JPS643113B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a pseudo-colorization method and apparatus for converting an image input replaced by a luminance signal into an arbitrary color with brightness to produce 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 is possible to obtain measurable scattered light by irradiating it randomly when it hits a bubble,
The intensity of the scattered light is thought to be proportional to the number of bubbles in a unit volume, and it has been found that the intensity of the scattered light corresponds to the concentration. but,
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 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 into R signal, G signal, and B signal, arbitrarily sets different cutoff levels for these three signals, cuts signals below that level, and outputs to a color display device, which outputs the color scheme and brightness corresponding to the brightness level. I am trying to create a color image consisting of Further, the pseudo colorization circuit of the present invention includes an RGB separate circuit that converts the luminance signal output from the TV camera into R signal, G signal, and B signal of the same level according to the brightness of the subject, and the three signals. and a cut-off circuit which arbitrarily sets different cut-off levels and cuts and outputs signals below the cut-off levels.

(Function) Therefore, an image of an object is input as a luminance signal corresponding to its brightness, and then it is once divided into RGB signals of the same level, and an arbitrary color signal is cut off at an arbitrary level. The signal is converted into a color image signal and reproduced on a color display device as a pseudocolor image according to the additive color mixing 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
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 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 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. and a cut-off circuit that cuts off color signals below a predetermined voltage level that are different from each other in the color signal circuit between the color display device 5 and the color display device 5. It creates a color image by adjusting the level. For example, as shown in FIG. 3, the cut-off circuit 7 includes a transistor 8 to which a color signal is input to the base, 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 according to 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 and beyond that. An example is a circuit in which the transistor 8 is driven only when the level of .
That is, between the emitter 9 of the transistor 8 and the ground, there is a series body of a variable resistor 9 and a resistor 11 inserted between the reference power supply 10 and the ground, and the resistance value between the emitter and the ground is The emitter side voltage level of transistor 8 is set at . Therefore, the cut-off circuit 7 operates the transistor 8 only when the voltage level of the color signal higher than the emitter side voltage level set by the variable resistor 9 is input to the base. By changing the resistance value of 9, 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. A bias circuit consisting of a capacitor 13 and a resistor 14 is connected to the emitter side of the transistor 8, and a reference power source is connected to the base side of the drive transistor 12 through a parallel body of a diode 15 and a resistor 16 together with the bias circuit. 10. In addition, in this example,
Although a cut-off circuit using an NPN transistor is mentioned, a cut-off circuit having another configuration or a cut-off circuit using other elements such as an operational amplifier may also be used.

The cutoff circuit 7 is provided in each color signal circuit between the RGB separate circuit 6 and the color display device 5, and has different operating points depending on the operation of the variable resistor 9. Therefore, when the color signal that has passed through the cut-off circuit 7 is amplified and input to the color display device 5,
Since the cut-off areas are different for each, all of the RGB signals, a combination of any two signals, one signal, or no signal are produced depending on the brightness level, thereby creating a color image. The most practical color display device 5 is a cathode ray tube, but various types of known types can be used. For example, the cathode ray tube of a color television may be used as is. Of course, it is also possible to use a color display using liquid crystal.

In the pseudo-color image system configured as above, the image of the object is input as a luminance signal corresponding to its brightness, and then the image is divided into RGB signals of the same level, and any color signal is cut off at an arbitrary level. By doing so, a color image signal is artificially created according to the additive color mixing method and is reproduced on the color display device 5 as a color image. That is, the luminance signal output from the TV camera 1 according to the brightness of the subject is divided into R and G signals of the same level in the RGB separate circuit 6.
signal, which is first converted into a B signal. Next, each color signal is set at an arbitrary cut-off level in a cut-off circuit 7 provided in each color signal circuit, and signals in a region below this level are cut-off.

For example, the R signal sets the cutoff amount to 0 and outputs all of it to the color display device 5 after amplification, while the G signal sets the low cutoff level to 1/2 of the maximum brightness level, and the B signal sets the low cutoff level to 1/2 of the maximum brightness level. By setting the maximum value of 4/5 degrees and outputting the G signal and B signal exceeding that value, the image on the color picture tube 5 will change to red or red depending on the brightness level, as shown in FIG. Displayed in pseudocolor in three colors: yellow and white. 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 is perceived by the human eye as black, dark red, red, yellow, and white.
It looks like a color. In addition, in order to clearly distinguish between black parts and dark red, the low cutoff level of the R signal can be set to about 1/5 or less of the maximum brightness level to suppress the color signal output in low brightness areas. be.

Here, the cutoff level is set by changing the resistance value of the variable resistor 9 of each cutoff circuit 7. That is, by changing the resistance value on the emitter side of the transistor 8, the operating point of the transistor 8 is changed.

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. 57-196, 095), and in this visualization device, if the diameter of the bubbles is sufficiently fine, uniform, and contained in large quantities, the intensity of the scattered light is It is thought to be proportional to the number of bubbles, that is, the bubble number density, which means that the intensity of scattered light corresponds to the concentration. Therefore, if the brightness change of scattered light is displayed in color in correspondence with the brightness level, it will be possible to visualize the fluid concentration. Changes can be visualized relatively and continuously.

(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
By converting these three signals to different cutoff levels and cutting off the signals below that level, output to the color display device, the R signal, G signal,
Since we selected and combined arbitrary B signals to create a color image consisting of a color scheme and brightness corresponding to the brightness level, we created a color image consisting of a color scheme and brightness corresponding to the brightness by using the analog image signal as is. can be created as a moving object image without cutting it into pieces. Further, the pseudo colorization circuit of the present invention includes an RGB separate circuit that converts the luminance signal output from the TV camera into R signal, G signal, and B signal of the same level according to the brightness of the subject, and the three signals. By providing a cut-off circuit that arbitrarily sets different cut-off levels and cuts and outputs signals below that level, it is possible to convert an analog black-and-white image signal into a color image signal with an arbitrary color scheme without converting it to a digital image signal. Since the image is converted, even if a high-speed, large-capacity computer is used, it is possible to achieve pseudo-color display, which could only be displayed in color on still images, at an extremely low cost without using a computer.

[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 separator, 7...cutoff circuit, 8...transistor, 9...variable resistor, 10...reference power supply.

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. A pseudo-colorization method characterized by arbitrarily setting a cut-off level, cutting signals below the cut-off level, and then outputting the cut-off level to a color display device to create a color image consisting of a color scheme and brightness corresponding to the brightness level. 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-coloring circuit comprising a cut-off circuit which arbitrarily sets different cut-off levels for the three signals and cuts and outputs signals below the cut-off levels.