JP3767576B2 - Color image reader - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a color image reading apparatus.
[0002]
[Prior art]
Conventionally, in order to detect the size of a scanned document when reading an image in a copying machine, facsimile machine, etc., the document is set on a glass substrate, and when reading an FBS, a light source is turned on just before the platen cover is closed, Some sensors take in waveform data and detect the document size (width in the main scanning direction) from the waveform data.
[0003]
On the other hand, in the image reading apparatus, a white reference plate is provided in the reading mechanism unit, and when reading is instructed, the light source is turned on and the read data obtained by scanning the white reference plate with the line image sensor is shaded. It is known to collect correction data, store it in a shading memory (RAM), and correct the data using the shading correction data stored in the shading RAM when the original document is read (for example, Patent Documents). 1).
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 2001-148765
[Problems to be solved by the invention]
In the conventional apparatus described above, the read data of the line image sensor when the light source is turned on just before closing the platen cover for size detection is stored in a memory for storing shading correction data in order to efficiently use the memory capacity. It is conceivable to store temporarily. That is, a memory for storing size detection data and a memory for shading correction data can be used together. However, when such a combination is used, the shading correction data is rewritten for taking in data for size detection. Therefore, it is necessary to fetch shading correction data again before reading the document.
[0006]
In particular, in the case of color reading, a shading memory is provided for each of the three color components of RGB, and shading correction is performed for each color component when reading a document. Therefore, when the shading correction data is rewritten for all the color components at the time of document size detection (acquisition of size detection waveform data), the shading correction data for all the color components is reproduced again immediately before reading the document. There is a problem that it is necessary to write, and it takes time to read the document.
[0007]
The present invention has been made paying attention to such problems, and provides a color image reading apparatus that does not require a memory for storing data for size detection and that does not take a long time to read. The purpose is to do.
[0008]
[Means for Solving the Problems]
When a document size is detected, the color image reading apparatus according to the present invention takes in output data of some color components out of a plurality of color component output data into a shading memory (RAM) in which shading correction data is stored, and takes this in. the I output data, to detect the document size, the output data of the other color component, a control means for controlling so as not to perform capture, the control means, at a predetermined timing, from the system memory a plurality of Control is performed so that the shading correction data of the color component is taken into the shading memory, and after the document size is detected, only a part of the color components for which the output data has been taken in for detecting the document size is read from the system memory. It is supposed to be controlled to re-import.
[0009]
In the color image reading apparatus according to the present invention, the control means can restrict access to the fetch memory for the output data of the remaining color components when the document size is detected.
[00 10 ]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail with reference to embodiments. FIG. 1 shows a block diagram of a configuration example of a color image reading apparatus according to this embodiment.
[00 11 ]
In FIG. 1, an MPU 1 (central processing unit) has a function of controlling the entire apparatus. As will be described later, the MPU 1 detects when the platen cover is closed, turns on the lamp of the image reading unit, operates the R signal detection unit, and scans the document in the main scanning direction. The waveform data is obtained, stored in the shading RAM, and controlled to obtain the document width from the waveform data.
[00 12 ]
An image reading unit 2, an operation unit 3, a display unit 4, a ROM 5, a RAM 6, and a printer 7 are connected to the MPU 1 via a system bus 8.
[00 13 ]
The image reading unit 2 processes a document image signal from a later-described three-line sensor. Specifically, the output of the 3-line sensor is analog-amplified and the digital data is output in multivalue. The image reading unit 2 includes a shading RAM 16 that stores shading correction data. The operation unit 3 has a start key for instructing the start of copying and the like, and a numeric keypad for inputting the number of copies and the number of copies. The display unit 4 displays various information such as the number of copies and the number of copies input by the operation of the operation unit 3 and the toner remaining amount of the printer 7. For example, an LCD (Liquid Crystal Display) is used as the display unit 4.
[00 14 ]
The ROM 5 stores in advance a program for controlling the operation of the entire apparatus. The RAM 6 stores data necessary for control by the MPU 1 and data that needs to be temporarily stored during the control operation. The RAM 6 includes a shading data storage unit 6a that stores shading correction data obtained during production. The printer 7 prints the image data read by the 3-line sensor on paper in color or monochrome. As shown in FIG. 2, the image reading unit 2 includes an R signal processing unit 11 < / b > R, a G signal processing unit 11 < / b > G , a B signal processing unit 11 < / b > B, a color conversion unit 18, and an image processing unit 19.
[00 15 ]
The R signal processing unit 11R includes a line image sensor 12R, an analog front end (AFE) circuit 13R, an A / D conversion unit 14R, a shading correction circuit 15R, and a line correction memory 17R. G signal processing unit 1G is provided with a line image sensor 12 G, and the analog front-end circuit 13G, an A / D conversion unit 14G, and a shading correction circuit 15G, a line correction memory 17G. The B signal processing unit 11B includes a line image sensor 12B, an analog front end circuit 13B, an A / D conversion unit 14B, and a shading correction circuit 15B. Here, the reason why the B signal processing unit 11B is not provided with a line correction memory is to delay other R signals and G signals based on the B signal. The shading correction circuits 15R, 15G , and 15B are provided with shading RAMs 16R, 16G, and 16B, respectively.
[00 16 ]
The line image sensor 12R is composed of a CCD, and each time a timing signal is applied, it separates and reads the R signal of the image of one scanning line of the document, and at a predetermined interval, the R of the image of the next one scanning line is read. The signals are read sequentially, and the read image data of one scanning line is output. The analog front end circuit 13R receives the output of the line image sensor 12R and amplifies the analog signal. The A / D converter 14R receives the analog output of the analog front end circuit 13R and converts it into a digital signal. Here, the shading correction circuit 15R includes a shading RAM 16R, and the shading RAM 16R stores the output of the A / D conversion unit 14R when reading the reference plate (white reference plate) as shading correction data. The shading RAM 16R stores the waveform data acquired by the R signal processing unit 11R only when the document width is detected. The shading correction circuit 15R corrects and outputs the output of the A / D conversion unit 14R at the time of document reading with the shading correction data. The line correction memory 17R receives the output of the shading correction circuit 15R, delays it by a predetermined line, and outputs it. The same applies to the circuits constituting the other G signal processing unit 11G and B signal processing unit 11B.
[00 17 ]
If the interval between the line image sensors 12R, 12G, and 12B is equivalent to four scanning lines, the shading correction circuit is delayed by four lines after the R signal of one scanning line is output from the shading correction circuit 15R. The G signal for one scanning line is output from 15G, and the B signal for one scanning line is output from the shading correction circuit 15B with a delay of four lines. Thus, R signals are delayed eight lines by the line correction memory 17 R, G signal is delayed four lines by the line correction memory 17G, are input to the color conversion unit 18. Therefore, the R, G, and B signals input to the color conversion unit 18 are on the same scanning line.
[00 18 ]
In the color converter 18, the R, G, B color signals are converted into L ^* , a ^* , b ^* . The data converted into L ^* , a ^* , b ^* by the color conversion unit 18 is supplied to the printer 7 via the image processing unit 19.
[00 19 ]
Here, the relationship between the shading data storage unit 6a of the RAM 6 serving as the system memory and the shading RAMs 16R, 16G, and 16B of the image reading unit 2 will be described. As shown in FIG. 5, the shading data storage unit 6a includes an R signal shading data storage unit 6aR, a G signal shading data storage unit 6aG, and a B signal shading data storage unit 6aB. These data storage units 6aR, 6aG, and 6aB are configured by a memory (for example, a non-volatile memory) whose stored contents are not erased even when the power is turned off.
[00 20 ]
On the other hand, the shading RAMs 16R, 16G, and 16B have a structure in which stored contents are erased when the power is turned off. At the time of shipment from the factory, for example, shading correction data obtained by scanning a white reference plate is stored in the shading correction RAMs 16R, 16G, and 16B, and further stored in the shading correction RAMs 16R, 16G, and 16B in the upward arrow direction of FIG. Each shading correction data is stored in the shading data storage 6aR, 6aG, 6aB of the system RAM 6. The stored shading correction data is basically unchanged regardless of whether the power is on or off. But of course it can be changed. The shading RAMs 16R, 16G, and 16B capture shading correction data in the downward arrow direction of FIG. 5 from the shading data storage units 6aR, 6aG, and 6aB at necessary timings. The necessary timing is, for example, when the power is turned on or immediately before the start of reading.
[00 21 ]
FIG. 3 is a cross-sectional view illustrating an outline of the FBS reading mechanism of the image reading unit 2 of the image reading apparatus according to the embodiment. A document table 31 formed of a glass plate is provided on the upper portion of the case body 30, and a document 32 is placed on the document table 31. A part of the left side of the document table 31 is covered with an insulating plate 34, and a white reference plate 33 is provided inward. A scanning unit 37 including a lamp 35 and a reflection mirror 36 is configured to be movable in the sub-scanning direction (left-right direction). Further, a reflection mirror unit 38, a condenser lens 39, and a CCD line image sensor 40 are provided in the case body 30. The CCD line image sensor 40 is a three-line sensor of R, G, and B.
[00 22 ]
When detecting the size of the document 32, the scanning unit 37 is moved until the light incident portion on the reflection mirror 36 reaches the position of the arrow A, and the lamp 35 is turned on. The light is reflected and enters the reflection mirror 36. This light is reflected by the reflection mirror 36, and further enters the CCD line image sensor 40 through the reflection mirror unit 38 and the condenser lens 39. Here, waveform data obtained by scanning the document 32 in the main scanning direction (front and back of the paper) at the position of the arrow A is stored in the shading RAM circuit 16R. The document size is detected based on the waveform data. When capturing shading correction data, the scanning unit 37 is moved until the light incident portion of the reflection mirror 36 is at the position of the arrow B.
[00 23 ]
Next, document reading processing by the FBS of the image reading apparatus according to this embodiment will be described with reference to the flowchart shown in FIG. In step ST1, the document is set on the document table 31 of the FBS. Subsequently, the process proceeds to step ST2. In step ST2, reading conditions such as paper size, resolution, and density are set from the operation unit 3. Next, the process proceeds to step ST3. In step ST3, it is determined whether or not the platen cover (not shown) is closed within 30 degrees. If the operator lowers the platen cover so as to start FSB reading, it is determined YES when it is detected that the angle sensor of the platen cover has an angle of 30 degrees or less, and the process proceeds to step ST4.
[00 24 ]
In step ST4, to move the optical reading system to the original end, together with lighting the lamp, it is operated only R signal processing unit 11 R, the waveform data in the main operating direction of the R component obtained by the line image sensor 12R Capture and store in the shading RAM 16R. At this time, the waveform data of the G component and the B component are not taken into the shading RAMs 16G and 16B. Next, the process proceeds to step ST5.
[00 25 ]
In step ST5, it is determined whether there is a reading start instruction. This determination is made based on whether or not the operator has operated the reading start key of the operation unit 3 . When the start key is operated, the process proceeds to step ST6. In step ST6, the shading correction data is captured (rewritten) into the shading RAM 16R. Waveform data for document size detection is stored in the shading RAM 16R. Instead, R component shading correction data is written from the shading data storage unit 6aR of the system RAM 6. In this case, the R component is transferred only to the shading RAM 16R used for size detection, and the G component and B component shading data is not rewritten to the shading RAMs 16G and 16B. Next, the process proceeds to step ST7.
[00 26 ]
In step ST7, the color signal reading process is executed by the R signal processing unit 11R, the G signal processing unit 11G, and the B signal processing unit 11B. Next, the process proceeds to step ST8. In step ST8, read data is output. Specifically, the data is output to the printer 7 or an external PC or stored in the memory of the own apparatus.
[00 27 ]
In the above-described embodiment, only the R signal processing unit 11R is operated, and the captured waveform data at the time of document width detection is stored in the shading RAM 16R. Instead, other G signal processing units 11G and B signal processing are stored. The unit 11B may be operated and stored only in the shading RAM 16G or 16B.
[00 28 ]
In the above embodiment, an example in which line sensors of RGB components are arranged side by side with a physical interval in the sub-scanning direction (an example in which two components are delayed by a line correction memory) is shown. The present invention can also be applied to a type in which data can be obtained simultaneously for three components.
[00 29 ]
【The invention's effect】
According to the present invention, when a document is detected, output data of some color components among the output data of a plurality of color components is taken into a shading memory in which shading correction data is stored , and the size of the original is determined by the fetched output data. The output data of the remaining color components is not captured, so even if the read data is color, the memory for storing the document size detection data may be small in capacity, and the processing time for document size detection Can be minimized.
[00 30 ]
In addition, by using the shading memory in which the shading correction data is stored as the output data capture destination at the time of document size detection, it becomes unnecessary to provide a special memory for document size detection.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration example of an image reading apparatus according to an embodiment of the present invention.
FIG. 2 is a block diagram illustrating a configuration of an image reading unit of the image reading apparatus according to the embodiment.
FIG. 3 is a schematic diagram illustrating an optical system of an image reading unit of the image reading apparatus according to the embodiment.
FIG. 4 is a flowchart illustrating an FBS reading process of the image reading apparatus according to the embodiment.
FIG. 5 is a block diagram illustrating a relationship between a shading data storage unit and a shading RAM of the image reading unit in the image reading apparatus system according to the embodiment;
[Explanation of symbols]
1 MPU
2 Image reading unit 3 Operation unit 4 Display unit 5 ROM
6 RAM
6a Shading data storage unit 7 Printer 8 System bus 11R, 11G, 11B Signal processing unit 12R, 12G, 12B Line image sensor 13R, 13G, 13B AFE circuit 14R, 14G, 14B A / D converter 15R, 15G, 15B Shading correction Circuit 16R, 16G, 16B Shading RAM
17R, 16G Line correction memory 31 Document table 32 Document 33 White reference plate 35 Lamp 37 Scanning unit

Claims (1)

When the document size is detected, some of the color component output data is loaded into the shading memory where the shading correction data is stored , and the document size is detected from the captured output data and the remaining data is detected. The control means for controlling the output data of the color components not to be taken in, and the control means fetches the shading correction data of a plurality of color components from the system memory into the shading memory at a predetermined timing. And, after the document size is detected, control is performed to re-import shading correction data from the system memory for only some of the color components for which output data has been captured for document size detection. A color image reading apparatus.

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