JP2001230967A - Device and method for processing image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily make proper the quantity of light made incident to an image input means. SOLUTION: This device is provided with a TV camera 1, using a CCD element or the like as the image input means, image memory 2 for storing an image photographed by the TV camera 1, image processing part 3 mainly composed of a microcomputer, a display part 4 such as a CRT as a display means and arithmetic processing part 5, mainly composed of a microcomputer as a shutter speed control instructing means. On the basis of image data read out of the image memory 2, the arithmetic processing part 5 analyzes the lightness data of an object and decides whether a shutter speed is to be controlled. When controlling the shutter speed, the shutter speed is determined, the data of that shutter speed are fed back to the TV camera 1 and corresponding to the data received from the arithmetic processing part 5, the TV camera 1 automatically controls the shutter speed at the time of next image pickup.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an object used in a factory facility or the like, for performing an image processing on an image picked up by an image input means such as a TV camera to perform an object inspection or measurement process. The present invention relates to an image processing apparatus and an image processing method for extracting an external appearance feature of an image.

[0002]

2. Description of the Related Art Conventionally, when inspecting or measuring an object such as a product or a part in a factory facility, an image taken by an image input means such as a TV camera is subjected to image processing to thereby provide an external appearance of the object. An image processing device for extracting a characteristic feature is used. In such an image processing apparatus, the type of lens (focal length, etc.) used in the TV camera and the distance from the tip of the lens to the object are determined based on the field of view of the object, and then the focus of the lens is adjusted. At the same time, the aperture adjustment for optimizing the incident light amount is performed to complete the setting of the optical system, and if the incident light amount needs to be adjusted at the time of actual inspection / measurement processing, by adjusting the lens aperture, The incident light amount was adjusted (see Japanese Patent Application Laid-Open No. Hei 6-139341).

[0003]

By the way, in the above conventional example, the TV camera (lens) is already fixed to the equipment, and it is difficult to set the optical system such as adjusting the aperture of the lens in terms of space. In addition, there are many cases where labor is required for the work, and furthermore, the adjustment work of the optical system may require the skill of the cause of the setting variation of each worker and the work, and everyone directly handles the image processing apparatus. Making it difficult.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an image processing apparatus and an image processing method capable of easily adjusting the amount of light incident on image input means. To provide.

[0005]

According to a first aspect of the present invention, there is provided an image input means for imaging an object and adjusting a quantity of incident light by changing a shutter speed to achieve the above object. Image processing means for extracting the appearance characteristics of the object by performing image processing on the obtained image; and adjusting the shutter speed so that brightness data indicating the brightness of the image satisfies a predetermined appropriate condition. And a shutter speed adjustment instructing means for instructing the image input means to easily optimize the amount of light incident on the image input means without changing the setting of the optical system of the image input means. Can be provided.

According to a second aspect of the present invention, in the first aspect of the present invention, the image input means changes a shutter speed in response to an instruction from the shutter speed adjustment instruction means, and does not require any manual operation. This makes it possible to optimize the amount of incident light.

According to a third aspect of the present invention, in the first aspect of the invention, there is provided a display means for displaying an instruction from the shutter speed adjustment instruction means, wherein the image input means changes the shutter speed by an external operation. The operator can manually adjust the shutter speed in accordance with the situation by externally changing the shutter speed in accordance with an instruction displayed on the display means.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the shutter speed of the image input means is changed by an instruction from the shutter speed adjustment instruction means. It has a similar effect.

According to a fifth aspect of the present invention, in the first aspect of the present invention, the image processing in the image processing means and the adjustment processing in the shutter speed adjustment instruction means are performed substantially simultaneously. It has a similar effect.

According to a sixth aspect of the present invention, in any one of the first to fourth aspects, the shutter speed adjustment instructing means performs an adjusting process before the image processing in the image processing means. An effect similar to that of the first invention is exerted.

According to a seventh aspect of the present invention, in order to achieve the above object, an image of an object is taken by image input means capable of adjusting the amount of incident light by varying a shutter speed, and an image obtained by the image input means is provided. On the other hand, in an image processing method for extracting an external feature of an object by performing image processing by an image processing means, the shutter speed is adjusted so that brightness data indicating the brightness of the image satisfies a predetermined appropriate condition. It is possible to provide an image processing method characterized by instructing an adjustment and capable of easily adjusting the amount of incident light to the image input means without changing the setting of the optical system of the image input means.

According to an eighth aspect of the present invention, in accordance with the seventh aspect of the present invention, the shutter speed of the image input means is varied according to an instruction from the shutter speed adjustment instruction means, and the incident light amount is reduced without any human intervention. Can be optimized.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In this embodiment, as shown in FIG. 1, a TV using a CCD element or the like as image input means is used.
A camera 1, an image memory 2 for storing an image captured by the TV camera 1, an image processing unit 3 mainly including a microcomputer, a display unit 4 such as a CRT as a display unit, and a shutter speed adjustment instruction unit And an arithmetic processing unit 5 having a microcomputer as a main configuration. TV
The camera 1 has a shutter for adjusting the amount of light incident on the CCD element. This shutter is a so-called CCD shutter that switches the energization of the CCD element to substitute for the shutter, or a mechanical (mechanical) shutter disposed between the CCD element and the lens, and has a variable shutter speed (exposure time). This makes it possible to adjust the amount of incident light. Further, the TV camera 1 has a built-in A / D converter for analog-to-digital conversion of a video signal of a captured image, and the image memory 2 stores digital image data output from the TV camera 1. .

The image processing section 3 has a conventionally well-known configuration. The image processing section 3 performs image processing on image data read from the image memory 2 to extract appearance characteristics of the object, and based on the extracted appearance characteristics, Performs inspection / measurement processing of objects. The object is, for example, a label attached to the product or a character printed on the product, and the appearance characteristics of the object are the presence or absence of the object, the position of the object, the shape of the object, the shape of the object. Means dimensions and the like. In the production line, these appearance characteristics are compared with a reference value or collated with a template, thereby detecting the inclination of the label, the blurring of the printed characters, and the like, and performing the inspection and measurement such as the quality judgment of the object.

The arithmetic processing unit 5 reads out the image data stored in the image memory 2 and analyzes the brightness (brightness data) of the illumination environment excluding a change in the captured object or the background image. In order to optimize the amount of incident light on the TV camera 1 so that image data appropriate for image processing in the image processing unit 3 is obtained based on the analysis result,
Control for instructing the TV camera 1 to adjust the shutter speed is performed. This brightness data is grayscale data when a grayscale image is handled as an image, and becomes lightness when a color image is handled. Further, the brightness data depends on the brightness of the object to be imaged. For example, when an object close to black is imaged and when an object close to white is imaged, the brightness data naturally differs. If the target object is not in the field of view of the TV camera 1, an image of only the background is captured.

The display unit 4 mainly displays an image picked up by the TV camera 1 and a man-machine interface (M) for general image processing for performing the above-described inspection / measurement processing.
MI), and an MMI for adjusting the shutter speed of the TV camera 1 as described later.

The operation of this embodiment will be described with reference to the flowchart of FIG. For example, a sensor or the like detects that an object (work) flowing on the manufacturing line has reached the field of view (inspection area) of the TV camera 1, and the image processing apparatus operates at a timing when a detection signal from the sensor is input. Start the inspection / measurement process. At the above timing, the image processing apparatus first loads image data from the TV camera 1 into the image memory 2. Thereafter, the image processing unit 3 performs image processing on the image data read from the image memory 2, and executes an inspection / measurement process as necessary. On the other hand, the arithmetic processing unit 5 analyzes the brightness data of the object based on the image data read from the image memory 2 and determines whether or not to adjust the shutter speed. When the adjustment of the shutter speed is not performed, the inspection / measurement processing ends, and an instruction to start the next inspection / measurement processing is waited. Further, when adjusting the shutter speed, the shutter speed is determined, the data of the shutter speed is fed back to the TV camera 1, the inspection / measurement process ends, and an instruction to start the next inspection / measurement process is waited for. .
The TV camera 1 automatically adjusts the shutter speed at the time of the next imaging according to the data received from the arithmetic processing unit 5.

Here, the determination of the necessity of the shutter speed adjustment in the arithmetic processing unit 5 will be described in detail. Based on the image data read from the image memory 2, the arithmetic processing unit 5 obtains the amount of change between the average value of the brightness data of the previously captured image and the average value of the brightness data of the currently captured image. Is larger than a preset threshold value, it is determined that shutter speed adjustment is necessary, and the shutter speed is determined based on the amount of change. As the threshold value, an appropriate value is input by an operator so that image data suitable for an algorithm (application) for performing image processing and inspection / measurement processing performed by the image processing unit 3 is obtained.
Alternatively, when the algorithm (application) is simple and does not require a change in the threshold value, the threshold value may be incorporated in advance and set.

As described above, according to this embodiment, the amount of light incident on the TV camera 1 becomes too large or too small after the TV camera 1 is installed and the optical system setting such as focus adjustment and aperture adjustment is completed. When it is necessary to adjust the amount of incident light, an arithmetic processing unit 5 serving as a shutter speed adjustment instruction unit.
To adjust the shutter speed so that the brightness data satisfies a predetermined appropriate condition, so that the amount of light incident on the TV camera 1 can be easily optimized without changing the setting of the optical system. Becomes

In the present embodiment, after the image processing in the image processing unit 3 is executed, the processing for analyzing the brightness data and instructing the shutter speed adjustment by the arithmetic processing unit 5 is performed. In order to analyze the image data including the brightness data, the image processing unit 3 may analyze the brightness data simultaneously with the image processing, and may provide the analysis result to the arithmetic processing unit 5. The processing from the analysis of the brightness data in the arithmetic processing unit 5 to the determination of the necessity of the shutter speed adjustment and the transmission of the shutter speed data to the TV camera 1 may be performed simultaneously in parallel with the image processing in the image processing unit 3. Alternatively, the image processing may be performed before the image processing in the image processing unit 3.

By the way, as a method of judging whether or not the shutter speed adjustment is necessary in the arithmetic processing section 5, as shown in FIG. 3, the distribution of the brightness data of the image read from the image memory 2 is shifted to an extremely bright side or a dark side. A method may be adopted in which it is determined whether the shutter speed is biased, and if any bias is found, it is not possible to obtain image data suitable for image processing in the image processing unit 3 and it is determined that shutter speed adjustment is necessary. For example, when treating an image as a grayscale image quantized by 8 bits, if the frequency of the maximum value (255) of the range (0 to 255) that the brightness data can take exceeds a predetermined threshold,
Since it is considered that overexposure occurs due to an excessive amount of incident light, the shutter speed is increased to reduce the amount of incident light, or if the frequency of the minimum value (0) of the brightness data exceeds a predetermined threshold, the incident light is reversed. Since the amount of light is considered to be too small, the shutter speed is reduced to increase the amount of incident light. Further, when the difference between the maximum value and the minimum value of the brightness data is smaller than a predetermined threshold value, it is determined that the shutter speed needs to be adjusted, or the variance value of the brightness data is larger than a predetermined threshold value. If it is larger, it may be determined that the shutter speed needs to be adjusted.

Instead of automatically adjusting the shutter speed by the TV camera 1 based on the shutter speed data given from the arithmetic processing unit 5, an instruction for adjusting the shutter speed in the arithmetic processing unit 5 is sent to the display unit 4. The shutter speed may be manually adjusted by displaying the displayed image and inputting the shutter speed data to the TV camera 1 as appropriate using an input device such as a keyboard. For example, when the setting of the optical system of the TV camera 1 is completed and a stable inspection / measurement process cannot be executed when the test operation is performed as a facility, and can be improved by adjusting the incident light amount of the TV camera 1, the arithmetic process is performed. Instead of automatically adjusting the shutter speed in accordance with an instruction from the unit 5, the shutter speed is manually adjusted using the input device as described above, and the shutter speed in the inspection / measurement process during the continuous operation thereafter. Can be determined. Instead of providing an input device for adjusting the shutter speed in the image processing apparatus, data of the shutter speed is transmitted from an external personal computer via a communication means (not shown) of the image processing apparatus to the TV camera 1 from the image processing apparatus. To adjust the shutter speed.

In a factory or the like, a TV camera 1
If the lighting environment of the place where the target is imaged changes between daytime and night, or if the door is adjacent to the above place and the lighting environment changes by opening and closing the door, It is necessary to adjust the shutter speed automatically according to an instruction from the arithmetic processing unit 5 during continuous operation. Therefore, the image processing apparatus is provided with switching means for switching between the manual shutter speed adjustment and the automatic shutter speed adjustment in accordance with an instruction from the arithmetic processing unit 5,
What is necessary is just to be able to cope with the case described above.

[0024]

According to the first aspect of the present invention, there is provided an image input means for picking up an image of an object and adjusting the amount of incident light by varying a shutter speed, and performing image processing on an image obtained by the image input means. Image processing means for extracting appearance characteristics of an object; and shutter speed adjustment instructing means for instructing adjustment of the shutter speed so that brightness data indicating the brightness of the image satisfies a predetermined appropriate condition. ,
There is an effect that it is possible to provide an image processing apparatus that can easily optimize the amount of light incident on the image input unit without changing the setting of the optical system of the image input unit.

According to a second aspect of the present invention, in the first aspect of the present invention, the image input means changes a shutter speed in accordance with an instruction from the shutter speed adjustment instructing means. This has the effect of enabling the optimization of

According to a third aspect of the present invention, in the first aspect of the present invention, there is provided a display means for displaying an instruction from the shutter speed adjustment instruction means, and the image input means changes the shutter speed by an external operation. Since the operator can externally change the shutter speed in accordance with the instructions displayed on the display means, the shutter speed can be manually adjusted according to the situation.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the shutter speed of the image input means is changed by an instruction from the shutter speed adjustment instructing means. To play.

According to a fifth aspect of the present invention, in the first aspect of the invention, the image processing in the image processing means and the adjustment processing in the shutter speed adjustment instruction means are performed substantially simultaneously, so that the same effect as the first aspect of the invention is obtained. To play.

According to a sixth aspect of the present invention, in any one of the first to fourth aspects of the present invention, the adjustment processing in the shutter speed adjustment instruction means is performed before the image processing in the image processing means. It has the same effect as.

According to a seventh aspect of the present invention, the object is imaged by the image input means capable of adjusting the amount of incident light by varying the shutter speed, and the image obtained by the image input means is subjected to image processing by the image processing means. In the image processing method for extracting the appearance characteristics of the target object by performing the above, the adjustment of the shutter speed is instructed so that the brightness data indicating the brightness of the image satisfies a predetermined appropriate condition. There is an effect that it is possible to provide an image processing method capable of easily adjusting the amount of incident light to the image input unit without changing the setting of the optical system of the unit.

According to an eighth aspect of the present invention, in accordance with the seventh aspect of the present invention, the shutter speed of the image input means is varied according to an instruction from the shutter speed adjustment instruction means, so that the amount of incident light can be optimized without any human intervention. There is an effect that it becomes possible.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment.

FIG. 2 is a flowchart of the same.

FIG. 3 is an explanatory diagram of the above.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 TV camera 2 Image memory 3 Image processing part 4 Display part 5 Operation processing part

Continuation of the front page F term (reference) 5B047 AA11 AB02 AB04 BA01 BB06 BC06 CA19 CA23 CB04 DB01 DB04 DC09 5C022 AA00 AB03 AC04 AC42 AC52 AC69

Claims (8)

[Claims] 1. An image input means for capturing an image of an object and adjusting a quantity of incident light by varying a shutter speed, and extracting an appearance characteristic of the object by performing image processing on an image obtained by the image input means. An image processing apparatus comprising: an image processing unit that performs an adjustment of the shutter speed such that brightness data indicating the brightness of the image satisfies a predetermined appropriate condition. . 2. An image processing apparatus according to claim 1, wherein said image input means changes a shutter speed in accordance with an instruction from said shutter speed adjustment instruction means. 3. An image processing apparatus according to claim 1, further comprising display means for displaying an instruction from said shutter speed adjustment instruction means, wherein said image input means changes a shutter speed by an external operation. . 4. An image processing apparatus according to claim 1, wherein a shutter speed of said image input means is changed by an instruction from said shutter speed adjustment instruction means. 5. The image processing apparatus according to claim 1, wherein image processing in said image processing means and adjustment processing in said shutter speed adjustment instruction means are performed substantially simultaneously. 6. The image processing apparatus according to claim 1, wherein an adjustment process is performed by said shutter speed adjustment instruction unit before image processing is performed by said image processing unit. 7. An object is imaged by an image input means capable of adjusting an incident light amount by changing a shutter speed,
In an image processing method for extracting an appearance characteristic of a target object by performing image processing on an image obtained by an image input unit by an image processing unit, brightness data indicating the brightness of the image is determined by a predetermined appropriate condition. An instruction to adjust the shutter speed so as to satisfy the following. 8. The image processing method according to claim 7, wherein a shutter speed of said image input means is varied according to an instruction from said shutter speed adjustment instruction means.