JPS63151177A - Binarization processor for picture signal - Google Patents

Abstract

PURPOSE:To obtain a distinct and highly accurate binarization processed data by controlling a slice level by means of the output of a D/A converter to D/A- convert a read-out data from an intensity of illumination distribution data, and correcting the unevenness of an illumination in a real time. CONSTITUTION:The screen of a white ground or the plain screen is illuminated previously, and the intensity of illumination distribution data is picked up through a camera 10, and the data is stored in an intensity of illumination distribution data memory 32. The data of one byte portion is read out from there, and is set in a data register 36, and is converted into an analog voltage by the D/A converter 34, and a slice voltage generator 22 is controlled by the said voltage, and the slice level in correspondence relation with the intensity of illumination is impressed on a comparator 14. Next, the camera 10 is started, and a picture signal from the camera 10 is classified into a binary data by the comparator 14 by means of comparing the largeness of it with the largeness of the slice level. At that time, because the comparator 14 is impressed by the slice level controlled by the intensity of illumination distribution data, an influence due to the uneven illumination is corrected.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a device that converts an image signal from a camera or the like into binary data and stores it in an image memory. Information about the illuminance distribution is stored in memory, and the illuminance distribution data is converted into an analog signal by a D/A converter, thereby controlling the slice level for binarization and eliminating the adverse effects of uneven illumination. This invention relates to a device that can correct disulfide data in real time and import disulfide data into an image memory with high precision.

[Prior Art] In various visual inspection apparatuses such as those for inspecting hybrid IC boards and printed wiring boards, an image of an object to be measured is provided as a two-dimensional intensity distribution of light. To perform digital image processing on the pattern image of the object to be measured, first photoelectric conversion is performed, and then the obtained analog image signal is converted into two
It is necessary to convert it to digitized data.

FIG. 2 shows an example of a conventional technique related to an image signal binarization processing device. The conventional device includes a camera 10, a slice level generator 12, a comparator 14 that compares an image signal from the camera 10 with a slice level (voltage) and converts it into binary data, and a serial signal from the comparator 14. It is comprised of a serial/parallel converter 16 that converts data into parallel data, an image memory 1B that stores the converted parallel data, an address counter 20, and the like.

Objects to be measured, such as hybrid IC boards and printed wiring boards, are illuminated by a lighting device, and pattern images of the objects to be measured are detected by a camera IO. The analog image signal obtained by the camera 10 is compared with the slice level V preset by the slice level generator 12 in the comparator 14, and is divided into binary data of "1" or "0" depending on the magnitude relationship between the two. Ru. This binarized data is input as serial data to the serial/parallel converter 16,
There, it is converted into 8-bit or 16-bit parallel data and stored in a storage cell at an address determined by address counter 20 of image memory 18.

[Problems to be Solved by the Invention] When converting an image signal into binary data in such digital image processing, non-uniform illuminance on the surface to be measured becomes a major factor that directly deteriorates data accuracy.

The only effective way to solve this problem is to physically manipulate the lighting equipment itself and spend time adjusting it to make the lighting uniform and stable. However, such adjustment work is extremely cumbersome. be.

Moreover, the most critical thing is the lifespan of the lamps used. In other words, since the illuminance distribution changes when a malfunctioning lamp is replaced, maintenance has become extremely difficult as complicated adjustments must be made each time.

The purpose of the present invention is to eliminate the drawbacks of the prior art as described above, and instead of physically improving non-uniform illuminance due to a light source, it is an object of the present invention to perform slice processing for binary image conversion using information regarding illuminance distribution inputted in advance. By controlling the level, image data obtained from non-uniform illumination is corrected to data of the same quality as the binary image data obtained under uniform illumination, resulting in clear and highly accurate binary processed data. An object of the present invention is to provide an image signal binarization processing device that can obtain the following.

[Means for Solving the Problems] The present invention, which can achieve the above objects, includes a comparator that compares an image signal with a predetermined slice level and converts it into binarized data, and a An image memory that stores binarized data, an illuminance distribution data memory that can be accessed simultaneously with the image memory and stores illuminance distribution information on the surface to be measured, and a D/A for reading data from the illuminance distribution data memory. This is a binarization processing device for an image signal, which is equipped with a D/A converter for conversion.

The slice level is controlled by the output of the D/A converter to correct illumination non-uniformity in real time.

[Function] The illuminance distribution data memory stores information regarding the illuminance distribution on the surface to be measured when irradiated by the illumination device, and the read data from there is converted into an analog signal obtained by D/A conversion and converted into a binary signal. Control slice level.

Therefore, in the present invention, even if the illumination by the lighting device is uneven, the illuminance and its distribution may change due to lamp replacement or the like. The slice level is controlled in real time according to the illuminance distribution at that time, and the data is corrected to be equivalent to the data obtained under uniform illumination and stored in the image memory.

As a result, clear and highly accurate binarization processing can be performed at all times, and subsequent digital image processing can be performed with high accuracy.

(Embodiment) Fig. 1 is a block diagram showing an embodiment of an image signal binarization processing device according to the present invention.This device converts an image of an object to be measured into an electrical signal as in the prior art. camera 10,
A comparator 14 to which the resulting analog image signal is supplied, and a slice level generator 2 to apply a slice level (voltage) for binarization to the comparator 14.
S22, and a serial/parallel converter 16 that converts the serial binarized data obtained by the comparator 14 into parallel data;
It includes an image memory 18 that stores converted parallel data, and an address counter 30 that controls the image memory 18.

The difference between the present invention and the prior art is that, as is clear from the figure, the illuminance distribution data memory is accessible by the address counter 30 at the same time as the image memory 18 and stores illuminance distribution information on the surface to be measured. 32, and a D/A converter 34 that converts read data from the illuminance distribution data memory 32 into an analog signal and controls the slice level of the slice voltage generator 22, and converts the output of the illuminance distribution data memory 32 into a D/A converter 34. The analog signal is converted into an analog signal by the /A converter 34, thereby controlling the slice level and correcting the influence of non-uniform illumination in real time. In this embodiment, part of the data read from the illuminance distribution data memory 32 is written in the data register 36 t9, and its output digital signal is sent to the D/A converter 34.

As for the illuminance distribution data memory 32, if one byte of illuminance data is normally allocated to every eight dots of image data, a sufficiently satisfactory correction resolution can be obtained. Furthermore, there is a phase difference in address between the image memory and the illuminance distribution data, and the illuminance distribution data is preceded by an appropriate number of bytes.

The operation of this apparatus configured in this way is as follows. First, a white or plain screen is illuminated with a lighting device,
Illuminance distribution information is taken up through the camera 10 and the data is stored in the illuminance distribution data memory 32. This initial setting operation is performed when the power is turned on, when replacing the lamp, or periodically after a certain period of time.

Before reading the leading data from the camera 10, one byte of data is first read from the illuminance distribution data memory 32 and stored in the data register 36. This data is converted into an analog voltage by the D/A converter 34, which controls the slice voltage generator 22 to apply a slice level corresponding to the illuminance to the comparator 14. Next camera 1
0 is activated, and the image signal from the camera 10 is divided into binary data of 1'' or 0'' by a comparator 14 by comparison with the slice level.

At this time, since the slice level controlled by the illuminance distribution data is applied to the comparator 14, the influence of non-uniform illumination is corrected. is controlled low. The thus binarized data is converted into parallel data by the serial/parallel converter 16 and stored in the image memory 18 specified by the address counter 30. At the same time, the next illuminance distribution data is read out from the illuminance distribution data memory 32 by the address counter 30, and the D/A converter 34 is controlled through the data register 36.

According to the present invention, the slice level for binarization is controlled by the illuminance distribution data memory that stores data corresponding to the illuminance distribution on the surface to be measured, so even if the illuminance distribution is uneven, it can be made uniform. Clear data similar to that obtained under illumination can be obtained, and subsequent image processing can be performed with high precision.

Although a preferred embodiment of the present invention has been described above in detail, it is important to note that the present invention is not limited to only such a configuration. In the above embodiment, the slice level generator 22 is controlled by the analog signal obtained by the D/A converter 34, but it is also possible to create the slice level by directly using the output of the D/A converter. It can also be configured. Furthermore, although a camera is used to obtain image signals, an image input device such as a line image sensor may also be used.

[Effects of the Invention] As described above, the present invention stores illuminance distribution information on a surface to be measured in a memory, controls the slice level for binarization accordingly, and performs binarization processing of an image signal. Even if the illuminance distribution on the surface to be measured is uneven, it is possible to obtain clear binarized image data that is equivalent to uniform illumination. It has the excellent effect of allowing various types of digital image processing to be performed with high precision.

In addition, since the illuminance distribution may be uneven as described above, there is no need to spend time adjusting the lighting equipment even when the lamp is replaced or the lighting changes due to maintenance etc. When R4# is turned on or when the illuminance changes, maintenance can be greatly simplified as all you need to do is use a plain screen illuminated by the lighting device to easily collect the illuminance distribution data through a camera, etc. and perform the initial settings. However, it has the effect of always allowing accurate data processing.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of an image signal binarization processing device according to the present invention, and FIG. 2 is a block diagram showing an example of a conventional technique. IO...Camera, 14...Comparator, 16...
・Serial to parallel converter, 18... Image memory, 22... Slice voltage generator, 30... Address counter, 32
. . . illumination distribution data memory, 34 . . D/A converter, 36 . . . data register.

Claims (1)

[Claims] 1. In a device equipped with a comparator that compares an image signal with a predetermined slice level and converts it into binarized data, and an image memory that stores the binarized data from the comparator, the image memory can be accessed simultaneously, and an illuminance distribution data memory that stores illuminance distribution information on the surface to be measured;
a D/A converter that converts read data from the illuminance distribution data memory into digital-to-analog;
A binarization processing device for image signals, characterized in that the slice level is controlled by the output of a converter, and the influence of non-uniform illumination is corrected in real time.