JPS60143064A - Method for setting density value of highlight and shadow point in picture scanning reproducing device - Google Patents

Abstract

PURPOSE:To set density by using a signal value of read density level of the titled device corresponding to a reference density so as to apply operation. CONSTITUTION:When a highlight density value DH and a shadow density value DS of an original picture are inputted from input terminals 13, 14, a computer 11 computes reading luminous energyes PH and PS corresponding to the highlight density value DH and shadow density DS by using a reading luminous energy value PO of the reference density. Then the offset and attenuation required for the density level signals PH, PS on the said computation are applied so as to convert them into output level signals OH, OS corresponding to the density value of the highlight point and the shadow value to be processed by the said device so as to adjust the offset value and the gain value of an amplifier.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for setting the density value of each illite and shadow part to be processed in an image scanning and reproducing apparatus.For example, in plate-making work in the printing field, Power of continuous tone 2-
The original image is scanned by an image scanning and reproducing device called a scanner to perform color separation or approximate separation.
I am getting a reproduced image.

However, when reproducing images using these image scanning and reproducing devices, there is a general difference between the density range of the original image and the density range of the reproduced image* reproduced by the above-mentioned device 1iK. It is common practice to determine the density values of a portion of the image and the shadow, and to adjust the device so that the corresponding density values respectively correspond to desired density values of the reproduced image.

As a method of setting the density values of such highlights and part of the shadows, for example, the density values of the highlights and part of the shadows of the original painting are determined by 61+1 using a densitometer, etc., and the density value of the highlight part is determined in advance. et nr: Standard・
・To match the illite density value, the difference in the original image signal II
The variable antenna (by adjusting the resistor) in the density range setting circuit adjusts the offset of the J-compounder and sets the original density range for the density value of a part of the shadow.
・There are generally known methods such as setting the density value for the highlight part, or setting the density value for the highlight and shadow parts respectively in the cent-up circuit using a rotary switch that switches multiple resistors. Yes However, in the former case, the density value of part of the shadow is set first, and then the density value of the highlight part is set. In this case, the initially set density value of the shadow part is normally changed by the subsequent highlight density 4f4 setting operation by adjusting the variable antenna, and both the highlight and the shadow part are changed independently. It has been extremely difficult to set the concentration value of 2 to a desired value. In the latter case, in addition to the disadvantages of the former, if you want to increase the precision of the density setting or widen the setting curve.

The problem was that the number of switches was extremely large. Further investigation shows that the two conventional methods require a constant light source, such as a laser, which is commonly used as a light source for reading original images. However, even if the light source should originally emit a constant amount of light, the amount of light will fluctuate due to long-term use or changes in the value voltage, etc., and no consideration has been given to this. In practice, it is necessary to verify whether the desired density value is obtained in the final reproduced image, and if the desired density value is not obtained, the light source alignment etc. There is a troublesome problem in that the image must be reproduced again after t'L.

As in the case of driving, the 1-force method is the standard for setting the 0 characteristic, which has many difficulties in obtaining the desired illite and shadow concentration) illite and shadow concentration r! Since the f: value has the above-mentioned problem, it has not been possible to solve the problem of reproducing a π image with desired interfloor characteristics.

The invention is to create a method of setting highlight and shadow density values that can overcome all of the above-mentioned problems inherent in conventional methods. That is, the method of setting the density value of a single highlight and shadow point in the image scanning and reproducing apparatus of the present invention is based on the FRR desired I of the original image.
・A degree value of illite point and one shadow point (DHmDB
), a method for setting the density values of a highlight point and one shadow point of an original image to be processed in the image scanning and reproducing device v1 corresponds to the calculated density values of a desired highlight point and one shadow point of the original image. Reading concentration signal (PH%P
8) is generated by an arithmetic unit (computer), and the calculated density level is converted into an output level signal (0,...OB) corresponding to the density value of a highlight point and one shadow point to be processed by the device. It is characterized by performing the necessary off-nut and attenuation of the signal (pH%p) and adjusting the offset ratio and gain value of the amplifier by 14.

Roughly speaking, as a configuration subordinate to the above-mentioned misfiring FfJVc, in calculating the calculated reading and V density signal (PMIP) corresponding to the density value of a desired highlight point and one shadow point of the original image, the device's corresponding to the reference density 11eK is used. The calculation is performed using the reading and the signal 4j value of the 9 density levels, -F:
9) To enable the desired density setting to be performed regardless of fluctuations in the amount of R defeat light.

In a configuration 2 that roughly follows the misfiring 8AK, the tone signal from the tone generation circuit is included in the output level signal C0Hb08) corresponding to the density value of a highlight point and one shadow point to be processed by the device. Desired sea bream characteristics can also be set at the same time by adjusting the ratio of sea bream.The method of the present invention will be explained in detail below.

First, the basic theory or idea behind the present invention will be explained in the following two ways.

The original image density is 0, that is, the reflectance is 1, and the reading in the part with the density < DJ and 9 light 117 Jla No. P
n is smaller than the product, and is generally expressed by the following formula (1).

FD=Po/jog"-'D・-...4(1) Therefore, if the density value of the desired highlight point of the original picture is rice, and the density value of one shadow point is D, then the reading light amount of each point is signal 8P1 (and P is shown in the following equations (2) and (3) OP"P/log, 'DH+11111@@11
11(2) O P=P/log-'D11111111@116(3)
Therefore, if the value of the reading light amount when the document density is low is kept constant, the reading light amount signal corresponding to the density of the highlight point and the density of a single shadow point will be It can be easily calculated by inputting the seven nine concentration values in the calculation section.

On the other hand, if the signal levels indicating the desired highlight and shadow density values of the image scanning and reproducing apparatus are respectively OH108, then the following relationships (4) and (5) hold true.

0 = α (P 10 β n... (4) HH O - α (P 10 β) Work... (6) Here, OH and 08 are #A insult It is an output signal that is manually obtained or actually attempted to be obtained from outside the scanning and reproducing device in response to each input. In some cases, OH and Og are dot percentages, e.g. 95% and 5%.
Let it be a signal bar that represents a numerical value such as . Further, α is the gain of the amplifier that controls the original image signal, and β is the set value corresponding to the offset.

(as above) Then, using the calculated value, calculate the offset value and gain value of the signal. 1) The image scanning and reproducing device can obtain a signal indicating the density value of the desired highlight part and a part of the shadow. By calculating Ks according to the above formula, a signal corresponding to the concentration value can be obtained.More specifically, the gain value α is By appropriately setting the variable antenna for determining the
By changing the value of , the calculated signal of the amount of light to be read, which corresponds to the concentration of a single shadow, is brought closer to the left side.

Next, while leaving the set offset value β as is, adjust the intensity value to the highest focus f) and 4) change the value of α on the right side of equation 4) to change the density value t (corresponding reading) of the highlight point. Move the calculated signal of the amount of light toward the left side and loosen it.

Then, each time the above operation is performed for one shadow point and highlight point, it is compared whether the signal level of the one shadow point and the highlight point is at the signal level indicating the density value to be set, and if it is not equal to 1, the same operation is repeated again. By using these steps, the desired set values of α and β can be converted to VC.

If it does not converge to the set value even after repeating this operation, fi
It is also possible to process it in a mini-cooker.

By the method described above, it is possible to set the densities of one illite point and one shadow point of v, draft to the desired highlight and shadow densities @ in the image scanning and reproducing apparatus ItK.

In addition, in the above method, the objective setting is made with P- constant, and if the output light m etc. of the original self-scanning light source is constant, it will indicate a certain value, but in reality, the It fluctuates due to changes in the amount of light etc. due to various causes. Therefore, P) 1% P8 becomes a value that corresponds to the change in P, and becomes a value that is rounded by the failure of P, and in practice, each time the original image is scanned, the reference value of P and the actual value of P. Pk1P8, which is the objective 2, cannot be obtained unless the fluctuations in the output light intensity of the original self-scanning light source are corrected. Therefore, in implementing the method of the present invention, for example,
Every time the image scanning and reproducing device performs image scanning, etc., 26 actual lines are detected by a sensor, etc., and 311 actual lines are included in the above calculation formula based on the principle of my invention, regardless of changes in the light intensity of the reading light source. , it becomes possible to set the desired density values of highlight points and shard points.

Fig. 1 shows a block diagram of 18 examples of control circuits for carrying out method 1r of the present invention.◎In Fig. 1, - (b) is a computer of the control calculation section, 4 is an input section, and the input section is the original high-speed Input of density setting value DH for light section +1111 (11
and the input of the density setting value of part of the shadow l1IIα4, the input of the desired highlight density value O or its halftone % (6) of the image scanning and reproducing device, and the input 111ilQI of the desired shadow density value 08 or its halftone dot %. include. The light 1 signal P of the light control signal P of the Harajino PiO is read and sent to the computer (6) via the Mitsushin A/D converter (J'I).
) is input to ◎) is computer (D/A for inputting calculated reading concentration value 9PH or P8 from 11)
The analog switch QIK, which manually inputs the internal signal to the analog switch <11 using the converter, is configured so that the external image signal (e) and the switch signal are also input.

The output from analog switch 4 enters differential amplifier 3υ and variable attenuator @. The offset value βI) from the computer 4FI enters another D/A converter t74, and its output analog signal is depaded and enters the differential amplifier 1v11 Qυ.

On the other hand, the signal line with gain value α from computer 4 enters the variable attenuator @, and the output of the differential J11 width amplifier Q9 and variable attenuator (2) is sampled and held (c) and sent to the A/D converter/signal. The output signal 0° is sent to the computer (ro) as shown in path 01.
is input.

The method of the invention is implemented in the control circuit of FIG. 1 as follows.

First, when the highlight density fm of the original image and the shadow density value D8 are input from the box and Q4, the computer circuit uses equations (2) and (3)K, and therefore the read light amount value P of the reference density, to calculate I. Calculate the reading light amount IIIPH and P8 corresponding to the illite a degree value and the shadow density value D8. Here, a signal calculated by the computer and corresponding to 7, -PK is converted into an analog signal by a D/A converter Qη, and is amplified by a differential amplifier 3υ according to an offset value β and a gain value α initially set therein. The amplified signal fl is converted into a digital signal 0. by the A/D converter), inputted into the computer music again, and compared with the signal value 08, which corresponds to the shadow output level, which was initially set at 94. If they are not equal, a new offset value β is sent to the D/A converter (2) to change the offset value of the p% differential amplifier eυ. Here, the computer sends a signal corresponding to P again to the D/A converter (G), and amplifies the facial signal with the offset value β changed by λL1, and generates a signal corresponding to the corrected shadow output level 0. and sOmkO are compared.

By repeating this operation, 08 and 0. are approximated or matched, and the offset value β at that time is obtained.

Next, the signal corresponding to the PH calculated by the computer is converted into analog by a %D/A converter (g), amplified using the offset value β set in the operation described in sIIIJ, and similarly converted to a KA/'D converter). After being digitally converted, oO, which is input to the ffi9o computer, is compared with oH, and if OH and 0 are not equal, the gain value α of the variable antenna (2) is converted.

M9t D/A converter (to) equivalent to 8rxpHrc
Input L*111thLr: Source of gain value α D4m
The number is amplified and corrected to obtain KOo. This 0. and 0 are compared and the gain value α is corrected, and 0. and Oll are approximated or matched to obtain the gain value α0. Then, the shadow reading light 1 value P8t is output again from the computer and 0 corresponding to P and K is obtained,
08 and 0°, and if it is correct, repeat the same operation to determine the desired offset value β and gain value α. By performing the above operations, the original image's high K is 0 so that the density values DH and Da of the light and shadow parts can be set to the desired I/light and shadow part density 41 for the image scanning and reproducing apparatus.

Figure 2 shows the block diagram shown in Figure 1 with tone (gradation).
FIG. 3 is a block diagram of an example circuit when a correction circuit is added.

The signal from the A/D converter (c) is connected to the tone generating circuit. From this @UK, the signal level Vi indicating the density value of a highlight point and a single shadow point
Although set by the above method, each tone, i.e., each dark g(
Indicates the rIk degree value at a certain point (no. 8 can also be set by the same method).
In general, it is possible to set the density value, or tone, of the image scanning and reproducing device with the desired gradation characteristics in more detailed density steps (Figures 8-1 and 8-2). The figure shows IMI processing 70
- It shows one specific example of a chart. Each operation of the software is performed as follows.◎(Start 81 (82) Press the analog switch) I can get 2a.

(83) Input the reading and 9 light intensity and enter psa.

(84) Read the highlight density setting value and set it as D) I 〇 (85) Read the shadow density setting value and set it as vD 5 (8
6) Input the highlight dot % and set it as OH.

(87) Input the shadow halftone dot % and set it to O.

(88) Calculate the signal of the highlight point by 8L and add P. (89) Calculate the signal of one shadow point and set it as P8.

(Sent the initial value of the 4UJD/A converter cAK offset value β. IK the most significant bit. 0 (41) Set the initial value to the variable attenuator).

IK the top focus.

(42) Set the determination bit as the most significant bit.

C48) Output the shadow signal P8 to the D/A converter (internality 8).

(44) Set the signal from the A/D humperter ■ to 0- (45) Completely compare D and Oo.

(46) D/A=+y/(-ta(o7sey)4n)C1
3<') Change the judgment focus to OK.

(47) Did you operate the required number of bits? (48) 111
Shift the J constant bit and apply UVC to the judgment bit of the D/A converter v. (49) Set the judgment focus to the top. Output signal Pn〇 (51) Set the signal of A/D converter (2) to 0.〇 (62 Compare N O and 0. @ (58) Change the judgment bit of variable attenuator to OVc) (54) Has the necessary number of bits been operated? (55) Shift the J constant bit and IK the judgment bit of the variable attenuator (56) Compare OH and Oo.

(57) Output a single shadow signal to the D/A converter (internal signal) (g). (58) Set the signal from the A/D converter to 0.

(59)08. ! :Compare with O@.

(60) End T0 Then, if you want to add gradation correction, make the following changes〇 (44) (44) Instead of K, input the signal from A/D converter (c) and then to the tone generation circuit) Then, the nose is manipulated in the same way as the mouth (51') (instead of 5υ, C44), which takes the obtained signal as 0.
<bs5 (58) Instead of rc, operate in the same way as (44).

As shown in FIG. 9, according to the method of the present invention, desired highlight and shadow density values can be set in the image scanning and reproducing apparatus, and desired floor FA characteristics can be roughly set. And this setting! lH1'l't, by automatically performing it every time J jIi images are scanned or when the main power of the self-axis device is turned on, it is possible to change the continuation and V light it, etc. 11J,! A desired density value can be obtained with constant accuracy, regardless of -Vi. If the densities of the highlights and part of the shadows of the original image scanning angle generating device are set by the method of the present invention, the signal obtained by scanning the original image is routed from, for example, to the A/D converter in FIG. is output, and after 7, the necessary contour correction,
Shaded, roughly enlarged.

Processing such as reduction is performed, and after going through various methods, the final result is 0, which can be expressed as F+(!-).

[Brief explanation of drawings]

FIG. 1 is a Gronk diagram showing a specific example of a control circuit implementing the method of the present invention, FIG. 2 is a Gronk diagram when a stage=IIi correction circuit is added, and FIG.
- The first part of one specific example of the chart, and FIG. 3-2 shows the second part. Uru...computer of rlJ calculation section, Suno...input section, Sou4α Gento, input end, assistant...Zokumitori Hikari@A/D
Combark, 0 barrel...D/A converter, clI...Analog switch, wire...External m* (No. 4, Qp-kai differential amplifier, to)...Variable attenuator, to) -D/jl
Converter, (c) II11 sample hold,
・A/D converter, G! I@...path, to)...tone generation circuit, (812~(86n, (44nC3l)(5g)...flowchart stage.N''''''''''''''A'''G7.i ::”':”””
'Patent Attorney Kaku 1) L & Hiroshi 7. . Figure 3-1. Fuki 3-2 Procedural Amendment (Voluntary) December 21, 1980 Commissioner of the Japan Patent Office Manabu Shiga ■, Minor case indication 1985 Patent Application No. 185447 Representative Tokusuke Hiroi 4, Agent 〒650 6, Column 7 of the detailed description of the invention in the specification to be amended, contents of the amendment The above will be amended as a separate sheet. (1) In the 2nd page of the specification, line 12, ``orita'' is corrected to ``any''. (2) On page 4, line 7, "for settings" is corrected to "for settings." (3) Correct ``PH'' in line 18 of the same No. 6 Tei line rPJ.
(4) On page 10, line 1, "concentration value" is corrected to "density value." (5) "Highlight" on page 10, line 6, "highlight"
I am corrected. (6) On page 10, line 7, ``yuru'' is corrected to ``yuku''. (7) Delete the 7th line on page 12 of the same page, ``The scene of trust PaJ.'' (8) Correct ``(1η'' in line 14, page 16 of the same page, to r(181J). Correct "signal" in line 9 to "trust P,". Oo) Correct "more than" in line 1 of page 19 to "1 or more". Procedural Amendment February 12, 1985 1 , Incident Display 1982 Patent Application No. 185447 2,
Title of the invention: Method for setting the density value of a single illite and shadow point in an image scanning and reproducing device 3; Person making the amendment; Relationship with the case; Patent applicant 4; Attorney:
650 Procedural Amendment (0December 21, 1981, Manabu Shiga, Commissioner of the Japan Patent Office■, Minor Case Indication, Patent Application No. 185447, 1985, 3)
Person making amendment Related to the case Patent applicant 4, agent 〒65
0 5. Date of correction command: Showa year, month, day 7, mTfE, cf) Contents The above will be corrected as shown in the attached sheet. (Attachment) 2. Claims (1) Processing by an image constant reproducing device in accordance with the density *("H*i)I!l) of one highlight point and shadow of the original image" In the method of establishing the density value of the highlight point and one shadow point of the original image to be calculated.The read density value 9CPg*Pg) on the df calculation corresponds to the density value of the highlight point and one shadow point of the Br image of Mm.
A large inspection is performed on the Karebe/I/ signal (0!r, 08), which is generated by the t-calculation unit (computer) and corresponds to the density of one highlight point and shadow to be processed by the hit device. The concentration level signal based on the dL calculation (1'JIhp
, ) required off-1! A method for establishing a density value of a single highlight and a single shadow in an image scanning and reproducing apparatus, characterized in that the gain value of one amplifier is adjusted by antennation. (2) Calculated output density signal corresponding to the density value of one highlight point of the original image (
In calculating PII & P8), the product of the device corresponding to the crystal IP concentration; the signal value of the Mitori concentration level is used for calculation. Method. (3) Output level (n (OH, 0,
], the method according to any one of Items 1 and 2 of the scope of the patent, which also includes a tone signal from a tone generation circuit.

Claims (3)

[Claims] (1) Method for setting the density value of a desired illumination point and one shadow point of an original image (rice, ng) KM correspondingly, the density value of an illumination point and one shadow point of an original image to be processed by the image scanning and reproducing device RK t, the calculation unit (computer) calculates the calculated reading density (PHsPs) corresponding to the density value of the desired light point and one shadow point of the original image.
Therefore, the output level signal (OH, 08) corresponding to the density value of the illumination point and one shadow point is generated σ and should be processed by the device. A method for setting the density value of a single point of illumination and shadow in an image scanning and reproducing device, which is characterized by performing offset and antenuation and adjusting the offset value and gain value of an amplifier. (2) Calculated reading density level signal (PH
2. The method according to claim 1, wherein the calculation of sPB) is performed using a value of the reading concentration level of the device 12 corresponding to the reference concentration. (3) Output level signal (Okl, 08
2. A method according to any one of claims 1 and 2, characterized in that the tone signal from a tone generating circuit is also included in the tone signal outputted from the tone generating circuit.