JPS6354272B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to a method for checking the light amount of an image light source in an image signal generating device such as a facsimile.

(2) Prior Art Conventional image signal generators such as facsimile machines use a light source that illuminates the original to be transmitted, and a system that uses the light from this light source to read the original to be transmitted and convert the resulting signal into a binary value. Amplification circuits and quantization circuits are used. In such an image signal generation device, determination when the light intensity of the image light source that illuminates the original to be transmitted has deteriorated can be made using a method that uses a dedicated light receiving element for checking, separate from the light receiving element for receiving the image signal, or A commonly used light intensity check method uses the output signal of a signal-generating light-receiving element to obtain a sampled signal corresponding to a specific position on the scanning line, and compares it with a reference value to determine whether light intensity has deteriorated. Ta.

FIG. 1 shows an example of a conventional method. In the figure, an image on a document 2 is scanned with light from an image light source 1, read by an image sensor 3 and converted into an electrical signal, and a quantization circuit 8 extracts a binarized image signal.

A quantization circuit 8 obtains a white or black image signal by an image signal amplification circuit 4 provided with a predetermined threshold value, and outputs it to a terminal 6.
At the same time, the light amount determination circuit 5 samples and determines the first bit of a row where the amount of light from a fluorescent lamp light source is relatively small at a specific position on the document 2, and if it is black, the amount of light on the white background is insufficient. Since it is sufficient, a defective (NG) signal is output from terminal 7.

Alternatively, the amount of light at a specific position on the document 2 may be detected and determined using a dedicated light receiving element. In either case, a dedicated light-receiving element and circuit are required, and a dedicated circuit for sampling corresponding to a specific position is also required. Furthermore, if dirt or the like happens to adhere to a specific location, the product may be rejected even though there is no problem in practice.

(3) Purpose of the Invention The present invention eliminates the above-mentioned drawbacks, and provides a light amount checking method that uses an image signal configuration to check the amount of light from an image light source without requiring a dedicated light-receiving element or circuit. The purpose is to

(4) Structure of the Invention In order to achieve the above object, the light intensity check method of the present invention irradiates an image with light from a light source, converts it into an electric signal with a light receiving element, and converts the image signal into a binary image signal with a quantization circuit. In the image signal generating device that obtains the image signal and inputs it to the processing device, the quantization circuit is used to generate one signal before inputting the image.
An image signal is detected by scanning a white background for a line, and the image signal is input to the processing device, and if the length of white is at least two consecutive scanning periods, the light intensity of the light source is determined to be sufficient, and even if black is detected, one scanning is performed. The light intensity of the light source is checked by determining that the light intensity of the light source is sufficient if the white color continues after a waiting time of 1/2 period or more, which is less than the effective period of .

(5) Embodiment of the invention FIG. 2 is an explanatory diagram showing the configuration of an embodiment of the invention.

In the figure, light from an image light source 1 is transmitted to a document 2.
The reflected light is read by the image sensor 3 and converted into an electrical signal, which is input to the quantization circuit 8. For the image signal input to the quantization circuit 8, a predetermined threshold value is set in the image signal amplification circuit 4, and binary signals of white and black are outputted to the terminal 6. The binarized image signal is input to a processor 9 in the control device 10, and the lengths of the white and black signals are counted to determine the amount of light.

3a to 3c are operational waveform diagrams of essential parts of the present invention, and show the output waveforms of the quantization circuit 8 of FIG. 2.

The video start signal VDST shown in FIG. 3A is repeatedly generated at the start of one line, and one line of white background before image input is scanned at a cycle _T1 .

The video signal VDSG shown in FIG. 5B is output from the quantization circuit 8, and white is detected if the light source is normal, and black is detected if the light source is degraded. Since the detection is to distinguish between rows, the same figure c
An enable (ENBL) period _T2 is set, and when VDSG is detected during that period, it indicates that one scan is valid.

FIG. 4 is a flowchart showing the operation of the main part of the present invention, and shows the processing procedure of the processor 9 of FIG. In the same figure, after the start, the VDSG detected by the quantization circuit 8 is detected as white or black using the method described above, and if it is white and continues for T' ₁ > 2T ₁ , the light amount of the light source is processed as OK. . If it is black, after a waiting time of T ₂ /2<T′ ₂ <T ₂ , if VDSG becomes white, it is treated as an OK light quantity, and if it is still black, it is treated as a deterioration in the light quantity of the light source. This makes it possible to distinguish between black detection based on dirt only at a specific location.

(6) Effects of the Invention As explained above, according to the present invention, the amount of light from an image light source in an image signal generating device such as a facsimile can be determined by an image signal quantization circuit without using a dedicated light receiving element and circuit. Using a processing device, it is possible to accurately check the amount of light from a light source by detecting the white background of one line of a document, counting the length of white and black, and excluding black detection based on dirt in a specific position. be.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the configuration of the conventional example, FIG. 2 is an explanatory diagram of the configuration of the embodiment of the present invention, FIGS. 3 a to c are operational waveform diagrams of the main parts of the embodiment, and FIG. 1 is a flowchart showing the operation procedure of the section, in which 1 is the image light source;
2 is a document, 3 is an image sensor, 4 is an image signal amplification circuit, 8 is a quantization circuit, 9 is a processor, 10
indicates a control device.

Claims (1)

[Scope of Claims] 1. An image signal generation device that irradiates an image with light from a light source, converts it into an electric signal with a light receiving element, obtains a binarized image signal with a quantization circuit, and inputs the obtained signal to a processing device, The quantization circuit is used to scan one line of white background before inputting the image to detect an image signal, and the image signal is input to the processing device so that the light intensity of the light source is sufficient if the length of the white is at least two consecutive scanning periods. Even if black is detected, the light intensity of the light source is checked by determining that the light intensity of the light source is sufficient if white continues after a waiting time of less than one scanning period and more than 1/2 period. Light intensity check method.