KR100267247B1 - Scanning apparatus for having a ccd trigger pulse generator with a position trigger - Google Patents

Abstract

PURPOSE: A scanning unit with an image location synchronization device of an image sensor trigger signal generator is provided to scan an image of a high resolution by synchronizing a trigger signal with a starting point of an available image. CONSTITUTION: A CPU(100) controls all operations of a scanning unit, sets up a period value and a coefficient value of a trigger signal, and an interrupt service. A trigger signal generator(200) receives the period value and generates a trigger signal. An over-shoot controller(300) generates a flag signal for obtaining a desired value of input minimum values. A synchronization signal generator(400) outputs a command for generating the trigger signal of a normal period to the trigger signal generator.

Description

A scanning device comprising an image position synchronization device of an image pickup device trigger signal generator.

The present invention relates to a scanning device, and more particularly, to an image pickup device that generates high-quality scanning by synchronizing a trigger signal to a start position of an effective image in a scanning device that generates a trigger signal at a predetermined period and scans an original. A scanning device comprising an image position synchronization device of a signal generator.

Today, products that perform scanning by using a scanning device are widely used, and the light sensitivity of the scanning portion of the scanning device is proportional to the illuminance accumulated in the imaging device just before applying a trigger signal that generates an output signal of the imaging device. do.

Therefore, maintaining a uniform amount of illuminance for each trigger signal period in a scanner device that generates an image by generating a trigger signal at regular intervals plays a very important role in obtaining an image of uniform sensitivity.

In addition, even if a constant illuminance is maintained, if the period of the trigger signal is changed, there is a high probability of obtaining an image of non-uniform sensitivity. Therefore, in order to obtain a good image quality, it is most important to apply a trigger signal of the same period to the image pickup device to maintain a uniform illuminance in the effective reading area.

In the prior art, a method of generating a pulse at a predetermined time by measuring a time of a trigger signal of an image pickup device of the scanner device using a timer of a central processing unit (CPU). In other words, the imaging device is driven by using the software of the general-purpose central processing unit.

The biggest problem with this method is that in order to generate the trigger signal, a large part of the CPU must be used for generating the trigger signal. The central processing unit of the scanner converts an analog signal, which is a video signal output from an image pickup device, into a digital signal in addition to generating a trigger signal. Shading correction to compensate for uneven lighting conditions, gamma correction to correct nonlinear distortion of the image pickup device and optical system, transfer of scanned images to the host computer, and control of input and output devices of the scanner device. It does a kind of work.

In order to process these kinds of tasks in a timely manner, a high performance processor is required, which is a factor in the price increase of the scanner device.

On the other hand, when the trigger signal generation of the same cycle is driven by the timer and software of the central processing unit, the central processing unit has to perform the interrupt and exception processing every cycle, there is a problem that can not use the central processing unit efficiently.

In order to reduce such a burden on the central processing unit, Korean Patent Application No. 97-74009, "Image pickup device trigger signal generator of a scanner device", to which the present application was previously issued, automatically generates a trigger signal and performs only simplified control in the central processing unit. The device was presented.

This device has the advantage of solving the interruption and exception processing delay which may occur when the image pickup device requiring the trigger signal of the same period is driven by the timer and software of the central processing unit.

However, the prior art has a problem in that the first part of the obtained image is brightened by generating a trigger signal from an effective image area in performing the imaging operation and temporarily discharging the accumulated charge before starting the operation.

To solve this problem, it was possible to remove the bright part by releasing a certain amount of charge in advance from the point of acquiring the effective image area, and to capture the image in the state where the remaining charge was released by periodically generating the trigger signal of the image pickup device. A method of removing the overshoot of discrete images by performing an operation has also been proposed.

However, such a conventional technique generates a trigger signal of a certain period while generating an overshoot of an image appearing at the beginning of the imaging operation by removing the remaining charges by generating a continuous trigger signal in performing the imaging operation. Since the CPU does not know the time of occurrence, the starting point of the valid region is changed every line.

Of course, when the image pickup device is moved to align each line, a position interrupt is generated to perform correction. However, since the period of the trigger signal is generated in units of microseconds (ms), a phenomenon in which some pixels are distorted sometimes occurs.

This causes a problem that the rectangular image is not aligned like a sawtooth because the starting point of every line of the image is distorted.

Accordingly, an object of the present invention is to generate a synchronization signal for each position interrupt by one or several system clock cycles so that a trigger signal is newly generated in accordance with the synchronization signal, thereby reading a valid image to align the starting point of the image. To prevent misalignment.

1 is a block diagram showing a connection relationship between an overshoot remover and a synchronization signal generator of an image pickup device trigger signal generator and a main part of a scanner according to the present invention.

2 shows the acceleration / constant speed / deceleration section while the shuttle scanning head is moving and illustrates the location of the position interrupt occurrence,

3 shows an image sensor trigger signal generator of a scanner apparatus according to the present invention,

4 is a time chart illustrating a process of reading and writing data to a corresponding device according to an address according to the present invention.

5 is a flowchart illustrating a process of controlling a scanning device having an image position synchronization device of an image pickup device trigger signal generator according to the present invention.

* Explanation of the symbols of the main parts of the drawings

100: central processing unit 200: trigger signal generator

300: overshoot controller 400: synchronization signal generator

210: address decoder 220: interval register

230: count register 240: control register

250: periodic trigger signal generator 251: down counter

252: short pulse generator 253: OR gate

254: latch 260: trigger signal counter

20: Scanning head A: Location interrupt occurrence point

According to the present invention for achieving the above object, in the scanning device having a shuttle scanning head for scanning a document by generating a trigger signal at a predetermined cycle in the image pickup device, and controls all operations of the scanning device and the trigger period value and A central processing unit configured to set an amount of the trigger and receive an interrupt based on the scanning head to execute an interrupt service; A periodic trigger signal generator configured to receive the trigger period value from the CPU and generate the trigger signal at the trigger period; An overshoot controller configured to periodically generate a trigger signal periodically through the periodic trigger signal generator, and generate a flag signal that allows to take a desired portion of the input pixel values captured by the continuously generated trigger signal; A position interrupt is generated from the central processing unit, and the trigger is generated in the periodic trigger signal generator in a normal cycle to readjust the trigger signal at a normal speed capable of scanning the trigger signal generated by the periodic trigger signal generator. Disclosed is a scanning device including an image position synchronizing device of an image pickup device trigger signal generator including a synchronization signal generator instructing.

Preferably, the periodic trigger signal generator comprises a short pulse generator for receiving a control signal for the presence of the trigger signal generation from the central processing unit to control the trigger signal generation; A down counter which loads the trigger period value from the interval register and down counts in synchronization with a system clock according to the control of the short pulse generator; The latch unit is configured to latch an overflow (OVF) signal at the moment when the count of the down counter ends and output a trigger signal.

Hereinafter, the objects, features, and advantages of the present invention described above will be described in more detail with reference to the preferred embodiments of the present invention shown in the accompanying drawings.

The terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to the intention or custom of a person skilled in the art, and the definitions should be made based on the contents throughout the specification.

Referring to FIG. 1, the overshoot controller and the trigger signal generator according to the present invention operate in connection with the central processing unit of the scanner device.

First, the CPU 100 transmits values for the image pickup device trigger signal period TS-Interval and the number of trigger signals TS-Number to the trigger signal generator 200, and the trigger signal generator 200 receives the trigger signal generator 200. The trigger signal is generated according to the image pickup device trigger signal cycle TS-Interval and the number of trigger signals TS-Number, and transmitted to the image processing apparatus (not shown) for the illuminance accumulated in the image pickup device.

On the other hand, the overshoot controller 300 generates a trigger signal periodically by the trigger signal generator 200, and takes a desired portion of the input pixel values captured by the continuously generated trigger signal. Generate a flag signal.

In addition, the central processing unit 100 is a position detection sensor (not shown) when the shuttle scanning head 20 passes the point (A) is changed from the acceleration section to the constant speed section (scanning area) as shown in FIG. The position interrupt is detected and transmitted to the synchronization signal generator 400 to transmit a trigger generation period adjustment signal for adjusting the trigger generation period.

On the other hand, the synchronization signal generator 400 receiving the trigger generation period adjustment signal at a normal cycle to the trigger signal generator 200 to readjust the trigger signal at a normal speed capable of scanning the trigger signal generated at a slow speed. Send a control signal to indicate that a trigger will occur.

Looking at the trigger signal generator 200 according to the present invention in detail with reference to Figure 3, the CPU 100 is the imaging device trigger signal period set in the CPU 100 in accordance with the address selection of the address decoder 210 The T_S_Interval value is transmitted to the interval register 220 for temporary storage, and the number of trigger signals T_S_Number set in the CPU 100 is temporarily stored in the number register 230.

On the other hand, the control register 240 receives the control information from the central processing unit 100 and temporarily stores.

In addition, when the START signal is generated according to the control information stored in the control register 240, the periodic trigger signal generator 250 loads the image element trigger signal period (T_S_Interval) value from the interval register 220 to the system clock signal. The synchronized down counter 251 down counts the loaded trigger signal period T_S_Interval value to generate a trigger signal at the counting value '0' and reload the trigger signal period T_S_Interval value.

On the other hand, since only the trigger signal of the effective read area is required in the actual scanner device, the trigger signal counter unit 260 controls the number of trigger signals of the effective read area.

In this case, when the generation of the trigger signal is stopped, the charge is charged in a section in which the trigger signal does not occur, and thus, the actual trigger signal is continuously generated with the previous period value under the control of the overshoot remover 300, and takes a picture. Can take an image of a desired portion.

Hereinafter, the operation of the scanning device having the image position synchronization device of the image pickup device trigger signal generator according to the present invention will be described with reference to the flowchart of FIG. 5.

First, referring to a process of generating a trigger signal by the periodic trigger signal generator 250, as shown in the time chart of FIG. 4, the trigger signal period (T_S_Interval) value from the central processing unit 100 in the DataTo is shown in the interval register. If the data is recorded at 220, the data is retained until the next recording time. In this case, it is assumed that the chip select number of the interval register 220 is '1'. In the illustrated control signal, nIOCS is an I / O chip select signal, nRD is a read signal, and nWR is a write signal.

Subsequently, while the trigger signal period T_S_Interval is applied to the data input signal of the down counter 251 of FIG. 3, the down counter 251 is operated by the START signal generated from the CPU 100, and the count is increased. At the moment of termination, the overflow OVF flows into the latch 254 to generate a trigger signal.

Looking at this process in more detail, if the value of the "n-th" bit of the control data transmitted from the CPU 100 to the control register 240 is 1, input the START signal to the short pulse generator 252, short The pulse generator 252 generates a short pulse based on the system clock to enable the down counter 251 of the periodic trigger signal generator 250 through an OR gate 253 operation, and the down counter 251. Loads a trigger signal period (T_S_Interval) value from the interval register 220 to perform a down count in synchronization with the system clock.

Next, when the count of the down counter 251 ends, the overflow OVF flows into the latch 254 to generate a trigger signal, and simultaneously transmits an enable signal to the LOAD DATA terminal of the down counter 251. By reloading the trigger signal period (T_S_Interval) value from the interval register 220.

Looking at the operation of the overshoot controller 300, since the down counter 251 having the trigger signal period (T_S_Interval) value must be operated continuously from the moment the power is supplied, the down counter 251 is controlled by the power signal and the counter. As soon as the value reaches zero, it reloads the period value. For this purpose, the overshoot controller 300 generates short pulses of one system clock at the moment when the count value becomes zero.

On the other hand, the overshoot controller 300 enables the flag signal to recognize the triggered and input charge value as a valid value. That is, only the image value input when the flag signal is High is valid.

At this time, the generation period of the trigger signal and the driving speed of the head motor (not shown) are interlocked and adjusted by the central processing unit 100 in the acceleration section, the constant speed section, and the deceleration section, respectively, as shown in FIG. Referring to FIG. 4, the CPU 100 generates an interrupt when the scanning head 20 enters a constant speed section in an acceleration section to adjust a head motor (not shown) at a constant speed, and generates a synchronization signal to synchronize. The trigger generation period adjustment signal for adjusting the trigger generation period is transmitted to the signal generator 400. That is, the trigger signal period (T_S_Interval) is changed to a period value for scanning.

The synchronization signal generator 400 performs a scanning by generating a trigger signal after changing a trigger signal period to an imaging device trigger period for scanning. That is, in a scanning device that generates a trigger signal at regular intervals in the image pickup device and scans the document, the trigger signal is synchronized to the start position of the effective image at a normal scanning speed to enable high quality scanning.

Subsequently, scanning continues while the scanning head 20 is moved. When the scanning head 20 leaves the scanning area, an interrupt is generated to slow down the head motor (not shown) and supply one line of original.

As described above, according to the present invention, a synchronization signal is generated for each position interrupt by one or several system clock cycles so that a trigger signal is newly generated in accordance with the synchronization signal. There is an effect of preventing the distortion of the image by aligning.

While the above has been described in detail with respect to preferred embodiments of the present invention, those skilled in the art to which the present invention pertains, various modifications can be made without departing from the spirit and scope of the invention as defined in the appended claims. It will be appreciated that modifications or variations may be made. Therefore, changes in the future embodiments of the present invention will not be able to escape the technology of the present invention.

Claims (2)

A scanning device having a shuttle scanning head for scanning a document by generating a trigger signal at regular intervals in an image pickup device, A central processing unit controlling all operations of the scanning apparatus, setting the trigger period value and the number of triggers, and receiving an interrupt according to the scanning head to execute an interrupter service; A periodic trigger signal generator for receiving the trigger period value from the CPU and generating the trigger signal at the trigger period; An overshoot controller configured to generate a trigger signal periodically through the periodic trigger signal generator, and generate a flag signal that can take a desired portion of the minimum values inputted by the continuously generated trigger signal; A position interrupt is generated from the central processing unit, and the trigger is generated at a normal cycle in the periodic trigger signal generator to readjust the trigger signal at a normal speed capable of scanning the trigger signal generated by the periodic trigger signal generator. And a synchronizing signal generator for instructing the image scanning apparatus. The method of claim 1, wherein the periodic trigger signal generator, A short pulse generator that receives a control signal for whether a trigger signal is generated from the central processing unit and controls the generation of a trigger signal; A down counter which loads the trigger period value from the interval register and down counts in synchronization with a system clock according to the control of the short pulse generator; And a latch unit for outputting a trigger signal after latching an overflow (OVF) signal at the moment when the count down of the down counter is completed.