JPH05110780A - Original recognition device - Google Patents

Abstract

PURPOSE:To surely and accurately recognize an original position and an original size by detecting accurately an end of an original. CONSTITUTION:An original information read means 10 reads optically original information and converts it into picture information of an electric signal. A picture element discrimination means 11 compares a density of the picture information inputted sequentially with a predetermined threshold level in the unit of picture elements and discriminates whether or not the relevant picture element is a picture element in an original area based on the density difference. When the picture element discrimination means 11 makes discrimination of the picture element in the original area consecutively for a predetermined number of times, an original end detection means 12 obtains the end of the original based on the scanning position and the predetermined number of times. An original area discrimination means 13 discriminates the original area based on the calculated position of the end of the original. A picture information extract means 14 extracts only the picture information in a range discriminated to be the original area and gives an output to a recording means 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document recognizing device suitable for a facsimile machine or a copying machine, and more particularly to accurately and reliably recognizing a document position and a document size by accurately detecting the document edge. The present invention relates to a document recognition device.

[0002]

2. Description of the Related Art Recently, LB is used after reading document information with an image sensor such as a CCD and converting it into image information of an electric signal.
2. Description of the Related Art So-called digital type copying machines and facsimile machines, which record with a printer such as a P (laser beam printer), have become widespread.

Further, in such a digital type copying apparatus or the like, document recognition is performed in which only the document information is selectively printed out by detecting the position and document size of a document placed at an arbitrary position on the platen glass. Devices with functions are emerging.

Conventionally, in this type of document recognition function, as described in, for example, Japanese Patent Laid-Open No. 62-76962, the platen glass side (hereinafter referred to as the back platen) of the document pressing plate (platen cover) is placed. The background should be black except for the original position as black or as a mirror surface.
The document position is recognized by detecting the change in the density of the image information detected in.

Further, in Japanese Patent Laid-Open No. 63-280569, the back platen is colored with a specific color, and a filter for cutting the reflected light from the back platen is provided. The position of the original was recognized based on the reflected light from the original.

However, such a recognition method has a problem that if the platen glass or the back platen is contaminated, it is erroneously recognized as document information.

In order to solve such a problem, for example, in Japanese Unexamined Patent Publication No. Hei 2-277038, only when the document information is continuously detected a predetermined number of times (the number of pieces), the original information is detected. A method of recognizing an area is disclosed.

[0008]

However, in the method of recognizing the original area based on the continuity of the original information as described above, the original area is determined when the original information is continuously detected. A deviation occurs between the detection position and the actual document edge. Therefore, there is a problem that the document edge cannot be accurately detected, and as a result, the document area cannot be accurately recognized.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide an original document recognition apparatus capable of accurately and reliably recognizing the original document area by accurately detecting the edge of the original document. It is in.

[0010]

In order to achieve the above-mentioned object, the present invention provides the following means in a document recognition device for recognizing a document area based on reflected light from a document and a back platen. There is a feature in the point. (1) Pixel determination means for determining pixels in the document area, and document edge detection for detecting the document edge based on the position and the number of times when the pixels in the document area are continuously confirmed a predetermined number of times And a document area determination means for determining the document area based on the detected position of the document edge. (2) Pixel determining means for determining pixels in the original area, temporary original edge storage means for storing the position as a temporary original edge when the pixels in the original area are confirmed, and after storing the temporary original edge, Further, there is provided a document area determining unit which determines the document area by regarding the provisional document edge as a true document edge when the pixels in the document area are continuously confirmed a predetermined number of times.

[0011]

According to the above configuration (1), when the pixels in the original area are continuously confirmed the predetermined number of times and it is confirmed that the pixels are in the original area, the pixels are moved up from the position by the predetermined number of times. Since the position is determined to be the document edge, the document edge can be accurately detected.

According to the above configuration (2), after the pixels in the original area are confirmed and the position is stored as a temporary original edge, the pixels in the original area are continuously confirmed a predetermined number of times. When it is confirmed that the document area is the document area, the temporary document edge is determined to be the true document edge, so that the document edge can be accurately detected.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings. FIG. 1 is a functional block diagram of the present invention.

In FIG. 1, the document information reading means 10 is
Original information is optically read from the reflected light of the light applied to the original and the back platen, and converted into image information of an electric signal. The pixel determination means 11 is the original information reading means 10 described above.
The density of the image information sequentially output from is compared with a predetermined threshold value on a pixel-by-pixel basis, and it is determined whether or not the pixel is a pixel in the original area based on the density difference.

When the pixel determination unit 11 continuously determines that the pixels are in the document area by a predetermined number (number) Nth, the document edge detection unit 12 determines the scanning position and the predetermined number of times. The document edge is calculated based on The document area determination means 13 determines the document area based on the calculated position of the document edge.

The image information extracting means 14 selectively extracts and records only the image information in the range determined to be the original area by the original area determining means 13 among the image information output from the original information reading means 10. Output to the means 15.

The operation of FIG. 1 will be described below with reference to the flowchart of FIG.

In step S10, the image information sequentially output from the document information reading means 10 in response to the main scanning and the sub-scanning is sequentially input to the pixel determining means 11 pixel by pixel.

In step S11, the density of the input image information is compared with a predetermined threshold value in pixel units by the pixel determination means 11. As a result, when it is determined that the pixel is a pixel within the document area, the count value N is incremented by 1 by the document edge detection unit 12 in step S13. If it is determined that the pixel is not a pixel in the original area, step S12.
At, the count value N is reset, and then the process returns to step S10.

In step S14, it is judged by the document edge detecting means 12 whether or not the count value N has reached the scheduled number of times Nth. If the count value N has not reached the scheduled number of times Nth, the process returns to step S10 and it is reached. It proceeds to step S15.

In step S15, the coordinates obtained by subtracting the scheduled number of times Nth from the coordinates of the pixel in question, in other words, the coordinates of the pixel are moved up by the number of pixels corresponding to the scheduled number of times Nth. The coordinates are registered in the document edge detecting means 12 as the coordinates of the document edge.

In step S16, the document area determining means 1
3 determines the document area based on the registered coordinates of the document edge. In step S17, the image information extraction means 15
However, of the image information output from the document information reading unit 10, only the image information in the range determined as the document region by the document region determination unit 13 is extracted and output to the recording unit 15.

FIG. 5 is a block diagram of an embodiment for realizing the document edge detecting function of the present invention.

In the figure, the sub-scanning address counter 4
A sub-scanning synchronization signal HCL is input to 1, and the counter 41 outputs address information indicating the sub-scanning position to the minimum value register 50a and the maximum value register 50b.

The main scanning synchronizing signal VCL is input to the main scanning address counter 42, and the address information indicating the main scanning position is output from the counter 42 to the maximum value register 50b and one input terminal of the subtraction circuit 49. ..

In the continuous pixel setting register 43, the predetermined number of times Nth is registered in advance for recognizing the area as a true original area when the original information is continuously detected a predetermined number of times. , The number of times Nth is the subtraction circuit 4
9 and the preset terminal PI of the down counter 46. The subtraction circuit 49 uses the count value of the main scanning address counter 42 to obtain the predetermined number N of times.
The value obtained by subtracting th is output to the minimum value register 50a.

In the original detection threshold register 44, density data ND serving as a threshold value for determining the original area is registered in advance, and the density data ND is input to one input terminal P of the comparator 45. The video data VD is input to the other input terminal Q of the comparator 45.

The output signal of the comparator 45 is input to the data load terminal LD of the down counter 46 and
It is input to the reset terminal R of the SR latch 47 via the inverter 48. Clock terminal C of the down counter 46
The main scanning synchronization signal VCL is input to LK, and the output signal is input to the set terminal S of the SR latch 47. S
The Q output signal of the R latch 47 is input to the minimum value register 50a and the maximum value register 50b.

FIG. 4 is a diagram showing the positional relationship between the scanning points A to D and the original 80 and the back platen 81.

In such a structure, the density data ND output from the original detection threshold register 44 and the video data VD are successively compared by the comparator 45. At this time, at the scanning point A in FIG. 4, since the reflected light from the back platen 81 is detected, the density of the video data VD becomes higher than the density data ND, and the output of the comparator 45 remains at the “L” level. is there.

After that, when the scanning point B is reached, the reflected light from the original 80 is detected, so that the density of the video data VD becomes lighter than the density data ND, and the output level of the comparator 45 changes from "L" level to "L" level. Transition to H "level.

When the down counter 46 detects the rising edge of the data load terminal LD, the down counter 46 continues pixel setting register 4
The preset number of times Nth, which is registered in advance in 3, is preset. This preset value is down-counted by the main scanning synchronization signal VCL input to the clock terminal CLK, and when the preset value becomes "0" at the scanning point C, the output CO of the down counter 46 becomes "H" level and the SR latch. 47 is set.

The minimum value register 50a is provided in the SR latch 47.
When the rising edge of the output signal is detected, the count value of the sub-scanning address counter 41 and the output value of the subtraction circuit 52 (that is, the Y and X coordinates of the scanning point B which has moved up from the scanning point C by the number Nth) are respectively determined. It is registered as the minimum position in the sub-scanning direction and the minimum position in the main-scanning direction.

In this way, manuscript information is sequentially input,
When the scanning position reaches the opposite end D of the document end, the density of the video data VD becomes darker than the density data ND,
The output level of the comparator 45 transits from the “H” level to the “L” level and the SR latch 47 is reset.

When the maximum value register 50b detects the fall of the SR latch 47, the count values of the sub-scanning address counter 41 and the main scanning address counter 42 (that is, the Y and X coordinates of the scanning point D) are respectively sub-divided. It is registered as the maximum position in the scanning direction and the maximum position in the main scanning direction.

According to this embodiment, even when the document area is recognized based on the continuity of the document information, the edge of the document can be detected accurately, so that the document area can be recognized accurately and surely. Like

FIG. 2 is another functional block diagram of the present invention, and the same reference numerals as those in FIG. 1 represent the same or equivalent portions.

In the figure, the temporary document edge storage means 16 is
When the pixels in the document area are confirmed by the pixel determining means 11, the scanning position is stored as a temporary document edge. After storing the provisional document edge, the document region determination means 17 further confirms the pixels in the document region continuously for a predetermined number of times Nth,
The tentative document edge is regarded as the true document edge, and the document area is determined.

FIG. 6 is a flow chart for explaining the operation of FIG. 2, and since the same processing is executed in the steps given the same reference numerals as those in the flow chart of FIG. 3, the description thereof will be omitted.

If it is determined in step S11 that the image information is within the document area, it is determined in step S21 whether the count value N is 0. If it is 0, in step S22 the pixel Are stored in the temporary document edge storage means 16 as the coordinates of the temporary document edge.

After that, when the count value N reaches the predetermined number Nth, the temporary document edge is regarded as the true document edge in step S15a, and the document area is determined based on the document edge in step S16.

FIG. 7 is a block diagram of an embodiment which realizes the above-mentioned document edge detecting function, and the same reference numerals as the above represent the same or equivalent portions, and therefore the explanation thereof will be omitted. The present embodiment is characterized in that the register 60 is used instead of the subtraction circuit 49 of FIG.

In such a structure, the scanning point B (see FIG.
(See reference), the density of the video data VD becomes lighter than the density data ND, and the output level of the comparator 45 transits from the “L” level to the “H” level. As a result, the count value of the main scanning address counter 42 (that is, the X coordinate of the scanning point B) is set in the register 60.

After that, when the pixels representing the original area are continuously detected and reach the scanning point C, the output CO of the down counter 46 rises and the SR latch 47 is set. As a result, the value of the register 60 is read into the minimum value register 50a as the minimum position in the main scanning direction, and the coordinates of the document edge are registered.

As is apparent, according to this embodiment, the document edge can be accurately detected as in the case of the first embodiment, so that the document area can be accurately and surely recognized.

[0046]

As described above, according to the present invention, even when the document area is recognized based on the continuity of the document information, the edge of the document can be accurately detected. You will be able to recognize it accurately and surely.

[Brief description of drawings]

FIG. 1 is a functional block diagram of the present invention.

FIG. 2 is another functional block diagram of the present invention.

FIG. 3 is a flowchart showing the operation of FIG.

FIG. 4 is a diagram for explaining the operation of FIG.

FIG. 5 is a block diagram of an embodiment for realizing a document edge detection function of the present invention.

FIG. 6 is a flowchart showing the operation of FIG.

FIG. 7 is a block diagram of another embodiment that realizes a document edge detection function.

[Explanation of symbols]

10 ... Original information reading means, 11 ... Pixel determination means, 12 ...
Document edge detecting means, 13 ... Original area determining means, 14 ... Image information extracting means, 15 ... Recording means, 41 ... Sub-scanning address counter, 42 ... Main scanning address counter, 43 ... Continuous pixel setting register, 44 ... Original detection threshold Register, 45 ... Comparator, 46 ... Down counter, 47
... SR latch, 48 ... Inverter, 49 ... Subtraction circuit, 5
0a ... minimum value register, 50b ... maximum value register

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kuniomi Hasegawa, 3-7-1, Fuchu, Iwatsuki-shi, Saitama Prefecture, Iwatsuki Plant, Fuji Zerox Co., Ltd. (72) Hiroshi Hayashi, 3-7-1, Fuchu, Iwatsuki, Saitama Prefecture No. Fuji Xerox Co., Ltd. Iwatsuki Plant (72) Inventor Atsushi Takahashi 3-7-1, Fuchu, Iwatsuki City, Saitama Prefecture Fuji Zerox Co., Ltd. Iwatsuki Plant, (72) Inventor Koji Yormoto 3, Iwatsuki City, Saitama Prefecture 7th-1 Fuji Xerox Co., Ltd. Iwatsuki Plant

Claims (2)

[Claims] 1. A document recognizing device in which a back platen is formed of a predetermined coloring member and which recognizes a document area based on light reflected from a document and the back platen, wherein the reflected light is optically read and an image of an electric signal is read. Document information reading means for converting into information, pixel determining means for comparing the image information with a predetermined reference value to determine pixels in the original area, and when pixels in the original area are continuously confirmed a predetermined number of times An original document characterized by comprising original document edge detection means for detecting an original document edge based on the scanning position and the scheduled number of times, and original document area determination means for determining an original document area based on the position of the original document edge. Recognition device. 2. A document recognizing device in which a back platen is formed of a predetermined coloring member and which recognizes a document area based on light reflected from a document and the back platen, wherein the reflected light is optically read and an image of an electric signal is read. An original information reading unit for converting into information, a pixel determining unit for comparing the image information with a predetermined reference value to determine a pixel in the original region, and a pixel in the original region is confirmed, the scanning position is temporarily changed. After storing the temporary document edge, the temporary document edge storage unit stores the temporary document edge as a document edge, and when the pixels in the document area are continuously confirmed a predetermined number of times after the temporary document edge is stored, the temporary document edge is determined as a true document edge. An original document recognizing apparatus comprising: an original area determining unit that determines an original area.