JP2526167Y2 - Oblique reading correction device - Google Patents

Description

[Detailed description of the invention] (Industrial application field) This invention relates to an oblique reading correction device, in particular, a CCD line sensor is arranged in a vertical plane in the main scanning direction of a document surface and is not parallel to the document surface. The present invention relates to an oblique reading correction device that can make the document information length corresponding to one pixel of the CCD of the CCD line sensor substantially constant over the entire length of the CCD line sensor.

(Prior Art) In recent years, in a copying machine or the like, a mechanism for optically reading a document placed on a platen and optically processing the document, and simultaneously optically reading the document and converting it to an electric signal, A device having a mechanism for electrically processing has been developed. The former mechanism is used for normal copying, and the latter mechanism is mainly used when editing the document information.

FIG. 4 shows a conceptual diagram of a document reading section of a copying machine having the two mechanisms. In the figure, 1 is a platen on which a document is placed, 2 is a reading device for optically reading a document placed on the platen 1 (hereinafter referred to as an optical reading device), and 3 is a reading device for reading electrically. Device (hereinafter, referred to as an electric reader). This electrical reader 3
It comprises a lens 3a and a CCD line sensor 3b.

In a copying machine provided with an optical reader 2 and an electric reader 3, the optical reader 2 is disposed opposite to the central portion of the platen 1 so that when enlarging or reducing a copy, an optical reader 2 is used. The target reader 2 is moved to the dotted line position 2 'shown.

For this reason, since the electric reader 3 cannot be arranged on the movement path indicated by the dotted line, it is arranged obliquely with respect to the surface of the platen 1 on the side of the platen 1 deviating from the movement path. I have.

(Problem to be Solved by the Invention) As described above, since the electric reader 3 is disposed on the side of the platen 1 and obliquely with respect to the surface of the platen 1, there are the following problems. .

Assuming that a document indicated by an arrow AB is placed on the platen 1, the positional relationship between the document AB and the CCD line sensor 3b is as shown in FIG. 5 and FIG.
FIG. 6 is a diagram schematically illustrating the description for easy understanding.

As shown, the left end 1 of the CCD line sensor 3b
A of the document AB is imaged at the pixel 3bl, C of the document AB is imaged at the central one pixel 3bc, and B is imaged at the rightmost pixel 3br. However, since AC> CB, the document information length 1 corresponding to the leftmost one pixel 3bl does not match the document information length l2 corresponding to the rightmost one pixel 3br, and they are different lengths.

As a result, without any correction, the CCD line sensor 3b
When the pixel information is read out from, the resolution changes while reading out the image information of one line.

In other words, the document A is read at a lower resolution on the A side, but changes to a higher resolution toward B.

Conventionally, in order to solve the above problem, image information read by the CCD line sensor 3b is temporarily stored in a page memory, and a difference in document information length per pixel of the CCD line sensor is corrected.

However, according to this correction method, since the correction processing is performed after storing the temporary image information in the page memory, there is a problem that the processing cannot be performed in real time, and a problem that the cost increases because the page memory must be installed. .

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate the above-mentioned problem of the prior art, and to correct a difference in document information length per pixel of the CCD line sensor in real time without using a page memory. It is to provide a device.

(Means and Actions for Solving the Problems) In order to achieve the above object, according to the present invention, a line sensor is arranged in a vertical plane in the main scanning direction of a document surface and non-parallel to the document surface. Image reading device,
The pixel data read from the line sensor is sequentially converted at intervals according to the degree of non-parallelism such that the document information length per pixel of the line sensor is substantially constant over one line. It is characterized in that it has a means for reading out by duplication or thinning.

According to the present invention, at intervals according to the degree of non-parallelism,
Since the pixel data can be sequentially overlapped or thinned out, the original information length per pixel of the line sensor can be arbitrarily corrected. As a result, the document information length per pixel of the line sensor can be made substantially constant over one line of the document, and image information with uniform resolution can be obtained.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings.

First, the principle of the present invention will be described with reference to FIG. Now, assuming that the length of the document AB is L, the number of pixels of the CCD line sensor 3b is N, and the maximum document information length per pixel of the CCD line sensor 3b is 1, to read the document AB with the same accuracy, , The CCD line sensor 3b only needs to have (L / 1) pixels.

However, since the number of pixels of the CCD line sensor 3b is N, the number of pixels of the CCD line sensor 3b is too large by {N- (L / 1)}. In the present invention, in order to eliminate this extra number of pixels, the correction of reading two pixels as one pixel is performed by taking into account the inclination (the angle θ in FIG. 5) between the CCD line sensor 3b and the document AB. This is performed over the entire length of the document.
The D line sensor 3b can be read almost uniformly at a rate of one pixel.

FIG. 3 shows an example in which the CCD line sensor 3b performs correction for reading two pixels as one pixel. That is,
In the 123rd pixel and the 128th pixel, correction is performed to read two pixels as one pixel. The interval of correction for reading these two pixels as one pixel is determined by the inclination θ of the CCD line sensor 3b and the document AB, and the interval becomes narrower as approaching the right end (r) of the CCD line sensor 3b. The numbers in the upper column of FIG. 3 indicate the pixel numbers when the correction has not been performed.

Here, the reason described above will be briefly described with reference to FIGS. 7 and 8, the angle ABF is assumed to be 90 ° for the sake of simplicity. The length on the document AB corresponding to one pixel at the r end of the CCD line sensor 3b is set to s as shown in FIG. 7, and this length s is multiplied by a factor at the A end on the document AB. The following relationship is obtained.

s' / s = 1 / sin γ · 1 / cos (π−2θ) That is, the length s ′ at the A end on the document AB is about ｛1 / sin γ · 1 / cos (π-2θ)｝ times (= m). Here, the angle BAF = γ.

Next, assuming that the length of the document AB is L and the number of pixels of the CCD line sensor 3b is N, the maximum document information length per pixel of the CCD line sensor 3b is ms as described above. In order to read with the same accuracy as that described above, the number of pixels of the CCD line sensor 3b only needs to be (L / ms). But CCD
Since the number of pixels of the line sensor 3b is N, ｛N− (L /
ms) The number of pixels of the CCD line sensor 3b is too large by (= z). Therefore, in this embodiment, the number of z pixels is removed as follows.

As shown in FIG. 8, the angle BFA = 2α is divided into z, and the division lengths on the document AB obtained by the z division are respectively s1, s2, s3,. If sz,
Correction is made so that two pixels constitute one pixel, one for each division length. That is, the respective division lengths s1, s2, s3,.
For −1 and sz, correction is performed with two pixels as one pixel.

Considering this on the CCD line sensor 3b, the right end (r) of the CCD line sensor 3b corrects (N × s1 / L) one pixel to two pixels, As the process proceeds to the left, correction is performed for (N × s2 / L) pixels in such a manner that one two pixel becomes one pixel. And CCD
At the left end (l) of the line sensor 3b, correction is performed on two (1) pixels as one pixel for (N × sz / L).

Correction intervals s1, s2, s3, ..., sz for reading two pixels as one pixel
−1 and sz are obtained by dividing each AFB in FIG. 7 into z, where z is a function of m and m is CC
Since it is a function of the inclination θ between the D line sensor 3b and the document AB,
The intervals s1, s2, s3,..., Sz-1, sz are determined by the inclination θ. Also, the interval at which two pixels are read as one pixel becomes narrower as it approaches the right end (r) of the CCD line sensor 3b.

Next, an embodiment of the present invention for realizing the above principle will be described with reference to FIG.

In the figure, reference numeral 10 denotes a timing signal generation circuit (hereinafter, referred to as a timing circuit), 11 denotes a CCD line sensor, 12 denotes a color separation unit, and 13 denotes an oblique reading correction unit. The oblique reading correction unit 13 is reset by the n D flip-flops 14a1 to 14an and the line synchronization signal y output from the timing circuit 10, and counts the bit synchronization signal x.
15. ROM 1 storing data (for example, “1”) for operating selector 17 using the output of counter 15 as an address
6, and a selector 17.

The ROM 16 stores data for operating the selector 17 at an address for performing the correction for reading two pixels as one pixel as described in the above-mentioned principle.

For example, in the example of FIG. 3, the data "1" is stored at addresses 128 and 134.

 Next, the operation of the embodiment shown in FIG. 1 will be described.

When the CCD line sensor 11 reads one line of the document AB,
The output from the timing circuit 10 is read out one pixel at a time and sent to the color separation unit 12. Binary data on the separated colors is output from the color separation unit 12 and input to a shift register composed of D flip-flops 14a1 to 14an.

As an example of the initial setting, when the line synchronization signal y is input to the counter 15, a predetermined value is preset in the counter 15, and the selector 17 selects the output of the D flip-flop 14an.

When the image information is binary from the color separation unit 12 and starts to be output to the shift register one bit at a time in synchronization with the bit synchronization signal x, the output signal of the D flip-flop 14an is selected from the selector 17. Output.

When this operation continues for a while and the data of "1" is output from the ROM 16 by the count value of the counter 15, the selector 17 operates and the D flip-flop 14a (n-1)
Select the output of As a result, one piece of pixel information is skipped (thinned out).

The same operation as described above is continued with the selector 17 selecting the output of the D flip-flop 14a (n-1), and when the counter 15 reaches a predetermined count value, the second "1" data from the ROM 16 Output to 17. Then,
The selector 17 selects the output of the D flip-flop 14a (n-2). For this reason, at this timing, the selector 17 outputs the image information thinned out once again.

When the above operation is continued for one line of the principle AB, the selector 17 almost outputs image information in which the maximum document information length per pixel of the CCD line sensor 11 described above in the principle is one pixel. , Over the entire length of the original AB.

In the above embodiment, one is read from the two-image information. However, the same pixel data may be read twice at the timing of thinning out one pixel to average the resolution of one line. .

Specifically, in the above description, the selector 17 shown in FIG.
Output of a (n-1), D flip-flop 14a (n-2)
Are selected in the order of the output of the D flip-flop 14a1 and the output of the D flip-flop 14a1 in the opposite order.

Note that the configuration of the oblique reading correction unit 13 realized using the shift register is merely an example, and the present invention is not limited to this.

(Effects of the invention) As is clear from the above description, according to the invention, the CC
When the D line sensor is arranged at an angle to the document surface, the document information length corresponding to one CCD pixel of the CCD line sensor can be transferred over the entire length of the CCD line sensor in real time without using page memory. There is an effect that it can be made almost constant.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is an explanatory view of the principle of the present invention, FIG. 3 is an explanatory view of the operation of the oblique reading correction unit of FIG. 1, and FIG. 5 and 6 are schematic diagrams of a device having a dynamic reading device and an electric reading device, FIGS. 5 and 6 are explanatory diagrams of problems of the conventional device, and FIGS. 7 and 8 are detailed explanatory diagrams of the operation of one embodiment of the present invention. It is. 10 Timing circuit, 11 CCD line sensor, 12
... Color separation unit, 13 ... Skew reading correction unit.

Claims (1)

(57) [Scope of request for utility model registration] 1. An oblique reading correction device for an image reading apparatus in which a line sensor is arranged in a vertical plane of a document surface in a main scanning direction and non-parallel to the document surface. The pixel data read from the pixel data is sequentially overlapped or thinned out at intervals according to the degree of non-parallelism such that the length of the document information per pixel of the line sensor becomes substantially constant over one line. An oblique reading correction device, comprising: a reading unit that reads the data.