JPH089108A - Image reader - Google Patents

Abstract

PURPOSE:To obtain the image reader in which quick and efficient reading is attained without excess read scanning even in the case of an original whose size is not in compliance with prescribed standards. CONSTITUTION:A prescribed background pattern P continuous in the lengthwise direction of a contact glass B is described on a rear side of an original retainer A. The reader is provided with an image processing section in which an original G is set on an upper side of the contact glass B, the original retainer A is covered thereon and the background pattern P is identified and detected from image data subject to read scanning.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to a copying machine, a facsimile machine, and other optical reading devices, and relates to an image reading device which can determine the end of a document and the effective area of the document without requiring a special sensor. .

[0002]

2. Description of the Related Art In a flatbed scanner applied to an image reading apparatus such as a facsimile apparatus, the reading range of a document is designated by a standard paper size such as A4 width or B4 width by a key operation, or by a reflection type. It is determined by detecting the paper size using a sensor.

[0003]

However, in the above-mentioned conventional image reading apparatus, if the document width is not in accordance with the standard such as A4 width or B4 width, the extra portion is read. Therefore, the processing time of the read image data is wasted, the communication time is used when communicating, and the recording paper is wasted when printing out.

On the other hand, the one using a reflection type sensor or the like cannot detect the paper size unless a special sensor is used, which is an obstacle to cost reduction. The present invention has been proposed in view of the above points, and an image reading apparatus that can perform a quick and wasteless reading without performing unnecessary reading scanning even when a document has a size that does not meet a predetermined standard. Its purpose is to provide.

[0005]

SUMMARY OF THE INVENTION An image reading apparatus according to claim 1 of the present invention, which has been proposed to achieve the above object, is characterized in that a back surface of a document holding plate is continuously specified in a longitudinal direction of a contact glass. In addition to describing the background pattern, the document is set on the upper surface of the contact glass, the document holding plate is covered, and the image processing unit for identifying and detecting the background pattern from the read and scanned image data is provided.

It is sufficient that the back surface of the document holding plate comes into contact with the document placed on the contact glass and the contact glass surface and can be read as image data at the same time as the document at the time of reading and scanning. May be read. Also, the background pattern continuous in the longitudinal direction of the contact glass means that when a document is placed on the contact glass, it extends outside the vertical or horizontal width of the document (depending on the document setting position) and May be detected.

The second and third aspects are characterized by the background pattern. In the second aspect, the pattern stripes whose density changes stepwise are formed on the upper and lower sides. ) Is formed of a material having a different light reflectance.

[0008]

In the image reading apparatus according to claim 1 of the present invention having the above-mentioned structure, since the back surface of the document holding plate has a specific background pattern, the document is placed on the upper surface of the contact glass. The edge of the document can be detected by identifying and detecting the specific background pattern during the reading and scanning operation of the image processing section with the holding plate covered.

In the image reading apparatus according to the second aspect,
Since the background pattern has a structure in which the pattern stripes with the density changed stepwise are written above and below, there are few errors during reading, and even if the document setting position is not limited, the effective reading range of the document can be accurately determined. Then, the edge of the document can be detected. In the image reading apparatus according to the third aspect, since the light reflectance of the background pattern is different from that of paper, the output level of the signal becomes clear and the reading range of the document can be easily detected.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The image reading apparatus is a flatbed scanner F as shown in FIG. 1, and an original reading table C composed of a transparent contact glass B on which an original G is placed.
A document holding plate A having a pressure plate 1 for pressing the document G attached to the back side thereof is attached to the document reading table C so as to be openable and closable.

The image reading apparatus of the present invention is characterized in that a specific background pattern P is marked on the back surface of the document holding plate A.
In the following, various modifications of the background pattern P will be described with examples. [Embodiment 1] An embodiment in the case of performing reading scanning with the background pattern P according to claim 1 will be described with reference to FIGS.

As shown in FIG. 2, the background pattern P is a pattern continuous in the longitudinal direction of the contact glass. When the original plate G is read and scanned using the pressure plate 1 on which the background pattern P is noted, the reading is performed. The sensor will read an image as shown in FIG. The read image signal at this time is output as a waveform shown in FIG. Figure 4 (a)
3 is a waveform when the line shown by the arrow A in FIG. 3 is scanned, and the original portion (G) and the pressure plate portion (1) are simultaneously output. When the reading scanning progresses and the line indicated by the arrow A is scanned, the waveform becomes as shown in FIG. 6B, and the specific background pattern (P) described on the pressure plate 1 is output. The image processing unit, which will be described later, can detect the effective reading range by determining the end of the document in the sub-scanning direction by detecting the background pattern (P) or the waveform. [Embodiment 2] Next, an embodiment in which the reading and scanning is performed with the background pattern P according to claim 2 will be described with reference to FIGS.

A pressure plate 1 having a background pattern P shown in FIG.
When the reading scanning of the original G is performed using, the reading sensor reads an image as shown in FIG. The background pattern P shown in FIG. 5 has a structure in which pattern stripes whose density changes stepwise are written above and below the pressure plate 1, so that the output level of the image signal to be read changes stepwise according to the density. Has become. The image signal obtained by this reading has the waveform shown in FIG. FIG. 7A shows a waveform when the line shown by the arrow C in FIG. 6 is scanned, and the original portion (G) and the pressure plate portion (1, P) are simultaneously output. Since the pressure plate portion (1, P) has a stepwise output level, the end of the document G in the main scanning direction can be determined. When the reading scan progresses and the line indicated by arrow D is scanned, the waveform becomes as shown in FIG. 7B, and only the specific background pattern P marked on the pressure plate 1 is output. By detecting the background pattern P or the waveform, the edge of the document G in the sub-scanning direction is determined. Therefore, when the background pattern P as shown in FIG.
Both vertical and horizontal edges of the document can be determined, and the same range as the original G can be set as the effective reading range.

If the background pattern P is used,
It is not necessary to limit the setting position of the document G, and even when the document G is set at the position where the image shown in FIG. , The original portion (G) and the pressure plate portion (1, P) can be easily distinguished, and the original width can be determined. Further, the original setting position need not be parallel or perpendicular to the scanning direction, and the vertical width and the horizontal width can be determined even when the original G is obliquely set as shown in FIG.
The above determination can be easily performed by connecting the left peak x1 and the right peak x2 for the main scanning and the detection point y1 of the first document data and the detection point y2 of the last document data for the sub scanning. Further, by rotating this original data, it is possible to make correction so as to match the scanning direction.

The document width determined by using the background pattern P as shown in FIG. 5 is once obtained based on the image signal of the first line, and then the process of obtaining the second line and subsequent lines is necessarily executed. You don't have to. This is because the effective range can be set for the image data of the second and subsequent lines based on the document width obtained based on the image signal of the first line.

However, in practical use, it is preferable to judge the document width each time based on the image signal of each line even in the image data processing of the second and subsequent lines. According to such a method, even when the document G is obliquely read and scanned as described above, the end position of the document G can be reliably determined for each line. In the background pattern P described in the above embodiment, the density is changed and the pressure plate portion (1, P) is changed.
However, the background pattern P according to the present invention is not limited to this, and, for example,
Black lines having the same density may be marked on the pressure plate 1 in a certain pattern. [Embodiment 3] An embodiment in the case of performing reading scanning with the background pattern P according to claim 3 will be described with reference to FIGS. 11 to 13.

As shown in FIG. 11, when the background pattern P is written on the pressure plate 1 made of a material having a light reflectance different from that of paper, and the reading scanning of the original G is performed, the reading sensor reads an image as shown in FIG. It will be. The image signal read at this time is output as a waveform shown in FIG. FIG. 13A shows a waveform when the line shown by the arrow F in FIG. 12 is scanned, and the original portion (G) and the pressure plate portion (1) are simultaneously output. When the reading scanning progresses and the line indicated by the arrow mark is scanned, the waveform becomes as shown in FIG. 13B, and the background pattern (P) described on the pressure plate 1 is output. In this case, since the light reflectance of the pressure plate portion (1) is different from that of the original portion (G), the edge of the original can be detected more easily than the output waveforms shown in the first and second embodiments. .

Here, if the background pattern P is not written on the pressure plate 1, the length of the original G when the image processing section happens to read the original G having the same reflectance as that of the pressure plate 1. Can no longer be detected. As a countermeasure against this, one background pattern P (black band) as shown in FIG. 11 is marked on the pressure plate 1. By doing so, even if the reflectance of the original G and the pressure plate 1 become the same, the length of the original G can be detected by detecting the background pattern P (black band). The background pattern P is not necessarily a black band as long as it can be detected.

The image reading apparatus of the present invention which is characterized by the background pattern P as described above is provided with an image processing section for discriminating the document surface from the background pattern P. Next, the image processing section will be described. . FIG. 14 is a block diagram showing the basic structure. The image reading apparatus shown in the figure is a light source 2 for projecting light onto a document G arranged on the front side of a pressure plate 1 on which a specific background pattern P is marked, and a reflected light from the document G is received to receive the document. A CCD sensor 3 for reading and scanning the G image line by line is provided.

The CCD sensor 3 is followed by a CCD.
By controlling the gain control circuit 4 for giving a predetermined gain to the analog image signal output from the sensor 3, the clamp circuit 5 for fixing the reference level of the input waveform of the image signal, and slicing the analog image signal with a desired threshold value, A binary converter 6 for converting into a binary image signal of "0" and "1" (black and white), a document size judgment circuit 7, a document data editing circuit 8 and the like are provided.

Of the above, the document size determination circuit 7 is C
The CD sensor 3 determines the size of the document G from an image signal obtained by simultaneously reading and scanning the document G and the pressure plate 1 which is the background thereof. The original size determining circuit 7 includes the background pattern determining means 10, the dot memory 11, and the basic pattern memory 12 shown in FIG. 15, so that the image signal input from the clamp circuit 5 is analyzed and the edge portion of the original G is analyzed. The part corresponding to can be detected. The basic pattern memory 12 may store a partial waveform of only the background pattern P, or may store an entire waveform considering the position where the background pattern P appears.

The length of the document G (length in the sub-scanning direction) is determined by the document size determination circuit 7 as follows. In the dot memory 11, image signals read line by line are sequentially stored. The background pattern determining means 10 reads the basic pattern of the background pattern P from the basic pattern memory 12 when the image signal is stored for a predetermined number of lines, and compares it with the stored image signal. As a result, when the image signals match, the length of the document G can be determined as if the reading of the document edge is completed and the background pattern P is detected.
The manuscript size judging circuit 7 judges the length of the manuscript G, and then notifies the manuscript data editing circuit 8 of the manuscript length, and
The CCD sensor 3 is notified that the scanning of the original G is completed.

Subsequently, the width (length in the main scanning direction) of the original G is judged by the original size judging circuit 7 as follows. The image signal stored in the dot memory 11 and the image signal stored in the basic pattern memory 12 are compared with each other in the same manner as the above-described determination of the document length. This is performed by detecting a portion (original G portion) that does not match the P portion). After determining the width of the document G, the document size determining circuit 7 creates a pulse signal as shown in FIG. 16 and outputs the signal to the document data editing circuit 8. The pulses a1 and a2 of the signal shown in the figure correspond to the positions of both ends of the document G, and the width S between them corresponds to the document width.

The manuscript data editing circuit 8 outputs a pulse signal corresponding to the manuscript length and manuscript width output from the manuscript size judging circuit 7, and 2 output from the binary converter 6.
This is a circuit that reads in synchronization with the signal of the binarized image data and performs an editing process that makes only the portion of the image data corresponding to the original data valid. Specifically, the portion of the original G that is not image data, that is, the portion that exceeds the original length is discarded, and the portion that exceeds the original width, that is, the portion corresponding to the pressure plate 1, has a function of performing whitening processing. are doing. The whitening process means that when the binary a converter 6 outputs the pulse a1 corresponding to the left end of the document G when reading while counting the number of bits of the binarized image data, This is a process of forcibly setting the previous image data to "0" (when the white is "1", it is set to "1". The same applies hereinafter), and similarly setting the image data after receiving the pulse a2 to "0". .

[0025]

As can be understood from the above description, according to the image reading apparatus of the present invention, it is possible to detect the size of the original document.
Since a sensor for reading an original can be used without using a special sensor, an inexpensive and highly functional device can be provided. In addition, even if the size of the original is a nonstandard size that does not correspond to a certain standard, the edge of the original can be easily detected, eliminating the need for extra scanning for scanning, shortening the communication time when communicating, and printing. It is possible to save recording paper when outputting. Furthermore, since the setting position of the document is not limited, the same effect can be obtained by an easy operation.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a facsimile apparatus to which an image reading apparatus according to the present invention is applied.

FIG. 2 is a view showing an example of a pressure plate having a background pattern according to claim 1 of the present invention.

FIG. 3 is a diagram showing an example of a read image when the pressure plate shown in FIG. 2 is used.

FIG. 4 is an explanatory diagram showing an example of an image signal obtained by reading and scanning the image shown in FIG.

FIG. 5 is a diagram showing an example of a pressure plate having a background pattern according to claim 2 of the present invention.

FIG. 6 is a diagram showing an example of a read image when the pressure plate shown in FIG. 5 is used.

7 is an explanatory diagram showing an example of an image signal obtained by reading and scanning the image shown in FIG.

FIG. 8 is a diagram showing another example of a read image when the pressure plate shown in FIG. 5 is used.

9 is an explanatory diagram showing an example of an image signal obtained by scanning and scanning the image shown in FIG.

FIG. 10 is a diagram showing another example of a read image when the pressure plate shown in FIG. 5 is used.

FIG. 11 is a view showing an example of a pressure plate having a background pattern according to claim 3 of the present invention.

FIG. 12 is a diagram showing an example of a read image when the pressure plate shown in FIG. 11 is used.

13 is an explanatory diagram showing an example of an image signal obtained by reading and scanning the image shown in FIG.

FIG. 14 is a block diagram showing an example of a basic configuration of an image processing unit.

FIG. 15 is a block diagram showing an example of the configuration of a document size determination circuit.

FIG. 16 is an explanatory diagram showing an example of a pulse signal obtained by analyzing an image signal.

[Explanation of symbols]

 1 Pressure Plate 2 Light Source 3 CCD Sensor (Image Reading Means) 7 Original Size Judgment Circuit 8 Original Data Editing Circuit A Original Holding Plate B Contact Glass G Original P Background Pattern A to Reading Scan Line Position

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Claims (3)

[Claims] 1. An image read and scanned by writing a specific background pattern continuous in the longitudinal direction of the contact glass on the back side of the document holding plate, setting a document on the upper surface of the contact glass, covering the document holding plate, and scanning. An image reading apparatus configured to include an image processing unit for identifying and detecting a background pattern from data. 2. The image reading apparatus according to claim 1, wherein the background pattern has a structure in which pattern stripes whose densities are changed stepwise are written above and below. 3. The image reading apparatus according to claim 1, wherein the background pattern is made of a material having a light reflectance different from that of paper.