JPS59221072A - Facsimile equipment - Google Patents

Abstract

PURPOSE:To binary code signals with priority given to the picture accuracy by fixing the charge store time of a CCD at the minimum value and therefore controlling said charge store time by the light quantity of a light source in a halftone read mode where a binary coded signal is easily affected by the reduction of the light quantity of the light source and the reduction of the CCD output. CONSTITUTION:The reading part of a facsimile equipment is provided with a data control circuit 1, a charge store time variable/fixed mode switching circuit 2, a charge store time generating circuit 3, a CCD sensor control circuit 4, a CCD sensor 5, a halftone circuit 6 and a binary coding circuit 7. The circuit 1 decodes the control signal, and the circuit 2 sets variably the charge store time in a halftone reading mode. While the charge store time is fixed in a white/ black binary reading mode. The information on the charge store time is given to the circuit 4 from the circuit 3. Based on this information, the video signal underwent the photoelectric conversion through the sensor 5 is binary coded by the circuit 7 and delivered. While the binary coded signal is delivered from the circuit 7 under the control of the circuit 6 in a halftone reading mode.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a facsimile machine, and particularly to an improvement in a reading method suitable for black-and-white binarization and halftone reproduction.

[Background of the invention]

Generally, in a facsimile machine, a signal obtained by optically scanning a document is binarized, and this binarized signal is compressed by, for example, the Ml method or the run length method, and then transmitted.

A recent proposal for such a known facsimile device is as follows.
The aim is to improve image quality and shorten transmission time.

However, in order to improve the image quality, for example, it is possible to increase the number of scanning lines in the document scanning device, but this will increase the amount of data that must be transmitted, which in turn will reduce the transmission speed. This will result in a longer time. Therefore, these types of problems are mutually exclusive.

Other problems with known facsimile machines include:
There is a problem in that the light intensity of the light source of the scanning device decreases over time.

In other words, a CCD (solid-state image sensor or charge coupled device) is commonly used as a scanning device.

In this case, the method for responding to changes in the light amount of the light source is CC
Six methods are known for controlling the charge accumulation time of D, and for controlling the charge accumulation time in a fixed manner, depending on the follow-up performance of the binarization element for binarizing the output of the COD, in response to changes in the amount of light.

However, in the former case, although the output of the COD does not decrease due to a decrease in the amount of light, it has the disadvantage that the charge accumulation time becomes longer, which inevitably increases the transmission time.

In addition, in the latter case, although the stain accumulation time does not increase due to the decrease in the light intensity, the CCD output decreases, and in that case, if the tracking performance of the binarization element is exceeded, the reliability of the binarized signal becomes The disadvantage is that the performance is reduced.

[Purpose of the invention]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a facsimile apparatus in which the COD output is optimized and the accuracy of the binary signal and image is not affected by the amount of light from the light source.

[Summary of the invention]

Accordingly, the present invention provides a facsimile machine having a black-and-white binary reading and reproducing function and a halftone reading and reproducing function, in which the binary signal is relatively unaffected by a decrease in the light intensity of the light source or a decrease in the CCD output. During binary reading, the CCD charge accumulation time is fixed to the minimum in order to give priority to the transmission time, while the binary signal is relatively unaffected by a decrease in the light intensity of the light source or a decrease in the CCD output. During easy halftone reading, image accuracy is prioritized, and the charge accumulation time of the CCD is controlled in accordance with changes in the amount of light from the light source.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

The figure is a block diagram showing a reading section of a facsimile machine. The reading section is a general data control circuit l.

Charge accumulation time variable/fixed switching circuit 2. Charge accumulation time generation circuit 3, CCD sensor control circuit 4. CCD Centl
°5, halftone circuit 6. It is composed of a binarization circuit 7.

A control signal is input to the data control circuit 1, and a reading operation is started. Is the control signal in halftone reading mode?
Contains control information that specifies whether it is a black-and-white binary reading mode or a black-and-white binary reading mode. The data control circuit 1 decodes the control signal, and if it is the halftone reading mode, the charge accumulation time variable/fixed switching circuit 2 sets the charge accumulation time to be variable. On the other hand, in the black-and-white binary reading mode, the charge accumulation time is fixed, and charge accumulation time information is given from the charge accumulation time generation circuit 3 to the CCD sensor control circuit 4.

The CCD sensor control circuit 4 drives the CCD sensor 5 according to this charge accumulation time information. The CCD sensor 5 gives the video signal obtained by photoelectric conversion to the binarization circuit 7,
Here, a binarized signal is created and this signal is output to the next stage image processing section (not shown).

On the other hand, in the halftone reading mode, under the control of the halftone circuit 6, the binarization circuit 7 outputs a binarized signal that has been subjected to halftone processing.

In this way, in the case of simple black and white binary reading, the charge accumulation time variable/fixed switching circuit 2 fixes the charge accumulation time to the minimum regardless of changes in the light intensity of the light source, giving priority to the transmission time of the facsimile device. In other words, the transmission speed can be improved. On the other hand, in the case of halftone reading, the charge accumulation time can be variably controlled by the switching circuit 2 in accordance with changes in the amount of light from the light source, so that priority is given to image quality, that is, fine image quality can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to switch between giving priority to transmission speed and image quality, depending on the monochrome binary reading mode and the halftone reading mode. Moreover, the charge accumulation time of the COD can be easily changed to be variable or fixed depending on the change in the light intensity of the light source of the reading section.

[Brief explanation of the drawing]

The attached figure is a block diagram showing the reading section of the facsimile machine. 1...Data control circuit, 2...Charge accumulation time variable/
Fixed switching circuit, 3...Charge accumulation time generation circuit, 4...
・CCJ) sensor control circuit, 5... CCD sensor, 6
... Halftone circuit, 7... Binarization circuit. Agent Patent Attorney Masami Akimoto

Claims (1)

[Claims] C converts optically read image signals into electrical signals
It has an OD, an accumulation time control means for controlling the charge accumulation time of the COD, a binarization means for binarizing the signal from the COD, and a halftone generation means for performing an operation for reproducing halftones. In the facsimile machine, a means for variably setting the charge accumulation time in the accumulation time control means is provided, and in the monochrome binary reading mode, the charge accumulation time is fixed by the means, and in the halftone reading mode, the charge accumulation time is fixed by the means. A facsimile machine characterized by being configured to have variable settings.