine for awaiting a next command.
In a next step S
2909
, the external equipment
2910
receives the image data and displays them in succession on a display or the like connected to the external equipment
2810
, thereby providing the user with the entire image of the film.
Then, in a step S
2910
, the user observes the displayed preview image, then sets the image fetching conditions and instructs the main scanning. As in the step S
2901
, the designated information including the kind of the film, the reading area (area designated by the user) and the reading resolution (resolution designated by the user), are transmitted to the firmware.
In a step S
2911
, the firmware of the system controller
2811
receives the reading conditions and executes the operations of the steps S
2902
to S
2908
under the conditions for the main scanning.
In a step S
2912
, the image data are transmitted to the external equipment
2810
and displayed by the software, and can be stored in another memory medium (such as hard disk, magnetooptical disk or floppy disk) of the external equipment
2810
.
In the above-explained film scanner, the shading data are usually obtained in a state prior to the start of scanning, where the scanning motor is stopped and the light source is turned on. However, in the actual image reading operation, since the scanning motor is activated, the light amount distribution of the light source becomes different from that in reading the shading data because of the fluctuation of the power supply voltage resulting from the driving of the scanning motor. For this reason the exact correction of the shading has not been possible and the deterioration of the image quality has been unavoidable.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an image reading apparatus capable of image reading of high quality.
Another object of the presen
Arita Shinichi
Kondo Kazuyuki
Sato Hidekage
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Grant II Jerome
LandOfFree
Image reading apparatus 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, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Image reading apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2825310