JPS60244162A - How to adjust the aperture of an ITV camera - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] An image containing an object (for example, a combustion flame) measured using an ITV camera or the like is captured into an electronic meter board, and at least This invention relates to a method for accurately measuring an object in an image by separating it into two regions and adjusting the direction and amount of the aperture of the camera.

[Background of the invention]

Traditionally, the aperture of cameras and other devices was adjusted based on the experience and intuition of the operator, but 1. ~I/-11't Most cameras (not including ITv cameras) are equipped with light-receiving elements. The newest type has a structure in which a light receiving element receives light from the front of the camera and automatically adjusts the aperture to an IP7-appropriate aperture using a microcomputer. However, since the light-receiving element receives the average light t in front of the camera, there is a serious problem in that when capturing an object with a large difference in brightness and darkness, the aperture may be incorrectly adjusted.

On the other hand, in TV cameras, the above-mentioned structure is hardly adopted, and the iris is currently adjusted by the operator relying on his experience and intuition while watching the TV monitor. When using such an ITV camera to monitor combustion flames during boiler operation, for example, the brightness of the flame changes depending on the load and type of fuel, which can lead to insufficient light or ration. Even if the combustion condition was monitored using a TV monitor, it was very difficult to judge the combustion state accurately, and the operator had to rely on his experience and intuition, which was a big burden.

Recently, an apparatus has been proposed that measures a combustion flame, processes the image, and determines and monitors the combustion state from the shape characteristics obtained as a result of the processing.

However, in general, the conditions under which the object is measured has a great influence on the subsequent image processing method and processing speed. Recently proposed devices measure the flame and the base of the flame with a fixed aperture, so changes in the load and type of fuel can result in insufficient light or halation. There was a problem with being left behind. In other words, when the aperture of the ITv camera was set at low loads, halation occurred near the rated load, and when set near the rated load, there was a lack of light at low loads.

[Purpose of the invention]

An object of the present invention is to provide an optimal aperture adjustment method for an ITV camera that allows the TV camera to measure an object well.

[Summary of the invention]

The present invention measures an image containing an object using an ITV camera, divides the image into at least two regions using brightness or brightness distribution (or temperature or temperature distribution) so that the object is included in the region, The feature is that the aperture of the ITV camera is adjusted according to the brightness of the divided images.

[Embodiments of the invention]

An embodiment of the present invention is shown in FIG. In Figure 1, 1
is a furnace, 2 is a burner, 3 is a flame, 4 is a cooling device, 5 is an image fiber, 6 is an ITV camera, 7 is a video signal,
8 is an A/D converter, 9 is a frame memory, 10Fi
11 is an electronic computer, 12 is a timing signal for executing A/D conversion, and 13 is the direction and amount of aperture adjustment.

Although the effects of the present invention are not impaired whether the aperture adjustment is done manually or automatically, automatic adjustment is preferable to compensate for the distance between the ITV camera 6 and the computer 11.

The combustion and combustion flame 3 during boiler operation is measured by an ITV camera 6 using an image fiber 5, and the video signal 7 is transmitted to the A/
The data is quantized by the D converter 8 and taken into the frame memory 9. In FIG. 1, the timing signal for A/D conversion is output from the electronic computer 11, but it is also possible to provide it manually.

The video signal 7 taken into the frame memory 9 is rl
! The IF image data 10 is input to the electronic computer 11, and the direction and amount of the aperture are determined according to the schematic flowchart shown in FIG. 2, for example.

The brightness histogram of the image data 10 shown in FIG. 1 is plotted as shown in FIG. 3, for example. Image data 10 in Figure 1
When targeting a part of the area, that is, a high-brightness area, the area is divided into two areas, ie, the area area and (2) using the RLMT shown in FIG.

Next, determine the area where the target exists. In this case, region I is selected because the high-brightness portion is the target, and the other image data (brightness data included in region ■) is selected.

’.

Next, it is compared whether the brightness of the selected area satisfies equation (1).

! fl　)　R,l@＜RLM? <R-,.

Here, RMAX; Maximum quantization level Ro; Minimum quantization level R, 1; Maximum brightness value RNla; Minimum brightness value R, LMT; Division limit brightness If Equation (1) i) is not satisfied, RMAX <R
1 degree, which becomes K as shown in Fig. 4. Operate the aperture of the ITV camera in the direction of closing, and adjust as shown in Fig. 5. The manipulated variable C can be determined, for example, by equation (2).

Σ −0 Here, kl+ k2i coefficient hI ; frequency at luminance R+ On the other hand, if equation (11) of equation (1) is not satisfied, Ro
≧Rmig Operate in the direction of opening the diaphragm. The manipulated variable C can be determined, for example, by equation (3).

j−0 Here, Zl y t2 ; Frequency (2) at i brightness R+ In equations (2) and (3), II N No. 8 indicates that the diaphragm is closed, and “+” No. 8 indicates that it is opened.

As shown in FIG. 6, the quantitative relationship between the diaphragm and the diaphragm is such that as the manipulated variable C increases or decreases, the amount of diaphragm does not change much when it is close to fully open, but shows a sudden change when it approaches fully open.

In this way, after adjusting the direction and amount of the aperture of the TV camera, a timing signal for executing A/D conversion is output as shown in FIG. 2, and the image data is read into the computer again.

By adjusting the aperture so that the brightness or brightness distribution in the area including the object falls within a predetermined range, an image suitable for subsequent image processing can be obtained.

By measuring the same object continuously or sequentially so that the absolute value of the manipulated variable C exceeds the limit value Ct, wt of the manipulated variable, it is possible to know the change in the condition of the object at the time of measurement, and it can also be used as a monitoring device. On the other hand, the aperture is not adjusted unless the absolute value of the manipulated variable C exceeds CIIHN.

This makes it possible to control frequent fluctuations in the aperture caused by disturbances.

〔Effect of the invention〕

According to the present invention, it is possible to automatically set the throttling according to the brightness of the flame, and the flame can be well monitored even if the combustion conditions (load, type of coal, etc.) change.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.
Figure 2 is a processing flow diagram, Figure 3 is an example of a brightness histogram, and Figures 4 and 5 are explanatory diagrams of how to divide into two areas.
FIG. 6 shows diagrams showing the quantitative relationship of the apertures. 1... Furnace, 2... Burner, 3... Flame, 4...
...Cooling device, 5...Image fiber, 6...I
TV camera, 7... Video signal, 8... A/D converter, 10... Image data, 11... Computer. Agent Patent Attorney Akio Takahashi Hikarubi (1 story) 5 pictures name 6 pictures

Claims (1)

[Claims] 1. When capturing an image using an ITV camera, the captured image is smoothly divided into at least two areas with predetermined brightness or temperature, and the ITV camera is divided into two areas based on the brightness or temperature of one of the divided areas. A method for adjusting the aperture of an ITV camera, characterized by determining the direction and amount of the aperture.