JP2004274334A - System and method for displaying monochromatic image, and device for converting image signal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a monochromatic image display system capable of obtaining an image suitable for a monitor. <P>SOLUTION: A CCD camera 21 outputs imaged color image signals (three primary color signals R, G, and B). The image signal processing part 23 of an image conversion device 25 makes setting such that the proportions of R, G, and B signal components become equal in generating a luminance signal Y and outputting the luminance signal Y to an EL panel 3 for displaying a monochromatic image as a back guide monitor for a vehicle. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a monochrome image display system that converts and generates a monochrome image signal based on R, G, and B signals of a captured color image and displays a monochrome image, an image signal conversion device used in the system, and a monochrome image display device. It relates to an image display method.
[0002]
[Prior art]
For example, in a vehicle back guide monitor system or a corner monitor system as shown in FIG. 9, an image of a corner portion or a rear portion around the vehicle 1 is captured by a monochrome CCD camera 2 and output from the CCD camera 1. A monochrome image is displayed on the display 10 based on the image signal.
[0003]
FIG. 10 shows the configuration of the display device 10 by functional blocks. The CCD camera 2 outputs an analog image signal based on the NTSC (National Television System Committee) system to the display 10. The image signal is A / D converted and filtered in the signal processing unit 4 on the display 10 side, and the signal components of a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a dot clock DCLK, and a luminance signal Y are discriminated. Is output.
[0004]
Of these, three signals Vsync, Hsync, and DCLK are output to the controller 5, and the luminance signal Y is output to the gamma correction circuit 6. The controller 4 generates the shift clock RCLKSH, the latch enable RLE, and the data RDATA based on the applied signals and outputs them to the row (scanning side) driver 7, and generates the shift clock CCLKSH and the latch enable CLE. Output to the column driver 8.
[0005]
The EL panel 3 includes, for example, organic EL as pixels, is driven by a row driver 7 and a column driver 8, and displays a monochrome image in a simple matrix system. A technique for correcting an image signal using the γ correction circuit 6 is disclosed in, for example, FIG.
[0006]
On the other hand, the γ correction circuit 6 performs γ correction on the luminance signal Y according to the characteristics of the EL panel 3, and outputs correction result data to the memory 9. The memory 9 is provided with a write address WADDR and a read address RADDR from the controller 5 to control writing and reading of data. Then, the data read from the memory 9 is output to the column driver 8 as data CDATA.
[0007]
[Patent Document 1]
JP 2001-326822 A
[Problems to be solved by the invention]
In the display device 10 having the above-described configuration, the color of the actual imaging target is converted into a monochrome image by the CCD camera 2 taking an image, and how each color is expressed in the monochrome image depends on the luminance. Determined by signal Y. As the luminance signal Y, a signal determined so that the color tone display in the monochrome image is the same is used. For example, when the luminance signal Y for monochrome display is generated from the RGB three primary color signals obtained in a color image, the ratio is generally as follows.
Y = 0.30R + 0.59G + 0.11B (1)
[0009]
However, when monitoring is performed on a monochrome image obtained by the display device 10 having the above-described configuration, when different colors have the same luminance component, there is a problem that it is difficult to identify an object. For example, in the case where a blue obstacle is present on a road surface that is close to black, such as asphalt, both are captured with the same luminance on the EL panel 3 and it is difficult to distinguish them.
[0010]
However, since the luminance signal Y is determined by the NTSC signal generated in advance inside the CCD camera 2 and output to the outside, conventionally, the ratio of the luminance corresponding to the actual color reflected on the monochrome image There was virtually no means for adjusting the.
Note that the gamma correction circuit 6 disclosed in Patent Document 1 corrects the luminance signal Y generated based on the equation (1) according to the characteristics of the EL panel 3, and thus solves the above problem. It is needless to say that the correction for performing the correction is not performed.
[0011]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a monochrome image display system and a monochrome image display method capable of obtaining an image suitable for a monitor.
[0012]
[Means for Solving the Problems]
According to the monochrome image display system of the first aspect, the imaging device outputs R, G, and B primary color signals for the captured color image. Then, the signal conversion means of the image conversion device sets the ratio ER of the R signal component to 0.30 <for the ratio EG of the G signal component of 0.59 when generating the luminance signal constituting the monochrome image signal. ER ≦ EG, the ratio EB of the B signal component is set to 0.11 <EB ≦ EG.
[0013]
That is, by setting the ratio of the R signal component and the B signal component in the luminance signal generated for a monochrome image to be larger than the ratio with respect to the conventional G signal component, visibility may be difficult depending on the background state. The red or blue object can be easily recognized even in a monochrome image. Therefore, an image suitable for monitoring can be obtained.
[0014]
According to the monochrome image display system of the second aspect, the signal conversion means sets the ratios EG, ER, and EB of the R, G, and B signal components to be substantially the same. That is, according to the inventors of the present invention, by setting the ratios of the R, G, and B signal components to be substantially the same, the visual recognition of a red or blue object in a monochrome image can be performed better than in the past. It was confirmed that it could be done.
[0015]
According to the monochrome image display system of the third aspect, the signal conversion means displays the same image three times with the brightness corresponding to each of the R, G, and B signals. With such a configuration, the proportions of the R, G, and B signal components in the monochrome image become substantially the same on average, so that the same effect as in claim 2 can be obtained.
[0016]
According to the monochrome image display system of the fourth aspect, when the same image is displayed three times at a luminance corresponding to each of the R, G, and B signals, the same image is repeated at a frequency of 180 Hz or more. The total scanning cycle is 60 Hz or more, and the occurrence of flicker can be prevented.
[0017]
According to the monochrome image display system of the fifth aspect, the present invention is applied to a vehicle-mounted display unit. That is, in a vehicle, a back guide monitor, a corner monitor, and the like are often performed using a monochrome image, so that the present invention can be effectively applied to a display device mounted on a vehicle. In particular, an image captured from the vehicle side often has a dark road surface such as asphalt as a background. Therefore, it is preferable to apply the present invention, because even if blue or red obstacles are placed on the road surface, they can be easily visually recognized.
BEST MODE FOR CARRYING OUT THE INVENTION
(First embodiment)
Hereinafter, a first embodiment in which the present invention is applied to a back guide monitor of a vehicle as in FIG. 9 will be described with reference to FIGS. 9 and 10 are denoted by the same reference numerals and description thereof will be omitted, and only different portions will be described below. The CCD camera 2 is replaced by a CCD camera (imaging device) 21 capable of shooting a color image, and the signal processing unit 4 is also replaced by a signal processing unit 22 accordingly.
[0019]
The control signal output from the signal processing unit 22 to the controller 5 is the same as that shown in FIG. 8 except that the signal processing unit 22 replaces the luminance signal Y with an 8-bit digital signal of the three primary color image signals output from the CCD camera 21. The data, that is, R (Red) [7: 0], G (Green) [7: 0], and B (Blue) [7: 0] are output to the image signal processing unit (signal conversion unit) 23. ing.
[0020]
The image signal processing unit 23 generates a luminance signal Y for monochrome display based on the three primary color image data based on the equation (2).
Y = (R + G + B) / 3 (2)
That is, unlike the expression (1), the image signal processing unit 23 generates the luminance signal Y by adding the three primary color image data at the same ratio and dividing the result by "3", that is, the average value.
[0021]
The luminance signal Y output from the image signal processing unit 23 is written directly into the memory 9 by the controller 5. The memory 9 is configured as a dual-port memory, so that writing and reading of data can be executed in parallel.
[0022]
Other configurations are the same as those of the display 10, and the above constitutes the display 24. The display 24 except for the EL panel (display means) 3 constitutes an image signal conversion device 25, and the CCD camera 21 and the display 24 constitute a monochrome image display system 26.
[0023]
FIG. 2 shows a detailed configuration of the row driver 7. In addition, for convenience of illustration, the number of row-side electrodes of the EL panel 3 is five. The row driver 7 includes a 5-bit shift register 27 (RSR1 to RSR5) and a 5-bit latch 28 (RL1 to RL5). The clock signal RCLKSH output from the controller 5 is supplied to the clock input terminal of each shift register 27, and the data RDATA is supplied to the first-stage shift register 27 (RSR1). The latch signal RLE output by the controller 5 is given to each latch 28. Each latch 28 latches the data output by the corresponding shift register 27, and outputs the scanning signals RO1 to RO5 to the respective latches 28. Output to the row side electrode.
[0024]
FIG. 4 shows a detailed configuration of the column driver 8. Again, for convenience of illustration, the number of column-side electrodes of the EL panel 3 is four. The column driver 8 includes four 8-bit shift registers 29 (CSR1 to CSR4), four 8-bit latches 30 (CL1 to CL4), and four 8-bit D / A converters 31 (DA1 to DA4). Have been.
[0025]
The clock signal CCLKSH output by the controller 5 is applied to the clock input terminal of each shift register 29, and the data CDATA is applied to the first-stage shift register 29 (CSR1). The latch signal CLE output from the controller 5 is given to each latch 30. Each latch 30 latches the data output from the corresponding shift register 27 and outputs the data to the D / A converter 31. . The D / A converter 31 converts the data supplied from the latch 30 into an analog signal and outputs data signals CO0 to CO4 to each data electrode.
[0026]
Next, the operation of the present embodiment will be described with reference to FIGS. 3 and 5 are timing charts showing the operation of the row driver 7 and the column driver 8, respectively. The controller 5 controls the drivers 7 and 8 at a timing based on a control signal provided from the signal processing unit 22.
[0027]
As shown in FIG. 3, the clock signal RCLKSH for the row driver 7 rises at an intermediate phase between the scanning timings T0, T1, T2,. The latch signal RLE rises at each scanning timing. Then, the controller 5 outputs the low-level data RDATA at the timing T0 which is the beginning of the scanning cycle. Then, the shift register RSR1 outputs RDATA to the next stage at the rising timing of the clock signal RCLKSH, and the latch RL1 latches the low-level data RDATA by the latch signal RLE rising at timing T1, and outputs the scanning signal RO1.
[0028]
Thereafter, since the low-level data RDATA is sequentially shifted by the clock signal RCLKSH, the scanning signals RO2 to RO5 are similarly output at the respective scanning timings T2 to T5.
[0029]
On the other hand, as shown in FIG. 5, the clock signal CCLKSH for the column driver 8 is set to be four times the frequency of the clock signal RCLKSH. Further, the latch signal CLE rises at each scanning timing, similarly to the latch signal RLE. Then, during the scanning timings T0 to T1, that is, during the period (0), the controller 5 serially reads 4-byte data from the memory 9 for outputting the data signals CO0 to CO4 to the respective data electrodes (for example, FFH). , 00H, BFH, 7FH).
[0030]
Then, the read data is shifted one byte at a time to the shift registers CSR1, CSR2, CSR3, and CSR4. When the latch signal CLE rises at the scanning timing T1, the data of each shift register 29 is collectively latched by the corresponding latch 30, and the four data electrodes apply the data signal CO0 corresponding to each data value. To CO4 are output simultaneously.
[0031]
Then, in the next period (1), data for outputting the data signals CO0 to CO4 in the next period (2) is read from the memory 9 and shifted by the shift register 29.
[0032]
In this case, the data read from the memory 9 is the luminance signal Y for monochrome display generated by the image signal processing unit 23 based on the expression (2). Therefore, the monochrome image display on the EL panel 3 is performed with a monochrome gradation corresponding to the luminance signal Y.
[0033]
As described above, according to the present embodiment, the CCD camera 21 outputs the captured color image signals (three primary color signals R, G, and B), and the image signal processing unit 23 of the image conversion device 25 sends the image signals to the EL panel 3. When generating and outputting the luminance signal Y for displaying a monochrome image, the ratios of the R, G, and B signal components were set to be the same based on the equation (2).
[0034]
That is, by setting the ratio of the R signal component and the B signal component in the luminance signal Y to be larger than that of the conventional G signal component, a red or blue object that sometimes becomes difficult to see depending on the background state. Can be easily visually recognized even in a monochrome image. Then, since the ratios of the R, G, and B signal components are set to be the same, it is possible to more appropriately determine the visibility of a red or blue object in a monochrome image. Therefore, an image suitable for a monitor can be obtained.
[0035]
In addition, by adopting such a configuration, the reflection ratio of green in the luminance of the monochrome image is relatively reduced, but the inventors have found that there is no effect that hinders the recognition of the object as the monitor image. Have confirmed.
[0036]
Further, the monochrome image display system 26 is applied to the EL panel 3 which displays a monochrome image as a back guide monitor for a vehicle. That is, the present invention is extremely effective for a back guide monitor that needs to perform monochrome display at low cost. In particular, an image captured from the vehicle side often has a dark colored road surface such as asphalt as a background. Therefore, if the present invention is applied, a blue or red obstacle is placed on such a road surface. This makes it easy to visually recognize them even in the case where they are placed, which is preferable (second embodiment).
FIGS. 6 to 8 show a second embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. Hereinafter, only different parts will be described. In the second embodiment, the controller 5 is replaced by the controller 31. Further, the image signal processing unit 23 is deleted, and instead of the memory 9, memories 32R, 32G, and 32B corresponding to image data of each of R, G, and B are arranged. That is, the data Red [7: 0] is written to the memory 32R, the data Green [7: 0] is written to the memory 32G, and the data Blue [7: 0] is written to the memory 32B at the same timing.
[0037]
Further, data read from these memories 32R, 32G, 32B is given to the column driver 8 via the multiplexer 33. The control of the multiplexer 33 is performed by the controller 31 outputting a 2-bit select signal SEL. The relationship between the select signal SEL and the selected data is as follows.
SEL = 0H → CDATA = Data R
SEL = 1H → CDATA = Data G
SEL = 2H → CDATA = Data B
SEL = 3H → CDATA = 0 (not selected)
Other configurations are the same as in the first embodiment.
[0038]
The controller 31, the memories 32R, 32G, 32B, and the multiplexer 33 constitute a signal conversion unit 34, and the signal processing unit 22, the signal conversion unit 34, the drivers 7 and 8, and the EL panel 3 constitute a display 35. are doing. Further, the display 35 excluding the EL panel 3 constitutes an image signal conversion device 36, and the CCD camera 21 and the display 35 constitute a monochrome image display system 37.
[0039]
Next, the operation of the second embodiment will be described with reference to FIGS. FIGS. 7 and 8 are timing charts of the drivers 7 and 8, which are different from the first embodiment in the operation timing. As shown in FIG. 7, in the second embodiment, a scanning cycle corresponding to image data of each of R, G, and B is set to one during scanning timings T0 to T5 corresponding to one scanning cycle in the first embodiment. It is to be executed every time.
[0040]
That is, the scanning timings TR-0 to TR-4 are scanning periods corresponding to the red image data R, the scanning timings TG-0 to TG-4 are green image data G, and the scanning timings TB-0 to TB-4 are The scanning cycle corresponds to the blue image data B. In the second embodiment, TR-0 to TG-0, TG-0 to TB-0, and TB-0 to TR-0 have a length of 5.5 msec or less. That is, since each scanning cycle is 180 Hz or more, the total scanning cycle for the three colors is set to 60 Hz or more.
[0041]
At the same time, as shown in FIG. 8, on the column driver 8 side, the controller 31 causes each of the colors R, G, B to be scanned during one scanning period TX-0 to TX-1 (X = R, G, B). Is read from the memories 32R, 32G, and 32B and output to the column driver 8 via the multiplexer 33.
[0042]
That is, when X = R, the controller 31 outputs the select signal SEL = 0H to select the data read from the memory 32R. When X = G, a select signal SEL = 1H is output to select data from the memory 32G, and when X = B, a select signal SEL = 2H is output to select data read from the memory 32B. The conditional expression of the select signal SEL shown at the bottom of FIG. 8 shows the above condition.
Each color data read within one scanning cycle is the same data as an image pattern except for a color difference.
[0043]
By performing such control, the EL panel 3 includes, as monochrome images, an image based on only red data, an image based on only green data, and an image based on only blue data in one scanning cycle. (At the given brightness) once each, for a total of three times. Repeating this display pattern is equivalent to equalizing the weights for the data of each color as in the first embodiment.
[0044]
According to the second embodiment configured as described above, the signal conversion means 34 displays the same monochrome image on the EL panel 3 three times with the brightness corresponding to each of the R, G, and B signals. I tried to make it. Accordingly, the proportions of the R, G, and B signal components in the monochrome image are the same on average, and the same effects as in the first embodiment can be obtained.
[0045]
In addition, since the operation is repeated at a frequency of 180 Hz or more for each of the R, G, and B signals, the total scanning cycle for the three colors becomes 60 Hz or more, and the occurrence of flickering can be prevented.
[0046]
The present invention is not limited to the embodiment described above and shown in the drawings, and the following modifications or extensions are possible.
In the first embodiment, the expression for obtaining the luminance signal Y is not limited to the expression (2). In other words, it is not always necessary to make the ratio of the data of each color the same. Conventionally, the ratio of the G signal component and the coefficient EG = 0.59 used in the equation (1) for obtaining the luminance signal Y is compared with the R signal component. May be set in the range of 0.30 <ER ≦ EG, and the ratio EB of the B signal component may be set in the range of 0.11 <EB ≦ EG. With such a configuration, it is possible to obtain an effect that the visual recognition of a red or blue object in a monochrome image is improved at least as compared with the related art.
[0047]
In the second embodiment, the controller 31 is configured to simultaneously read out the data by simultaneously outputting RADDR [12: 0] to the memories 32R, 32G, and 32B. The controller 31 may output a read control signal to each of the memories 32R, 32G, and 32B so that reading is performed separately.
The display means is not limited to the EL panel 3 having an organic EL element as a pixel, but can be applied to any device that displays a monochrome image.
The present invention is not limited to a display unit for a vehicle, and can be widely applied to any display unit that displays a monochrome image.
By adopting the method as in the second embodiment, one monochrome image is output using three 8-bit images. Therefore, the number of gradations is 3 instead of simply outputting an 8-bit monochrome image. This has the effect of doubling.
[Brief description of the drawings]
FIG. 1 is a functional block diagram illustrating a configuration of a monochrome image display system according to a first embodiment in which the present invention is applied to a back guide monitor of a vehicle. FIG. 2 is a diagram illustrating a detailed configuration of a row driver. 3 is a timing chart showing the operation of the row driver. FIG. 4 is a diagram showing a detailed configuration of the column driver. FIG. 5 is a timing chart showing the operation of the column driver. FIG. 6 is a diagram showing a second embodiment of the present invention. FIG. 7 is a diagram corresponding to FIG. 3 FIG. 8 is a diagram corresponding to FIG. 5 FIG. 9 is a diagram showing an outline of a conventional back guide monitor of a vehicle FIG. 10 is a diagram corresponding to FIG.
3 is an EL panel (display means), 21 is a CCD camera (imaging device), 23 is an image signal processing unit (signal conversion means), 24 is a display, 25 is an image signal conversion device, 26 is a monochrome image display system, 34 Denotes a signal conversion means, 35 denotes a display, 36 denotes an image signal conversion device, and 37 denotes a monochrome image display system.

Claims (10)

An imaging device configured to output R, G, and B primary color signals for a captured color image;
In order to display a monochrome image on a display means, in a monochrome image display system comprising an image signal conversion device having a signal conversion means for converting and generating a monochrome image signal based on the R, G, B signals,
The signal conversion unit sets the ratio EG of the G signal component to 0.59 when generating the luminance signal that constitutes the monochrome image signal.
When the ratio ER of the R signal component is 0.30 <ER ≦ EG,
A monochrome image display system, wherein a ratio EB of a B signal component is set to 0.11 <EB ≦ EG. 2. A monochrome image display system according to claim 1, wherein said signal conversion means sets the ratios EG, ER, and EB of the R, G, and B signal components to be substantially the same. An imaging device configured to output R, G, and B primary color signals for a captured color image;
In order to display a monochrome image on a display means, in a monochrome image display system comprising an image signal conversion device having a signal conversion means for converting and generating a monochrome image signal based on the R, G, B signals,
The monochrome image display system according to claim 1, wherein the signal conversion means displays the same image three times at a luminance corresponding to each of the R, G, and B signals. 4. The monochrome image display system according to claim 3, wherein, when the same image is displayed three times at a luminance according to each of the R, G, and B signals, each is repeated at a frequency of 180 Hz or more. The monochrome image display system according to any one of claims 1 to 4, wherein the monochrome image display system is applied to an on-vehicle display unit. An image conversion apparatus used in the monochrome image display system according to claim 1. A monochrome image display method for converting and generating a monochrome image signal based on R, G, and B primary color signals of a captured color image and displaying the monochrome image on a display means,
When the luminance signal constituting the monochrome image signal is generated, if the ratio EG of the G signal component is set to 0.59,
When the ratio ER of the R signal component is 0.30 <ER ≦ EG,
A monochrome image display method, wherein a ratio EB of a B signal component is set to 0.11 <EB ≦ EG. 8. The monochrome image display method according to claim 7, wherein the ratios EG, ER, and EB of the R, G, and B signal components are set to be substantially equal. A monochrome image display method for converting and generating a monochrome image signal based on R, G, and B signals of a captured color image and displaying the monochrome image on a display unit.
A method of displaying a monochrome image, wherein the same monochrome image is displayed three times at a luminance corresponding to each of the R, G, and B signals. 10. The monochrome image display method according to claim 9, wherein when the same image is displayed three times at a luminance corresponding to each of the R, G, and B signals, the display is repeated at a frequency of 180 Hz or more.

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