JPS61232775A - Picture reader - Google Patents

Abstract

PURPOSE:To remove a black shadow produced with respect to a circumference and to read the picture information by storing a reading signal from an original start position by a memory means in accordance with a detecting result, deciding the size of the original by the reading signal and making the circumference of the data of the memory means corresponding to the size of the original a white picture element. CONSTITUTION:An original start position detecting circuit 12 detects a start position of an original when white picture elements are supplied in a bundle every one line supplied from a scanner section 11 and supplies to an output circuit 13. The output circuit 13 outputs a signal from the original start position, namely a start position of the white picture element to a memory 14 and the reading signal with respect to the original is stored. An original end processing circuit 29 obtains coordinates Fa, Fb of an original end section (f) in the memory 14 in accordance with the original completing position supplied from AND circuits 27, 28. According to the coordinates, the coordinate of an entire original is decided and several mm of the circumference of a storage range of the original in the memory 14 is made white picture element. The picture signal with respect to the original in the memory 14 can remove an excessive black picture element in the circumference of the original.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an image processing system that is used in, for example, a facsimile machine, an image information file device, etc., and reads image information on a document placed on a document table as a binary image signal. Regarding a reading device.

[Technical background of the invention I! ] Recently, a device has been developed and put into practical use that reads image information on a document placed on a document table by optical two-dimensional scanning and binarizes the read image signal.

[Problems in the background art] However, when reading an image of a document with the above-mentioned device, due to slight differences in the size of the document or inappropriate position, as shown in FIG. 7(a), The drawback was that a black linear shadow appeared around the document. Especially when reading a book, the shadow becomes large, as shown in FIG. 7(b). If the image signal read in this state is used, it not only looks unsightly, but also has the disadvantage that the encoding efficiency deteriorates during encoding.

[Purpose of the Invention] This invention was made in view of the above circumstances, and its purpose is to remove the black spots that occur around the document when reading the document, and to read image information. An object of the present invention is to provide an image reading device.

[Summary of the Invention] In order to achieve the above object, the present invention converts image information of a document on a document table into binary information and outputs the binary information, which converts the image information on the document into an electrical signal, The document start position is detected by this converted reading signal, the reading signal from the document start position is stored in the storage means based on this detection result, the size of the document is determined by this stored reading signal, and the size of the document is determined. The area around the data in the storage means corresponding to the data is set as a white pixel.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 2 shows a document placement section in the image reading apparatus of the present invention. That is, 1 is a main body of an image forming apparatus such as a printer, and an original table (transparent glass plate) 2 for supporting an original P is provided on the upper surface of this main body. A document cover 3 that can be opened and closed is provided near the document table 2 . The back surface of the document cover 3, that is, the side that contacts the document table 2, is formed in black. A scanner section constituted by a line sensor (not shown) is provided on the lower surface side of the document table 2. As shown in FIG. With this, for example, when the original P is placed on the original platen 2 and the original cover 3 is closed, the original platen 2
When viewed from the bottom side, as shown in FIG. 3, the area other than the original P is black.

FIG. 1 shows the main parts of the electric circuit. Reference numeral 11 denotes a scanner section, which is composed of a line sensor made up of a COD (not shown) and a binarization circuit that binarizes the output of this line sensor. This converts the signal into a binary signal. An image signal for each line output from the scanner section 11 is supplied to a document start position detection circuit 12 and an output circuit 13. The document start position detection circuit 12 detects the start position of the document P when a group of white pixels are supplied for each line supplied from the scanner section 11. A position detection signal is supplied to the output circuit 13.

The output circuit 13 outputs a signal to the scanner section 1 when a start position detection signal is supplied from the document start position detection circuit 12.
A signal from the document start position, that is, the white pixel start position of the reading signal supplied from 1 is outputted, and this output is supplied to the memory 14. This memory 14 stores image signals for one screen supplied from the output circuit 13. For example, as shown in FIG. 4, an image signal corresponding to a document P is stored. Image storage end address corresponding to each line (for example, the 4th
Point 0 or point e shown in the figure) is stored in a separate area.

On the other hand, 15 is a determination unit that determines the size of the document in the memory 14 using the stored contents of the memory 14. This determining unit 15 determines the position of W where white pixels clustered upward from the corresponding image storage end address (for example, point 0 or point e shown in FIG. 4) for each vertical line in the memory 14 are detected. By checking the width, the height H of the document is detected, and the document is grouped to the left from the corresponding image storage end address (for example, point d or point e shown in FIG. 4) for each horizontal line in the memory 14. By checking the position where a white pixel is detected for the width h, the width W of the document is detected and the size of the document is determined.
5.26 and AND circuits 27.28.

That is, the counter 21 is a counter that defines the width W for the height detection. The counter 22 is a counter that specifies the address of the pixel signal supplied to the white detection circuit 25. The white detection circuit 25 is connected to the memory 14
The end position of the document is detected when a group of white pixels are supplied from signals for each line of several lines (width W) in the vertical direction supplied from the end position detection signal as a result of this detection. is outputted to one end of the AND circuit 27. The other end of the AND circuit 27 is supplied with an address signal from the counter 22. As a result, when the AND circuit 27 receives the end position detection signal from the white detection circuit 25, the AND circuit 27 registers the counter 22 corresponding to the end position of the document in the memory 14, that is, the start position of the white pixel.
It outputs the address value supplied from.

Further, the counter 23 is a counter that defines the width of the width detection. The counter 24 is the white detection circuit 2
This counter specifies the address of the pixel signal supplied to the pixel signal 6. The white detection circuit 26 detects the end position of the document when a group of white pixels is supplied from the signal for every several lines (width h) in the horizontal direction supplied from the memory 14. As a result,
The end position detection signal is outputted to one end of the AND circuit 28. The other end of the AND circuit 28 is supplied with an address signal from the counter 24. Thereby, when the end position detection signal is supplied from the white detection circuit 26, the AND circuit 28 outputs the address value supplied from the counter 24 corresponding to the document end position in the memory 14, that is, the start position of the white pixel. It is something.

Further, 29 is a document edge processing circuit, which uses the coordinates (Fa,
Fb) is determined, and the coordinates of the entire document are determined based on these coordinates, and as shown in FIG.
A few millimeters around the storage range of the original in the image is set as white pixels (masked with a constant width).

Next, the operation in such a configuration will be explained.

For example, right now, a document P is placed on the document table 2 and the document cover 3 is placed on the document table 2.
Close. Then, according to instructions from a start key (not shown),
The scanner unit 11 starts reading.

Thereby, the scanner unit 11 binarizes the signal read from the original P and outputs it to the original start position detection circuit 12 and the output circuit 13. Then, the document start position detection circuit 12 detects the start position of the document P when a group of white pixels are supplied for each line supplied from the scanner unit 11, and generates a start position detection signal as a result of this detection. is supplied to the output circuit 13. As a result, when the output circuit 13 receives the start position detection signal from the document start position detection circuit 12, the output circuit 13 transfers the signal from the document start position, that is, the white pixel start position, of the reading signal supplied from the scanner section 11 to the memory 14. Output to. As a result,
The read signal for the original P is stored as shown in FIG.

Next, the determination unit 15 determines the vertical direction in the memory 14.
By checking the position where white pixels clustered upward from the image storage end address corresponding to each line (for example, point 0 or point e shown in FIG. 4) are detected for the width of W,
Detects the height H of the document and stores it in the horizontal direction in the memory 14.
By checking the position where white pixels clustered to the left are detected for a width of h from the image storage end address corresponding to each line (for example, point d or point e shown in FIG. 4),
The width W of the original is detected and the size of the original is determined.

That is, the data at the address indicated by the counter 22 in the line corresponding to the count value of the counter 21 is sequentially read out from the memory 14 and output to the white detection circuit 25. As a result, when a group of white pixels is supplied from signals for each line of several lines (width W) in the vertical direction, the white detection circuit 25 detects the starting point of the white pixel as the end position of the document. Then, an end position detection signal as a result of this detection is output to one end of the AND circuit 27. As a result, the AND circuit 27 is connected to the white detection circuit 25.
When the end position detection signal is supplied from the counter 22
The count value supplied from the memory 14 is outputted to the document edge processing circuit 29 as an address value corresponding to the document end position of the memory 14, that is, the start position of the white pixel.

Further, the data at the address indicated by the counter 24 in the line corresponding to the count value of the counter 23 is sequentially read out from the memory 14 and outputted to the white detection circuit 26. As a result, when a group of white pixels is supplied from signals for each line of several lines (width h) in the horizontal direction, the white detection circuit 26 detects the starting point of the white pixel as the end position of the document. As a result of this detection,
The end position detection signal is output to one end of the AND circuit 28.

As a result, when the end position detection signal is supplied from the white detection circuit 26, the AND circuit 28 uses the count value supplied from the counter 24 as an address value corresponding to the document end position in the memory 14, that is, the start position of the white pixel. It is output to the document edge processing circuit 29.

Therefore, the document edge processing circuit 29 is the AND circuit 27.2.
The coordinates (Fa, Fb) of the document end f in the memory 14 are determined based on the document end position supplied from 8, and the coordinates of the entire document are determined based on these coordinates.
As shown in the figure, a few millimeters around the storage range of the original in the memory 14 are set as white pixels (masked with a constant width).
. As a result, the image signal for the original in the memory 14 can remove the extra black pixels around the original.

Furthermore, since there is no redundant information, encoding efficiency is improved, allowing efficient image communication and image recording.

In addition, since the edge of the document is detected in several lines, that is, at a predetermined width, as shown in Figure 6, data of continuous thin black pixels from the edge of the document (for example, data for the closed page of an open book) Even if there is a problem, the edge of the document can be reliably detected.

In the above embodiment, the document end position is detected by detecting a group of white pixels. The point at which the value exceeds a certain value may be set as the document end position.

Further, although the document start position is detected before storing data in the memory, the detection is not limited to this, and detection may be performed after data is stored in the -H memory. In this case, to find the position and size of the document, you can detect the line in which white pixels are clustered from three directions in Figure 3, and then use relative addresses, or A method may also be used in which a line in which a pixel exists is detected and shifted on the memory. Furthermore, detection of the document start position is not necessarily necessary. In this case, it is necessary to detect a cluster of white pixels from four directions, top, bottom, right and left, but in order to ensure the shadow removal function, it is necessary to make the document cover black.

Alternatively, the document cover may be eliminated and non-reflective black pixels may be used.

[Advantageous Effects of the Invention 1] As described in detail above, according to the present invention, it is possible to provide an image reading device that can read image information by removing black shadows that occur around the document when reading the document.

[Brief explanation of the drawing]

FIG. 1 to FIG. 6 show an embodiment of this invention.
Figure 1 is a diagram schematically showing the overall configuration, Figure 2 is an external view showing the configuration of the document placement section, and Figure 3 is a diagram showing the bottom surface of the document table with a document placed on the document table. 4 is a diagram showing an example of the storage state in the memory, FIG. 5 is a diagram for explaining an example of a mask by the document edge processing circuit, and FIG.
The figure is a diagram for explaining the original reading state. P... Original N (object to be read), 2... Original table, 3...
Document cover, 11...Scanner section, 12...Document start position detection circuit, 13...Output circuit, 14...
Memory, 15... Judgment unit, 21.22.23.24.
... Counter, 25.26 ... White detection circuit, 27.2
8...AND circuit. Applicant's Representative Patent Attorney Takehiko Suzue Figure 1 15' Figure 5 Figure 6 Figure 7

Claims (2)

[Claims] (1) An image reading device that converts image information of a document on a document table into binary information and outputs the binary information, which includes a reading device that converts image information on the document into an electrical signal, and a reading signal from the reading device. A detection means for detecting a document start position, a storage means for storing a read signal from the document start position detected by the detection means, and a determination means for determining the size of the document based on the read signal stored in the storage means. , means for setting white pixels around the data in the storage means corresponding to the size of the document determined by the determination means. (2) The image reading device according to claim 1, wherein the size determination by the determining means is performed by detecting an edge of the document detected by a group of white pixels.