JPH04167861A - Picture reader and position detecting method for its read means - Google Patents

Abstract

PURPOSE:To attain the entry while visually observing coordinates of a reference point on a tablet panel and to detect the relation of position between a line sensor and a pickup element by providing at least one pickup element at the position visually recognized. CONSTITUTION:A paper sheet is set on a tablet panel 1 and a reference point CP is marked at an optional position. The mode to read a coordinate of a pickup element 3a on the panel 1 is set by the switch operation and a mode changeover circuit 4 outputs only an output signal of the element 3a. The center point of the element 3a is matched with the point CP by visual observation and x/y scanning circuits 6a,6b scan the panel 1 to read the coordinate of the point CP. The mode is switched into the picture input mode by the switch operation and the circuit 4 outputs a signal of pickup elements 3a,3b. A line sensor 2 is scanned to allow an image pickup element Pa to pick up the point CP and to detect coordinates of points La, Ra at the center position of the elements 3a,3b and the result is stored in a storage circuit 8. A control circuit 7 detects a relative relation of positions among the elements 3a,3b,Pa based on the points CP,La and Ra.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image reading device and a method for detecting the position of its reading means.

[Prior Art] In a conventional image reading device, a line sensor and a plurality of pickup elements such as a pickup coil for detecting the position of the line sensor are housed in a frame, and are not visible from the outside. be.

A method for detecting the position of a line sensor in this image recognition device is, for example, as disclosed in Japanese Patent Publication No. 60-55867, in which the positions of the line sensor and a plurality of pickup coils are determined in advance. The position of the line sensor is detected based on the positional relationship and each coordinate read by a plurality of pickup coils.

[Problem to be Solved] In the conventional line sensor position detection method described above, if the line sensor and the plurality of pickup elements are mounted misaligned, a reading error will occur. Must be set extremely strictly. That is, mounting each device requires a highly accurate assembly technique or a fine adjustment mechanism to eliminate positional errors, which increases costs accordingly.

The present invention provides position detection of an image reading device and its reading means that does not require strictness in setting the relative positional relationship between a line sensor and a plurality of pickup elements, and therefore can simplify the assembly process and reduce costs. The purpose is to provide a method.

[Means for Solving the Problems] The present invention provides a tablet board, a line sensor that is configured by a plurality of image sensors and scans the tablet board to read an image, and a position of the line sensor on the tablet board. In an image reading device that includes a plurality of pickup elements for detecting an image, the image reading device is configured by providing at least one of the plurality of pickup elements at a position that is visible from the outside, and the image reading device is configured to include a plurality of pickup elements for detecting The coordinates of the reference point on the tablet board are read by a pickup element provided at a possible position, and each of the reference points is imaged by a different image sensor of the line sensor, and each of the plurality of pickup elements is read at this time. The above problem is solved by detecting the relative positional relationship between the line sensor and the plurality of pickup elements based on the coordinates and the coordinates of the reference point.

[Example code] Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 shows the configuration of an image reading apparatus according to the present invention. In the figure, 1 is a tablet board, and a magnetic field with a uniform magnetic flux density is generated on the surface of the tablet board. Reference numeral 2 is composed of a plurality of image pickup elements, and is a line sensor for reading image information, and 3a and 3b are pickup elements for reading coordinates on the tablet board 1, which are pickup coils in this example. The pickup element 3a is provided at a position that is visible from the outside (as shown in the second figure).

4 is a mode switching circuit that selectively outputs the output signals from the pickup elements 3a and 3b.

2 to 4 constitute a hand scanner 5.

6a is an X-direction scanning circuit for scanning the tablet board 1 in the X direction and detecting the X coordinates of the pickup elements 3a and 3b; 6b is a circuit for scanning the tablet board 1 in the y direction and detecting the X coordinates of the pickup elements 3a and 3b. 7 is a y-direction scanning circuit for detecting pickup elements 3a and 3b.
8 is a storage circuit that stores image information read by the line sensor 2 and its coordinates; 9 is a storage circuit 8;
This is a display unit that displays an image based on the stored contents.

FIG. 2 shows the configuration of the hand scanner 5.
In the same figure, the same numbers as in FIG. 1 indicate the same parts.

As shown in the figure, the pickup element 3a is provided exposed from the hand scanner body and is visible. Note that the pickup element 3a may be provided inside the main body, and the main body case at that position may be formed of a transparent member so that it can be visually recognized from the outside. P1 to Pz are imaging elements that constitute the line sensor 2.

Next, a method for detecting the relative positional relationship between the line sensor 2 and the pickup elements 3a and 3b will be explained with reference to the flowchart in FIG.

First, a sheet of paper is placed on the tablet board 1, and a reference point CP is marked at an arbitrary position (step 2).

Next, a switch (not shown) is operated to switch to a digitizer mode for reading the coordinates of the position of the pickup element 3a on the tablet board 1 (step 2). As a result, the mode switching circuit 4 outputs only the output signal from the pickup element 3a.

Next, the center point of the pickup element 3a is visually aligned with the reference point CP, and the X-direction scanning circuit 6a and the V-direction scanning circuit 6b scan the tablet board 1 to read the coordinates of the reference point CP. That is, the X direction scanning circuit 6a and the y
The direction scanning circuit 6b sequentially applies current to each scanning line of the tablet board 1 to generate a magnetic field, and by detecting the peak value of the output signal generated from the pickup element 3a by this magnetic field, the coordinates of the pickup element 3a are determined. Read (x cp, y cp) (step ■).

Next, the above switch is used to switch to image input mode (step ■). Thereby, the mode switching circuit 4 outputs the signals generated from the pickup elements 3a and 3b.

Next, the line sensor 2 is scanned to image the reference point CP using an arbitrary image sensor. Here, it is assumed that the reference point CP is imaged by the image sensor Pa shown in FIG. Point 1 where the center of the pickup element 3a is located when the reference point CP is imaged by the image sensor Pa. Coordinates of a (xj2a
, y12a), and the coordinates of the point Ra where the center of the pickup element 3b is located (Xra, y ra)
is detected and stored in the memory circuit 8 (step ■)
.

Coordinates (x cp, y cp), (xj2a,
yj2a ), (x ra, y ra) are shown in Figure 4 (
Assume that the positional relationship is as shown in a). Next, the control circuit 7 calculates the length and angle θa of each side a-c of the triangle connecting the points CP, La, and Ra (step 2).

The length of each side is ff1a-f(xcp-xfa) 2 + (ycp-yJ!a) 21'/2i b =
f (x cp −x ra) 2+(yCp−y
ra) 2) l/2 1c= ((xJ!a −xra) 2+ (yJ2
a - yra) 21 "2. Also, the angle θa is θa-2Xarctan[((s-J2a)1/2 (s-, ffc)/s (s-job)l.

Here s = (I2a + Il b + p c
) / 2.

In this way, the relative positional relationship between the pickup elements 3ax 3b and the image sensor Pa is detected.

Next, the line sensor 2 is scanned again and the reference point CP is imaged with any imaging element other than the imaging element Pa. Here, it is assumed that the reference point CP is imaged by the image sensor pb shown in FIG. Similarly to the above operation, the coordinates (xj2b, yj!b) of the point Lb where the center of the pickup element 3a is located when the reference point CP is imaged by the image sensor pb
) and the coordinates (x rb, y rb) of the point Rb located at the center of the pickup element 3b are detected and stored in the storage circuit 8.

Coordinates (x cp, y cp), (xJ2b,
yJ2b), (x rb, y rb) are shown in Figure 4 (
Assume that the positional relationship is as shown in b). Next, in the same manner as above, the control circuit 7 controls the points CP, Lb and Rb.
The length and angle θb of each side 1a' to l1c- of the triangle connecting the are calculated.

In the manner described above, the relative positional relationship between the image pickup elements Pa and pb of the pickup element 3a13b1 is detected.

Next, assuming that the pickup elements 3 a s 3 b and the line sensor 2 are located at the positions shown in FIG. 5 on the tablet board 1, the operation of reading an image based on the above detection results will be described.

The coordinates of the center point of the pickup element 3a are (xl.

yl), and the coordinates of the center point R of the pickup element 3b are (x
r, yr). Since the relative positional relationship between the image sensors Pa, Pb and the pickup elements 3a and 3b has been determined by the above operation, the coordinates (Pax, Pay) of the reading point Pa- of the image sensor Pa-10- and the coordinates (Pax, Pay) of the image sensor pb are Coordinates of reading point pb- (Pbx,
Pby) can be calculated.

Pax=xp+Ila @cos (θa ten θ) Pay
=yJ2+j2a #s in (θa + θ)P
bx = xJ2+, fla −・cos (θb〇)
Pby=yjl! +f'a −・s in (θb+
θ). Here, θ-arctan(y r-yJri / (x r-x
J2).

Next, the coordinates (Pnx, Pny) of the reading point Pn- of the n-th image sensor Pn from the image sensor P1 are calculated.

Pnx −Pax+(Pbx−Pax)(na)/(
b-a) Pny = Pby + (Pby-Pay) (n
-b)/(b-a). Here, nSa and b are numbers indicating the order of the image sensors PnSPa and pb from the image sensor Pi, respectively. That is, (na) /
(ba) represents the ratio of the distance between the image sensor Pn and the image sensor Pa to the distance between the image sensor pb and the image sensor Pa.

As described above, the image sensors P1 to P of the line sensor 2
The coordinates of each reading point according to n are detected and stored in the storage circuit 8 together with the image information.

In the above embodiment, the positional relationship between the line sensor and the pickup element was calculated by scanning the line sensor multiple times and reading one reference point with different image sensors. Two reference points are provided, each reference point is read by a different image sensor during one scan of the line sensor, and the same calculation as in the above embodiment is performed to determine the positional relationship between the line sensor and the pickup element. Good too. Further, the reference point may be a specific point in the figure, such as the intersection of sides of a triangle or quadrilateral.

Further, in the above embodiment, a current is passed through the tablet board to generate a magnetic field, and the position of the pickup coil is detected based on the change in the induced current generated in the pickup coil. The position of the pickup coil 12 may be detected based on a change in the induced current generated in the tablet board by passing a current through the coil to generate a magnetic field.

In addition, in the above embodiment, a pickup coil was used as the pickup element, but the pick-up element is not limited to this. Electrodes are also used, and electrodes are also provided on the tablet board, and the pick-up element is activated based on the change in capacitance between each electrode. The position may be detected.

Alternatively, a photocoupler consisting of a light emitting element and a light receiving element may be used as the pickup element, and the position of the pickup element may be detected based on changes in the amount of light reflected from the tablet board.

[Effects] According to the present invention, since at least one pickup element is provided in a visible position, the coordinates of the reference point on the tablet board can be entered while being visually checked, and therefore the relative positions of the line sensor and the plurality of pickup elements can be input. It becomes possible to detect relationships. In addition, after reading the coordinates of the reference point, the positional relationship between the line sensor and the pickup element can be extremely easily read by reading the reference point using different image sensors of the line sensor. This eliminates the need for matching operations, making it possible to simplify the process and reduce costs.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of an image reading device according to the present invention, FIG. 2 is an explanatory diagram for explaining the specific configuration of the main part of FIG. 1, and FIG. A flowchart for explaining the operation, and FIGS. 4 and 5 are explanatory diagrams for explaining the operation of FIG. 1. 1...Tablet board P1-Pz...Image sensor 2...Line sensor 3 a s 3 b...Amount of pickup elements Upper applicant Seikosha Co., Ltd.

Claims (2)

[Claims] (1) A tablet board, a line sensor that is composed of a plurality of image sensors and scans the tablet board to read an image, and a plurality of pickup elements for detecting the position of the line sensor on the tablet board. An image reading device comprising: at least one of the plurality of pickup elements is provided at a position visible from the outside. (2) A tablet board, a line sensor that scans the tablet board and reads an image, which is composed of a plurality of image sensors, and a plurality of pickup elements for detecting the position of this line sensor on the tablet board. A method for detecting the position of a reading means in an image reading device, characterized in that at least one of the plurality of pickup elements is provided at a position visible from the outside, The coordinates of the reference point on the tablet board are read by the pickup element, and each of the reference points is imaged by a different image sensor of the line sensor, and the read coordinates of each of the plurality of pickup elements and the reference point at this time are A method for detecting a position of a reading means, comprising detecting a relative positional relationship between the line sensor and the plurality of pickup elements based on the coordinates of the reading means.