JPS643112B2 - - 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 We 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 rough density distribution and density change as a whole, 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 record 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 inexpensive pseudo-colorization device for moving object images. Second thing
The purpose of

(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 these three signals into R, G, and B signals, sets different low cutoff levels and high cutoff levels, cuts signals below and above these, and outputs each color signal at different brightness levels. The images are distributed and output to a color display device to create a color image with a color scheme and brightness corresponding to the brightness level. Further, the pseudo coloring circuit of the present invention converts the brightness signals output from the TV camera into R signals, G signals, which have the same level, depending on the brightness of the subject.
An RGB separate circuit that converts the three signals into B signals, and a cutoff that sets different low cutoff and high cutoff levels for the three signals, cuts signals below and above these levels, and distributes each color signal to different brightness levels. It has a circuit.

(Function) Therefore, the image of the object is inputted as a luminance signal corresponding to its brightness, and then divided into RGB signals of the same level, which are then cut off at different high cut-off levels and low cut-off levels. is converted into an artificial color image signal distributed into different brightness levels and reproduced on a color display device as a pseudocolor image according to the additive color method.

(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 connected to a TV for imaging.
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.
Consisting of at least Of course, it is also possible to use modulation transmission, but in this case it goes without saying that image signal related 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 RCB 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. and the color display device 5, the cut-off circuit includes a high cut-off circuit 17 that cuts off color signals above a mutually different predetermined voltage level, and a low cut-off circuit 7 that cuts off color signals below a mutually different predetermined voltage level. are composed of two signals of the same level that are output in response to the luminance signal.
It uses RGB signals at different voltage levels to create color images.

For example, as shown in FIG. 3, the high cut-off circuit 17 connects the color signal to a variable resistor 19 which is the base bias of the transistor 18.
An example is one that inputs the color signal to the collector to ground the color signal above a certain level, and is branched from the resistor 20 between the RGB separator 6 and the low cut-off circuit 7. In this high cut-off circuit 17, the resistor 20
The RGB separator 6 side is grounded through a series resistor 21 and variable resistor 19, and the low cut-off circuit 7 side is connected to the collector of the transistor 18. Further, the emitter side of the transistor 18 is grounded, and the base side is connected to the variable resistor 19. Therefore, by changing the resistance value of the variable resistor 19 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 18 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 19 is cut off. Note that this high cut-off circuit 17 is
Each color signal circuit is provided with a different drive level, that is, a high cut-off level.

A low cut-off circuit 7 is provided at the next stage of the high cut-off circuit 17. As shown in FIG. 3, the low cut-off circuit 7 includes, for example, a transistor 8 to which a color signal is input to the base side, a variable resistor 9 inserted between the emitter of the transistor 8 and the ground, and a bias circuit. The operating point of the transistor 8 is set by the resistance value of the variable resistor 9 on the emitter side, and the color signal input to the base is set at a voltage level determined based on the operating point. An example is a circuit in which the transistor 8 is driven only when the level is higher than that level. That is, a variable resistor 9 inserted between the reference power supply 10 and the ground is connected between the emitter of the transistor 8 and the ground.
There is a series body consisting of a resistor 11 and a resistor 11, and the voltage level on the emitter side of the transistor 8 is set by the resistance value between the emitter and the ground. Therefore, this low cut-off circuit 7 operates the transistor 8 only when a color signal voltage higher than the emitter side voltage level set by the variable resistor 9 is input to the base. By changing the resistance value of the color signal, the low level region of the color signal corresponding to the value is cut out and not output.
Further, the collector of the transistor 8 is directly connected to the emitter of the drive transistor 12, and is provided so as to amplify the cut-off color signal and output it to the color display device 5. still,
A capacitor 13 is connected to the emitter side of the transistor 8.
and a resistor 14, and the base side of the drive transistor 12 is connected to the reference power source 10 together with the bias circuit through a parallel body of a diode 15 and a resistor 16. The low cut-off circuit 4 is provided in each color signal circuit between the high cut-off circuit 17 and the color display device 5, and has different operating points depending on the operation of the variable resistor 9. Further, this low cut-off circuit 7 is similar to the high cut-off circuit 1.
It is also possible to insert it in the previous stage of the color display device 5, first cut off the low cut off, and then cut off the high cut off before outputting it to the color display device 5.

Therefore, when the color signals that have passed through the high cut-off circuit 17 and the low cut-off circuit 7 are amplified and input to the color display device 5, the cut-off areas are different, so that the color signals are divided into different areas (edges) depending on the brightness level. (including cases where they overlap), creating a color image. In this embodiment, both cutoff circuits 7 and 17 use NPN transistors, but other cutoff circuits may be used, such as those using other transistors or other elements such as operational amplifiers. It can also be a circuit.

Further, the most practical color display device 5 is a cathode ray tube, but various known types can be used. For example, the cathode ray tube of a color television may be used as is.

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 signals of the same level, each of which has a different high cut-off level and low cut-off level. By being cut off at the off level and distributed to different brightness levels, a color image signal is artificially created and reproduced as a color image on the color display device 5 according to the additive color mixing method.

That is, the brightness signal output from the TV camera 1 according to the brightness of the subject is sent to the RGB separate circuit 6.
The R signal, G signal, and B signal are at the same level as each other.
It is first converted into a signal. Next, each color signal is cut off in cutoff circuits 7 and 17 provided in each color signal circuit in different regions above and below a set high cutoff level and below a low cutoff level, respectively.

For example, to set the 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 the 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 cut-off 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 FIG. 4, pseudo-color display is performed in five colors: red, purple, blue, cream, and green. 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. Note that, in order to clearly distinguish between black parts and dark red, the low cutoff level of the R signal may be set slightly higher than the lowest brightness level to suppress the color signal output in the low brightness area. Here, each setting of the high cutoff level and low cutoff level is set for each cutoff circuit 1.
This is done by changing the resistance values of variable resistors 19 and 9 of 7 and 7.

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.

(Effects of the Invention) As is clear from the above explanation, the pseudo colorization method of the present invention converts the luminance signals output from the TV camera according to the brightness of the subject into R signals of the same level by RGB separate circuits. It converts these three signals into G and B signals, sets different low cut-off levels and high-cut levels, cuts signals below and above these levels, and distributes each color signal to different brightness levels. By outputting to a color display device, the R signal, G signal, and B signal are distributed to different areas according to the brightness level and colored, so the analog image signal can be used as is and the color scheme corresponding to the brightness can be created. A color image consisting of brightness can be created as a moving object image without fragmenting it. Furthermore, the pseudo colorization circuit of the present invention 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.
By providing an RGB separate circuit and a cut-off circuit that sets different low cut-off levels and high-cut levels for the three signals, cuts signals below and above these levels, and distributes each color signal to different brightness levels. By converting the analog black and white image signal into a color image signal with an arbitrary color scheme without converting it to a digital image signal, even if a high-speed, large-capacity computer is used, it is still possible to display only static images in color. Colorization can be achieved at an extremely low cost without using a computer or the like.

[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 picture tube, 6...RGB separate circuit, 7...Low cut-off circuit, 8...Transistor, 9...Variable resistor, 10...Reference power supply, 1
7...High cut-off circuit, 18...Transistor, 19...Variable resistor, 20...Resistor.

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. By setting a low cutoff level and a high cutoff level, and cutting signals below and above these levels, each color signal is distributed to different brightness levels and output to a color display device, and the color scheme and brightness corresponding to the brightness level are determined. A pseudocolorization method characterized by creating a color image consisting of 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 pseudo color device characterized by having a cut-off circuit that sets different low cut-off levels and high cut-off levels for three signals, cuts signals below and above these levels, and distributes each color signal to different brightness levels. circuit.