JPS61138942A - Calibrating method of input part of color film inspection device - Google Patents

Abstract

PURPOSE:To calibrate an input part easily and securely by shifting data in a conversion table vertically or horizontally for a gain drift and an offset drift. CONSTITUTION:A color negative film 1 to be inspected is photographed by a TV camera 4 and converted by an AD converter 5 into a digital value, which is converted logarithmically by a logarithmic converting circuit 6 to obtain a density signal DS. In this case, the logarithmic converting circuit 6 shifts the conversion table in the horizontal direction of an input axis side to make offset corrections or shifts the conversion table upward and downward to an output axis side to make gain corrections. Then, the density signal DS is inputted to a color correcting circuit 7 to make color corrections and inputted to a look-up table 8 to perform gradation conversion, and the the image is displayed as a positive image on a color monitor 10.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a carrier plane method for the input section of a color film verification device that evaluates color originals prior to photographic printing. ) Conventionally, such a color film verification device is known, for example, one disclosed in Japanese Patent Application Laid-open No. 57-207238. is displayed on a color monitor. Therefore, a monitor who inspects color originals such as negative films only needs to observe the automatically corrected color images and judge only those that are inappropriate for 6 degrees or color balance, and those that are out of focus and do not need to be printed. , automatic correction or difficult ones (color feria,
The monitor operator only needs to operate the manual operation input section to correct the color and density of the color image (backlight, different light sources, etc.), so it is not necessary for the monitor to be an experienced and capable monitor, and to improve accuracy. Even without an expensive automatic color film analysis device, it is now possible to obtain high-quality printed photographs. The correction information determined by the monitor or automatically calculated is recorded on a recording medium such as paper tape or magnetic tape, and is recorded when the color film is loaded into an automatic printer at the time of photo printing. Printing is performed by controlling the printing exposure amount based on the correction information read from the inspection medium.

However, such a verification method using a conventional device does not take into account the calibration of the image input section of the device at all, and therefore has the drawback that the accuracy of verification cannot be maintained against changes in gain or offset.

(Object of the invention) This invention was made under the above circumstances,
SUMMARY OF THE INVENTION It is an object of the present invention to provide an efficient and accurate method for calculating the input section of a color film verification device.

(Summary of the Invention) The present invention relates to a method for calibrating a color film testing device, and the color film testing device includes an imaging device that captures an original color image to be verified, and a video signal from the imaging device that converts the video signal into a digital quantity. An converter that converts and this An transformation! ! ! ! A conversion table that converts the H output digital quantity into a density signal using a logarithmic table, a color correction circuit that color-corrects the output of this conversion table, and a gradation that independently converts the gradation of the three primary color signals from this color correction circuit. It consists of a conversion child actor and a color monitor child actor that converts the output of this gradation conversion child actor into an analog quantity and displays it.Offset correction is performed by shifting the conversion table in the horizontal direction on the input axis side, and the conversion table is Gain correction is performed by shifting the output axis in the vertical direction on the output shaft side.

(Embodiment of the invention) Figure 1 shows the color film certification IF that is the subject of this invention.
This shows the negative film 1 as a color original.
is emitted by a light source 3 through a light control unit 2 and a mirror box 2A, and the entire image is captured by a TV camera 4 as an imaging device.
The image is taken with The video signals vS of the three primary colors ROB from the TV camera 4 are each input to the AD converter 5 and converted into digital quantities, and then logarithmically converted using a function as shown in FIG. 2, which is converted into a look-up table. circuit 6
and is converted into a concentration signal O5. The density signals DS obtained by logarithmic conversion in the logarithmic conversion circuit 6 are respectively input to the color correction circuit 7, where color correction is performed according to a predetermined calculation formula, negative/positive conversion is performed if necessary, and gradation conversion is performed. After being input to the look-up table 8, it is converted into an analog quantity by an OA converter 9, and is input to a color monitor 10 such as a CRT to display the image of the negative film 1. Further, a control circuit 20 consisting of a microcomputer or the like is designed to perform overall control;
0 controls the light intensity of the light source 3, the aperture of the light control unit 2, and the magnification for imaging of the TV camera 4, as well as a logarithmic conversion circuit 6 and a color correction circuit 7. It is designed to control the luer aquatic table 8, and is connected to a key fob 30 operated by a monitor, and further connected to a data output device 40 for recording the test results of the negative film l on a magnetic tape, floppy disk, etc. has been done.

As shown in FIGS. 3(A) and CB), the light control unit 2 consists of a box-shaped frame 23 having a rectangular opening 21 at the top and a circular optical path hole 22 at the bottom. A pair of light shielding plates 24 and 25 are arranged at different levels within the frame 23 so as to sandwich the optical path hole 22.
Each of them is moved in the direction of the arrow shown in the figure by a drive mechanism (not shown). Light shielding plates 24 and 2
The aperture of the light control unit 2 is adjusted by the moving layer 5, and an optical path is generated. Further, different gradation conversion tables are set in the lookup table 8 for each color RGB, and for example, a data table as shown in FIG. 4 is set.

In such Wr&, the negative film L,1 is irradiated with a predetermined amount of light by the light source 3 controlled by the control circuit 20, and its image is captured by the TV right camera and sent to the ^D converter 5.
After being converted into a digital quantity by the logarithmic conversion circuit 6, color correction is performed using the density signal OS converted by the logarithmic conversion circuit 6, gradation conversion is performed by the lookup table 8, and the color monitor 1
0, the image is displayed as a positive image. In this case, the control circuit 20 controls the light amount of the light source 3 to be constant, and adjusts the brightness of the color monitor 10 by controlling the aperture of the light control unit 2 [! I try to do that. That is, under the control of the control circuit 20, the light shielding plates 24 and 25 are moved toward the center of the optical path to reduce the aperture, thereby narrowing the optical path and reducing the amount of light irradiated from the light source 3 to the negative film 1. The brightness of the displayed image on the color monitor lo decreases. Conversely, the aperture can be increased by moving the light shielding plates 24 and 25 to the outside of the optical path. This increases the optical path, increases the amount of light irradiated from the light v, 3 to the negative film 1, and increases the brightness of the image displayed on the color monitor 10. Therefore, the amount of light transmitted through the negative film l depending on the aperture of the light control unit 2 changes at the same ratio for the three primary colors of RGB. The change does not affect other G and B color corrections.

The solution is to control the overall display image only by controlling the brightness.

The aperture of the light control unit 2 can be determined by checking the brightness of the image displayed on the color monitor 10. When the f4 degree is insufficient or the brightness is excessive, the light control unit 2 can be adjusted via the control circuit 20 by operating the keys on the keyboard 30 to obtain the appropriate brightness. The image with the brightness corresponding to this is displayed on the color monitor 10.
will be displayed.

Here, in the present invention, in the logarithmic conversion circuit 6 having the characteristics shown in FIG. 2, by shifting the conversion table in the horizontal direction and the vertical direction, the offset drift and the gain drift are compensated for.
The operation of this +-replay will be explained below with reference to FIG.

In FIG. 5 showing the conversion table for one color, the horizontal axis vx
indicates the output of the TV right camera, that is, the input of the to-a conversion circuit 6, and the vertical axis ■! indicates the amount of light incident on the TV right camera,
Fo (Vi) indicates the output of the logarithmic conversion circuit 6. And a function! (Vl-11) has an offset of 'On'
shows the basic function of gain ゛°1'', and the standard conversion table for this standard ISO number I is m.When the standard function has offset β and gain α, the function is II (Vx=αlx+β), and it would be good if we could obtain a conversion table corresponding to this 11. As shown in the figure, the correction relationship is)o(Vx)=-logVx, and the offset correction is Ix*11. The 2nth order correction function is +7n (Vl
) = a? If n Vl +b2n, (2r++
1) The next correction function is It=1. +2n, 1(V1
) -Iagl+, the 2r+ order correction function is corrected. Here, the 2nth correction function is hn(V1)-1ng
(a2nV+◆b2n), and the error from the target A is log Δ”f?n, +(V1)-f2n(V1)-I
ogl+ -(-log(a2nV+ +b2n))l
Ilog(a2nV+ +b2*)/I+. Here, f2n('/x) is ■! Considering that the gain can be corrected for
g(+1◆β')/It, so (a?nV+ +b2n)/I+=(1++β')/
I+β -a2nVl◆b2n-11, so the correction function is f2n-+ (Vx)-f2n(Vx-β°)*-lo
g(a?nVx*b?na+nV+-b2CI+)
-1 ng (a2nVx+I+ -a7nVl). In addition, gain correction is performed by giving a light amount such that Ixm12, and the 2i-1st order correction function is f? n
−+ (Vx)m-log(azn-IVi+b2n-
+ ), then the 2nth correction function is 2n-1 so that te f2n (Vi) □ - IogI7 in Ix-12
Correct the following correction function.

Here, the 2n-1st order correction function is f2n, +(Vi)=
-1ng (azn-+V◆b2n-1), and the error from the target value is lag Δ-f2n(Vi)-f2n-+
(Vi)=-1ngrz-((-1ng(azn-IV
z◆b2n-+N-1,og(azn-+V2÷b2n
-1)/+2, so the corrected lSg number is f2n(Vi)*f2n-+ (Vx)"IOgΔto1
ag(azn-+Vx+b2n-1)+log(azn
-+V2+b2n-1)/I2 proverb-1ag (+2(a
zn-1Vi+bpn-1)/(atn-+V2+b2
n-1) 1, the zero-order correction function is fn(Vy
)-1ng (anvK4b11) then azn*l2azn-+/(azn-+V2+b2n-
1) Since a2+1+1-a7n, is it a? ++*[2a? +n・++/(aprn-++V?
+b7n-1), and further t12n・l"II-a2nVI kll-1'1l-az(n-l)V1112n-b2
n-+ +2/(azn-+V2+b2n-1)"b2
n-+ +2/(az(n-nV2+b2n-1)a2
nm12a2+n-n/ (az(n-++V2+1+
-a2(n-++V+1-I+a7+n-++/ ((
Vi-V1) az(n-+rl+ 1a12a?+n
-++/ 1Voa2(n-+++I+1vo*v2-
v.

b2nab2n-+ +2/(a2+n-1)V2+b
2n-1)=lz f[+-az(n-++V+l
/ (az(n-++V2+1+-a2(n-++
V+1 = (L++2-V+Iza2(n-++l / (
Voa2<n-1+÷Ill, and the coefficients a, , and b are am-1 and kls-, respectively.
It can be expressed by the relational expression of l. Then, finding a general solution for the coefficients am and b-, a2na12a2(n-++/(Voa2(N-+++)
I1) ÷l, na7nshinl82n, and further the following condition Vxs a Ig+β a6 樟1, be =0
■1 snow plo O(p <
q+24-100(q<1 Later vo-v2-vl-αqlo◆β-αρIo-βro α(
q-p)I.

◆l,n VOlo'-1LP"-1+pn-+'q+ ・-+
pqn-f -ql+-1ノ4) Ill IQII! 1
QII/((z(pnl+pn-742+...+pqn-
++qn-pn-pnlq−−−−−−−p2qn−
2-pqn-1)+pn l=q'/(apII◆(l
-α) pO mqn/ (ap'+(1-a)qn l, and 6o+7%-1 -βpnJo11 also holds true for relation &b21+ under similar conditions.

From the above, the 2nth-order correction function becomes f2n(Vx)−1og(a2nVx+b2n), and roughly speaking, if n is large enough, pn −Q, so = logl! As a result, it is possible to correct the gaino drift α and offset drift β of five people.

The above ri4 formula is shown in FIG. 5. First, the offset drift component β° for the light amount r1 is shifted to the right to obtain fl(Ih), and then +2(Vx) is obtained by shifting the offset drift component β° for the light amount r1 upward by the gain drift logΔ2 for the light II2. . In this way, in one calibration, for example, the light amount is 1
Since an error log Δ occurs with respect to 1, if the shift operation is repeated several times in the opposite direction, the value converges to a value that compensates for the drift.

Further, in the present invention, the conversion table itself is created using, for example, n bits, and the calculation of gain drift α and offset drift β is performed using, for example, (n-2) bits and then loaded into the conversion table. In this way, l
It is possible to perform 1tilTX and obtain shift data with high precision.

From the above, when fo= -fog(Vx) Vl-aIx◆β +1"PIO T2='llO, the offset correction (It-1+) is the error l
adΔ=-1og++-(-1agV1)-Iog4+
/ItVxJx◆β“ If we think of it, Vl=Il÷β.

log(V+/I+)−fog(1++β”)/I+
β'*V+-[1-al+" 13-L= (a-1)
+1+, +3f+ (Vx)"fo (VK-β')*
-fog(Vx-V++11) = -log (aIx+β-α■1-β÷L)=
-log (alx++1-all), and the gain correction (+!-12) is the error lag Δ--logl2-i (Vl) = -lo
gl2-log(Vz-Vr[1)-log(Vl-V
+÷11)/12 m lag(a12+ β-(Ell-β+I1)
/+2- log(αI2- al+◆[1)/1
2f7(Vx)−f+ (Vi)stag Δ= −
fog(alz+1l-all) stag(ah-ah
*1.1)/■2=-log(cclx+I+-ct
+1)Iz/ (a■?-(Ell+111)).

(Effect of the invention) As mentioned above, the color film test of this invention! /cat
According to the input part calibration method, by simply shifting the data of the conversion table Y rows or up or down for gain, lift, and offset drift,
This can be achieved easily and reliably.

[Brief Description of the Drawings] Fig. 1 is a block configuration diagram showing an example of a color film verification device, Fig. 2 is a diagram showing an example of output characteristics of logarithmic conversion,
Figure 3 (A) is a plan view showing an example of the light control section, and Figure 3 (B)
4 is a diagram showing an example of the characteristics of the gradation conversion table, and FIG. 5 is a diagram for explaining the method of the invention. l...Negative film, 2...Dimmer, 3...Light source. 4... TV right camera 5... AD converter, 6... Logarithmic conversion circuit, 7... Color correction circuit, 8... Lookup table, 9... OA converter, 10...・Color monitor, 20...control circuit, 30...keyboard,
40...Data output device. Applicant's representative Yu Yasugata 3rd 2nd session Brown 4 Prisoner output Yamaba JZ

h2 Iχ [Continued amendment 1985 2) -470 2. Name of the invention: Calibration method for the manual section of a color film testing device 3. Relationship with the person making the amendment case Patent applicant: Nakanuma, Minamiashigara City, Kanagawa Prefecture 21Q# rI′! ! (52G)
Fuji Photo Film Co., Ltd. 4, Agent 5, Image of correction 6, Contents of correction (1) [Offset β] on page 11 of specification jR1O. The phrase ``gain α'' is corrected to ``offcent drift I·β, gain drift α.'' (2) Insert ";" after ra2n J in each of the formula on the bottom line of page 14 and the formula on page +5, line 11R9. (3) Same, page 13, line 5 r V6 mV? -V+
Insert "here," in J's rift. (4) Same, page 16, line 5 (7) r (1-α)P'
Insert J ノBEni ")". (5) Same, page 18, line 10, Ryumasa says. β (6) Same, page 13, line 2 says “◆□” 4. and correct it. (7) Same, page 19, No. 3 says "rloglg" i1
og+! ” he corrected. (8) On page 13, line 18 of the same OG, the text "r (n-2) J" is corrected to "r(fl◆2)".

Claims (4)

[Claims] (1) An imaging device that images the original color image to be verified, and A that converts the video signal from this imaging device into a digital quantity.
A D converter, a conversion table that converts the output digital quantity of this AD converter into a density signal using a logarithmic table, a color correction circuit that color-corrects the output of this conversion table, and three primary color signals from this color correction circuit. In a method for calibrating an input section of a color film testing device comprising a tone converting means for independently converting the tone, and a color monitor means for converting the output of the tone converting means into an analog quantity and displaying the converted value, the conversion table is provided. An input of a color film verification device, characterized in that offset correction is performed by shifting the conversion table in the horizontal direction toward the input shaft side, and gain correction is performed by shifting the conversion table in the vertical direction toward the output shaft side. How to calibrate the section. (2) A method for calibrating an input section of a color film verification apparatus according to claim 1, wherein the offset correction is performed by inserting a reference density plate for offset correction. (3) A method for calibrating an input section of a color film verification apparatus according to claim 1, wherein the gain correction is performed by inserting a reference density plate for gain correction. (4) The scope of the claim is that the conversion table is created using n bits, the offset correction and gain correction calculations are performed using bits larger than n, and data is loaded into the conversion table using n bits. A method for calibrating an input section of a color film verification device according to item 2 or 3.