JPS643114B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a pseudo-coloring method and circuit for converting an image input replaced with a luminance signal into an arbitrary color with brightness to create a color image.

(Prior Art) As one of the methods for visualizing fluid flow, there is a tracer method that allows the trend of the entire flow region to be easily observed at a glance. Among them, the bubble tracer method, which uses air bubbles as a tracer, is suitable for observing complex flows because it can be used extremely easily without contaminating the flow. However, the conventional bubble tracer method can only be used for qualitative measurements because there is no means for quantitative measurements.

However, as a result of various studies conducted by the present inventors to realize quantitative and concentration measurements using the bubble tracer method, we found that if a fluid contains fine and homogeneous bubbles densely, when light is applied, this light It was discovered that it is possible to obtain measurable scattered light by diffuse reflection when it hits a bubble, and that the intensity of the scattered light is considered to be proportional to the number of bubbles in a unit volume, which means that the intensity of the scattered light corresponds to the concentration. I came to the conclusion. However, although this luminance change allows visual observation of the overall rough density distribution and density change, it is not suitable for observing a partial and detailed density situation.

In order to make quantitative information about concentration and mixture expressed by changes in brightness easier to see and visualize,
One extremely effective method is to display colors in accordance with the intensity of brightness. This method is especially useful for researching and understanding the phenomenon of turbulent mixing in the water flow model mentioned above.

Conventionally, one of the pseudo colorization methods is
As shown in Fig. 1, the analog image signal input as an image in the image sending side (TV camera) converter A is converted into a digital image signal by a sampling circuit according to a certain sampling mode, and then is stored in the memory of computer B. There is a method that stores the image in a color image and, when reading it out, performs color designation processing in stages according to the intensity of brightness and displays it on the display C as a pseudo-color image. Here, the intensity of brightness of each pixel is classified according to the number of memory bits. For example, in the case of 4 bits, it is divided into 2 ⁴ =16 steps. Therefore, the color of the image signal/luminance signal converted into a digital signal can be specified according to the number of steps. For example, specify a color such as red if the brightness is within a certain range, blue if the brightness is lower, and green if the brightness is higher.

(Problem to be Solved by the Invention) However, in this case, the brightness change is simply expressed by a difference in color, and is not accompanied by brightness, such as bright red or dark red. That is, even if the colors are displayed in the same color, they include brightness or density with a certain range and are not accurate. In addition, in this pseudo-colorization method, an analog image signal is sampled in a certain mode, temporarily stored in computer B as a digital image signal, and then when read out, a color specification process is performed and a color image is displayed on display C. It is a thing,
Since it is a so-called still image communication method that requires processing time, it can be used when dealing with still images, but
It is insufficient to observe concentration changes in the flow field of a fluid water flow model. In other words, sampling is generally taken at 126 to 512 points on one scanning line, but even if you try to reduce the number of sampling points D to shorten the processing time on the receiving side and get closer to a moving image, the screen will be rough and lack accuracy, and on the other hand, the number of sampling points Even if you use a high-speed, large-capacity computer to speed up the processing by increasing the number of samples to increase accuracy, it will take several seconds to several minutes to obtain a still image if the number of samples is increased. It is not possible to perform pseudo-colorization processing for videos. Therefore, it cannot be used for the above-mentioned density visualization that requires precise pseudo-color display of moving body images.

In this way, although there has been a desire for a pseudo-colorization method that converts an input image into an arbitrary color image in real time, there has been no technology to achieve this.

The present invention meets the above-mentioned needs, and includes:
The first object of the present invention is to provide a pseudo-colorization method and circuit that can convert an input image converted into a luminance signal into an arbitrary color image in real time, and also to provide an extremely inexpensive pseudo-colorization device for moving object images. A second object is to provide a pseudo-coloring method that can emphasize an image output at a specific brightness level and display it brightly.

(Means for Solving the Problems) In order to achieve the above object, the pseudo colorization method of the present invention uses an RGB separate circuit to convert the luminance signals output from the TV camera to the same level according to the brightness of the subject. Converts the R, G, and B signals into R, G, and B signals, sets different low cutoff levels and high cutoff levels for these three signals, cuts signals below and above these levels, and converts the RGB signals according to the brightness level. It distributes each color signal into different brightness levels, amplifies any one color signal more than the other color signals, and outputs it together with the other color signals to a color display device, and has brightness changes and brightness within a certain range. A color image consisting of different colors is created for each level, and the brightness of the color in a specific brightness area is emphasized.
The pseudo colorization circuit of the present invention also includes an RGB separate circuit that converts the luminance signal output from the TV camera into R, G, and B signals of the same level depending on the brightness of the subject, and an RGB separate circuit that converts the three signals. A cut-off circuit that sets a low cut-off level and a high cut-off level that are different from each other, cuts signals below and above the levels, and distributes each color signal into different brightness levels according to the brightness level of the RGB signal; The present invention includes a variable gain amplifier circuit that amplifies any one of the three color signals distributed by the cutoff circuit more than the other color signals.

(Function) Therefore, after the image of the object is input as a luminance signal corresponding to its brightness, the image is once divided into RGB color signals of the same level in the RGB separation circuit 6, and each signal is divided into RGB color signals with different high cut-off levels and low cut-off levels. The signal is cut off at the cutoff level and distributed to different brightness levels, and any signal is amplified and emphasized and converted into an artificial color image signal, which is then reproduced as a pseudocolor image on a color display device according to the additive color mixing method. Ru.

(Example) The structure of the present invention will be described in detail below based on an example shown in the drawings.

FIG. 2 shows an outline of the pseudo-color image system of the present invention in a block diagram for an industrial television system as an application example. This pseudo-color image system is based on baseband transmission using a coaxial cable 2, and is
A camera 1, an amplifier circuit 3 that amplifies weak image signals and brightness signals, a pseudo color circuit 4 that converts brightness signals into color signals, and a color display device 5.
At least become. Of course, it is also possible to use modulated transmission, but in this case it goes without saying that related image signal processing circuits such as an amplitude modulation circuit and a demodulation circuit are required.

As the TV camera 1, an industrial black and white TV camera is used because a luminance signal is used in the pseudo color system of the present invention. Although it is possible to use a color television camera by extracting only the luminance signal, it is expensive and impractical.

The pseudo coloring circuit 4, as shown in FIG.
An RGB separate circuit 6 that converts a luminance signal into an R color signal (hereinafter referred to as R signal), a G color signal (hereinafter referred to as G signal), and a B color signal (hereinafter referred to as B signal) of the same level, and this RGB separate circuit 6. In the color signal circuit between the display device 5 and the color display device 5, there is a high cut-off circuit 14 that cuts off color signals above a mutually different predetermined voltage level, a low cut-off circuit 7 that cuts off color signals below a mutually different predetermined voltage level, and these cut-off circuits. circuit 14,7
a variable gain amplifier circuit 19 that amplifies any one of the R signal, G signal, and B signal distributed to different brightness level areas in the color signal with a relatively higher degree of amplification than the other color signals; The correspondingly outputted RGB signals of the same level are distributed for each predetermined luminance level, and any color signal is further amplified with a higher gain than other color signals to create a pseudo-color image.

For example, as shown in FIG. 3, the high cut-off circuit 14 inputs a color signal to the variable resistor 16, which is the base bias of the NPN transistor 15, and the collector, and when a color signal of a certain voltage level or higher is input. An example is something that causes a ground fault. This high cut-off circuit 1
4 is branched from a resistor 17 between the RGB separate circuit 6 and the low cut-off circuit 7. That is, the RGB separate circuit 6 side of the resistor 17 is grounded through a series body of the resistor 18 and the variable resistor 16, and the low cut-off circuit 7 side is connected to the input side of the variable gain amplifier circuit 19. Furthermore, the emitter side of the transistor 15 is grounded, and the base side is connected to the variable resistor 16. Therefore, by changing the resistance value of the variable resistor 16 and setting it to a certain value, the drive level between the base and emitter is determined based on this value, so that when the color signal reaches a voltage level higher than this drive level, the transistor 1
5 is driven and the color signal is grounded. As a result,
The high level of the color signal based on the setting value of the variable resistor 16 is cut off. The high cut-off circuit 14 is provided in each color signal circuit, and different drive levels, that is, high cut-off levels are set for each color signal circuit.

Furthermore, as shown in FIG. 3, for example, the low cut-off circuit 7 inputs a color signal to a variable resistor 9, which is the base bias of an NPN transistor 8, and a collector of an NPN transistor 12, and outputs a color signal below a certain voltage level. An example is one that causes a ground fault when input. This low cut-off circuit 7 has its emitter side connected to the collector of the NPN transistor 8 installed together.
The base of the NPN transistor 12 is connected to apply a bias voltage from the reference power supply 10.
Therefore, when a color signal higher than the operating point of the transistor determined by the variable resistor 9 serving as the base bias is input, the transistor 8 is driven, the bias voltage is grounded, and the transistor 1 is
2 is not driven. That is, the color signal is output without a ground fault. However, when a color signal below the operating point is input, transistor 8 is not driven and the bias voltage is lower than transistor 12.
and drives this transistor 12. That is, the color signal is grounded and is not output. A series body of a resistor 11 and a variable resistor 9 is inserted on the base side of the transistor 8, and a resistor 13 is inserted between the base side of the transistor 12 and the reference power supply 10.

Further, as shown in FIG. 3, the variable gain amplifier circuit 19 is, for example, a complementary Darlington circuit provided with a variable resistor 20 on the input base side, and is capable of changing the input signal voltage. Therefore, one example is one that results in a change in the amplification degree for the final output color signal. This variable gain amplifier circuit 19 is
The collector of the NPN transistor 21 is connected to the base of the PNP transistor 22 via the bias resistor 23, and the emitter of the NPN transistor 21 is connected to the collector of the PNP transistor 22. The output signal voltage is changed by changing the resistance value of the variable resistor 20, and as a result, the amplification degree of the entire signal 19 is made variable. Note that the reference numeral 24 is an emitter grounding resistor.

The color signal that has passed through the high cut-off circuit 14, low cut-off circuit 7, and variable gain amplifier circuit 19 is further output to the color display device 5 through necessary circuits. Color display device 5
Although it is possible to use a liquid crystal display device, it is practical and preferable to use a cathode ray tube, especially a color television tube.

In this embodiment, both cutoff circuits 7 and 14 use NPN transistors.
It is also possible to use other transistors, other elements such as operational amplifiers, or other cut-off circuits.

In the pseudo-color image system configured as described above, an image of an object is input as a luminance signal corresponding to its brightness, and then divided into RGB color signals of the same level in the RGB separation circuit 6, each of which has a different high level. Since color signals are distributed for different brightness levels by being cut off at the cutoff level and the low cutoff level, they are reproduced as a color image on the color display device 5 according to the additive color mixing method. Here, the image is colored in an arbitrary color scheme by making the cutoff points of the high cutoff circuit 14 and the low cutoff circuit 4 of each color signal circuit different.

For example, to set a high brightness band to green, set the high cutoff level to the maximum brightness level and raise the low cutoff level to the high brightness side, and to set a medium brightness band to blue, set the high cutoff level to the maximum brightness level and raise the low cutoff level to the high brightness side. Set the cutoff level to about 2/3 of the maximum brightness level, raise the low cutoff level to the medium brightness side, and set the high cutoff level to about 1/3 of the maximum brightness level to set the low brightness band to red. When the low cutoff level is set to the lowest brightness level, the image on the color picture tube 5 is displayed in pseudo color in three colors: red, blue, and green. At this time, if the low cutoff level is set slightly below the high cutoff level of the lower area, no signal areas, that is, black areas, will not be generated at the color boundaries, which is suitable for observing luminance changes. . In this case, as shown in Figure 4, red, purple, blue, cream,
Displayed in pseudo-color with five green colors. Moreover, each color has a brightness corresponding to a brightness level. For example, taking red as an example, even in the red region there are bright red, dark red, and colors intermediate between these, and if the brightness level becomes extremely low, red appears black. Therefore, this pseudo-color image appears to the human eye as six colors: black, dark red, purple, blue, cream, and green. still,
In order to clearly distinguish between the black part and the dark red,
By setting the low cutoff level of the R signal slightly higher than the lowest luminance level, the color signal output in a low luminance region may be suppressed.

In this way, a color image having brightness and having an arbitrary color scheme can be obtained in correspondence with the brightness level. By the way, in the case of this color image, there is a possibility that it becomes difficult to observe changes in brightness in a low luminance level region due to a decrease in brightness. Therefore, it is possible to relatively amplify the color signal in the low luminance area, that is, the R signal, in the variable gain amplifier circuit 19 than other color signals, and make it bright and emphasized. This increases the resistance value of the variable resistor 20 of the G signal circuit and the B signal circuit to lower the input signal voltage, while lowering the resistance value of the variable resistor 23 of the R signal circuit to relatively increase the input signal voltage. As a result, the R signal is amplified more than the G signal and the B signal. Of course, if the resistance value of each variable resistor 20 in each color signal circuit is preset to a high value, it is sufficient to reduce only the resistance value of the R signal. As a result, it is possible to construct a color screen in which images in low-luminance areas are extracted brightly.

In this embodiment, the color signal after cutoff processing is input to the variable gain amplifier circuit 19 to greatly amplify only the desired color signal, but the color signal after high cutoff or the color signal after low cutoff is input to the variable gain amplifier circuit 19. The color signal may be input to the variable gain amplifier circuit 19. However, it is difficult to cut off the amplified signal, especially high cut-off, so it is preferable to input the color signal after high cut-off to the variable gain amplifier circuit. In this case, it is necessary to increase the low cut-off point in the greatly amplified color signal circuit in accordance with the degree of amplification.

The pseudo-color image system configured in this manner can be usefully used to display objects in color in response to changes in brightness. For example, the present inventors have developed a visualization device that reproduces the flow field of a water flow model using a fluid containing a large amount of fine and uniform air bubbles, illuminates it with a slit beam, and visualizes the flow field of an arbitrary cross section using scattered light. Therefore, it has already been proposed (Japanese Patent Application No. 57-196095), and in this visualization device, if the diameter of the bubbles is sufficiently fine and uniform, and a large number of bubbles are included, the intensity of the scattered light is equal to the number of bubbles in a unit volume. In other words, it is considered to be proportional to the bubble number density, which means that the intensity of the scattered light corresponds to the concentration. Therefore, if the brightness change of the scattered light is displayed in color in correspondence with the brightness level, it will be possible to see the fluid concentration change. This allows for relative and continuous visualization. Moreover, by amplifying any color signal with a higher gain than other signals in the color signal circuit, any brightness area, that is, density area, can be brightly emphasized. Therefore, when reproducing a flow field involving combustion or reaction, there is a certain relationship between bubble density and brightness, which indicates the presence and amount of fuel or combustion air.
A region where fuel and combustion air are mixed at a desired ratio can be easily extracted and displayed from a color image of the entire flow field.

(Effects of the Invention) As is clear from the above explanation, the pseudo colorization method of the present invention converts the luminance signal output from the TV camera according to the brightness of the subject into an R signal of the same level using an RGB separate circuit. , G signal, B
convert the signals into signals, set different low cut-off levels and high cut-off levels for these three signals, and cut signals below and above the levels.
By distributing the RGB signals into different brightness levels according to the brightness level, amplifying any one color signal more than the other color signals, and outputting the same to the color display device along with the other color signals, By creating a color image that has brightness changes and consists of different colors for each brightness level within a certain range, and emphasizing the brightness of the color in a specific brightness area, the analog image signal can be used as is to adjust the brightness of the subject. It is possible to create a color image consisting of a corresponding color scheme and brightness as a moving object image without cutting it, and to emphasize the brightness of a color corresponding to a specific brightness. In addition, the pseudo colorization circuit of the present invention can adjust the color of the TV according to the brightness of the subject.
An RGB separate circuit that converts the luminance signal output from the camera into R, G, and B signals of the same level, and sets the three signals to different low cut-off levels and high cut-off levels to lower and lower levels. Cuts the signals above and RGB
a cut-off circuit that distributes each color signal into different brightness levels according to the brightness level of the signal;
Since a variable gain amplifier circuit is provided that amplifies any one of the three color signals distributed by the cut-off circuit more than the other color signals, the analog black-and-white image signal is not converted into a digital image signal. Since it is converted into a color image signal with an arbitrary color scheme and only the arbitrary color signal is relatively amplified and output, it is possible to directly emphasize and brighten the image output at a specific brightness level from the analog image signal without using a computer or the like. Displayed pseudocolor images can be produced very inexpensively.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an outline of a conventional pseudo-coloring system, Fig. 2 is a schematic block diagram of a pseudo-coloring image system showing an example of the pseudo-coloring system according to the present invention, and Fig. 3 is a schematic block diagram of a pseudo-coloring image system. The circuit diagram, FIG. 4, is a principle diagram showing pseudo coloring. 1...TV camera, 4...pseudo coloring circuit, 5...
Color display device, 6...RGB separate circuit, 7...Low cut-off circuit, 14...High cut-off circuit, 19...Variable gain amplifier circuit.

Claims (1)

[Claims] 1. The luminance signal output from the TV camera according to the brightness of the subject is converted into R, G, and B signals of the same level by an RGB separate circuit, and these three signals are converted into different signals. Set the low cut-off level and high cut-off level to cut signals below and above the level, distribute the RGB signals to different brightness levels according to the brightness level, and cut off any one color signal. is amplified more than other color signals and output to a color display device along with other color signals to create a color image that has brightness changes and consists of different colors for each brightness level within a certain range, and also to display colors in a specific brightness area. A pseudocolorization method characterized by emphasizing brightness. 2. Depending on the brightness of the subject, the brightness signals output from the TV camera are converted into R and G signals of the same level.
RGB separate circuit that converts the signal and B signal,
A cut-off circuit that sets different low cut-off levels and high cut-off levels for the three signals, cuts signals below and above these levels, and distributes the RGB signals into different brightness levels according to the brightness level. and a variable gain amplification circuit that amplifies any one color signal of the three signals distributed by the cut-off circuit more than the other color signals.