Information input device

Details Information input device Information input device

1998-01-15

2001-06-19

Lee, Cheukfan (Department: 2722)

Facsimile and static presentation processing

Facsimile

Picture signal generator

C358S404000, C358S442000, C358S444000

Reexamination Certificate

active

06249359

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an information input device and method that scans in character and graphical-based information contained in printed form and converts this information into computer-readable image data or character codes.
2. Description of the Related Art
The microcomputer revolution of the past decade has brought about universal access to processing power and computing options once reserved exclusively for expensive mainframe architectures. And, as personal computer development advances at an ever increasing pace, so too does the variety and adaptation of their use in the marketplace. This has spurred a rapid introduction of intelligent, microcontroller-driven consumer products mentioned only in science fiction novels just a few years before.
One of the most active trends in contemporary computing has been in the field of document processing, and more particularly, converting printed information into electronic form. Peripheral devices known as “handheld scanners” have been developed to automate this conversion process. A conventional handheld scanner reads optical images by touching the roller installed on its tip to images such as characters and rolling over them. The optical signal obtained is converted to an electrical signal through photoelectrical conversion, and is then processed by an image processor in order to provide computer-readable character codes or image data. In this roller-type scanner, distance is calculated based on the rotation of the roller. For example, 16 pieces of image data may be read for every 1 mm of movement, and the obtained image data are then processed by an image processing means. Consequently, the roller must be firmly contacting the image while it is moved. If this condition is met, it becomes possible to read ideal image data regardless of the movement speed (hereinafter referred to as “scanning speed”).
However, as explained above, it is not always easy for the operator to maintain firm contact with the image while moving the roller; in some cases the roller might be moved while it is not in contact with the image. Since the roller does not rotate if it is not in contact with the image while being moved, distance cannot be determined. Consequently, an accurate image that corresponds to the scanning speed cannot be read. Furthermore, this type of image input means requires an encoder unit that outputs a pulse signal that matches the distance moved based on the roller movement or roller rotation, thus increasing the overall frame size of the apparatus. For example, for small-size scanners such as pen-type scanners, the area that actually reads images is only around 10 mm wide. However, the area that contacts the manuscript ends up being at least 30 mm wide because of the encoder. Additionally, frequent use of the scanner may cause wear or damage in the moving area (roller area), rendering the scanner unfit for long-term use.
Accordingly, a handheld scanner shown in prior art
FIG. 15
has been developed to remedy the problems inherent in roller-type handheld scanners. As shown in this figure, this scanner possesses two line sensors
1011
and
1012
utilized as one-dimensional image sensors (hereafter referred to as “the first sensor
1011
”
0
and “the second sensor
1012
”). It also possesses two light passage holes
1117
and
1118
which are spaced a specified distance apart. The light from LED
1
1010
passes through the two light passage holes
1117
and
1118
and illuminates the characters, etc. on the page being scanned. The reflected light is intercepted by the first sensor
1011
and the second sensor
1012
via optical system
1013
.
Image processing by the scanner illustrated in prior art
FIG. 15
will be described in more detail in reference to prior art FIG.
16
. Prior art
FIG. 16
is a block diagram of the configurations of the image input area and the image processing area, and is used for explaining image data processing. As such, the figure shows only those configuration elements that are necessary for explaining image data processing. In
FIG. 16
,
20
is a scanner (image input unit); the first sensor
1011
and the second sensor
1012
read characters in different positions based on the timing signals issued by read timing signal generation circuit
21
, and temporarily stores the data in buffer
22
.
On the right side of
FIG. 16
, image processing unit
30
comprises buffer
31
, speed detection unit
32
, and image correction unit
33
. This speed detection unit
32
comprises the first attribute extraction unit
321
, the second attribute extraction unit
322
, attribute buffer
323
, attribute comparison unit
324
, and speed determination unit
325
. This image processing unit
30
is typically installed inside an information processing device, such as a personal computer (not shown). Note that buffer
31
installed inside this image processing unit
30
is extremely large, allowing it to store all the image data that will be sent from image input unit
20
during a scan operation.
In this configuration, the first sensor
1011
and the second sensor
1012
in image input unit
20
read characters in different positions based on the timing signals issued by read timing signal generation circuit
21
. The image data that is read is first temporarily stored in the buffer
22
, and is then sent to image processing unit
30
and stored in buffer
31
. In this way, while image input unit
20
is scanning data, all of the image data read by the first sensor
1011
and the second sensor
1012
is stored in buffer
31
of image processing unit
30
.
When scanning is completed, image data is extracted from buffer
31
. After the scanning speed of image input unit
20
is determined by speed detection unit
32
, the distortion in the image data is corrected by image correction unit
33
based on the scanning speed. In other words, in speed detection unit
32
, the first attribute extraction unit
321
extracts the attributes of the image data generated by the first sensor
101
at a certain point in time; the attribute data is then stored in attribute buffer
323
; and then the attributes of the image data from the second sensor
102
extracted by the second attribute extraction unit
322
is compared with the attribute data in the above-mentioned attribute buffer
323
by attribute comparison unit
324
, in order to determine whether there is a match. If the two pieces of image data match each other, that means the second sensor
1012
has reached the read-out position of the first sensor
1011
. Speed determination unit
325
then determines the scanning speed based on the elapsed time. Based on this scanning speed, the distortion in the image data is corrected by image correction unit
33
.
By adopting such a method, the image distortion caused by changes in scanner speed is corrected, and distortion-free image can be obtained. Furthermore, this method provides various advantages over roller-type scanners. For example, the absence of an encoder unit makes the scanner smaller; the scanner tip need not contact the material to be read, resulting in improved operability; and the absence of a moving area such as a roller results in increased durability.
However, as explained above, a conventional dual line sensor image input device requires a distortion correction process that is based on speed detection. In order to perform this process, an extremely large buffer (buffer
31
in
FIG. 16
, for example) is usually installed in the image processing area, and speed detection and image correction are performed after all of the image data has been sent into this buffer.
Prior art
FIG. 17
illustrates a timing diagram that shows the image data input processing operation of a manual image input device using the above-described conventional dual line sensor.
FIG. 17
shows the image input operation performed by image input unit
20
; shows the data transfer operation from image input unit
20
to image processing unit
30
; and shows the image correction operation (

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