JPH10174118A - Image pickup system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To convert an image signal into a plurality of signal forms by having only one conversion table physically in the image pickup system consisting of an information processing unit such as a computer and an image pickup unit connected to the information processing unit to be used. SOLUTION: An image pickup unit 1 is connected to a computer 2 by interfaces 17, 22, a digital signal of a image picked up by the image pickup unit 1 is processed by an image pickup program of the computer 2. Furthermore, the image pickup unit 1 is provided with a conversion table 15 to convert a form of an image signal into a different form and the conversion table is calculated and processed by the image pickup program for processing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information processing apparatus such as a computer, an imaging unit connected to the information processing apparatus, and an imaging system comprising an imaging program operating on the information processing apparatus. The present invention relates to an imaging system having a conversion table for converting signals.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 4, an imaging unit 101 having a connection terminal of a PC card standard, a computer 102 having a connection terminal of the same standard, and an imaging system comprising an imaging program thereof are known. I have. This imaging system includes an imaging unit 101 and a computer 10.
2 for imaging.

In the image pickup unit 101, reference numeral 111 denotes a lens unit; 112, an image pickup device such as a CCD; 113, an A / D converter for converting an analog image signal from the image pickup device 112 into a digital signal; Converter 11
3, an image pickup signal processing unit (DSP) for performing predetermined signal processing on the image signal digitally converted in step 3,
116 is a conversion table for signal conversion, 117 is a recording medium (memory) for recording an image signal, 118 is an interface for external connection conforming to the PC card standard, 119 is a control unit of the image pickup unit 101, and 120 is a conversion table Selector that switches between 115 and 116 (Selecto
r).

In the computer 102, reference numeral 121 denotes a CPU unit, 122 denotes an interface for external connection conforming to the same PC card standard as the interface 118 of the imaging unit 101, 123 denotes a display device such as a liquid crystal display, and 124 denotes a storage device. , 125 are memories for storing imaging programs.

In the above configuration, the digital signal processed by the signal processing unit 114 of the image pickup unit 101 is represented, for example, in the form of luminance / color difference. On the other hand, in the computer 102, the captured image is finally converted into a 256-color palette format or R (red) 5b.
It may be displayed on a display in the form of it, G (green) 5 bits, B (blue) 5 bits, or recorded as a file in the storage device 124.

For this reason, the imaging unit 101 converts the digital image signal processed by the signal processing unit 114 into a signal format of R5 bits, G5 bits, and B5 bits, and converts the digital image signal into 256 colors. A conversion table (2) 116 is provided for converting the image into a color number of a pallet. The digital signal of the captured image can be converted into a signal suitable for processing by the computer 102 and transmitted.

As described above, since the imaging unit 101 has the conversion tables 115 and 116, it is not necessary to convert the digital image signal by software in the computer 102, and the processing speed can be improved.

Conventionally, the luminance / color difference signal is 16b
The conversion table (1) receives luminance / color difference signals of 0 to ffffh as input and supplies them to the address line.
It outputs data converted to signals of it, G5 bit and B5 bit format. Similarly, the other conversion table (2) similarly receives the luminance / color difference signals of 0 to ffffh as input and supplies them to the address lines, and outputs data converted to signals of the pallet numbers of 0 to ffh. However, both the conversion palette (1) and the conversion palette (2) are configured by a ROM having a data width of 16 bits.

In the image pickup system shown in FIG. 4, a signal flow for obtaining an image signal in the form of a pallet number or R5 bits, G5 bits, or B5 bits is as follows.

First, the lens unit 111 and the image sensor 1
The information of the picked-up image is stored in the image sensor 112 as electric charges using the reference numeral 12.

Next, the electric charge stored in the image pickup device 112 is read out to the A / D converter 113, and the signal A / D converted by the A / D converter 113 is then converted to the signal processing unit 11.
In step 4, the signal is converted into a luminance / color difference signal.

Next, R5 bit, G5 bit, B5bi
To obtain a signal in the format of t, the selector 120 is switched to the conversion table (1) 119 to provide a luminance / color difference signal to the address of the conversion table (1) 115.

When a signal in the form of a pallet number is obtained, the selector 120 is switched to the conversion table (2) 116 to provide a luminance / color difference signal to the address of the conversion table (2) 116. Finally, the output signal obtained from the conversion table is recorded in the memory 117.

When an image signal for one screen is recorded in the memory 117 by the above signal flow, the imaging program takes in the image signal into the computer 102.

The image signal captured by the computer 102 is displayed on a display by an imaging program or recorded in a storage device 124 as a file.

[0016]

However, in the conventional imaging system as described above, the conversion table is constituted by the ROM, and the conversion table cannot be changed. For this reason, the imaging unit physically stores a plurality of conversion tables as necessary, such as a conversion table from a luminance / color difference signal to a pallet number and a conversion table from a luminance / color difference signal to R5 bit, G5 bit, and B5 bit. Therefore, there is a problem that a large capacity of the ROM is required, which leads to an increase in the circuit area on the substrate.

When a captured image is represented in the form of, for example, a 256-color palette, the number of colors is small. If the same color as that of a certain pixel does not exist in the palette, an approximate color in the palette is substituted. There is a need. Therefore, the difference between the actual color and the substitute color is often large.

Furthermore, when a document or business card is photographed and the photographed image is represented in the form of a 256-color palette, the number of colors is small, and the amount of information relating to luminance is reduced. In addition, characters often become difficult to read due to low resolution.

The present invention has been made in order to solve the above-mentioned conventional problems. Physical conversion into a plurality of signal formats is possible with one conversion table, thereby reducing the circuit area. It is an object of the present invention to provide an imaging system capable of performing such operations.

Another object of the present invention is to provide an imaging system capable of minimizing a difference between an actual color of a captured image and a substitute color when expressed in a palette format as much as possible.

Another object of the present invention is to provide an imaging system capable of increasing the resolution and making characters easier to read when photographing a document or business card in a 256-color palette. .

[0022]

An imaging system according to the present invention is configured as follows.

(1) An imaging system comprising an information processing apparatus, an imaging unit connected to the information processing apparatus for use, and an imaging program therefor, wherein a digital signal of an image captured by the imaging unit is converted into a different image signal. It has a rewritable conversion table for converting to a format, and the conversion table is used in an imaging program operating on the information processing apparatus.

(2) In the above system (1), the image pickup unit and the information processing device are provided with connection terminals conforming to the PC card standard.

(3) In the above system (1) or (2), the conversion table stores the digital signal of the captured image as a palette composed of a combination of 256 color numbers and red, green and blue signal values. Can be rewritten into a conversion table that converts the color numbers.

(4) In the system of the above (1) or (2), the conversion table comprises a digital signal of a picked-up image by 5 bits of a red signal component, 5 bits of a green signal component, and 5 bits of a blue signal component. It can be rewritten to a conversion table that converts it into a pallet signal.

(5) In the above system (3) or (4), the imaging program calculates a conversion table when part or all of the elements of the pallet are changed, and rewrites the conversion table.

(6) In the system of the above (5), the imaging program changes some or all of the elements of the pallet according to an instruction input from the user.

(7) In the system of (6), the imaging program changes some or all of the elements of the pallet when the indoor imaging condition or the outdoor imaging condition is set.

(8) In the system of (6), the imaging program changes some or all of the elements of the pallet when the conditions for imaging the document are set.

(9) In the system of the above (8), the imaging program changes the elements of the palette to grayscale colors.

(10) In the system of the above (5),
The imaging program changes some or all of the elements of the pallet when it is estimated that the setting has been switched to the setting of indoor imaging conditions or when it is estimated that the setting has been switched to the setting of outdoor imaging conditions.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments.

(First Embodiment) FIG. 1 is a block diagram showing a configuration of a first embodiment of the present invention. The configuration of the imaging system of the present embodiment is the same as that of the system of FIG. 4, and an imaging unit (Camera Unit) 1 having a connection terminal conforming to at least one PC card standard shown in FIG. Is connected to a computer (Computer) 2 through a connection terminal that also conforms to the PC card standard to perform imaging.

In the image pickup unit 1 shown in (a), 11 is a lens unit (Lens Unit), 12 is an image pickup device such as a CCD, 13 is an A / D converter, and 14 is an A / D converter 13 for digital conversion. An imaging signal processing unit (DSP) for performing predetermined signal processing on the obtained image signal, a conversion table (Table) 15 as a memory, a recording medium (Memory) 16 for recording the image signal, and a PC card standard 17 An interface (I / F) 18 for external connection conforming to the standard is a control unit (Control Unit) of the imaging unit 1.

In the computer 2 of FIG. 2B, 21 is a CPU unit, 22 is an interface for external connection conforming to the same PC card standard as the interface 17, 23 is a display device such as a liquid crystal display (Desplay), and 24. Is a storage device, and 25 is a memory for storing an imaging program.

In this embodiment, the memory of the conversion table 15 is constituted by a RAM, and can be rewritten by an imaging program. Also, this memory is 6553
It has a capacity of 6 words and inputs 16-bit luminance / color difference signals as addresses, and 16b corresponding to each address.
Input or output it data.

The flow of an image signal in the imaging system configured as described above is the same as in the conventional example. First, information of a captured image is accumulated as charges in the imaging element using the lens unit 11 and the imaging element 12.

Next, the charge stored in the image sensor 12 is represented by A
Read out to the A / D converter 13 and then to the A / D converter 1
The signal A / D converted in step 3 is converted into a luminance / color difference signal by the signal processing unit 14.

Next, a luminance / color difference signal is given to the address of the conversion table 15 and its output value is output as R5 bit, G5b
A signal in the form of it, B5 bit or a signal in the form of a pallet number is obtained.

Finally, the output signal obtained from the conversion table 15 is recorded in the memory 16.

In this embodiment, the imaging program allows the user to change the captured image signal from the R5 bit, G5 bit, and B5 bit format to the pallet number format and vice versa. Can be instructed.

In this embodiment, when the user specifies the format of the signal of the captured image, the conversion table can be rewritten according to the flow of FIG. Hereinafter, the operation will be described.

That is, first, step S1, step S
In step 2, the format of the captured image signal is set to R5bit, G5bi.
Change the format of t and B5 bits to the format of pallet number, or change the format of pallet number to R5 bit and G5
It is determined whether the format is changed to bit, B5 bit.

Then, R5 bit, G5 bit, B5b
When the format of the pallet is changed to the format of the pallet number, a conversion table is calculated from the pallet data in step S3.

At this time, the pallet data is 0 to 25
It is composed of a combination of a color number of a palette that takes an integer value of 5 and signal values of R, G, and B (each 8 bits). Using the data of the palette, a palette number format is obtained from a luminance / color difference signal. The method of calculating the conversion table to be converted into a signal is as follows.

First, each luminance / color difference signal (0 to ffffh
R8 bit, G8 bit, B8 bit
Compute a signal of the form

Generally, when the luminance signal of the luminance / color difference signals is Y, the color difference signal is Cr in the R direction, and Cb is in the B direction, the signal values of R, G, and B are respectively calculated by the following equations. You.

R = kRY × Y + kRCr × Cr + kRCb × Cb G = kGY × Y + kGCr × Cr + kGCb × Cb R = kBY × Y + kBCr × Cr + kBCb × Cb where kRY, kRCr, kRCb, kGY, kGC
r, kGCb, kBY, kBCr, and kBCb are constants.

Next, the R8 bit, G8 bit, B8
The color of the palette closest to the signal in bit format is searched. The values of the R, G, and B elements of the signal in the format of R8 bits, G8 bits, and B8 bits are respectively X
R, XG, XB, and the i-th palette (i is 0 to 25)
The signal values of R, G, and B corresponding to the color number of (5) are YiR, YiG, and YiB, respectively.

At this time, in this embodiment, the colors of the closest palette are YiR, YiG, and YiB when the value of E in the following equation is the smallest, respectively, as the R component, the G component,
This is the color used as the B component.

E = (XR-YiR) ² + (XG-Yi
G) ² + (XB-YiB) ² The pallet number i at this time becomes data when the luminance / color difference signal having the elements of Y, Cr, and Cb in the conversion table as addresses.

On the other hand, in step S2, the format of the signal of the captured image is changed from the format of the pallet number to R5bit, G5bi.
If it is determined that the format should be changed to the format of t, B5 bits, the luminance / color difference signals (0 to ffffh values) are converted to R5
A conversion table for converting into a signal in the format of bit, G5 bit, B5 bit is calculated.

Finally, the conversion table calculated above is written in the conversion table 15 in step S5.

As a result, the imaging unit 1 can cope with conversion into a plurality of signal formats by having only one conversion table 15, and it is not necessary to physically have a plurality of conversion tables.

(Second Embodiment) In the first embodiment, when a captured image is expressed in the form of a palette of 256 colors, the number of colors is small. Similar colors need to be substituted. Therefore, the difference between the actual color and the substitute color may be large.

Therefore, in this embodiment, by rewriting a part or all of the elements of the palette and further rewriting the conversion table of the imaging unit 1 according to the instruction from the user, the actual colors of the captured image and the palette format This provides a means for reducing the difference from the substitute color when represented by.

In the present embodiment, the user is provided with a means which can set the conditions for photographing the imaging system indoors, conditions for photographing outdoors, or conditions for photographing a document or business card.

This is realized by pressing a button on the screen or a specific keyboard using the mouse of the computer 2.

Reference numerals 31, 32, and 33 in FIG. 3 show the data structures of the respective pallets when the user sets the photographing conditions indoors or outdoors, or when the user sets a document or business card.

In this embodiment, when the photographing condition is set to room, the palette is composed of the basic color and the room color. Here, the basic color is a color that is set regardless of whether it is indoors or outdoors.
For example, black, white, a color having a small color difference, a color selected at an equal sample interval in the (R, G, B) three-dimensional space, and the like. On the other hand, the room color is a color that exists a lot in the room, such as a skin color or a color used in office equipment.

In this embodiment, when the photographing condition is set to the outdoor, the palette is composed of the basic color and the outdoor color. Here, the basic color is the same as the case where the shooting condition is set to indoor, while the outdoor color is a color that is often present outdoors, such as a greenish or blueish color.

In this embodiment, when the photographing condition is set to a document or a business card, the palette is (R, G, B) = (0,
(0,0), (R, G, B) = (1,1,1), ...
As shown in (R, G, B) = (255, 255, 255), the signal values of R, G, and B are composed of equal 256 gray scale colors. This is because when shooting a document or business card, it is often required that the resolution be high, and therefore, the amount of information related to luminance is required to be greater than the fact that the captured image contains color information. It is.

After the palette is set in this way, the luminance and luminance are set using the palette data by the method shown in the first embodiment.
A conversion table for converting the color difference signal into a signal in the form of a pallet number is calculated. Then, the calculated conversion table is written in the conversion table 15.

As a result, for indoor photography and outdoor photography, it is possible to reduce the difference between the color when the photographed image is represented in the palette format and the actual color.

The resolution of a document or a business card can be increased.

(Third Embodiment) In the above-described second embodiment, the pallet data is newly rewritten and the conversion table of the imaging unit 1 is rewritten according to an instruction from the user. The imaging program determines the imaging conditions, rewrites some or all of the elements of the pallet as a result, and further rewrites the conversion table 15 of the imaging unit 1 so that the captured image is expressed in the actual color and pallet format as much as possible. This is to provide a means for reducing the difference from the substitute color when the color is changed.

In the present embodiment, it is assumed that the imaging program is provided with means for estimating whether the imaging program is shooting indoors or outdoors.

In the imaging system according to the present embodiment, for example, information indicating whether indoor or outdoor shooting is performed is
The estimation is made based on the value of R gain / B gain obtained from the signal processing circuit 14 in the imaging unit 1.

That is, in a state where the white balance is appropriate, when the value of the R gain is large, it is presumed that the outdoor is outdoors, and
When the value of the gain is large, it is presumed that the room is indoors.

Further, it can be estimated from the aperture value and the electronic shutter value in the image pickup unit 1. That is, when the aperture value is small or the exposure time of the electronic shutter is short, it is assumed that the camera is outdoors, and when the aperture value is large or the exposure time of the electronic shutter is long, the camera is assumed to be indoors.

In this embodiment, similarly to FIG. 3 shown in the second embodiment, when the photographing condition is assumed to be indoors, the palette is composed of the basic colors and skin colors, the colors of office equipment and the like. I do.

On the other hand, when the photographing condition is set to outdoor,
The palette consists of basic colors and outdoor colors such as blue and green colors.

After the palette is set in this way, a conversion table for converting the luminance / color difference signal into a signal in the form of a palette number is calculated using the palette data by the method described in the first embodiment. Then, the calculated conversion table is written in the conversion table 15.

As a result, for indoor photography and outdoor photography, it is possible to reduce the difference between the color when the photographed image is represented in the palette format and the actual color.

[0076]

As described above, according to the present invention,
In an imaging system including an imaging unit, an information processing apparatus to which the imaging unit can be connected, and an imaging program operating on the information processing apparatus, a digital signal of an image captured by the imaging unit is converted into a different image signal format. By having a rewritable conversion table and having the function of calculating the conversion table by the imaging program, it is possible to provide a means for physically converting a single conversion table into a plurality of signal formats.

Further, according to the present invention, when the user sets the conditions for photographing indoors or the conditions for photographing outdoors, the photographing program changes some or all of the elements of the pallet, and then performs the conversion. By calculating the table and rewriting the conversion table of the imaging unit, it is possible to provide a means for minimizing the difference between the actual color of the captured image and the substitute color when represented in the palette format as much as possible.

According to the present invention, when the user sets the conditions for photographing a business card or a document, the imaging program changes the elements of the palette to grayscale colors, then calculates a conversion table, and converts the conversion table of the imaging unit. By rewriting, it is possible to provide a means for increasing the resolution and making the characters easier to read.

Further, according to the present invention, when it is assumed that the imaging program has been switched to indoor photography or that it has been switched to outdoor photography, part or all of the pallet is changed, and then the conversion table is calculated. By rewriting the conversion table of the imaging unit,
It is possible to provide a means for minimizing a difference between an actual color of a captured image and a substitute color when represented in a palette format as much as possible.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of a first embodiment of the present invention.

FIG. 2 is a flowchart showing a processing operation of the first embodiment.

FIG. 3 is an explanatory diagram showing a data configuration of a pallet according to a second embodiment.

FIG. 4 is a block diagram showing a configuration of a conventional example.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 imaging unit 2 computer (information processing device) 101 lens unit 102 imaging element 103 A / D converter 104 imaging signal processing unit 105 conversion table (memory) 106 recording medium 107 PC card standard compliant external connection interface 108 control unit 109 CPU unit 110 Interface for external connection conforming to PC card standard 111 Display device 112 Storage device 113 Memory

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takashi Aizawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Makoto Hiramatsu 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inside (72) Inventor Kenichi Kondo 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc.

Claims (10)

[Claims] 1. An imaging system comprising an information processing apparatus, an imaging unit connected to and used by the information processing apparatus, and an imaging program therefor, wherein a digital signal of an image captured by the imaging unit has a different image signal format. Has a rewritable conversion table for converting to
An imaging system, wherein the conversion table is used in an imaging program that operates on the information processing apparatus. 2. The imaging system according to claim 1, wherein the imaging unit and the information processing device have connection terminals conforming to a PC card standard. 3. The conversion table can be rewritten as a conversion table for converting a digital signal of a captured image into a color number of a palette composed of a combination of 256 color numbers and red, green, and blue signal values. The imaging system according to claim 1 or 2, wherein: 4. The conversion table can be rewritten into a conversion table for converting a digital signal of a captured image into a pallet signal composed of 5 bits of a red signal component, 5 bits of a green signal component, and 5 bits of a blue signal component. The imaging system according to claim 1, wherein: 5. The imaging system according to claim 3, wherein the imaging program calculates a conversion table and rewrites the conversion table when part or all of the elements of the pallet are changed. 6. The imaging system according to claim 5, wherein the imaging program changes a part or all of the elements of the pallet according to an instruction input from a user. 7. The imaging program according to claim 6, wherein a part or all of the elements of the pallet are changed when an indoor imaging condition or an outdoor imaging condition is set.
An imaging system according to any of the preceding claims. 8. The imaging system according to claim 6, wherein the imaging program changes a part or all of the elements of the pallet when the conditions for imaging the document are set. 9. The imaging system according to claim 8, wherein the imaging program changes an element of the palette to a grayscale color. 10. The imaging program changes part or all of the elements of the pallet when it is estimated that the setting has been switched to the setting of indoor imaging conditions or when it is estimated that the setting has been switched to the setting of outdoor imaging conditions. Item 6. The imaging system according to Item 5.