JPH01113875A - Image input device - Google Patents

Abstract

PURPOSE:To omit the detection of a start pulse and a clock counting job by adding a memory to write output data on an image sensor temporarily in the memory via the clock of the image sensor and then reading the data out of the memory via the clock of a computer, etc., in a read state. CONSTITUTION:The output data received from an image sensor 1 is written in a 1-line memory 13 via a write clock S3 for a period during which an encoder pulse S6 received from a D flip-flop 7 is kept at a high level. Then the data is read out of the memory 13 via a read clock while the pulse S6 is kept at a low level. The data read out of the memory 13 is sent to a serial/parallel converter 6 and given to a personal computer 12 via a 1st buffer 8. Thus it is possible to obtain an image-input device that can be applied regardless of the performance of the computer 12.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an image input device, a so-called image scanner, which has become increasingly popular in recent years as a peripheral input device for personal computers and word processors.

<Prior art> In recent years, human-powered image devices using solid-state image sensors, such as COD linear image sensors, to replace image pickup tubes have been used in personal computers to input documents and convert them into electronic files, or to input images. It has become easier to create document files that are mixed with text created on a personal computer. In addition, as the sensitivity of image sensors themselves has increased, the reading length has become wider and faster, and devices with chips of 2000 pixels or more arranged in one line can now be driven at 5 to 10 msec eC/line. It's coming.

FIG. 5 is a block diagram showing the configuration from such a conventional image input device to the I10 slot of the personal computer 12.

In the figure, l is an image sensor, 2 is a drive signal generation circuit that generates various drive signals based on the clock from an oscillator 3, and 4 is a disk in which a slit window is formed according to the scanning of the image input device. A photointerrupter that outputs an encoder pulse by crossing it; 2 is a switch that is operated by holding down when reading a document, etc.;
6 is a serial/parallel converter that converts the serial output of the image sensor 1 into parallel according to the clock from the drive signal generation circuit 2; 7 is a serial/parallel converter that converts the encoder pulse from the waveform shaping circuit 5 into a start pulse from the drive signal generation circuit 2; A D flip-flop for synchronization, 8 is a first buffer to which the output of the serial/parallel converter 6 is given; 9 is a first buffer to which the output of the D flip-flop 7, a start pulse, a clock, and a switch signal corresponding to the operation of the switch 11 are supplied. The second buffer provided, 10, is an address decoder.

FIG. 4 is a waveform diagram of signals at each part, (A) is a configuration diagram of one line of output data of the image sensor I, (B) is a start pulse output from the drive signal generation circuit 2, (C) (D) shows the clock output from the drive signal generation circuit 2, and (D) shows the output data of the image sensor I, respectively.

Generally, in an image sensor, as shown in FIG. 4(A), in one line, dummy data and invalid data exist before and after the line, and valid data exists between them. The start pulse is a pulse with a period of 1 line, as shown in FIG. 4(B), and the clock is
The number corresponds to the number of pixels! It is included in the line, for example,
For example, 16 dummy parts, 5-12 valid parts, 200 invalid parts.
In this case, the number of clocks in one line is 728. In synchronization with these start pulses and clocks, the image sensor 1 outputs data "1" or "0" depending on the document to be photographed, as shown in FIG. 4(D).

Next, the operation of this conventional example will be explained.

First, the data output of the image sensor 1 is converted into parallel data by the serial/parallel converter 6 during one cycle of the start pulse, and is applied to the first buffer 8. The first buffer 8 is enabled by the output of 10, and data is sent to the data bus. The conditions before this read period include the states of the encoder pulse, start pulse, and clock, and the state of the switch 1.
The state of whether or not 1 is pressed is input to the second buffer 9, and the second buffer 9 is enabled by the output of the address decoder IO, and data is sent to the data bus.

Note that the D flip-flop 7 synchronizes the encoder pulse and the start pulse in order to reduce malfunctions on the personal computer 12 side, but if the cycle of the encoder pulse is different from the start pulse If it is long enough, this D flip-flop 7 is unnecessary.

FIG. 6 is a flowchart for explaining the above operation. Switch 1! is turned on or a start pulse has arrived, and the second buffer 9 detects whether the encoder pulse has changed from the previous state, that is, from high level to low level or from low level to high level. Judging by the output.

Next, after this condition is met, data (1 byte) is read every time eight clocks are counted. In other words, this is after one byte of data has been completed by the serial/parallel converter 6. Here, the data is read in byte units, but when using the word transfer of a 6-bit personal computer, it may be arbitrarily read in 6-bit units. In this example,! Since there are 728 lines, the process is repeated 728/8=91 times to complete one line and return to the original routine again. For example, if the memory forming the display screen is 512 rices, the end of one screen is as follows.
The process may end at step 512, or may end by detecting that the switch 11 has been turned off midway through.

In such a conventional image input device, the period during which the personal computer 12 is allowed to read data is a period of eight clocks, and if reading is not completed within this period, the next clock cannot be counted. Otherwise, the display will be extended to the right side, or the display will be half-finished.

For example, if this clock is 3 μsec,
3x8=24μsec, and as a computer,
Requires fairly high speed.

If the clock is 3 μsec, in the conventional example mentioned above,! As a line, 3x728=2184"i2゜2m5e
This is an image sensor with high-speed performance of 2m5ec/line class, but it still exists today, and the processing capacity of personal computers becomes a problem.

In addition, the personal computer I2 has a heavy burden of software processing such as counting clocks and detecting start pulses, and for example, if there is an interrupt processing such as a keyboard operation when reading data, it may malfunction. There is a drawback in that almost all interrupt routines must be prohibited before the scanner data processing can be performed.

<Object of the Invention> The present invention has been made in view of the above points, and an object of the present invention is to provide an image input device that can be applied regardless of the performance of a personal computer.

<Structure of the Invention> In order to achieve the above-mentioned object, the present invention provides an image input device that inputs an image read by an image sensor to a computer or the like, and a memory into which output data of the image sensor is written or read; A switching circuit is provided for switching and outputting the clock of the image sensor as a write clock and the clock of the computer, etc. as a clock based on encoder pulses corresponding to scanning of the image sensor. Output data is written in the memory in accordance with the write clock, and data in the memory is read out in accordance with the read clock and sent to the computer or the like.

According to the above configuration, the output data of the image sensor can be written to the memory using the image sensor's clock, and can be read at any time using the clock of the computer, etc., which reduces software processing and reduces the computer's access time. In addition, processing can be performed without relying on the entire system.

<Example> Hereinafter, an example of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram of one embodiment of the present invention, and parts corresponding to the conventional example in FIG. 5 are given the same reference numerals.

In the figure, ■ is an image sensor, 2 is a drive signal generation circuit that generates various drive signals based on the clock from an oscillator 3, and 4 is a disk in which a slit window is formed according to the scanning of the image input device. A photointerrupter outputs an encoder pulse by crossing it; 11 is a switch that is operated by keeping it pressed when reading a document; 6 is a serial/parallel converter that converts serial data from the line memory 13 to parallel data, which will be described later. ,
7 is a D flip-flop for synchronizing the encoder pulse S1 from the waveform shaping circuit 5 with the start pulse S2 from the drive signal generation circuit 2; 8 is a first buffer 1.9 to which the output of the serial/parallel converter 6 is applied; 1 is a second buffer to which the output S6 of the D flip-flop 7 and the switch signal S5 are applied, and 10 is an address decoder.

This configuration is basically the same as the conventional example shown in FIG.
Furthermore, as explained based on FIG. 4, dummy data and invalid data exist before and after valid data in the output of one line of the image sensor l, and in this embodiment, similar to the conventional example described above, , 916 dummies, 512 valid portions, and 200 invalid portions, each consisting of 728 lines.

In the image input device of this embodiment, a line memory 13 is provided between the image sensor l and the serial/parallel converter 6, and a line memory 13 is provided between the image sensor l and the serial/parallel converter 6. Based on the encoder pulse S6 from the flip-flop 7, the clock s3 of the image sensor 1 from the drive signal generator circuit 2 is switched as a write clock, and the clock (CPU clock) of the personal computer I2 is output as a read clock. Changeover switch I
4.

In this embodiment, as described below, the D flip-flop 7
While the encoder pulse S6 output from the image sensor is at a high level, according to the write clock S3, the image sensor! Write the output data from to line memory I3,
While the encoder pulse S6 is at a low level, the data in the line memory 13 is read out in accordance with the read clock and output to the serial/parallel converter 6, and sent to the personal computer 12 via the first buffer 8.

The clock from the personal computer 12 is output as a read clock in byte units by a gate circuit 15 consisting of a counter 16 and an AND gate 17.
Further, this read clock is given to the serial/parallel converter 6 as a conversion clock. The counter 16 of this gate circuit 15 is reset by the output of the address decoder IO.

Next, the operation of the image input device having the above configuration will be explained based on the signal waveform diagram of FIG. 2.

FIG. 2(A) shows the encoder pulse S11 output from the waveform shaping circuit 5 in response to the scanning of the image input device.
) is the start pulse S2 output from the drive signal generation circuit 2, FIG. 2(C) is the image sensor clock S3 output from the drive signal generation circuit 2, and FIG.
) is the data output S4 of the image sensor l, Fig. 2 (E)
2(F) is the encoder pulse S6 output from the D flip-flop 7, and FIG. 2(G) is the switch signal S5 corresponding to the operation of the switch 1, and FIG. Clock S7, FIG. 2(H) is an enlarged view of FIG. 2(G).

In the image input device of this embodiment, as shown in FIG. , 728 clocks S3 from the image sensor shown in FIGS. 2(G) and 2(H) from the changeover switch 14 are written into the line memory I3 as a writing clock, and the encoder pulse S
6 is at a low level, the data in the line memory 13 is read out using the clock of the personal computer 12 as a read clock, 8 times each from the changeover switch 14 as shown in FIGS. 2 (G) and (H), for a total of 91 times. and output to the serial/parallel converter 6.

The personal computer 12 reads the data (1 byte) after 8 reading clocks have finished, that is, after 1 byte of data has been prepared by the serial/parallel converter 6.
Let's lead the way! There are 728 lines, so 72
8/8=Repeat 91 times and complete for 1912 minutes. In addition,
The prerequisites for reading the personal computer 12 are that the encoder pulse S6 is at a low level and the switch 1 is
1 must be pressed, and this is determined by the output of the second buffer 9.

In this way, data for one line is once written into the line memory 13 during the period when the encoder pulse S6 is at a high level, using the clock S3 of the image sensor I as a writing clock, and during the period when the encoder pulse S6 is at a low level, data for one line is written into the line memory 13. 13 is read out using the clock of the personal computer I2 as a readout clock and sent to the personal computer 12. Therefore, the personal computer I2 reads data for one line at an arbitrary period while the encoder pulse S6 is at a low level. All you have to do is read the data of
Data in the line memory 13 can be transferred in byte units without the need for processing such as detection of a start pulse or counting of clock cycles, and the processing speed is not limited to the processing speed of the personal computer 12.
It is no longer necessary to prohibit interrupts from the personal computer 12 during almost the entire period during which output data from the image sensor I is read, as in the conventional example.

Furthermore, the data read is performed during the low level period of the encoder pulse S6, that is, at least during the I line period, and therefore, in the case of the conventional example described above, 2.2 m
Since the process only needs to be completed within the period c, the process can be completed with plenty of time and can be applied to most computers.

FIG. 3 is a flowchart corresponding to the operations described above.

First, in step n1, the personal computer I2
The display screen is cleared and the process moves to step n2, where it is determined whether or not the switch 2 is turned on. When it is determined that the switch 2 is turned on, the process moves to step n3 and whether or not the encoder pulse S6 is at a low level is determined. If it is at a low level, the process moves to step n4 to read the data, and then moves to step n5.

In step n5, it is determined whether reading of one line of data has been completed, and when it is determined that it has been completed, the process moves to step n6, and it is determined whether or not the switch 11 is turned on, and it is determined that it is turned on. If so, the process moves to step n7, where it is determined whether reading of one screen of data has been completed, and when it is determined that it has been completed, the process is terminated.

In the embodiment described above, data is written in the line memory 13 during the high level period of the encoder pulse S6 and read out during the low level period, but it is of course possible to do the opposite in other embodiments of the present invention. It is.

Furthermore, the present invention is of course applicable not only to a so-called handy type in which the image input device itself is manually operated, but also to a type in which the image input device is driven by a motor while a document is placed on it.

<Effects of the Invention> As described above, 1. According to the present invention, a memory is provided, and the output data of the image sensor is once written into the memory using the clock of the image sensor, and when reading, the data of the memory is written using the clock of a computer or the like. Since it is configured to read data, there is no need to detect start pulses or count clocks as in conventional systems, reducing software processing and providing sufficient time for reading data, making it suitable for most personal computers. It will be applicable.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG. 2 is a block diagram of an embodiment of the present invention.
Figure 3 is a flowchart for explaining the operation of Figure 1, Figure 4 is a signal waveform diagram of each part, Figure 5 is a signal waveform diagram of each part in the figure.
The figure is a block diagram of the conventional example, and FIG. 6 is a flowchart for explaining the operation of the conventional example. 1... Image sensor, 12... Personal computer, 13... Line memory, 14... Changeover switch (switching circuit).

Claims (1)

[Claims] (1) In an image input device that inputs an image read by an image sensor into a computer or the like, the output data of the image sensor is input to a memory in which the output data is written or read, and the image is input based on encoder pulses corresponding to the scanning of the image sensor. A switching circuit is provided that switches and outputs the clock of the sensor as a write clock and the clock of the computer or the like as a read clock, and writes the output data from the image sensor to the memory in accordance with the write clock, and reads the data from the memory. An image input device characterized in that the data is read out according to the read clock and sent to the computer or the like.