JPH01204567A - Picture reader - Google Patents

Abstract

PURPOSE:To facilitate the adjustment of an output level by an adjustment personnel by supplying an adjustment signal to a signal processing means by a signal generating means to adjust the output level of the signal processing means. CONSTITUTION:The reader consists of a control circuit 1, a photoelectric conversion circuit 2, a switching circuit 3, a signal processing circuit 4, an adjusting signal generating circuit 6 and an input circuit 7. Then in order to adjust the output level of the signal processing circuit 4 to apply gamma correction with respect to the output signal of the switching circuit 3, the adjusting signal is supplied to the signal processing circuit 4 by the circuit 6. Thus, it is not required to read the original for plural number of times. Thus, the output level is easily adjusted by the adjustment personnel.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to an image reading device that performs signal processing such as (γ) correction adjustment on a photoelectrically converted signal.

[Prior Art] Generally, an image reading device uses a signal processing circuit to perform γ correction on an image signal obtained by photoelectrically converting an original image, and outputs an image signal that is proportional (linear) to the image gradation of the original. It is configured.

[Problems to be Solved by the Invention] In conventional image reading devices of this type, the γ characteristics of the signal processing circuit are set according to the characteristics of the constituent circuits at the time of manufacture, but there are the following problems. That is, for example, the adjuster prepares a document with a barcode written on it, reads this document image with a reading device, reproduces the document image with a recording device, and compares both the document image and the reproduced image. The γ characteristics of the signal processing circuit are adjusted by adjusting the γ characteristics of the signal processing circuit. ``However, there was a problem in that the adjuster had to read the original image multiple times in order to set the appropriate γ characteristics, making the adjustment work complicated.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an image reading device that can solve these problems and facilitate adjustment of the output signal level of the device.

[Means for Solving the Problem] In order to achieve such an object, the present invention photoelectrically converts either reflected light or transmitted light from a document to read the document image, and converts the read signal into a signal. In an image reading device that performs predetermined signal processing on a signal by a signal processing means, and then outputs a signal-processed read signal,
The present invention is characterized by comprising a signal generating means for supplying an adjustment signal for adjusting the output level of the signal-processed read signal to the signal processing means.

[Function] In the present invention, in order to adjust the output level of the signal processing means, the signal generation means supplies an adjustment signal to the signal processing means, so there is no need to read the document multiple times as in the conventional case. Therefore, the adjustment of the output level by the adjuster can be facilitated.

The adjuster no longer needs to read and reproduce the original image every time the γ characteristic is adjusted, and the adjustment work is greatly simplified.

[Example 1] Hereinafter, the present invention will be described in detail based on an example shown in the drawings.

FIG. 1 shows the circuit configuration of an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a control circuit that generates a timing signal that instructs the operation timing of each circuit in the tree embodiment. The control circuit 1 is a ROM that stores timing in advance.
The timing generation circuit 100 is configured using, for example, a timing generation circuit 100.

2 is a photoelectric conversion circuit that receives reflected light or transmitted light from the original image and photoelectrically converts the original image.

The photoelectric conversion circuit 2 includes a solid-state image sensor (CCD) that performs photoelectric conversion.
) 101 and (:D) and a waveform processing circuit 102 that shapes the waveform of the output signal of 101.

Reference numeral 3 denotes a switching circuit that selectively switches between the output signal of the photoelectric conversion circuit 2 and an adjustment signal to be described later using a changeover switch 103.

A signal processing circuit 4 performs γ correction on the output signal of the switching circuit 3. In the signal processing circuit 4, 104 and 106 are γ for the analog output signal of the switching circuit 3.
This is a changeover switch for switching whether or not to perform correction.

105 is an analog γ conversion circuit that performs γ correction on the analog output signal.

107 is an A/D converter that converts the output signal of the changeover switch 106 into an analog/digital (A/D) converter.

A digital γ conversion circuit 10B performs γ correction on the output signal of the A/D converter 107, and has a memory called a lookup table that stores γ correction values for performing γ correction in the form of a table.

Note that the analog γ conversion circuit 105 and the digital γ conversion circuit 108, which can make the γ correction value variable, are well known, so a detailed explanation thereof will be omitted.

109 is a three-state buffer that outputs the output signal of the digital γ conversion circuit 108.

110 is a three-state buffer that outputs the output signal of the A/D converter 107;
A/D converter 1 in response to operation instructions for 09 and 110.
It is determined whether or not to perform γ correction on the output digital signal of No. 07.

Furthermore, switching of the switching circuits 104 and 106 is determined by instructions from a control circuit.

6 is an adjustment signal generation circuit that generates adjustment signals related to the present invention.

The adjustment signal is a signal used to make the γ correction values of the analog γ conversion circuit 105 and the digital γ conversion circuit 108 appropriate for the original image.

In the adjustment signal generation circuit 6, a D-type flip-flop (D-F/F) 113 holds level information indicating the level of the adjustment signal manually input from the input circuit 7.

A memory 114 sequentially stores the output of the DF/F 113, and outputs the stored contents sequentially under instructions from the control circuit 1.

A D/A converter 115 performs digital-to-analog (D/A) conversion on the level information sequentially output from the memory 114 and outputs it to the switching circuit 3.

7 is a circuit for inputting instructions from the operator, and has an instruction key 112-1 for instructing switching of the switching circuit 3, and an input key 112 for manually inputting level information regarding the adjustment signal to the adjustment signal generation circuit 6. .

Furthermore, the input circuit 7 has changeover switches 104 and 106.
It also instructs the three-state buffers 109 and 110 to switch the signal switching system.

Next, the operation of this embodiment will be explained. Note that the signal processing circuit 4
The signal processing system is (1) second changeover switch 104 - analog six-converter circuit 105 - second changeover switch 106 - A/
D converter 107 -> three-state buffer 110 system or (2) second changeover switch 104 -> second changeover switch 106-/D converter 107 - digital γ conversion circuit 1013 -> three-state buffer 109 system is selected. It is assumed that

First, the operator instructs the connection between the photoelectric conversion circuit 2 and the switching circuit 3 using the instruction key 112-1. The original image read by the photoelectric conversion circuit 2 is reproduced via a signal processing circuit 4 by a recording and reproducing device (not shown).

Next, the operator presses the instruction key 112-1 to select the switching circuit 1.
03 is switched to the adjustment signal generation circuit 6 side.

Based on the above-mentioned reproduced original image, next, when the operator inputs, for example, the inverse value of the γ correction table as the level information of the adjustment signal corresponding to the output of the photoelectric conversion circuit 2 from the data person Kaki-112, , this numerical information is stored in memory. Numerical information output from the memory 114 in response to instructions from the control circuit 1 is converted into an analog adjustment signal by the D/A converter 115, and is output after being γ-corrected by the signal processing circuit 4 via the switching circuit 103. The image is reproduced by an output device (not shown).

The operator inputs γ inverse transformation information or linear level information from the input circuit 7 to adjust the γ of the signal processing circuit 4.
The characteristics can be known, and the gamma characteristics of the gamma conversion circuits 105 and 108 can be converted to appropriate ones.

It is also possible to modify the γ characteristics of the γ conversion circuits 105 and 108 individually by changing the connections of the changeover switches 104 and 106 and the three-state buffers 109 and 110.

The operator only needs to read the original image once.
Since there is no need to perform a document image reading operation multiple times as in the conventional case, adjustment for γ correction can be greatly simplified.

FIG. 2 shows the configuration of another embodiment of the invention.

This embodiment shows another form of the circuits 112 to 115 shown in the first diagram.

In FIG. 2, 120 is a timing circuit that generates a signal synchronized with the timing generation circuit 100. In FIG. 121
is a control key for instructing the connection terminal of the switch 124. Reference numeral 122 is a data person key that manually inputs information regarding the adjustment signal.

Reference numeral 123 is a D-F/F that holds human power information of the human key. Reference numeral 124 denotes a changeover switch, which is used to switch between inputting data to the input terminal of the memory 125 or outputting stored data from the memory 125 by inputting an instruction from the control key 121.

125 is first-in-first-a-ra l~ (FIFO
) memory. 126 is a D-F/F that holds output data of the memory 125; 127 is a counter that counts the number of words in the memory 125.

An inverter 128 inverts the level of the timing signal from the timing generation circuit 100 and inputs it to the counter 127 . 129 is J that holds the output of counter 127
It is K-F/F. 130 is a four-man power AND circuit that uses the outputs of the JK-F/F 129 and the inverter 128 as human power.

Further, a signal 200 is a synchronization signal (SH signal) in the main scanning direction of the CGD 101, and a signal 201 is a clock signal for the counter 129. 202 is a counter ripple carry output signal generated every time the counter 129 counts a predetermined value.

203 is a clock manual signal of JK-F/F129. 204 is an output signal of the Q terminal of JK-F/F129. 205 is CCD dark output period No. 8. 2
06 is a clock signal of the memory 125.

207 is an n-bit serial data output signal.

208 is a clock signal of the D/A converter 116. 2
09 indicates an analog output signal of the D/A converter 116.

FIG. 3 shows the signal generation timing in FIG. 2.

In FIG. 3, first, the control key 121 allows manual input from the data person key 122, and the data person key 122 stores data in the memory 125. When outputting data from memory 125 (:CD
A memory clock 206 is supplied to the memory 125 in accordance with the accumulation time Tc of 101 (see FIG. 4). In addition, S.H.
Pulse 200. Dark output period signal 205 and CGD
Period T from the end of outputting the signal of one line of 101 until the arrival of the SH pulse. (See FIG. 4) is not supplied with the clock signal 206. Further, the number of clocks of the clock 206 is the number of words of the memory 125 (assumed Nw) and D
-F/F, the total number of clocks supplied to 126 is (Nw+1). CCD 101 part 1
By repeatedly supplying the clock 206 to the memory 125 every line period Tc, the memory 125 periodically generates the adjustment signal.

Furthermore, by selecting the words of the memory 125 in detail, the analog signal 209 shown in FIG. can generate a signal. In addition, the period X5-Xe corresponding to one output line period of [:CD 101 is narrowed, and
When the generation of the adjustment signal from 25 is repeated several times within one line, the reproduced image is output in the form of a bar code.

Therefore, the operator can easily set the γ correction characteristic of the signal processing circuit 4 by referring to the bar code.

In this example, an example using the FIFO memory 125 has been described, but as another example, f4LO
(First in La5t out) It is also possible to use a configuration in which a pair of memories is used. In this case F
Data will be input and output in the reverse order compared to when IFO is used. Also, instead of FIFO memory, RAM
(Random access memory) may be used to store data once at a fixed address, and by updating the address, information may be output and an adjustment signal may be generated.

The present embodiment has been described above, and the advantages of the present invention are as follows.

(1) The γ conversion can be appropriately adjusted for various transparent originals made by different companies.

(2) The number of bits of the D/A converter and memory is A.
By making the number of bits the same as that of the /D converter and having the number of memory words of 2n or more, it is possible to provide a distortion-free and highly accurate adjustment signal generation source.

(3) A memory with a large number of words can be used without changing the circuit configuration itself, and a highly accurate adjustment signal generation source can be obtained. Furthermore, by repeatedly inputting the same data several times when storing information in the memory, the adjustment signal can be made into a concise staircase waveform. The same effect can also be achieved by using a memory with 9 fewer words.

(4) Depending on the number of data (number of words), the γ characteristic and its slope can be arbitrarily set by the number of data in one line section and setting data.

[Effects of the Invention] As explained above, according to the present invention, in order to adjust the output level of the signal processing means, the signal generation means supplies an adjustment signal to the signal processing means, so that the conventional There is no need to read the document multiple times as described above, and the adjustment of the output level by the adjuster can therefore be achieved easily.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a circuit diagram showing another configuration of the adjustment signal generation circuit 6 of the embodiment of the present invention, and FIG. 3 is a circuit diagram of the circuit shown in FIG. 5 is a timing chart showing operation timing. DESCRIPTION OF SYMBOLS 1... Control circuit, 2... Photoelectric conversion circuit, 3... Switching circuit, 4... Signal processing circuit, 6... Adjustment signal generation circuit, 7... Input circuit.

Claims (1)

[Claims] After photoelectrically converting either reflected light or transmitted light from the original to read the original image, and performing predetermined signal processing on the read signal by a signal processing means. , an image reading device that outputs the signal-processed read signal, comprising: signal generating means for supplying the signal processing means with an adjustment signal for adjusting the output level of the signal-processed read signal. An image reading device characterized by: