JP2000196863A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide image information, excluding useless black framing included in read and obtained image information through recognition of an out-of- original area in the image information obtained by reading effective read area and converting pixels belonging to the recognized out-of-original area in the image information into white pixels. SOLUTION: An image processing part 3 quantizes the image signals of a main scanning line unit from an image sensor 2 by an A/D conversion part and converts them to multi-level image information. The multi-level image information is inputted to a multi-level image processing part, the processings of gamma correction, a halftone processing and an MTF correction processing, etc., are performed there, and they are binarized and outputted by a binarization processing part. This image reader 1 is provided with an out-of-original area recognition means for recognizing the out-of-original area in the image information obtained by reading the effective read area, and an out-of-original area correction means for converting the pixels belonging to the out-of-original area in the image information recognized by the out-of-original area recognition means to the white pixels.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an image reading apparatus.

[0002]

2. Description of the Related Art In an image reading apparatus, when reading a document placed on a document reading surface (contact glass),
An effective reading area corresponding to a fixed area such as A4, B5, or A3 is determined by automatic detection by a document width sensor or setting by a user, and by reading the effective reading area, the effective reading area on the contact glass is read. It is possible to obtain the image information of the original that will be placed.

[0003]

However, as shown in FIG. 5, when the original placed on the contact glass is a so-called book original such as an open book, the original is automatically detected by an original width sensor. Alternatively, the effective reading area set by the user is generally a wide area including the area of the book document because the book document does not match the standard size.

In the case of a normal original sheet, the light for illuminating the original does not leak outside because the original is placed on the contact glass and then pressed by the original pressing plate. Since the document cannot be pressed by the document pressing plate, light outside the book document in the effective reading area leaks out without being reflected by the document. Therefore, the area outside the book document is read as a black area that does not reflect light.

[0005] As a result, as shown in FIG. 14, the obtained image information is such that the original area in the fixed area (effective reading area) is bordered black, and not only does the appearance look poor, but also When recording the obtained image information,
When recording is performed by the electrophotographic method, there is a problem that toner is wasted due to a black border having no meaning as the content of image information, and when recording is performed by the ink jet method, ink is wasted.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide an image reading apparatus capable of obtaining image information from which unnecessary black borders contained in image information obtained by reading are removed. And

[0007]

According to a first aspect of the present invention, there is provided an image reading apparatus for reading a predetermined effective reading area on a document reading surface to obtain image information. A non-document area recognition means for recognizing a non-document area in the image information obtained by reading the area, and a document for converting pixels belonging to the non-document area in the image information recognized by the non-document area recognition means to white pixels And an outside area correcting means.

According to a second aspect of the present invention, there is provided an image reading apparatus which obtains image information of a predetermined effective reading area by reading a predetermined effective reading range in units of a main scanning line while sub-scanning a document reading surface. For each piece of image information for each main scanning line, a non-document area correction unit that converts pixels belonging to a continuous black pixel row from the black pixel at the end of the effective reading range to white pixels is provided.

According to the third aspect of the present invention, there is provided an image reading apparatus.
5. The image reading device according to claim 1, wherein the non-document area correction unit includes a black pixel column in which image information of a plurality of main scanning lines adjacent to the main scanning line to be corrected is continuous from a black pixel at the end of the effective reading range. Only in the case of including the pixel information, the pixels belonging to the continuous black pixel column from the black pixel at the end of the effective reading range of the image information for the main scanning line to be corrected are converted into white pixels.

[0010] The image reading apparatus according to the fourth aspect is the third aspect.
5. The image reading device according to claim 1, wherein the non-document area correction unit converts pixels belonging to a continuous black pixel column from the black pixels at the end of the effective reading range of the image information for the main scanning line to be corrected to white pixels. In addition to the above, the image information of a plurality of main scanning lines adjacent to the main scanning line to be corrected, including a black pixel row continuous from the black pixels at the end of the effective reading range, is continuous from the black pixels at the end of the effective reading range. Also, pixels belonging to the black pixel column are converted to white pixels.

[0011] The image reading apparatus according to the fifth aspect is the second aspect.
In the image reading device described in the above, the area outside the document correction means, for each of the image information of each main scanning line,
A pixel that belongs to a continuous black pixel row from the black pixel at the end of the effective reading range is converted to a white pixel, and a pixel that belongs to a continuous black pixel row from the black pixel at the beginning of the effective reading range is also converted to a white pixel. It is characterized by being.

[0012] The image reading apparatus according to the sixth aspect is the second aspect.
5. The image reading device according to claim 1, wherein the non-document area correction unit includes a black pixel column in which image information of a plurality of main scanning lines adjacent to the main scanning line to be corrected is continuous from a black pixel at the end of the effective reading range. And / or only if it includes a continuous black pixel column from the black pixel at the beginning of the effective reading range,
Pixels belonging to a continuous black pixel row from the black pixels at the end of the effective reading range of the image information for the main scanning line to be corrected,
And / or converting pixels belonging to a continuous black pixel column from the black pixels at the beginning of the effective reading range of the image information for the main scanning line to be corrected into white pixels.

According to a seventh aspect of the present invention, there is provided an image reading apparatus according to the sixth aspect.
5. The image reading device according to claim 1, wherein the outside-of-document area correction unit includes a pixel belonging to a continuous black pixel column from a black pixel at the end of the effective reading range of the image information for the main scanning line to be corrected, and / or Pixels belonging to a continuous black pixel column from the black pixel at the beginning of the effective reading range of the image information for the main scanning line to be corrected are converted into white pixels, and black pixels continuous from the black pixel at the end of the effective reading range. The end of the effective reading range of the image information of a plurality of main scanning lines adjacent to the main scanning line to be corrected, including a column and / or a black pixel column continuing from the black pixel at the beginning of the effective reading range. Pixels belonging to a continuous black pixel row from black pixels and / or pixels belonging to a continuous black pixel row from the black pixel at the beginning of the effective reading range are also converted to white pixels.

According to an eighth aspect of the present invention, in the image reading apparatus according to any one of the first, second, third, fourth, fifth, sixth, and seventh aspects, the out-of-document area correcting means includes the effective reading section. A pixel belonging to a predetermined boundary range adjacent to a black pixel row continuing from the black pixel at the end of the range and / or a black pixel row continuing from the black pixel at the beginning of the effective reading range is also converted to a white pixel. It is characterized by the following.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
An embodiment of the present invention will be described in detail.

FIG. 1 shows a block configuration of an image reading apparatus 1 according to an embodiment of the present invention.

In FIG. 1, the image sensor 2 is
As shown in FIG. 5, a scan placed on a contact glass serving as a document reading surface is read in units of main scanning lines, and a scan that is sub-scanned by a sub-scanning mechanism (not shown) controlled by the scanner control unit 4. The image information at the line position is sequentially read, and the obtained image signal is input to the image processing unit 3.

As shown in FIG. 2, the image processing unit 3 converts the image signal from the image sensor 2 into A / D signals in units of main scanning lines.
The data is quantized by the conversion unit 31 and converted into multi-valued image information. The multi-valued image information is input to the multi-valued image processing unit 32, where processing such as gamma correction, halftone processing, and MTF correction is performed. After that, it is binarized by the binarization processing unit 33 and output.

As described above, the scanner control unit 4 controls the sub-scanning mechanism, the control of turning on / off the light source for illuminating the original, and the control related to the reading of the original image information such as the detection of the width of the original.
The plotter control section 5 is for recording and outputting the read image information on recording paper. However, the image reading device 1
The present invention is not limited by the use of the image information obtained by reading, and the image information obtained by reading is transferred to another device via an interface, displayed on a display, or transmitted by facsimile. It may be used for applications such as slipping.

The operation display unit 6 is provided with various keys for accepting operation inputs from a user, such as an instruction to start reading and designation of a size (A4, B5, etc.) of a document to be read. And a display unit such as a liquid crystal display for displaying an operation state and a message of the apparatus.

The system control unit 7 is a microcomputer which controls each unit of the apparatus based on the control procedure stored in the ROM 8 using the RAM 9 as a work area. ROM8
Is a read-only memory in which a control procedure for the system control unit 7 to control each unit of the apparatus is written. RAM
Reference numeral 9 denotes a random access memory serving as a work area of the system control unit 7. The RAM 9 also has an image processing unit 3
A storage area is reserved for a line buffer group 9a for storing several lines of image information in units of main scanning lines output from the main scanning line.

FIG. 3 shows a specific configuration of the line buffer group 9a.

In FIG. 1, a line buffer group 9a is
Line buffer (l), line buffer (l-1), line buffer (l-2), line buffer (l-3),
And a line buffer (1-4). The line buffer (l) stores the image information of the main scanning line currently being processed, and the line buffer (l-1) stores the image information of the line immediately before the currently processed main scanning line. Similarly, the line buffer (ln) (n = 2, 3, 4) stores image information for the line n lines before the main scanning line to be processed.

When the processing for the main scanning line to be processed is completed, the line buffer group 9a is shifted, and the image information output from the line buffer (1-4) in units of main scanning lines is read by the image reading apparatus 1. Becomes the image information to be finally output, and is used for the purpose of being recorded on the recording paper by the plotter control unit 5.

Returning to FIG. 1, the system bus 10 is a signal line through which each section of the device exchanges data with each other.

With the above configuration, the image reading apparatus 1 performs the reading processing procedure shown in FIG.

In the figure, a system control unit 7 monitors the state of the operation display unit 6 and indicates the start of reading [Start].
It is monitored whether the key is pressed (No in decision 101)
loop).

A user who wants the image reading apparatus 1 to read a document can read a sheet-shaped document or a spread book (book document).
When a [Start] key on the operation display unit 6 is pressed after placing a document such as
Then, it is determined whether or not the document pressing pressure plate is closed (decision 102). Although not shown, the original pressing plate is normally provided with an image reading apparatus of a type in which an original is placed and read on a contact glass, and is provided so as to be freely opened and closed on the contact glass. The status is ON / OF according to the opening / closing of the document pressing plate.
F is detected by a mechanical switch or an optical switch such as a photo interrupter.

If it is determined in decision 102 that the document pressing pressure plate is closed, that is, if the light from the light source for document illumination does not leak outside (Yes in decision 102), the scanner control unit 4 detects The effective reading range corresponding to the fixed original size such as A4, B5, or the like designated by the user via the operation display unit 6 (step 103), and the determined effective reading range is read. A normal document reading process for directly outputting the image information binarized by 3 is performed (process 104).

In the judgment 102, when the original pressing platen is open, that is, when a sheet-shaped original is placed but the user forgets to close the original pressing platen, or
When the original pressing plate cannot be closed because the book original is placed (No in decision 102), the light from the original illumination light source leaks out and is binarized by the image processing unit 3. If the output image information is output as it is, as shown in FIG. 14, the output image information becomes unsightly because the original area is surrounded by a black area having no meaning as the content of the image information. An effective reading range corresponding to a document width detected by the scanner control unit 4 or a standard size such as A4 or B5 specified by the user via the operation display unit 6 is determined (process 105), and the determined effective reading range is determined. , A book document reading process is performed (process 106). It should be noted that the book document reading process of the process 106 is substantially the same as the process 104 if the read document is not a book document smaller than the effective reading area or a normal document.
The result is similar to that of the normal document reading process. Therefore, it is possible to deal with only the book original reading process (process 106) without determining the open / closed state of the original pressing platen in the determination 102.

Next, a specific processing procedure of the book document reading processing of the processing 106 will be described. Before that, the effective reading area determined in the processing 105 and the processing 1
The relationship between various parameters and the like in the specific processing procedure of the book original reading process 06 will be described with reference to FIG.

In FIG. 3, the book original placed on the contact glass corresponds to a standard area (effective reading area) based on the original reference position, that is, a sheet of the minimum standard size that can accommodate the area of the book original. Is placed in the designated area. The effective reading area is configured by collecting the main scanning lines Lmax in total in the effective reading range Pmax.

The effective reading range Pmax is a reading width in terms of the number of pixels, and is determined by the determined width of the fixed area and the pixel density. Specifically, for example, if the determined fixed area is A4 and the pixel density is 8 pixels / mm, the effective reading range Pmax is 210 mm × 8 pixels / m
m = 1680 pixels.

The total number of main scanning lines Lmax is a read length in terms of the number of lines, and is determined by the determined length of the fixed area and the read line density. Specifically, for example, if the determined fixed area is A4 and the read line density is 3.85 lines / mm, the total number of main scanning lines Lma
x is 297 mm × 3.85 lines / mm = about 1143 lines.

The scan line L indicates a main scan line currently being processed from the first line to the Lmax line. The maximum reading range Rmax is
It corresponds to the width of the contact glass in terms of the number of pixels, and indicates the maximum readable range.

FIG. 6 shows a relationship between an image signal for one main scanning line and various parameters in a specific processing procedure of the book original reading processing of processing 106 described later.

In the drawing, the effective reading range Pmax of the image signals of the maximum reading range Rmax output from the image sensor 2 is processed as a valid image signal. FIG.
As shown in FIG. 5, if the book document is placed in the effective reading area without being aligned with the document reference position and the document pressing pressure plate is kept open, the effective reading range Pmax at the scan line position shown in FIG. It is composed of a document range having a meaning, and a black-level front document range Bf and a rear document range Bb sandwiching the document range and not reflecting light from a light source for document illumination. Therefore, the document range is determined by the image processing unit 3
When the binarization is performed, the binarization according to the content is performed and there is no problem. However, the pixels belonging to the front document range Bf and the rear document range Bb become black pixels by the binarization, and have a black frame surrounding the document range. It doesn't look good.

Therefore, in the present embodiment, the processing 1 shown in FIG.
As the book original reading process 06, specific processing procedures shown in FIGS. 7 to 11 are performed.

First, in FIG. 7, the system control unit 7
Substitutes 1 for the variable L, 1 for the variable P, and resets the variables Bf, Bb, Sf, and Sb to 0 (process 201).

Then, the image information for one line is read (process 202). That is, the scanner control unit 4
Step sub scanning is performed, one main scanning line is read by the image sensor 2, and the binarized image information output from the image processing unit 3 is stored in the line buffer (1).

Next, V (P), that is, whether the value of the Pth pixel among the first to Pmax pixels constituting the image information for one main scanning line stored in the line buffer (1) is 1 or not. It is determined whether it is not (0) (decision 203). In this embodiment, it is assumed that the pixel value 1 corresponds to a black pixel and the pixel value 0 corresponds to a white pixel.

If V (P) is 1, that is, if the pixel at the beginning of the effective reading range is a black pixel (decision 20)
(Yes in 3), the variable Bf for counting the number of pixels constituting the black pixel row continuous with the black pixel at the beginning of the effective reading range is incremented (process 204). And the variable P is P
It is determined whether the processing is completed for all the pixels in the effective reading range while the black pixels continue from the beginning of the effective reading range to the end of the effective reading range (decision 205).

If the variable P has not yet reached Pmax (No in decision 205), the variable P is incremented and the next pixel is processed (process 206).
Return to If the determination 203 is No, the number of pixels Bf counted so far in the process 204 becomes the number of pixels constituting a black pixel column that is continuous with the black pixel at the beginning of the effective reading range, and the process proceeds to the process 207.

If the determination 205 is Yes, it means that the scan line position currently being read is a place where the black pixels are continuous from the beginning of the effective reading range to the end of the effective reading range, not including the original range. And the number of pixels Bf counted by the process 204 until then is P
It becomes equal to max, and the process proceeds to decision 212.

In the process 207, the variable P is incremented, the pixel to be processed is moved to the next pixel, and the value of V (P) becomes 1
It is determined whether or not (0) (determination 208). And V
If the value of (P) is 1 (Yes in decision 208),
The variable Bb for counting the number of pixels constituting the black pixel row continuous with the black pixel at the end of the effective reading range is incremented (processing 204), and it is determined whether the variable P has reached Pmax (determination 211) and reached. In this case (No in decision 211),
It returns to processing 207.

If the value of V (P) is 0 in the judgment 208 (No in the judgment 208), the variable Bb is reset to 0 (step 209), and the process returns to the step 207.

Thus, as the value of the variable Bb when the determination 211 is Yes, the number of pixels forming a black pixel row continuous with the black pixels at the end of the effective reading range is held. That is, the judgment 208 is No because the pixel P being processed
Belongs to the document range, and V (P) repeatedly changes to 1 or 0 according to the content of the image in the document range.
The value of the variable Bb when the judgment 208 is No and the judgment 211 is Yes during the No loop of 1 indicates the number of pixels constituting a black pixel row continuous with the black pixels at the end of the effective reading range. become.

When the determination 211 is Yes or when the determination 205 is Yes, that is, a black pixel row continuous with the black pixel at the beginning of the effective reading range is formed for the main scanning line currently being processed. When the number of pixels Bf to be executed and the number of pixels Bb forming a black pixel row continuous with the black pixel at the end of the effective reading range are determined, it is determined whether or not the variable Bf value is not 0 (decision 212). Is 0, that is, if there is no black pixel column that is continuous with the black pixel at the beginning of the effective reading range (No in decision 212), the main pixel that has a black pixel column that is continuous with the black pixel at the beginning of the effective reading range is present. A variable Sf indicating how many scanning lines are continuous is reset to 0 (processing 213), and a determination 223 is made.
Move to

If the value of the variable Bf is not 0, that is, if there is a row of black pixels continuous with the black pixel at the beginning of the effective reading range (Yes in decision 212), only the value ΔB is added to the variable Bf (step 214). . The value ΔB will be described later. In addition, the variable Sf indicating how many main scanning lines in which a black pixel row continuous with the black pixel at the beginning of the effective reading range is present is incremented (process 215), and the variable Sf reaches the value 5. That is, whether a main scanning line in which a black pixel row continuous with the black pixel at the beginning of the effective reading range exists for five consecutive lines including the main scanning line currently being processed has appeared, in other words, the beginning of the effective reading range The main scanning line in which a black pixel row continuous with
After the continuous appearance of the lines, it is determined whether or not a black pixel row continuous with the black pixel at the beginning of the effective reading range exists in the main scanning line currently being processed (decision 216).

If the judgment 216 is No, the process goes to the judgment 223 without doing anything. If the determination 216 is Yes, the pixel values of the first to Bf-th pixels in the line buffer (1) storing the main scanning line currently being processed are set to 0. That is, those pixels are converted into white pixels (process 217).

Then, the counter variable n is set to 1 (step 218), the pixel values of the first to Bf (n) pixels of the line buffer (ln) are set to 0 (step 219), and n is set to 4. It is determined whether or not n has reached (determination 220). If n has not yet reached 4 (No in determination 220), n is incremented and the process returns to step 219 (step 221). n is 4
Is reached (Yes in the determination 220), a variable Sf indicating how many main scanning lines are continuous with a black pixel row continuous with the black pixel at the beginning of the effective reading range.
Is reset to 0 (process 213), and the flow shifts to decision 223.

As a result, the pixels belonging to the black pixel row from the first pixel to the Bf-th pixel at the beginning of the effective scanning range of the main scanning line currently being processed are converted into white pixels, and as shown in FIG. When the book original placed on the contact glass is read without adjusting to the range, the band-shaped black region at the start end of the effective reading range generated in the read image information can be removed.

Also, the pixels belonging to the black pixel column from the first pixel to the Bf-th pixel at the beginning of the effective reading range of the main scanning line currently being processed are not unconditionally converted to white pixels, but are currently being processed. Is converted only when all four lines adjacent to the main scanning line have a black pixel row that is continuous with the black pixel at the beginning of the effective reading range. Opportunities for conversion to pixels can be reduced.

Also, for the four lines adjacent to the main scanning line currently being processed and having a black pixel row continuous with the black pixels at the beginning of the effective reading range, the first to Bf-th pixels at the beginning of the effective reading range are respectively provided. (N) (n = 1, 2, 3,
4) Since the pixels belonging to the black pixel column up to the pixel are converted into white pixels, it is possible to prevent an unnecessary black area from remaining at the beginning of the effective reading range.

In the present embodiment, the first pixel to the first pixel of the main scanning line currently being processed only when there is a black pixel row continuous with the black pixel at the beginning of the effective reading range in all four adjacent lines. The pixels belonging to the black pixel column up to the Bf pixel are converted to white pixels, but the number of adjacent lines is four.
It is not limited to a line.

In the judgment 223, it is judged whether or not the variable Bb value is not 0. If the variable Bb value is 0, that is,
If there is no black pixel row that is continuous with the black pixel at the end of the effective reading range (No in decision 223), how many main scanning lines have a black pixel row that is continuous with the black pixel at the end of the effective reading range. The variable Sb indicating whether the process is performed is reset to 0 (process 224), and the process proceeds to the determination 324.

If the value of the variable Bb is not 0, that is, if there is a row of black pixels that is continuous with the black pixel at the end of the effective reading range (Yes in decision 223), the value B is added to the variable Bb (process 225). . The value ΔB will be described later. In addition, the variable Sb indicating how many main scanning lines are continuous with the main scanning line in which the black pixel row continuous with the black pixel at the end of the effective reading range is incremented (process 226), and the variable Sb reaches the value 5 That is, whether a main scanning line in which a black pixel row continuous with the black pixel at the end of the effective reading range exists for five consecutive lines including the currently processed main scanning line has appeared, in other words, the end of the effective reading range The main scanning line in which a black pixel row continuous with
After the continuous appearance of the lines, it is determined whether or not a black pixel row continuous with the black pixel at the end of the effective reading range exists in the currently processed main scanning line (decision 227).

If the judgment 227 is No, the process goes to the judgment 234 without doing anything. If the determination 227 is Yes, the pixel value of the (Pmax−Bb) th to Pmax pixel of the line buffer (1) storing the currently processed main scanning line is set to 0. That is, those pixels are converted to white pixels (process 228).

Then, the counter variable n is set to 1 (processing 218), and the (Pmax) of the line buffer (ln) is set.
-Bb (n)) or the pixel value of the Pmax pixel is set to 0 (step 230), and it is determined whether n has reached 4 (decision 23).
1) If n has not yet reached 4 (decision 231)
No), n is incremented and the process returns to the process 230 (process 232). If n reaches 4 (decision 231)
Yes), the variable Sb indicating how many lines of the main scanning line in which a black pixel row continuing to the black pixel at the end of the effective reading range is present is reset to 0 (processing 23).
3), proceed to decision 234;

As a result, the pixels belonging to the black pixel column from the (Pmax-Bb) pixel of the main scanning line currently being processed to the Pmax pixel at the end of the effective reading range are converted into white pixels, as shown in FIG. As described above, when a book document smaller than the effective reading area is placed on the contact glass, the band-shaped black area at the end of the effective reading range which occurs in the read image information can be removed.

The (P) of the main scanning line currently being processed is
max-Bb) pixel or Pm of the end of the effective reading range
The pixels belonging to the black pixel column up to the ax pixel are not unconditionally converted to white pixels, but all four lines adjacent to the currently processed main scanning line are connected to the black pixel at the end of the effective reading range. Since conversion is performed only when a pixel row exists, it is possible to reduce the chance that black pixels that should not be converted to white pixels are converted to white pixels due to erroneous recognition.

The four lines adjacent to the main scanning line currently being processed and having a black pixel row continuous with the black pixels at the end of the effective reading range are also referred to as (Pmax−
Bb (n)) (n = 1, 2, 3, 4) pixels or the pixels belonging to the black pixel column from the end of the effective reading range to the Pmax pixel are converted into white pixels. Unnecessary black areas can be prevented from remaining.

In the present embodiment, the (Pmax-Bb) of the main scanning line currently being processed only when there is a black pixel row continuous with the black pixel at the end of the effective reading range in all four adjacent lines. The pixels belonging to the black pixel column up to the pixel Pmax at the end of the effective reading range are converted into white pixels, but the number of adjacent lines is not limited to four.

In the judgment 234, it is judged whether or not the variable L corresponding to the current scan line position has reached Lmax. If the variable L has reached Lmax (judgment 2
34 (Yes), the reading process ends.

If the variable L has not yet reached Lmax (No in decision 234), the line buffer is shifted (process 235). That is, the image information for one line stored in the line buffer (l-4) of the line buffer group 4a is output, and the image information for one line stored in the line buffer (l-3) is output to the line buffer. (L-
4), the image information for one line stored in the line buffer (l-2) is transferred to the line buffer (l-3), and the image information for one line stored in the line buffer (l-1) is transferred. The image information is transferred to the line buffer (l-2), and the image information for one line stored in the line buffer (l) is transferred to the line buffer (l-1). Free for processing.

Then, the variable Bf (3) is changed to the variable Bf (4)
, And the variable Bf (2) is substituted into the variable Bf (3),
The variable Bf (1) is substituted for the variable Bf (2), and the variable Bf is substituted for the variable Bf (1) (process 236). As a result, the variable Bf (n) (n = 1, 2, 3, 4) contains black continuous from the black pixel at the beginning of the effective reading range for the main scanning line stored in the line buffer (ln). The number of pixels belonging to the pixel column (may be 0) is stored, and those variables are referred to in step 219.

Further, the variable Bb (3) is substituted for the variable Bb (4), the variable Bb (2) is substituted for the variable Bb (3), and the variable Bb (1) is substituted for the variable Bb (2). The variable Bb is substituted for the variable Bb (1) (process 237). This allows
The variable Bb (n) (n = 1, 2, 3, 4) includes a continuous black pixel column from the black pixel at the end of the effective reading range for the main scanning line stored in the line buffer (ln). The number of pixels (sometimes 0) is stored, and those variables are referred to in step 230.

Then, the variable L is incremented (step 238), and the process returns to step 202.

FIG. 12 shows image information of the total number of pixels Pmax of the L-th line currently being processed and the (L-n)
Each image information of (n = 1, 2, 3, 4) lines is shown.

The pixels belonging to the continuous black pixel row Bf from the black pixel at the beginning of the effective reading range of the L-th line are converted into white pixels by the processing 217, and the (Ln) (n = 1, 2,.
3, 4) Black pixel columns Bf (n) (n = 1, 2, 3,...) Continuous from the black pixels at the beginning of the effective reading range of each line
4) is converted into a white pixel by the process 219. Also,
The pixels belonging to the continuous black pixel row Bb from the black pixel at the end of the effective reading range of the L-th line are converted into white pixels by the process 228, and the (Ln) (n = 1, 2, 3, 4) line , The black pixel row Bb (n) (n = 1, 2, 3, 4) continuous from the black pixel at the end of the effective reading range
0 is converted to a white pixel.

In step 214, ΔB is added to the variable Bf, and in step 225, ΔB is added to the variable Bb.
B is the variable B actually counted up to the point of decision 212
f or the variable Bb, that is, a black pixel row continuing from the black pixel at the beginning of the effective reading range or a black pixel row continuing from the black pixel at the end of the effective reading range, and tends to occur at the boundary between the document range of the book document. Corresponds to a region where black pixels are not continuous but the frequency of appearance of black pixels is high and looks blackish. For example, if the read pixel density is 8 pixels / mm and a boundary portion of 5 mm is expected, ΔB becomes 8 × 5 = Set to 40 pixels.

As a result, image information obtained by reading a book document in a document area smaller than the standard area (effective reading area) is output from the image processing unit 3 at the stage of FIG.
The outside of the document area that was present as a black frame as shown in FIG. 4 is converted to a white area as shown in FIG. As a result, the appearance of the obtained image information is improved, and a recording material such as toner or ink is not wasted in order to record a meaningless black frame as the content of the image information.

The black area outside the manuscript area can be recognized by a complicated recognition method such as extraction of a figure by image recognition. In this case, a huge memory for storing the whole manuscript image information is required. High-speed arithmetic processing unit and dedicated LS
However, in the present embodiment, the original image information can be processed in units of main scanning lines to recognize and remove a black area outside the original area. The circuit scale can be reduced, and it can be realized at low cost.

[0074]

According to the first aspect of the present invention, white pixels are set outside the area corresponding to the document placed on the document reading surface in the image information obtained by reading the effective reading area. Because it is converted, it is possible to eliminate useless black pixels that are meaningless as the content of image information outside the area of the book original, which was read without opening the original presser plate and closed, and the obtained image information looks good. Therefore, user satisfaction is improved, and the amount of recording agent such as toner and ink required when recording the obtained image information can be reduced by eliminating unnecessary black pixels. Is obtained.

According to the second aspect of the present invention, for each piece of image information for each main scanning line, a pixel belonging to a continuous black pixel row from the black pixel at the end of the effective reading range, that is, the reference of the original reading surface. Pixels that constitute a band-shaped black area near the end of the effective reading range, which occur when an original such as a book original placed according to the position is read without opening the original presser plate, are converted to white pixels. Therefore, it is possible to eliminate unnecessary black pixels that are read without opening the document holding plate and are not meaningful as the content of the image information outside the area of the book document, and the obtained image information also looks good, The user satisfaction is also improved, and the amount of use of a recording agent such as toner or ink required when recording the obtained image information can be reduced by eliminating unnecessary black pixels. Is obtained .

According to the third aspect of the present invention, in addition to the same effects as those of the second aspect, the main scanning line including the continuous black pixel row from the black pixel at the end of the effective reading range includes a plurality of lines such as five lines. If they are not adjacent, the pixels included in the main scanning line to be corrected and belonging to the continuous black pixel row from the black pixels at the end of the effective reading range are not converted to white pixels, so the black area at the end of the effective reading range is accurately recognized. As a result, the effect of reducing the chance of erroneously correcting a non-black area to a white image is reduced.

According to the fourth aspect of the present invention, in addition to the same effect as the third aspect, a black pixel row adjacent to the main scanning line to be corrected and continuing from the black pixel at the end of the effective reading range is included. Even for a plurality of main scanning lines, since the pixels belonging to the black pixel row are converted into white pixels, a black area is not left at the end of the effective reading range of the main scanning lines, and the obtained image information is obtained. Has an effect of improving the appearance.

According to the fifth aspect of the invention, in addition to the same effect as the second aspect of the invention, the image information for each main scanning line is continuous from the black pixel at the beginning of the effective reading range. Pixels belonging to the black pixel row, that is, effective when a document such as a book document placed with a gap without being aligned with the reference position of the document reading surface is read with the document holding plate open without closing the document holding plate. The pixels constituting the black band in the vicinity of the start of the reading range are converted to white pixels. Therefore, the image reading outside the book document area without reading the document holding plate without closing it is meaningless waste. Black pixels can be reliably eliminated, the obtained image information looks even better, user satisfaction is improved, and the obtained image information is recorded to the extent that unnecessary black pixels can be reliably removed. When Effect it is possible to reduce the amount of recording agent of toner or ink or the like which is required to obtain.

According to the invention of claim 6, in addition to the same effect as the invention of claim 5, in addition to the black pixel row continuing from the black pixel at the end of the effective reading range, and / or the start of the effective reading range start end. If a main scanning line including a black pixel row continuing from a black pixel is not adjacent to a plurality of lines such as five lines, a black pixel row continuing from a black pixel at the end of the effective reading range included in the main scanning line to be corrected is included. Since the pixels belonging to and / or the pixels belonging to the continuous black pixel column from the black pixel at the beginning of the effective reading range are not converted into white pixels, the black area at the end and the beginning of the effective reading range can be recognized with high accuracy. The effect of reducing the chance of erroneously correcting a non-image portion to a white image is obtained.

According to the seventh aspect of the present invention, in addition to the same effect as the sixth aspect of the present invention, the black pixel at the end of the effective reading range adjacent to the main scanning line to be corrected is continuous. Regarding a plurality of main scanning lines including a black pixel row and / or a black pixel row continuing from the black pixel at the beginning of the effective reading range, the pixels belonging to the black pixel row are converted into white pixels. A black area is not left at the end or the beginning of the effective reading range of the scanning line, and the effect of further improving the appearance of the obtained image information is obtained.

According to the eighth aspect of the present invention, a predetermined sequence of black pixels adjacent to a black pixel row continuous from the black pixel at the end of the effective reading range and / or a continuous black pixel row from the black pixel at the beginning of the effective reading range. Although the pixels belonging to the boundary range of the above, that is, the boundary between the belt-like black region at the end portion and / or the start end portion of the effective reading range and the original region, are not completely black,
Pixels that make up a portion that looks black to the eye are also converted to white pixels, so that the obtained image information can be prevented from appearing to be surrounded by a black outer frame.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a block configuration of an image reading apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of an image processing unit of the image reading device according to the embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a line buffer group of the image reading apparatus according to the embodiment of the present invention.

FIG. 4 is a flowchart illustrating a reading processing procedure in the image reading apparatus according to the embodiment of the present invention.

FIG. 5 is a diagram showing a book document placed on a contact glass and various relationships.

FIG. 6 is a diagram illustrating an image signal level for one line.

FIG. 7 is a flowchart illustrating a book document reading processing procedure;

FIG. 8 is a flowchart showing a book document reading processing procedure together with FIG. 7;

FIG. 9 is a flowchart showing a book document reading processing procedure along with FIGS. 7 and 8;

FIG. 10 is a flowchart showing a book document reading processing procedure along with FIGS. 7, 8 and 9;

FIG. 11 is a flowchart showing a book document reading processing procedure together with FIGS. 7, 8, 9 and 10;

FIG. 12 is a diagram illustrating image information of five consecutive lines.

FIG. 13 shows an image obtained by the image reading apparatus according to the present invention;
FIG. 9 is a diagram illustrating image information when a book document smaller than a standard size is read.

FIG. 14 is a flowchart showing image information obtained when a book document smaller than a standard size is read by a conventional image reading apparatus.

[Explanation of symbols]

 Reference Signs List 1 image reading device 2 image sensor 3 image processing unit 4 scanner control unit 5 plotter control unit 6 operation display unit 7 system control unit 8 ROM 9 RAM 9a line buffer group 10 system bus 31 A / D conversion unit 32 multi-value image processing unit 33 binarization processing unit

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 5B047 AA01 AB01 BA02 BB02 BC15 CA14 CB09 CB12 CB22 DC01 DC07 DC09 DC11 5B057 AA11 BA24 CA02 CA06 CA12 CA16 CB02 CB06 CB12 CB16 CC03 CE20 DA08 DA17 DB02 DB05 DB08 A07DC36 CA10

Claims (8)

[Claims] An image reading apparatus that obtains image information by reading a predetermined effective reading area on a document reading surface, wherein an outside document area recognition section recognizes an outside document area in the image information obtained by reading the effective reading area. An image reading device, comprising: means for converting a pixel belonging to the non-document area in the image information recognized by the non-document area recognizing means into white pixels. 2. An image reading apparatus which obtains image information of a predetermined effective reading area by reading a predetermined effective reading range in units of main scanning lines while sub-scanning a document reading surface. An image reading device, comprising: a non-document area correction unit that converts pixels belonging to a continuous black pixel row from the black pixel at the end of the effective reading range into white pixels. 3. The image forming apparatus according to claim 2, wherein the image information for a plurality of main scanning lines adjacent to the main scanning line to be corrected includes a black pixel row continuing from a black pixel at the end of the effective reading range. The method according to claim 2, wherein pixels belonging to a continuous black pixel column from the black pixels at the end of the effective reading range of the image information for the main scanning line to be corrected are converted into white pixels. The image reading device according to claim 1. 4. The non-document area correction means converts pixels belonging to a continuous black pixel column from the black pixels at the end of the effective reading range of the image information for the main scanning line to be corrected to white pixels. A black pixel continuous from the black pixel at the end of the effective reading range of the image information of a plurality of main scanning lines adjacent to the main scanning line to be corrected, including a black pixel row continuing from the black pixel at the end of the effective reading range. 4. The image reading apparatus according to claim 3, wherein pixels belonging to a column are also converted into white pixels. 5. The non-document area correction means converts, for each piece of image information for each main scanning line, pixels belonging to a continuous black pixel column from the black pixels at the end of the effective reading range to white pixels, 3. The image reading apparatus according to claim 2, wherein pixels belonging to a continuous black pixel row from the black pixel at the beginning of the effective reading range are also converted into white pixels. 6. The non-document area correction means, wherein the image information of a plurality of main scanning lines adjacent to the main scanning line to be corrected is a black pixel row continuous from a black pixel at the end of the effective reading range, and / or And, as long as it includes a continuous black pixel column from the black pixel at the beginning of the effective reading range, it belongs to a black pixel column continuous from the black pixel at the end of the effective reading range of the image information for the main scanning line to be corrected. And converting pixels belonging to a continuous black pixel row from the black pixels at the start end of the effective reading range in the image information of the pixels and / or the image information for the main scanning line to be corrected to white pixels. Item 3. The image reading device according to Item 2. 7. The non-document area correction means includes: a pixel belonging to a black pixel row continuing from a black pixel at the end of the effective reading range of the image information for the main scanning line to be corrected; While converting the pixels belonging to the continuous black pixel row from the black pixel at the beginning of the effective reading range of the image information for the main scanning line into white pixels, the black pixel row continuing from the black pixel at the end of the effective reading range, or And / or from the black pixel at the end of the effective reading range of the image information of a plurality of main scanning lines adjacent to the main scanning line to be corrected, including the black pixel row continuing from the black pixel at the beginning of the effective reading range. 7. The method according to claim 6, wherein pixels belonging to a continuous black pixel row and / or pixels belonging to a continuous black pixel row from the black pixel at the beginning of the effective reading range are also converted to white pixels. Image of Reader. 8. The non-document area correction means may include a black pixel row continuing from a black pixel at the end of the effective reading range and / or a predetermined black pixel row adjacent to a black pixel row continuing from a black pixel at the beginning of the effective reading range. Wherein the pixels belonging to the boundary range are also converted into white pixels.
8. The image reading device according to any one of 3, 4, 5, 6, and 7.