JPS62204659A - Light source controller for picture input device - Google Patents

Abstract

PURPOSE:To save man-power by obtaining a data uniforming the lightness by the read output of a standard picture pattern so as to control the light source. CONSTITUTION:An optional light source control data is written in a RAM 14, then the standard picture pattern is read and when the value is at the outside of a permissible value, a CPU 16 calculates and outputs a light source control data so as to be kept within the permissible value based on an OUT-DATA. Simultaneously, each section of the equipment is brought into the setup mode and its operation output data IN-DATA is written in the prescribed address of the RAM 14 corresponding to lamps LMP1-LMP8. When the write is finished, a lamp driver 15 is driven by a light source control data after the correction outputted from the RAM 14 to light the lamps LMP1-LMP8.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention is an image input device that reads image information of a surface to be read, such as a drawing, and outputs it as a digital signal, in which a reading portion of the surface to be read is uniformly illuminated. The present invention relates to a light source control device for use in a computer.

[Background of the invention]

In an image input device, it is necessary to uniformly illuminate the reading portion of the surface to be read (generally a drawing).

This is an important issue for improving the S/N of the obtained image signal. Therefore, the prior art can be classified into the following four types. (1
) Use a special light source such as a linear lamp.

(2) Install a light shielding plate or the like in the optical path. (3) Install multiple light sources and adjust their arrangement and amount of light emitted. (4) Process the image signal to correct the effects of uneven illumination.

FIG. 3 is a block diagram of an image input device designed to achieve illumination uniformity according to the prior art (3) described above. Hereinafter, an outline of the image input device and a conventional light source control device will be explained based on this diagram. The reading portion of the drawing to be read 1 is provided with a plurality of light sources 21 to 2.
□, and the image information of FIG. 1 is input to the photodetector element 4 via the lens 3. The photodetector element 4 outputs an electrical image signal PD having a size corresponding to the density of the image information shown in FIG. ．． A/D converter6. Output signal OUT via output sofa 7, etc.
- Converted to DATA. Here, when a CCD line sensor is used as the photodetection element 4, the photodetection cells 01 to On arranged in a row as shown in the drawing correspond to the length of this cell Q l ""-' On row. Since image information in a certain range (this is referred to as a reading area) is photoelectrically converted at one time, it is necessary to uniformly illuminate this reading area. For this reason, the plurality of light sources 21-2□ are arranged at optimal positions, and their power supply currents 11-io are appropriately controlled and provided by a light source control device 8 surrounded by a dashed line in the figure. In other words, the power supply current 11~in is the light source 21~
It is adjusted by variable resistors vR1 to VR connected in series with 2n. Further, the supply time of the power supply current 11-in is controlled by turning on and off the switching transistors TR, -TR, according to the operating time of the monostable multivibrator (MM) 9 instructed by the lighting time setting device 10.

In such a conventional light source control device 8, uniform illumination is achieved using variable resistors VR, to VRn and a lighting time setting device l.

This can be achieved by adjusting the , but there are the following problems.

(2) Since the adjustment of the variable resistors VR, .about.VR and the lighting time setting device 1o depend on each other, the time required for their adjustment becomes long.

(2) Adjustment values (set values of variable resistors VR, -VRn and lighting time setting device 10) are not reproducible due to variations in dimensions and light emitting characteristics between products of the light sources 21 to 2o. Therefore, together with the above-mentioned point (2), a great deal of effort and time was required for adjustment.

■Equipped with variable resistors VR, ~VRn in the device component parts,
This led to larger configurations and higher costs.

(2) The uniformity of illumination deteriorates due to age-related changes in the brightness of the light sources 21 to 2n and variations in that change, which requires correction and adjustment, which requires a great deal of effort as well as the initial adjustment. This is the output signal of the photodetector element 4 (image signal P
This will be explained with reference to FIG. 4 showing D). That is, when the drawing to be read 1 is a white paper with uniform image density, for example,
The value of the image signal PD output from the photodetection element 4 must be a constant value for each photodetection cell c1''cn. However, as the brightness of each light source 21 to 2n changes over time, the output error ε and the S/N of the signal PD
will deteriorate. Therefore, it was necessary to correct this, but to do so, the adjustment had to be made again manually, which required a great deal of effort and time.

[Purpose of the invention]

The present invention has been made to solve the above-mentioned problems, and allows the initial adjustment at the time of completion of the device and the correction adjustment after aging to make the illumination uniform in the reading area extremely simple and quick. It is possible to significantly save labor, and its configuration does not require a variable resistor and is a highly integrated circuit using general-purpose ICs.

It is an object of the present invention to provide a light source control device for an image input device that can be made smaller and lower in cost.

[Summary of the invention]

The device of the present invention does not perform analog control using a variable resistor as in conventional devices, but performs digital control.
First, a standard image plane with a known image density is read based on preset data, and the read output signal at that time is used to find data that equalizes the brightness of the read area, and this is written to the read/write memory. The light source is controlled according to the written data, and the data write operation described above is repeated as necessary to rewrite the data in the read/write memory, thereby achieving the above object.

[Embodiments of the invention]

The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a light source control device for an image input device according to the present invention.
It is a clock generator that provides 14 is a readable/writable memory (read/write memory) whose address is specified by the output signal of the counter 13, here RA
At M, light source control data is written as described later.

Reference numeral 15 denotes a lamp driver that turns on and off each of the light sources, here lamps LMP+-LMPe, according to the light source control data written in the RAM 14. Here, the above RAM14
In this case, data can be written (input) when the OE terminal is LOW (hereinafter abbreviated as It L 1'') and the WE terminal is HIGH (hereinafter abbreviated as (l HI+)), and data can be read (input) when these are reversed. output) becomes possible.

Further, the same signal terminal is used for writing and reading data. Further, arbitrary light source control data can be written into the RAM 14 by a data input means (not shown) when reading a standard image plane, which will be described later, and at any desired time thereafter.

Reference numeral 16 denotes an arithmetic processing unit (hereinafter referred to as CPU), which is an A/D converter of an image input device when reading a standard image surface with a known image density prior to reading a desired surface to be read (here, a drawing). 6 (see FIG. 3), outputs 8-bit light source control data (IN-DATA) for equalizing the brightness of the reading area of the drawing by the lamp LMP+"LMPa. Here, ,
As the standard image surface, for example, white paper, which is known to have uniform image density over the entire surface, is used. 17 is an input buffer for providing light source control data to the RAM 14;

CPU-wT, RUN-MO and CLA-CM
D is a signal controlled by the CPU 6, and the timing chart of these signals and each part signal is shown in FIG.

In other words, when the RAN-MD double signal is "L"', RA
The data output of M14 is disabled and enters the data write state (setup mode), and the input buffer 17
The output of is enabled and the light source control data (IN-DATA) from the CPU 16 is given to the RAM 14,
written. The write strobe signal to the RAM 14 at this time is the CP low υ digit signal. Also, at this time, the counter 13 (RAM address) is set by the CPU 16 to the RAM 14.
Write the data to (cpu-υT times signal 11 L
11 and then returns to trH'''' again).

1゜Note that when data (IN-DATA) is written to the RAM 14, the data is also supplied to the lamp driver 15, but at that time, the lamps LMP, ~LMP, only blink for a short time, so there is no particular inconvenience. do not have. When the RLIN-MD double signal is "H", the data output of the RAM 14 is enabled and the data read state is reached, that is, the lamp LMPI is actually
~LMP, the state where the drawing is read by controlling the lights on and off (RU
The output of the input buffer 17 is disabled, and the light source control data written in the lamp drivers 15 to RANM4 are output. At this time, the CPU
・The WT double signal “H” is held and the counter 13 (R
AM address) is incremented by the clock period of the clock generator 11.

Next, a procedure for controlling the light source using the above-described apparatus of the present invention will be explained. First, arbitrary light source control data is written into the RAMI 4 by a data input means (not shown). Next, the standard image plane (white paper) is read with an image input device, and if the reading result at that time is within a certain error tolerance, a desired drawing is read from then on using the data written in the RAM 14 at that time. When the read result is outside the above-mentioned allowable value, the CPU 16 performs the following correction operation to eliminate the error. First, CP
U16 calculates light source control data based on the reading result OUT-DATA (see Figure 3) so that it falls within the above tolerance, that is, the brightness of the read part of the drawing becomes uniform. ,Output. The CPU 16 simultaneously puts each part of the device into setup mode, and sends the calculated output data ('IN-DATA) to each lamp LMP, to M.
The data is sequentially written to predetermined addresses in the RAM 14 corresponding to P. When this writing is completed, the RUN -MD double signal becomes "H" and the RUN mode is entered.The lamp driver 15 is driven by the corrected light source control data output from the RAM 14, and the lamps LMP, -LMP,
Turns on and off. Here, the output data of RAM14 is 1
One pit is defined as information that instructs ON/OFF of one lamp LMP, and the lamp driver I5
Turn on and off the lamps LMP, ~LMP8 through
Lights on/off are controlled. Note that this lighting/extinguishing control is performed in synchronization with the reading operation of the photodetector element 4 (see FIG. 3) of the image input device.

In addition, correction adjustment for uniformizing the illumination of the lamps LMP to LMP8 after aging can be performed using the same procedure as the above-mentioned initial adjustment.

〔Effect of the invention〕

As described above, the present invention does not perform analog adjustment using a variable resistor, but the initial adjustment at the time of completion of the device and the correction adjustment after deterioration over time for uniform illumination are extremely simple and quick. This can significantly save labor. It also has the advantage of being highly integrated using general-purpose ICs, making it more compact, and reducing costs.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the device of the present invention, and FIG.
The figure is a timing chart of the signals of each part of the device, Figure 3 is a block diagram of an image input device to which the conventional device is applied, and Figure 4 is a block diagram of the image input device to which the conventional device is applied.
The figure is a graph for explaining the output error in a conventional device. 1...Drawing (reading target surface), 4...Photodetection element, 6...
...A/D converter, 14...RAM (read/write memory). 15... Lamp driver, 16... CPU (arithmetic processing unit), LMP, -LMP,... Lamp.

Claims (1)

[Claims] 1. A photodetection element that reads image information on the surface to be read at one time in a certain range and converts it into an electrical image signal of a size corresponding to the density of the image information, and a photodetection element that detects the image information on the surface to be read by this photodetection element A plurality of light sources that illuminate the reading area and an A/D that converts the signal from the photodetector into a digital signal.
In the image input device comprising: a converter, the light source is controlled based on a digital signal from the A/D converter when a standard image surface with a known image density is read prior to reading a desired surface to be read; an arithmetic processing unit that outputs light source control data for uniformizing the brightness of the read area by the arithmetic processing unit; a read/write memory in which the light source control data output from the arithmetic processing unit is written; and a read/write memory that reads the standard image surface. data input means capable of writing arbitrary light source control data into the read/write memory at the time of the read/write memory and at any desired time thereafter; and turning on/off each of the light sources in accordance with the light source control data written in the read/write memory. 1. A light source control device for an image input device, comprising: a light source driver.