CA1208765A - Video image recording methods and devices - Google Patents

Abstract

Abstract of the Disclosure Video image recording device for photographically re-cording video images selected from video input signals on sheets of film, provided with means for reducing or completely eliminating recorded image drift. Recorded image parameter controls are provided which are calibrated in terms of Dunn Density Index numbers, which are related to the densities of the recorded video images. Image polarity inversion control means are provided for the recorded image and for each indi-vidual video input signal channel.

Description

¦ This is a division of Application Serial No. 404,609, ¦filed June 7, 1982.
¦VID~O I~GE ~ECORDING M~TIIODS AND DEyICES

3 Back~round of the Invention 5 IField of the Invention. The present invention I
6 ¦ relates to video image recording methods and devices, and more 7 ¦ particularly to video image recording apparatus of the type 8 ¦ adapted to receive input video signals from ho~t video signal 9 ¦ yeneratin~ devices and to photographically record video images l0¦ correspondin~ to selected portions thereof, and the methods ll ¦ executed by such devices and the operators thereof.
12¦ Description of the Prior Art. Video image record~
13¦ in~ methods and devices for photographically recording, ser-14¦ iatim, selected pluralities o~ the images borne by input video 15l signals on x-ray type sheet film or the like in predetermined 16¦ collocation are known in the prior art. For example, a video 17¦ ima~J~ recordin~ device of this type is shown and described in l8¦ ~ni-ted Stat~s Patent No. 4,027,315, issued ~o Howard Hunter l9l sarlley on May 31, 19~7.
20¦ Such prior ar~ video imaye recordinq methods and 21 ¦ devices have in general been characterized by the problem of

2~ ¦ "recorded ima~e drift", i,e., changes over time in the reLa-~31 tionshi~ between the density of any particular photographically 241 record~d pixel or imaye element and the magnitude of the cor-251 respondin~ portion of the input video signal, due to thermal 26¦ v~riations in component values, component aging, line voltatJe 271 fluctuations, and other equipment variables, the control of 281 all of which is no-t economlcally feasible.
291 Prior ar~ video image recording methods and devices 301 have attemp-ted to deal with the recorded image drift problem, 3l e.cJ., by varying the ex~osure time, the lens apertur~, or the ~21 mean lig~lt oLI-tput o~ t~le in~ernal monitor in accordance wi~h I
;

1 the brightness o~ the image produced on the monitor screen by 2 ¦ an internally generated, single-valued signal applied to ~he

3 ¦ monitor cathode ray tube control grid, which internally gen-41 erated signal was not a function of the input video signal.
5¦ ~urther, the imaye p~rameter control means of such 61 prior art video ima~e recordiny devices have in ~eneral merely 71 been monitor brightness and contrast controls which in the ~¦ manner common to broadcast television monitors were uncali-9¦ brated.
10¦ Some prior art video image recording devices of 11¦ this type have been provided with simple photometers arranged 12¦ to "view" part of the monitor screen and externally accessi-13¦ ble pushbuttons, automatic devices, or the like for applying a 14¦ fixed-level, internally generated signal to the monitor ca-15¦ thode ray tube control grid while the photometer output signal ~61 is read on an externally viewable meter.
17¦ Despite the provision of these expedients, however, 18¦ the o~eratiQn of such prior art video image recording devices 19¦ has involved the carrying out of expensive, time-consuminy 20 ¦ manual calibration,procedures ~analogous to the monitor align-21¦ ing procedures established in European Broadca~ting Union 22¦ technical recommendation E.~.~.R. 23-1980(E) and ASMPTE recom-23 ¦ mended prac~ice RP71-1977, in the course of which recordinys 24¦ are made at various image parameter control settings and those 2sl recor~in~s ~evelopPd and cross-compared by the human operator 26 ¦ to determine which image parameter control settings produce 27 -the desired density and photo~raphic contrast in the recorded 28 ¦ images.
29 ¦ Related Art. The documents listed immediately 30 ¦ below contain information which is or might be considered to 31 ¦ be material to the examination of this patent application.

il2~B~7ti5 1¦ U.S. Patent No. 3,852,602 21 U.S, Patent No. 4,027,315 31 German OffenlPgungsschrift

4 No. 2,303,800 "Ultrasound Backgrounds Black or White?"
by Margaret R. Gasson, page 24, et seq., 6 Radiolo~ Today, February Maxch, 1980.

- ~ , 11 . .
12 I Su~nary of the Invention 14¦ Accordingly, it is an object of the present inven-15 I tion to provide video image recording devices in which the 16 ¦ parameters of the image displayed on the screen of the internal 17 ¦ monitor are automatically regulated in accordance with charac-18¦ teristics ~ the input video s.ignal, whereby the need for 19 I manual calibration procedures is greatly reduced or completely 20¦ elimi.nated.
21¦ It is another object of the present invention to 22 provide improved video image reco~ding devices in whi.ch the 23 polarity of the image displayed on ~he intPr~al moni~or screen 24 may be reversed by the manipulation of externally accessible manual control means without manually adjusting the externally 26 accessible monitor image control means.
27 Other objects of the present invention will in part 28 be obvious and will in part appear hereinafterO
29 The present invention~ accordingly, comprises the several steps and the relations of said steps wi.th respect to 31 each o~her, and the apparatus embodying features of cons-truc-32 tion, con~binations of elements, and arrangements of parts ~2~

1¦ which are adapted to eEfect the steps of the methods of video ~¦ ilnage recording disclosed herein, all as exemplified in ~he ~ followiny disclosure, and the scope of the present invention 4 1 will be indicated in the appended claims.

5 ~ In accordance with a principal feature of the 61 present invention, video image recording devices are p~ovided 7 in which the video brightness and video contrast of the inter-8 I nal monitor display are automatically regulated in accordance 9 I with characteristics of the video input signal and the setting of at least one externally accessible video image parameter ~~
11 control.
12 ¦ In accordance with another principal feature ~f the 13 I presen~ invention, video image recording devices are provided 14 ¦ in which the vicleo brightness and video con~rast of the inter-15¦ nal monitor display are automatically regulated in accordance 16¦ with characteristics of the video input signal and the settings 17¦ f plural externally accessible video ima~e parameter controls.
1~¦ ~n accordance with yet another principal feature of ~91 the present invention~ video image recording devices are pro-vided in which the video brightness and video contrast of the 21 internal monitor display are regulated in accordance with 22 two values of the same image parameter, each of which is 231 1nanually se-ttable on a different one of two externally ac-241 cessible image parameter controls.
~S1 In accordance with another principal feature of the 26¦ presellt invention, the image signal levels which are applied 27 1 to the internal monitor control grid to provoke said measured 28 values of the same image parameter are selectable by the user 291 of the video image recording device.
3~1 In accordance wlth an additional principal feature 31 ¦ of the present invention, said same image parameter is a para-32 meter of the video image on the screen of the internal monitor , ~ 5 1¦ and said externally accessible image parameter contxols are 21 calibrated in accordance with a photographic parameter of the 31 corresponding recorded images, which photographic parameter 4 itself varies in accordance with said same image parameter.
In accordance with another pr.incipal feature of the b present invention, said externally accessible image parameter 7 ¦ controls are calihrated in terms of an index number called 8 ¦ herein the "Dunn Density Index" or l'Dunn Number".
9 ¦ In accordance with an additional feature of the 10 ¦ present invention, said externally accessible image parame~er 11 1 controls are calibrated in terms of a "High Dunn Density Index"
12 ¦ or "IIDDI" and a "Low Dunn Density Index" or "LDDI'I, respective-13 ¦ ly. l'he High Dunn Density Index will sometimes be called the 14 "High Dunn Number" or "HDN" herein, and the Low Dunn Density Index will sometimes be called the "Low Dunn Number" or "LDN"
161 her~in.
17 In accordance with yet another principal feature 18 of the present invention, video image recording devices em-19 bodying the present invention are also provided with an addi-tional externally.accessible control by means o~ which the 21 polarity of the images displayed on the screen of the internal 2~ monitor can be reversed, and the operation of said additional 23 externally accessible control automatically revises the indi-24 c~tions on said externally accessible image parameter controls to corresponding values for reverse polarity image conditions.
26 In accordance with a yet further principal feature 27 of the present invention, certain em~odiments of the present 2B invention having said additional externally accessible control 29 means are provided with a pluralit~ of video input channels for receiving different video input signals from different 31 host devices, or duplicate video input signals from the same host device, or both, and a separate image polarity reversal lZ~b76S

1 ¦ swi tch is provided for each o~ said video input channels.
21 For a fuller understanding of the nature and objects 3j of the present invention, reference should be had to the fol-4~1 lowin~ detailed description, taken in connection with the ac-5 1l Coml~anying drawings.

6~1 71 Brief Description of the Drawin~s 9~ Figs. lA through lD, when juxtaposed in the manner l~ ¦ indicated in Fig. lC, constitute a schematic block diagram of 11~ a video image recording device embodying the present invention;
l2 Figs. 2 through 4, 5A, 5B, 6 through 9, lOA, ~OB, lOC, l3 lOE and 11 through 15 together constitute a circuit diagram of l4l said video image recording device embodying the present invention;
lS Fig. 16 is a perspective view, partly in phantom~ of l~¦ said video image recording device embodying the present invention;
'17¦ and la¦ Fig. 17 represents the control panel of said video 19¦ image recording device embodying the present invention.
~ol 2l Description of the Preferred Embodiments 2 1 Glossar~

251 Before discussing the preferred embodiment'in detail, 26¦ it is to be noted that the following terms are used herein in 27 ¦ the manner defined belowO

~81 The term "video signal" as used herein denotes a~y 291 signal or group o~ associated signals capable of exciting a 3n ¦ ~ideo image recordin~ device embodying the present invention 31¦ to produce a corresponding video image or video images on the 32 ¦ display scxeen of its internal video image display device~

1 Thus, the term "videP siynal" as used herein is not 21 limited to signals or sets of si~nals carried by a single con-3¦ ductor or carrier wave, or to sets of signals all carried by 41 the same transmission medium.
51 The term "video signal" as used herein embraces not 61 o~ly video signals of the type found in broadcast and closed-71 circuit television pxactice, but also spe~ialized signals or 81 sets of signals of the kind provided by cer~ain host devices 9¦ known in the prior art, including but not limited to ~-y 10¦ type signals of the kind sometimes produced, e.g., by scinti-11¦ cameras, signals of the kind produced by slow-action or stop-12¦ action video systems, including storage vidicon systems,- ig-~31 nals of the kind produced by charqe-coupled retinas or cameras, 14¦ storage devices, and thP like, and signals of the type pro-15¦ duced by polar and vector scan type video systems.
16¦ The term "video signal" as used herein is not limited 17¦ to monochrome signals, but also embraces color video signals, 18¦ including ~ut not limited to the standard color television 19¦ hroadcast signals comprising luminance signals~ chrominance 20¦ signals, and color~burst signals.
21¦ The term "format signal" as used herein denot~s the 221 part of parts of a video signal which carry information re-231 garding the collocation of the elements of the corresponding 241 video image or images, whether separately defined as pixels or 251 not, and also denotes the part or parts of a video signal which 2b¦ carry information regarding the significance of the magnitude 271 of -the signal or signals corresponding to ~he tone or bright-2~1 ness levels, gray levels, hue levels~ and saturation levels of I the corresponding video image or images. ~hus~ format signals, 301 as that term is used herein, include sweep-synchronizing sig-311 nals, blanking signals, "back porch" signals, and color burst 32 ¦ signalsO

. 7 ~Z~37~

1 ~ The term "image signal" as used herein denotes the ~¦ part or parts of a video signal which carry information re-31 garding the tone or brightness of the individual elements of 4~ the corresponding video ima~e, and the hue and saturati~n of s¦ the correspondin~ video image ele~ents when the corresponding 6~ video ima~e is in color, whether or not said elements are 7j separately definsd as pixels.
8~ As will now be evident to those having ordinary skill 9 ¦ in the art, informed by the present disclosuxe, the signal 10¦ or signal set called the "video signal" herein is sometimes 11¦ called the "composite video signal" by those having ordinary 12 skill in the art, and the signal or signal set called the 13 ¦ "image signal" herein is sometimes called the i'video signal"
14~ by those having ordinary skill in the art. Thus, the terms 15¦ "~ideo" and "video signal" may sometimes be used to denote a 16¦ si~nal or signal set which preferably is called the "image 17 ¦ si~nal" according to the terminology established herein.
181 While the term "video siynal" is used herein in its 19¦ broadest acceptation, as defined immediately above, it is to be understood that in certain emhodiments of the present inven-21 tion the format of the video input signals preferably conforms 22 to Revision TR-135 of Electronic Industries Association Stan-23 dard R5-170, which was promulga~ed by that associati~n in No-24 vember of 1957. In particular, it is to be preferred in cer-tain embodiments of the present invention that in the video 26 sic~nals processed thereby the reference black level differs 27 from the blanking level by the voltage difference indicated in 2~ Fig. 2 of that standard, i.e., that the reference black level 29 differs from the blanking level by 7.5% of Beta plus or minus 2.5~ of Beta, where Beta is the voltage difference between the 31 blanking level and the reference white level. This is not to 32 say that devices embodying the present invention cannot be ~ , 1¦ successf~llly operated with video input signals not conforming 21 to said RS-170 standard, but rather that certain especially 3¦ conv~nient and desixable features of the present invention cdn 41 be relatively easily provided when the video input signals con-form to this standard, or at least the part thereof emphasized 6 clirectly hereinabove.

7 In accordance with the principles of the present in-~ vention, this standard for input video signals to devices em-9 bodying the present invention is adopted so that when the ref-erence black level of the standard obtains in the video input 11 signal the developed film density corresponding to the reference .
12 black level will be equal to or slightly greater than g~oss 1~ fog plus camera flare, and the first step above black of a 14 uniform ten-step gray scale extending between the black and .51 white levels of the developed film will lie substantially at 16¦ ~.1 above ~Jross fog.
17¦ The term "peak white image signal sample (PWISS) ~¦ as used herein denotes a signal corresponding in amplitude 19¦ to the peak whi-te level of a video signal received by a video 20¦ image recording de~ice embodying the present invention.
21¦ The term "back porch image signal sample" (BPISS~
22¦ as used herein denotes a signal corresponding in amplitude 231 to the "back porch" level of a video signal received by a video 241 signal recordi~g device embodying the present.invention~
2sl The term "low image signal sample" as used herein 26¦ denotes a siynal corresponding in amplitude to the back porch 271 level of a video signal received by a video signal recording 28¦ device embodying the present invention, a~gmented by a first 291 predetermined percentage of the difference between tlle peak 301 white level and the back porch level of that video signal.
31¦ The term "high image signal sample" as used herein ~2 denotes a signal corresponding in amplitude to the back porch , I

1~013~6~; ~

l level o~ ~ video signal received by a video si~nal recordin~
2 device embodying the present invention, augmented by a second 3 predetermined percentage of the difference between the peak 4 white level and the back porch level of that video signal, which second predetermined percentage is greater than said 61 first ~redetermined percentage.
7 The term "high image signal sample" will sometimes be desi~nated by the expression "HISS" herein and the term 91 "low image signal sample" will sometimes be desi~nated by the 10¦ expression "LISS" herein. Said first predetermined percentage 11 will sometimes be called the "LISS level" herein, and said 12, second predetermined percentage will sometimes be called the 13¦ "1-1ISS level" herein.
14¦ The terms "host video si~nal generating device", 15¦ "host video device", and "host device" are used synonymously 16¦ herein to denote any device which provides video signals ca-17¦ pable of e~citing any video image recording device embodying 18¦ the pr~sen-t-invention to provide corresponding video images 19¦ on i-ts internal monitor screen. Such host devices include, 201 but are not limited to, medical diagno~stic devices such as 21¦ ~amma ray, x-ray, ultrasound, and thermographic imaging cam-22¦ eras. As is well known to those having ordinary skill in ~he 231 ~rt, the video signals provided by some host devices differ in ~41 some ways from standard broadcast television or closed-circuit 251 television video signals, and sometimes do not consist of a 26¦ single signal, but rather also include one or more auxiliary 271 signals. It is to be ~derstood that the term "video signal"
28¦ as used hereil1 embraces not only video signals of the type 29 ¦ found in broadcast and closed-circuit television practice J
3~ ¦ but also specialized signals or sets of signals of the kind 31¦ provid~d by certain host devices known in the art.
321 The term 'video image" as used hereln genera-1y de 7~5 1 notes the image produced ~n the display screen of a video 21 signal monitor or the like when the video slgnal monitor is 3 excit~d by means of a correspondiny video signal, unless the 4~ context indicates otherwise.
5 ~ The term "video image recording device~ as used 6 herein denotes a device adapted to receive one or more input ~¦ video signals from one or more host video signal generating ~ devices, and to photographically record selected ones of the 91 video images carried thereby.
10¦ As -the term "image polarity" is used herein, two 11¦ video images of the same object have the same image polarity 12¦ if one of them does not appear to be a photonegative of *he 13¦ other, i.e., if the lights and shades or pixel tone~ of the ~¦ two video images do not appear to be in inverse order.
15 ¦ ~s is known to those having ordinary skill in the 16 ¦ art, the great majority o~ host devices, if not all of them, 17 ¦ are provided with built-in viewing monitors on which are 18 ¦ displayed the video images corresponding ~o the video signals 19 ¦ on the output termin~ls thereof. Thus, the term "normal image 20 ¦ polarity host devioe" as used herein denotes a host device 21 ¦ which when connected to supply its output video signal to a 22 ¦ video ima~e recordin~ device embodying the present invention, 23 which has its image polarity switch set to NEG, and its ~41 channel image polarity switches open, produces on the in-251 ternal video monitor screen of that video image recording 26¦ device video images having the same image polarity as the 27 ¦ corxesponding images appeaxing on its own buil~-in viewing 28 ¦ monitor screen. Further, the ter~ "reverse image polarity 29 ¦ host device" as used herein denotes a hos-t device which when 30 ¦ connected to supply lts output video signal to a video image 31 ¦ recording device embodying the present invention, which has its 32 ~ image polari~y switch set to NEG, produces on the internal '' ~ ~

~ 765 1 yideo monitor screen o~ that video image xecording device a 2 vicleo image having the opposite image polarity fr'om the video 3 image viewed on its own built-in viewing monitor screen.

S Interconnection Conventions , .. ~

7 The schematic diagram and the circuit diagram of the

8 preferred embodiment of the present invention shown and de-91 scribed in detail herein are both divided between pluralities ~¦ of different figures o~ the drawings. The schematic diagram 11¦ is in Figs. lA through lD. The circuit diagram is in Figs. 2 12 ¦ through 15.
13 ¦ Each link (i.e., interconnection having negligible 14 ¦ impedance) extending between circuit points located in differ-15 ¦ ent ones of those figures 4f the drawings is specified herein 16¦ by means of the following conventions:
'17¦ 1. From each of such circuit points there extends a 18 ¦ lead which terminates adjacent an edge of the figure in 19¦ which the point lies.
201 Exam~le: The lead extending from switch 14 to 21¦ the left-hand edge of Fig. 2.
22 2. Each figure is assumed to have four of such edge~
23 ¦ (not shown) which together form a rectangle which is 24¦ the locus of the ends of all such leads.
25 ¦ 3. One of said ,four edges is arbitrarily designated 261 as the top (or T) edge, and the other three edges are 271 then designated the right-hand lor R), bottom (or B), 28 ¦ and left-hand (or L) edges, in clockwise orderO
29 ¦ 4~ Any lead which terminates adjacent an edge of a 30 ¦ figure is considered to be, and is called, a terminal 31 ¦ of that figure.
32 ¦ 5. Each terminal of a figure of the drawings may be l'D

:~LZ(~8'^f65 1 uniquely identified by a code desi~nation, sometimes 2 called a "h~e n~ber"~ which may be easily deduced 3 from the fi~ure itself iE not written adjacent that 4 terminal.
S h. Each home number consists of three terms; the 6 first term, the middle (or alphabetic) ter~, and the 7 third ~erm.
8 7. The right-hand letter of the alphabetic term

9 of every ho~e numher (or the single letter if there is only one letter) at the T-edge of every figure -11 is T. The ri~Jht-hand letter (or single letter if 12 there is only one letter) of every home number at ,the 13 R-edge of every figure is R. ~he right-hand letter 14 of the alphabetic te~m (or single letter if there is only one letter in the alphabetic term) of the 16 home nu~bers at the B and L edges are B and L, respec-17 tively. When the alphabetic term consists of more 18 than one letter, all the letters of the alphabetic 19 ~erm but the right-hand letter are part of the figure ~ designation 21 Example: The home number lDRl is located ad-22 jacent the uppermost lead extending to the right-hand 23 edge of Fig. lDo 24 8. ~very home number in each figure has as its first term the numerical part of the designation of 26 tha~ figure. When the alphabetic term is made up of 27 more than one letter, all of the letters except the 28 rightmost letter are ~art of the figure designation.
29 9. The third terms of the home numbers a~ any Eig-ure edge are identifying numerals assigned to the 31 terminals at that edge. Along the R and L edges 32 these iden-tifying numerals generally increase in order lZ~8'765 1 ¦ from the T-edge toward the B-edge. Similarly, the 2 idcntifyin~ numerals (third term5) of the home num-3 ~ers alon~ the T and 8 ed~es increaqe in order from 4 -the L-edge toward the R-edge.
S lQ. The home numbers of one or more other terminals 6 will be found near certain terminals in ~he ~igures 71 of these drawings. These remote terminal home numbers 8 are called "remote numbers: and each seryes to indi-91 cate the remote terminal to which the terminal adja-

10 ¦ cent it is linked, i.e.~ interconnected by an inter- -

11¦ connection having negligible impedance. By "terminal

12 I adjacent it" in the previous sentence is meant th~

13 ~ terminal adjacent to which the remote number is located.

14 ¦ The expression "terminal n~ber" is used when

15 ¦ a term ~eneric to both home numbers and remote numbers

16 ¦ is required. Specifying more than one link to inter-

17 ¦ connect any pair of points does not imply -that more lB ¦ than one such link is to be used in constructing an 19¦ embodiment of the invention; the redundant links are s~ecified merely for convenience in circuit tracing 21¦ and not to indicate necessary structure.

23¦ Bus Conductor~

25 ¦ In the circuit diagram ~Figs. 2 through 15) bus 26 ¦ conductors linkin~ figure terminals of different figures are 27 ¦ specified by bus conductor designations of the form BxCy, 2a ¦ where x is the bus number, and y is the conductor number within that bus. A bus conductor designation located adjacent I a figure terminal indicates that the designated bus conductor 31 ¦ is directly, conductively connected to the circuit point asso-I ciated with -that ~igure terminal.
1~1 ~L2~37~

l ¦ Example: As shown in Fig. ~, conductor lO of bus l is 2 ¦ connected to terminal 15 of image polarity switch 14 41 The Dur,~
S l 6 ¦ In order to be able to operate video image recording 7 ¦ devices embodying the preqent invention with maximum efficiency 81 the significance of the Dunn Density Indices must be understood.
9¦ The immedi~te practical application of the Dunn ¦ Density Indices arises from the fact that the common logarithm -ll¦ of the High Dunn Densi~y Index/Low Dunn Density Index ratio, 12~ or Dunn Ratio, is related to the H ~ D or characteristic curve 13¦ of any particular film which may be selected to be used in a ~4¦ video image recording device embodying the present invention in such a way that the operator of that device can readily 16¦ determine the Dunn Ratio corresponding to any desired maximum ~71 and minimum film image density when given the H & D curve of

18¦ the film. ~

19 Given that most monochrome photographic transparency

20 ¦ film viewing is k~own to he facilitated by a density range from

21 0.1 above gro~s fo~ to 2.0, due to the well-known phenomenon

22¦ o~ bri~htness adaptation, it is con~enient to denominate these 231 two densities as the High Standard Density or ~SD and Low Stan-24¦ dard Density or LSD for each particular film which might be 25 ¦ used in a video image recording device embodying the present 26¦ invention, and this nomenclature is adopted herein.
271 For any particular film, processed in accordance with 28¦ the processing mode used in preparing a corresponding H ~ D
291 curve, a pair of Log E values corresponding to the HSD and 301 LSD of that film can be determined ~rom said corresponding 3~¦ curve. These Log E values will be called, respectively, the 321 High Standard Log E or HSLE and the Low Standard Log E or 87~j5 ~l LSLE herein.
21 Given the HSLE and the LSLE in any paxticular case, 31 i.e., film and processing mode, the Dunn Ratio may easily be S I ///

121 /// .
131 /// .
141 /// ' 16 ~

19~ ///
2~1 ///

~51 ///
2~1 /// .

~ s 1 ¦ dete~ined by subtractin~ the LSL~ fro~ the HSLE and looking 2 ¦ up the an-tilogarithm of the difference in a table of common 3l 10~3arit~ns. The antilogarithm of the difference, determined 4 ¦ as just described, will be the desired value of Dunn Ratio.
5 ¦ The conversion of HSLE~ LSL~ pairs to their cor~esponding 6¦ Dunn Ratios may, of course, be carried out by the use ~f a 71 so-called scientific pocket calculator of well-known type, or 1 by easily provided special tables ~r nomographs.
91 The application of the Dunn Ratio of the present 10¦ invention in the practice of video image recording usin~ video 11¦ image recording devices embodying the present invention closely 12¦ parallels the development of the zone system of photogr~phy ~3¦ by Weston, Adams, et al. According to that system the photo-14¦ graphic subject is analyzed with a light meter to determine 15¦ it~ bricJlltness range and appropriats exposure and development 161 adjustments are made in accordance with the brightness range 17¦ data to fit a selected portion oE th~ light values o~ the lB¦ pho~ograph~c subject into the linear region of the El & D
~ curve of the film on which the photographic subject is to be recorded.
21 In a somewhat similar bu-t at the same time uniquely ~2 different and inventive manner the Dunn Density Index tech-_3 nique of the present inVention makes it possible for the oper-24 ator of a video imaye recording device embodying the present invention to simply and rapidly adjust the brightness range 26 of the internal video image display device tu fit the relative-27 ly fixed parameters of exposure and processing dictated by the H ~ D curve of the film or other photographic medium being emL~loyed.
31 As will be evident to those having ordinary skill in 32 the art, informed by the present disclosure, the Dunn Ratio technique of the present invention is not limi~ed to the ~ 3 Z~ 517ti~;i 1 ¦ employment of the abovedescribed High Standard Densities and 2 ¦ Low Standard Densities. Other density pairs may be settled 3 ¦ upon and corresponding tables or nomographs supplied, or the 4 ¦ operator may determine the Dunn Ràtio from the H & D curve of 5 ¦ the film (and processing mode) being used and a table of common 6 ¦ antilogarithms ox a "scientific" pocket calculator. Further, 7 ¦ it is to be understood that the incorporation of suitable 8 ¦ means for calculating Dunn Ratio in video image recording de-9 ¦ vices embodying the present invention falls within the scope 10 ¦ of the present invention.
11¦ The application of the Dunn Ratio technique of the 12 ¦ present inven-tion using non-standard density values may-be 13¦ described as follows:
14 ¦ 1. The operator examines the H & D curve corres-15 ¦ ponding to the selected film and proces~ing mode and deter-16 ¦ mines therefrom the desired high and low density values.
17 ¦ 2. The operator draws a horizontal line on the 18¦ ~ curve-from each desired density value on the vertical 19¦ axis to the corresponding point on the H ~ D curve itself.
3. From the points of intersection of the horizon-21¦ tal lines with the H & D curve the operator draws vertical 221 lines to the horizontal axis, and there reads off the values ~¦ of Lo~J E corresponding to the desired density values.
241 4. The operator then subtracts the smaller Log E
251 value just determined from the larger Log E value just deter-2b¦ mined and finds the common antilo~arithm of the resulting 271 difference in a table of common antilogarithms. The common 2~1 antilogarithm of the differnce is the Dunn ~atio corresponding 2~1 to the density values determined in Step 1.
301 S. The operator then consults a suitable set of 311 tables, such as may be provided by those having ordinary skill ¦ in the art, informed by the present disclosure, and determines I
, ~137~S

1 therefrom a suitable High Dunn Densit~ Index ~HDDI) yalue, and 2 enter~ this value into the HDDI indicato~ on the control panel 3 of the vid~o image recording device of the present invention 4 being employed.
6. The operator then divides the HDDI v~lue just 6 obtained by the Dunn Ratio ~DR) obtained in Step 4 and gets, 7 as the quotient, the corresponding LDDI, which he immediately ~ enters into the LDDI indicator on the control panel of the 9 video image recording device of the present invention which is 10 being employed.
11 As will be evident to those having ordinary skill in 12 the art, it may be necessary in some cases to make a trial 13 exposure and thereafter make minor adjustments in order to 14 achieve ~he desired photo~raphic density and contxast, because of variations from the ideal experienced in both available 16 films and processor characteristics.
17 It is to be understood that fur-ther adaptation of 1~ the Dunn Ratio technique to automatic operation o~ video image 19 recording devices also lies within the scope of the present 2~ invention. For example, it lies within the scope of the pre-21 sent inven-tion to provide a video image recording device with 22 a built-in densitometer and an operating mode wherein the

23 display screen of the internal video image display device is

24 excited to produce a known overall light output. When a film 2~ area exposed to the known overall light output is processed 26 in a predetermined processing mode and inserted into said 2~ built-in densi~ometer, the effects of film selection and pro-28 cessing can be correctly determined in the form of an index 29 number called the Dunn Film and Processiny Index or DFPI, in terms of which said densitometer is calibrated. It is yet 31 further to be understood that the provision of additional 32 o~erating means and methods to cau~e the Dunn Indices to be ~2~ iS

1¦ directly entered into their corresponding storage locations in 21 vldeo i~a~e recording devices e~bodying the present invention 3 when a selected ~ilm has been exposed to a standard display 4¦ ~creen li~ht output, processed, and submitted to the built-in sl densitometer is within the scope of the present invention.
6¦ In accordance with a preferred method of the present 71 invention for operating vide~ image recording devices embodying 81 the present invention, which devices are provided with LDDI
91 and HDDI indicators similar to indicators 40 and 42 of Fig. 17, 10¦ and corresponding Dunn Density Index control switches, similar 11¦ to control switches 18 and 2a of Fig. 17, the operator of this .
12¦ video image recording device prepares the device for rec~rding 13¦ video images on a particular type of film hy (1) selecting 14¦ the standard Exposure Value (EV~ from the following Exposure ~5¦ V~lue Selection Table in accordance with the existing or se-16 ¦ lected f-stop and exposure time values set in the device;

18 ¦ -EXPOS LECTION 'rABLE

20¦ EV f5~6 . f8 fll fl6 f22 f32 2~1 8 1/~ 1/4 1/2 1 2 24 I 9 1/15 1~8 1/4 1/2 1 2 2~ I 1~ 1/30 1/15 1/8 1/~ 1/2 26 I 11 ~1/30 1/15 1/8 1~4 -1/2;
27 l 28 ¦ (2) determining from a suitable corresponding H & D or charac-29 ¦ teristic curve, or from prior expe~ience, the desired maximum 30 ¦ density of the developed film; (~ selecting the LDDI and 31¦ HDDI corresponding to the selected film type and maximum den-321 sity value from the following Dunn ~ensity Index table;

I t~'O
l ~, lZ08765 l DUNN DENSITY INDEX ~ABLE
2 _ ~ _ Maximum 3 Densi~y MRE~ 31 NMB/NMC Ortho-M MR-l GTA FUJI~US
4 I Exposure Value 6 I
5 1 2.0 - .2/4.0 - .2/7~0 .1/4~0 6 1 1.8 - - - .2/5.6 .1/3.5 .1/5.2 7 1 1.6 - - - .2/4.0 ~1 9 Expo~ure Value 7 2.0 .3/5.5 .4~7.8 .6/5.2 .5/13.8 .2/9.0 -11 1~8 .3/4.5 .4/~.8 ~6/4.5 .5/11.~ .2/7.0 .1/10.5 12 1.6 .3J3.5 .4/5.8 .6/3.8 .5/9.0 .2/5.2 .1/6.0 ~41 Exposure Value 8 ~sl 2.0 .6/11 .g/15.5 1.2/10.5 1.0/27.5 .5/18 161 1.8 .6/9 .9/13.8 1.2j9 1.0/22.5 .5~14 .3/21 171 1.6 .6/7 .9/11.5 1.2/7.5 1.0/18 .5/10.5 .3/12 19~ Exposure Value 9 201 2.0 1.~/22 ,1.8/31 2.4/21 2.0/55 1~0/36 211 1.8 1.2/18 1.8/~7.5 2.4/18 2.0/45 1.0/28 .6/~2 2~1 1.6 1.2/14 1.8/2~ 2.4/15 2.0/36 1.0/21 ~6/2~
2~1 24 Exposure Value 10 25I 2.0 2.~ 4 3.6/62 4.8/42 - 2.0/72 261 1.8 2.4t36 3.6/55 4.8~36 4.0/9~ 2.0/56 1.2/84 27 ~ 1.6 2.4/28 3.6/46 4.8/30 4.0/72 ~.0/42 1.2/48 ~9 xposure Value 11 301 2.0 4.~/88 - 9.6/84 311 1.8 4.8/72 - 9.6/72 - - -32~ 1.6 4 8/56 6.0~94 9.6/60 - 4.0/a4 2.4/96;

21!

;

" I ~2~8~S

1 and (4) manipulating the LDDI and HDDI control switches of the 2 device to cause the tabulated LDDI and HDDI value to appear on 31 the corresponding LDDI and HDDI indicators of the device.
4 I As an example, entering the preceding table with the 5 ¦ film type NM~/NMC, Exposure Value 8, and maximum density 1.8, 6 I the corresponding LDDI Will be found to be 0.9, and the corre-7 I sponding ~DDI will be found to be 13.8.
~8 ¦ It is to be understood that the provision of more 9 ¦ extended tabulations of the same type falls within the scope of 10 ¦ the present invention. E.g., it is within the scope of the Il ¦ present invention to provide a Dunn Density lndex Table like 12 ¦ the preceding, except that the tabulated values of maximum 13 ¦ density differ by 0.1, rather than 0.2.
14 ¦ It is to be particularly noted that in accordance 15 ¦ with the principles underlying this method of the present in-16 vention the tabulated LDDI and HDDI values are so aelected, ~71 eml~irically, that the corresponding minimum developed film 18¦ density ll~s substantially at 0.05 above gross fog.

~91 The data tabulated in the above Dunn Density Index 20¦ Table were determ~ned under particular conditions of exposure 21¦ and film processing, viz~, exposure of the films in a Dunn 22¦ Camera Model 627 TLC and processing thereof in a PAKO 14 film 23 processor, using Dupont CRONEX MCD chemicals. As will be 24 understood by those having ordinary skill in the art, those data are to be regarded as representative only, and thus will 2~ not necessarily apply directly in any particular installation 27 I of a video image recording device embodying the present inven-28 ¦ tion. It is believed, however, that those data may be adapted 2~ for use in such installations by making a few representative 301 tests for any given film type and accordingly modifying the 3~1 tabulated values by the application of a simple correction ~21 factor.

1'~?87t;5 ~1 It is further to be understood that it falls within 2l t~le scope of the present invention to implement the values of 3 , the above Dunn Density Index Table, or any similarly con~truc-ted 41 table, in the memory of a particulax video image recor~ing de-S I vice e1nbodylng the present invention, and to provide that par-6~ ticular video image recording device with manually settable 7 I means (e.g., pushbuttons) corresponding to particular film 8 types, and other manually settable means corresponding to maxi-9 ¦ mum developed film density values, and yet other manually set-10 ¦ table means corresponding to expo~ure value tEV) values, where- -11¦ by the operator need not consult that table in preparing the 12 I device to record ~ideo images on films of particular types 13¦ (indicated on certain ones of said manually settable means~.

151 //~

2~1 ///

261 ~/~

~1 "' ~91 /~/

2;1 lZ08765 1 Schematic Dia~ram 3 ¦ Referring now to Figs. lA through lD, there is shown 4 ¦ a schematlc dia~ram of the preferred embodiment of the present ~ ¦ invention, it being understood that some of the conductors 6 ¦ showl~ in these figures are interconnected in accordance with 7 ¦ the interconnection conventions defined hereinaboye.
8 1 It is to be particularly noted that the principal 9 ¦ elem~nts or blocks of the schematic diagram of Figs. lA through ~¦ lD are cross-referenced to the substantially corresponding 11¦ figures of the detailed circuit drawing of Figs. 2 through lS
12 ¦ by ~eans of figure numbers located at the upper right-hand 13 ¦ corner of each block. Thus, it may be seen from Fig. lD that 1~¦ the portions of the video ~onitor 56 of the preferred embodiment 15¦ which are of particular significance in relation to -the inven-16¦ tion claimed herein are shown in Fig. ll of the present draw-17 ¦ ings.
18 1 I-t is further to be understood that not all of the 19¦ control bus conductors or control lines which in fact extend 20¦ between the combinations of circuit elements represented by 21¦ the blocks of Figs. lA through lD are shown in Figs, lA
221 through lD. Rather, for clearness of illustration, a number 2~1 f control bus conductors and the like are not represented 241 in FicJs. lA through lD, and reference must be had to Figs.
251 2 through 15 and the correspondin~ text of the present speci-261 fication for a detailed description and showing of these de-281 leted control bus conductors, etc.
2 1 For the great~st facility in understanding the sche-91 matic diagram of Figs. lA through lD, these figures should 301 be juxtaposed as shown in the lower portion of Fig. lC.
1 Referring now to Fi~o lA, it will be seen that the 321 device of the preferred embodiment comprises a plurality of l ..
2~
l , 12~876S

1 ~ front panel switcheS~ collectively represented by the rec-2 ¦ tLln41e or block 10. As also seen in Fiy. 1~ the front panel 3 I switches represented by block 1~ are shown in detail in Fig. 2.
4 ¦ sy reeerence to Fiy. 2 it can be seen that these 5~ front panel switches include an exposure switch 12, an image 6 I polarity selection switch 14, an input channel selection switch 7 ¦ 16, a Low Dunn Density Index selection switch 18, and a High 81 Dunn Density Index selection switch 20. As will be explained 9 I hereinafter, the switches represen~ed by block 10 also include 10 ¦ a store command swi~ch 22 by means of which selected values 11¦ of Hiyh Dunn Density Index and Low Dunn Density Index are 12¦ entered into corresponding memory locations, and a monitor .
13 ¦ display screen viewing donr safety switch 24 by ~eans of which 14¦ the ~ilm exposing operation of the device of the preferred 15¦ embodiment is prevented whenever the door which normally 16¦ covers the monitor display screen viewiny~port is open.
17¦ Referring again to Fig O lA, it will be seen that 18¦ the front ~anel switches of block 10 are interconnected with 19¦ a multiplexer unit represented ~y block 32, by means of a 20¦ bus 34. As seen i~ Figs. 5A and 5B, the multiplexer unit 32 21¦ co~prises four integrated circuit multiplexers of the kind 22¦ identified by the commercial designation 74LS253. Bus 34 will 2~1 sometimes be referred to herein as "bus 1". Multiplexer unit 24¦ 32 will sometimes be referred to herein as th~ ~'input multi-251 plexer".
26¦ As further seen in Fig. lA, input multiplexer 32 is ~7¦ interconnected with other parts of ~he circuit of the device 28 ¦ 30 of the preferred embodiment by means of conductors 0,lt and 291 3 of a bus designated herein as "bus 7". (Bus 7 is shown in 311 Flg. lB.) As also seen in Fiy, lA, input multiplexer 32 is 321 connected to a bus 36, which will sometimes be called "bus 3"
I hereln, and w ch 1S the principal ds~a bus of the device 30 1~ 7~5 I
1¦ of the preferred embodiment.
2¦ As also seen in Fig. lA, the front panei disp]ays 31 of the device 30 of the pre~erred embodiment are represented 4l1 by a rectangle or block 38, and the circuit arrangement of the same is shown in ~ig. 3. The appearance of the front panel 6 displays as mounted in tha front panel of the device 30 of 7 the preferred embodiment is shown in Fig. 17. As seen in 8 Fig. 17, the front panel displays comprise a Low Dunn Density 9 Index (LDDI) display 40 and a High Dunn Density Index IHDDI) display 42. The front panel displays further comprise a 11 status display 44 which indicates certain conditions of op- ;
12 eration of the device 30 of the preferred embodiment. ~or 13 ex~nple, the status display 44 as shown in Fig. 17 is indica-14¦ ting that the next exposure made by depressing exposure control ¦
15¦ 12 will be the sixth exposure remaining on the particular 16¦ sheet of film which is currently in the device 30.
17¦ ~s further seen in Fig. lA, signals for exciting 18¦ disulays 4~, 42, 44 are supplied thereto by means of a bus 46, ~9¦ which will some~imes be called "bus 2" herein. ~he exciting 20¦ signalx on bus 2 are supplied by an 8 charac~er, ? segment 211 decoder/driver 48 the circuit of whlch is shown in Fig 6. As 231 also seen in Fig. lA, the signals determlning the characters l to be displayed by the displays which are under the control 241 of decoder/driver 48 are received by decoder/driver 48 from l bus 3. As will be evident to those having an ordinary skill 26¦ in the microprocessor systems ar , informed by the present ¦ disclosure, decoder/driver 48 must be supplied with additional 291 signals in order to correctly and completely carry out its l functions. As is generally the case in Fi~s. lA through lD, 30¦ however, the conductors for supplying these additional control 31~ signals, as well as certain necessary exciting or biasing I voltages or currents, are not shown, but rather must be de-~6 ;5 1¦ termined from the circuit diagram of Fi~s. 2 through 15.
2¦ Al~o shown in Fig. lA is the rectangle or block S0 31 representing the monitor light output reading photometer o~
4¦ the device 30 of the preferred embodiment, the circuit of sl which is shown in detail in Fig. 4. As seen in Fig. 4, the 6 I licJht-sensin~ element of photometer 50 is a photodiode 52.
7 As seen in Fig. 16, photodiode 52 is located in the light-tight housing of the video image recording device 30 of the preferred 9 embodiment of the present invention, and is 50 located as to receive li~ht from the display screen 54 of monitor 56. In ac-11¦ cordance with the principles of the present invention, photo-12 ~ diode 52 is so juxtaposed to display screen 54, and so oriented 13¦ with respect thereto, and so supplied with suitable optical 1~¦ input means, if necessary, that its effective field of view 151 is limited to the central portion of display screen 54.
16¦ During the manufacture of the device 3a of the preferred em-'71 bodiment the output voltage of photometer 50 (sheet terminal 18¦ 4Rl) is so calibrated that it substantially matches the output 19¦ of a standard photometer located on the principal axis per-20 ¦ pendicular to the center of display screen 54 under all op-21 ¦ erating conditions. The calibration process is described in 22¦ detail hereinbelow in connection with Fig. 4.
23 1 As further seen in Fig. lA, the dis~lay screen light 241 output signal on conductor 58, provided by photometer 50, is 2~ ¦ supplied directly to an analog signal input terminal of an 26 ¦ analog-to-digital converter represented by rectangle or block 27 ¦ 60, the circuit of which is shown in Fi~. 7, and the output 28 ¦ si~nal set of analog-to-digital converter 60 is applied to 29 ¦ bus 3. As explained above, the conduc~ors for certain control 30 ¦ signals and supply voltages necessary to the operation of con-31 ¦ verter 60 are not shown in Fig. lA, for clarity of disclosure.
3 I Referrin~ now to Fig. lB, it will be seen that the ~L2~'76S

l device 30 of the preferred e~bodimjent conlprises a micropro-21 cessor G0 which is connected to bus 3 and also to bus 62, 3l1 which will sorneti~es be referred to herein as "bus 4". As 4 may be seen by comparing Figs. lA and lD, following the sheet interconn~ction convention described hereinabove, a signal 6 representing the vertical synchronizing pulses generated in 71 the video monitor of device 30 are supplied to microprocessor 8 60 via terminal lBBl of Fig. lB. As will be evident to those 91 having ordinary skill in the microprocessor systems art, in-formed by the present disclosure, microprocessor 60 sPrves to 11 control and coordinate the operation of the other elements of 12 the device 30 of the preferred embodiment. ~
13 Also found in Fig. lB is the rectangle or block 64 14 which represents the program memory associated with micropro-cessor 60. The content of this program memory is set out 16 hereinbelow. As will be evident to those having ordinary 17 skill in the microprocessor systems art, informed by the 18 present disclosure, instructions are read from memory 64, and 19 transmitted to microprocessor 6n or other elem~nts of device 30 via bus 3, in response to the presentation of corresponding 21 address siqnals thereto, from microprocessor 60 over bus 4 22 and from the address latches represented by the rectangle 23 or block 66 over bus 68, which is sometimes called "bus 7"
24 herein. In addition to serving the function of holding ad-dress si~nals for selective presentation to memory 64 on bus 26 7, address latch unit 66 also serves to provide certain 228 control signals (bits) to, e.g., photome-ter 50, the d1gital-29 to-analog converters represented by blocks in Fig. lC, mul- ¦
tiplexer 32, and decoder~driver 48, all by way of conductors 31 which are not shown in the schematic diagram of Figs. lA
32 through lD for clarity of disclosure.

An additional memory unit Eound in F1g. lB is repre-r lS765 1 sented by the block 70 found therein. Memory (Nitron (Regis-2 tered T.M.) 7033) unit 70 is a non-volatile memory which serves 3 to store certain data entered into device 30 by means of input 4 switches (internal and external) and thus protect this data against loss due to power line failure, normal shutdown, and like 6 causes. Among said certain data are the High Dunn Density 7 Indices and Low Dunn Density Indices which were previously 8 selected for the respective input channels of device 30 by means 9 of displays 40 and 42 and switches 14, 16, 18, 20, and 22 (one set of Dunn Density Indices for each displayed image polarity), 11 and the preselected exposure time for each respective input 12 channel of device 30 (one value for each displayed image polarity~.

13 This data is supplied to non-volatile memory 70, and read there-14 from, by way of bus 72, which is sometimes called "bus 5" herein.
In accordance with the principles of the present invention, data 16 is supplied to non-volatile memory 70, and read therefrom by 17 way of bus 5, the expander represented by rectangle or block 74 18 of Fig. lB, and bus 4. The block 74 of Fig. lB represents, 19 inter alia, an input-output expander of well-known type, (see Fig. 9) which serves to route information derived 21 from microprocessor 60 onto either bus 5 or bus 76, sometimes 22 called "bus 6" hereinl and to briefly store the information 23 provided by microprocessor 60, in the well-known manner.
24 ~eferring now to Fig. lC, there are shown rectangles or blocks 80 and 82 representing two ten-bit latching digital~
26 to-analog converters which respectively supply analog control 27 signals to the brightness and contrast control signal terminals 28 of the video monitor 56 of the device 30 of the preferred em-29 bodiment, via conductors 86 and 88, respectively. As further seen in Fig. lC, brightness signal converter 80 and contrast 31 signal converter 82 both receive their input signals from 32 bus 3. As will be evident to those having ordinary skill in 1 the art, informed by the present disclosure, however, the 2 converters 80 and 82 are independently supplied with "chip 3 select" and other control signals of types well-known to those 4 having ordinary skill in the art by means of conductors which are not shown in the schematic diagram, for clarity of disclo-6 sure.
7 Referring now to Fig. lD, there is shown therein a 8 rectangle or block 56 representing the monitor 56 of the device 9 30 of the preferred embodiment (see Fig. 16). The photodiode 52 of photometer 50 is also shown in Fig. lD, juxtaposed to 11 display screen 54 (Fig. 16) in such manner as to be able to 12 provide the monitor display screen light output signals ~n 13 conductor 58 (Fig. lA) in the manner described hereinabove.
14 In the device 30 of the preferred embodiment monitor or video image display device 56 is a commercially available monitor 16 known as a Tektronix (Registered T.M.) Model No. 634 Video 17 Monitor, modified in accordance with the teachings of the 18 present invention to provide direct current restore (DCR) pulse 19 signals, horizontal synchronizing pulse signals, and vertical 20 synchronizing pulse signals on respective externally accessible 21 terminals 90, 92, and 94 (Fig. lD). Terminals 96, 98, 100 and 22 102 are terminals provided as part of the unmodified Tektronix 23 (Registered T.M.) Model No. 634 Video Monitor for receiving 24 raster synchronizing signals, complete video signals, bright-

25 ness determining signals, and contrast determining signals,

26 respectively.

27 Also shown in FigO lD is a rectangle or block 110

28 which represents a circuit sometimes called the "video switch-

29 ing network" or "video switch" herein, which is a particular

30 feature of the present invention.

31 As further seen in Fig. lD, video switch 110 com-

32 prises a multiplexer control unit 112 which itself controls 1;2~876S

1 the operation o~ two analog multiplexers 114 and 116 of well-2 known type. soth channel selection multiplexer 114 and Auto-3 Comp video multiplexer 116 are of the type commerically desig 4 nated by the reference LF13201 in the device 30 of the pre-ferred embodiment. The circuit of multiplexer control unit 6 112 is shown in Fig. lOA. It is to be noted, however; that 7 blocks 114 and 116 each represent only an LF13201 analog m~l-3 tiplexer. The parts of video switch 110 other than multi-9 plexer control unit 112 and its associated buses are shown in detail in Figs. lOB and lOC~ The sub-circuits 118, 120, and 11 122, and HISS-LISS network 124, 126, 128, found within block .
12 110 are schematically represented only, reference being had to 13 Fi~s. lOB and lOC for actual circuit details.
14 Switch 132 and its associated buffer 136 make it pos-sible, if desired, to supply to terminal 96 of monitor 56 an 16 external synchronizin~ siynal supplied via 1nput channel 17 2 (142).
18 A~ further seen in Fig. lD, analog multiplexer 114 19 can receive as separate and independent video input signals, on video input lin~s 140, 142, 144, and 146, the four video 21 input signals received by the device 30 of the preferred em-22 bodiment of the present invention at its respective video 23 input terminals 15Q, 152, 154, and 156 (Fig. 16). As parti-24 cularly seen in Fig. lOB, signal lines 140, 142, 144 and 146 are at least in par~ coaxial lines of well-known type, the 26 outer conductors or shields o~ which are all connected to the 27 system ~round of device 30. Each coaxial line 140, 142, 144 and 28 146 and its associated coaxial input ~erminal 150, 152, 154, 29 156 will sometimes be referred to herein as an ~input channel"

31 or "video input channel".
The respective video input channels comprising signal 32 lines 140, 142, 144, ancl 146 will sometimes be called chan-' .~il;l ~2(~7~

~¦ nels 1, 2, 3, and 4 herein. In the device 30 o~ the preferred 2¦ en~odiment of the present invention, the video input signal 3 carried by any one of these channels can be selected for re-4¦ cording by video i~a~e display device 56 (Fig. 16~, or more cor 5l rectly for the recording of particular parts thereof, by oper-6 atin~ switch 16 (Fig. 17~ to the corresponding channel number.
71 Thus, the video input signal supplied by video input signal ¦ source 160 (~ig. 17) may be selected for recording, or the ~¦ recording of parts thereof, by the device 30 of the preferred embodiment by operating switch 16 (Fig. 17) $o its "1" posi-11 ! tion; etc. I
12 It is to be particularly noted that the present 31 invention is not limited to the provision of four video input 14~ channels in a video image recording device, nor to the connec-~ ¦ tiOII of a separate video input signal source to each video 16l input channel, as shown in Fig. 16. Thus, while in ~ig. 16 17 each video input terminal 150, 152, 15~ 156 is shown to be con-18¦ nected to a corresponding separate and independent video input 19 sic~nal source, 160, 162, 164, 166, respectively, i~ also lies 201 within the teachings of the present invention to, e.g., have 211 no video input signal source connected to terminal 150, but 22¦ rather to provide for the operation of analog multiplexer 114 2~ ¦ in such a way that, e.g., the video input signal supplied by 24 source 162 is selected for recording by device 30 when switch 25 1 16 is either in its 1 position or its 2 position~
26 ¦ In general, then, embodiments of the present inven-2~ ¦ tion may be provided in which any desired number of desired 29 I sets of recorded image parameters, i.e., LDDI, I~DDI, and ex-3~ I posure time, can be recalled and applied to the processing of 31 I the input video signal received on any one of any deslred num- ¦
¦ ber of input channels, for eitller positive or negative filtn 32 I ima~e ~olarity, as indicated on switch 14.

lZ~8~6~
1 It is to be understood, however, that in accordance 2 with the teachings of the present invention the operation of 3 analog multiplexer 114 to present the same video input signal 4 for r~cording at two or more positions of switch 16 does not S mean that any particular frame or frames of that video input ~ signal will be recorded in exactly the same way irrespec~ive 7 of the position of switch 16. To the contrary, device 30 is 11 //~

13 /~/

15 I //~

211 /~/

23l ///

///

32 ~
~.

~ 876S

1 so constructe~ and arranged that the pair of Dunn Density In-2 dices corresponding to position 1 of switch 16 may not be the 3 same as the pair of Dunn Density Indices corresponding to po-4~ sition 2 of switch 16, and thus the density and photographic 51 contrast of ~he image recorded with switch 16 in position 1 61 may not be the same as the density and photographic contrast 7 I of the image recorded with switch 16 in position 2, even though 8I the video inpu-t signal frame or frames ~rom which the position 9~ 2 recording is made is substantially identical to the video 10¦ input signal frame or frames ~rom which the position 1 record- -11¦ ing is made. .
12¦ As pointed out above, memory unit 70 stores certain 13 data, such as Dunn Density Indices and exposure times, for 14 ¦ each input channel of device 30. Thus, for example, memory 15¦ unit 70 has a location HDDI(l) for the storage of the desired 16 I HDDI value corresponding to channel l; a location L~DI(l) 17¦ for the stora~e of the desired LDDI value corresponding to 1~ ¦ chann~ a location E~(ll for the storage oi the desired 19 exposure time value corresponding to channel 1; a location ~0 I IfD~I(3~ for the s~orage of the desired HDDI value corresponding 21 I to channel 3; a location ET~2~ for the storage of the desired 231 exposure time value corresponding to channel 2; etc.
I In accordance with a particular feature of the pre-2~ ¦ sent invention, the location in memory unit 70 into which a new data value is to be written is selected ~y means of the 26 channel selection switch, i.e., switch 16 of device 30 (Fig.

2B ¦ 17). Thus, when it is desired to change the ~DDI value stored 29 ¦ in ~IDDI(3), cllannPl selection switch 16 is placed in its po-¦ sition 3, the desired new IIDDI(3) content value is made to 31 appear on display 42 (Fig 17) by manipulating switch 20 in 32 I the manner described hereinahove, and switch 22 is raised to its ¦ STORE position, whereupon a new }IDDI value, indicated at that 1 time on display 92, is entered into location HDDI(3l of memory 2 unit 70. Similarly, to enter a new value into LDDI(4), switch 3 16 is ~et to its position 4, the desired new LDDI value is 4 made to appear on display 40, and switch 22 is raised to its S¦ STORE position, whereupon the desired new LDDI value, correspond-61 ing to the value indicated on display 4~ at that moment, is 7 ¦ entered into LDDI(4).
~¦ Thus, it will be seen that the recording parameter 9 ¦ data stored in the channel 1 locations of memory unit 70 may 10¦ be entirely different from the recording parameter date stored .
11 ¦ in the channel 2 locations of memory unit 70j as a result of .
12 ¦ which the recording made from a given input video signaL.
13 ¦ frame or frames by device 30 when set to select channel 1 may 14 ¦ be considerably dif~erent from the recording made from the 15 ¦ same input video signal frame or fran~es by device 30 when set 16 ¦ to select channel 2.
17 ¦ Further, the stored exposure time value corresponding lB ¦ to any selected input channel may be changed by (1~ closing 19 ¦ switch 336 (Fig. 5A), which causes the currently stored ex-posure time value for that chan~el to appear on indicator 42, 21¦ expressed in vertical sync intervals of the selected input 22¦ video signal, ~2) manipulating switch 20 to change the indi-23 ¦ cated exposure time value to the desired new exposure tim~
24 ¦ value, (3) momentarily raising switch 22 to replace the pre-25 ¦ viously stored exposure time value with the newly indicated 26 ¦ exposure time value in the corresponding exposure value storage 2~ ¦ location of memory 70, and then (4) opening switch 336. A
28 desired change in stored exposure time value f~x the opposite 2~1 image polarity of the same input channel can be effected by 301 following the same series of steps with image polarity switch 31l 14 in its opposite position.
321 As w.ill also be seen by those having ordinary skill ~i~08765 ~¦ in the ar-t, informed by the present disclosure, and particu-21 larly in vi~w of Fi~. lD, analog multiplexer 114 is controlled, 3¦ and the the particular video input si~nal supplied to buffer 41 118 is selected, by signals impressed on analog multiplexer 5¦ 114 by multiplexer control unit 112 via bus 170.
61 The signals applied to multiplexer control unit 112 71 via bus ~ which bring about the selection of a particular 81 video input channel signal as the input signal to buffer 118 9 ¦ are -themselves determined by the position of channel selection 10¦ switch 16 ~Fig. 17), as will be evident to those having or- -11¦ dinary skill in the art, informed by the present disclosure. ¦.
12 ¦ Referring again to Fig. lD, it will be seen that the 13 I coll~on output connection 134 of analog multiplexer 114 pro-14 ¦ vides the input'signal for buffer 118, which in turn provides 15 ¦ the input signal for subcircuit 120. Subcircuit 120 is a sam-1~ 1 ///
1~ 1 ///

241 /~
251 ", ~7 I ///
2~ I //~

30 ~
~1 I ///
32 ~

;~6 ~ 76S

1 ¦ ple-and-hold circuit which senses and stores the peak white 2 ¦ m~yni~ude of the imaye signal compo~ent of the video signal 3 ¦ selec-ted by analog mul~iplexer 114. The voltage signal (PWISS) 4 ¦ corresponding to this peak white magnitude is provided on the s¦ output terminal of sample and-hold subcircuit 120, i.e., at 61 the left-hand terminal of resistor 128, as seen in Fig. lD.
71 Subcircuit 120 will sometimes ~e called the "peak 8 ¦ white sample~and-hold circuit" herein.
9 ¦ It is to be particularly understood that in the pre-ferred embodiment of the present invention the values of re-11 sistors 124, 126, and 128 are so selected that the HISS level .
12 is 95~ and t}le LISS level is 15%, as those terms are defined 13 hereinbelow, and that thus, in the preferred embodiment, 14 the HISS signal voltaye will be substantially equal to the peak white volta~e of the image si~nal component o~ the video signal 16 selected by analo~ multiplexer 114. In other embodiments of the 17 present inventi.on, however, in which it is desired that the 18 HISS not b~ equal to the peak white ma~nitude o~ the image 19 signal component of the selected video signal (PWISS), the value o~ resistor 128 will be increased accordingly. Further, 21 it is to be understood that in some embodi.ments of the present 22 invention resistors 126 and 128 will be variable resistors.
23 Also sh~;wn in Fig. lD is the sample-and-hold sub-24 circuit 122 which will sometimes be called the "back-porch-san~ple-and-hold CirGUit" herein. Back-porch-sample-and-hold 26 circuit 122 receives as its inpu~ the portions of ~he video 27 si~nal selected by analo~ multiplexer 114 which exist during ~9 time intervals determined by analog multiplexer 116. These tirne intervals correspond to the "DC restore" time intervals of the input video signal selected by analog multiplexer 114.
31 Thus, i-t will be seen by those havin~ ordinary skill in the art, informe~ by t~le present disclosure, that back-porch-sample-and-~!7 - I lZ~l3~i5 1l hold circuit 122 senses and stores the "back porch" or "black-2 est ~lack" level of the ima~e signal component of the video 3 sic3nal selected by analo~ multiplexer 114. This back porch ~ signal appears on the output terminal 123 of back-porch-sample-S and-hold circuit 122.
6 Since the full amplitude range of the image signal 7 component o~ the video signal selected by analog multiplexer 8 114 extends from the peak white voltage level, produced at the 9 output terminal of peak-white-sample-and-hold circuit 120 to the "back porch" voltage level, produced at the output terminal 11 of back-porch-sample-and-hold circuit 122, i~ follows that the .
12 high image signal sample ~HISS) and low image signal sample ~3¦ (LISS), as those quantities are defined hereinabove, will be 14 ¦ produced at predetermined poi~ts of a resistor network con-15¦ nected between the output terminals of subcircuits 120 and 16¦ 122. Resistors 124, 126, and 128 constitute~ this network in 17¦ the devi.ce 30 of the preferred embodiment of the present lRl invention. -In the device 30 of the preferred embodiment of the 19¦ present invention the value of the ~IISS is substantially equal ~¦ to the peak white level less 5~ of ~he full range of ~he image 21¦ signal, and the value of the LISS is substantially equal to 22¦ the back porch level augmented by 15% of the full range of the 23¦ image signal.
241 Referring agaln to Fig. lD, it will be seen that the ¦ Auto-Comp analog video multiplexer 116 receives as three of 27 its inputs the HISS, the LISS, and the video signal selected by analog multiplexer 114. It will also be seen that the 281 signal on the s.ingle output connection 125 of analo~ multi-i plexer 116 is connected to the video input terminal 98 o~
301 video monitor 56 via buffer 129. Further, it will be seen in 3'1 Fi.g. lD tha~ the operation of analog multiplexer 116 is con-trolled by multiplex controller 112 via bus 17~ Multiplex r?~3 1208~65 1 contr~ller 112 is itself controlled by signals received from 2¦ microprocessor 60 (Fig. lB) via expander 74 (Fig. lB) over 3¦ busses ~ and 6.
4 As will be obvious to those having ordinary skill in 5 I the art, informed by the present disclosure, then, the selec-6 I tion of the video input signals supplied to video monitor 156, 7 whether }IISS, LISS, or a complete video signal, is controlled 8 by microprocessor 60 9 As further seen in Fig. lD, the synchronizing signal applied to the external synchronizing terminal of monitor 56 -~
11 is normally derived from the common ou~put connection 134 12 of analog multiplexer 114, and passed through buffer 136. How- ¦
13 ever, when manually operated switch 132 is operated into its 14 normally open position (dashed), a separate external synchron-1~ izin~ signal may be supplied via video input channel 142.
16¦ Referring now to Fig. 2, there are shown the electri-17¦ cal interconnections between the front panel switches (Fig. 17) 18¦ of the dev}ce 30 of the preferred embodiment and the associated 19 ¦ terminals of input multiplexer 32 (Fig. lA), which intercon-20¦ nections are n~ade by way of a bus 1.
21¦ Exposure switch 12 (Figs. 2 and 17) is a normally 22 ¦ open, push~to-close switch of well-known type. Manual de-231 pression of switch 12 brings about the exposure of a predeter-241 mined area of the film casset~e 180 in device 30 (Fig. 16).
25 ¦ Monitor display screen viewing door switch 24 (Figs~
26¦ 2 and 1~) is not a front panel switch, but rather, as seen in 27~ Fig. 16, is incorporated into the frame of the monitor display 28 I screen viewing door 182 of device 30 in such a position that 29 ¦ it is depressed, and thus closed, when and only when moni~or 30 I display screen viewing door 182 is fully closed. Switch 24 311 serves, via the circuit, progral~ming, etc., oi device 30, to 321 prevent the exposure of any photoplate 180 in device 30 unless 3L~087~5 1 monitor display screen viewing door 182 is fully closed.
2 As also seen in Fig. 2, store command switch 22 (Fiq.
~¦ 17) is a normally open switch the actuator or operating handle 41 ~f which is normally resiliently maintained in its central 51 (open) position. When the actuator of store con~and switch 6¦ 22 is manually raised to its uppermost position, conductor 8 71 of bu~ 1 is connected directly to system ~round, and ~he nunn ! numbers displayed on displays 40 and 42 are entered into memory 91 unit 70, as explained hereinabove.
As also seen in Fig. 2, the front panel image polarity 11¦ switch 14 of device 30 ~Fig. 17) is a single poie, double-throw 121 switch the actuator or operating handle of which can be manually 13¦ placed in an upper position or a lower position. When polarity 14¦ switch 14 is in its upper or positive image position, conduc-15¦ tor 10 of bus 1 is grounded to system ground, the image on 16¦ display screen 54 (Fi~. 16) will be of opposite polarity from 17¦ the image on the viewing monitor display screen of the host 18¦ device, and thus any corresponding film image, when developed, 19¦ will be of the same polarity as the image seen on the host ~ol device viewing monitor display screen at the time of exposure.
21¦ When front panel image polarity switch 14 is in its lower or 22¦ negative image polarity position and an exposure on the photo-23 plate in cassette 180 is made, the corresponding film imagP, 24¦ when developed, will be o~ opposite polarity from the image on ~51 the host device viewing monitor display screen at the time of 26¦ exposure.
27 ¦ Low Dunn Density Index switch 18 (Figs. 2 and 17) is 28 ¦ a single-pole, double-throw switch the actuator or operating 29 ¦ handle of which is spring-biased to normally remain in its 30 ¦ central (open switch~ posi~ion~ When switch 18 is manually 31¦ retained in its uppermost position as seen in Fig. 17, and 32 thus BlC2 is grounded, the numerical value shown on display 40 lZO1~7~i5 1 (Fig. 17) increases until it reaches a predeterrlined upper 2 limit When switch 18 is manually retained in its lowermost 3 ¦ position as seen in Fig. 17 and thus BlC4 is grounded, the 4 numerical value shown on display 40 (Flg. 17) decreases until S it reaches a predetermined lower limit.
6 ~1igh Dunn Density Index switch 20 tFig. 2) is a 7 I singlP-pole, double-throw switch the actuator or operating 8 I handle of which is spring-biased to normally remain in it ~ ¦ central (open switch) position. When switch 20 is manually 10¦ retained in its uppermost position as seen in Fig. 17 and ~lC5 11¦ is thus grounded, the numerical value shown on displa~ ¦
12 ¦ 42 (Fig. 17) increa~es until it reaches a predetermined upper 13 ¦ limit. Wl-en switch 20 is manually retained in its lowermost 14 ¦ position as seen in Fig. 17 and BlC6 is thus grounded, the 15¦ numerical value shown on display 42 ~Fig. 17) decreases until ~ ¦ it reaches a predetermined lower limit.
17 ¦ Channel selection switch 16 (Fi~s. 2 and 17) is a 181 manually operable, four-pole slide switch having four ac~ive 19¦ positions each of which corresponds to one of the video input ~1 channels of device,30 as indicated by corresponding legends 21¦ written next to switch 16 on the front panel of device 30 22¦ ~Fig. 17). As taught elsewhere herein, channel selection switch 231 16 not only serves to select the channel whose video signal is 24I to be recorded when exposure switch 12 is depressed, but also serves to select the locations in memory unit 70 in which the 2~1 numerical values displayed on displays 40 and 42 are to be 27 ¦ stored when the actuator of store command switch 22 is raised.
28 ¦ Referring now to Fig. 3, there are shown the electri-291 cal interconnec~ions between the front panel display means 40, 301 ~2, 44 of device 30 (Fig. 17) and the fron~ panel display ex-31 I citin~ bus 2 of device 30 (Fig. lA). Displays 40 and 42 are 32 solid state display devices of the ~ype commercially known by lZ(~8765 1 ¦ the reference designation NSN3881. Display 44 (Fig. 17) is 21 a solid state display device o~ the type commerically known 31 by the reference designation NSN781.
41 }~eferring now to FicJ. 4, there is shown in detail the circuit of the video image display device light output 61 measurin~ photometer 50 of the device 30 of the preferred em-7¦ bodiment.
8`¦ As seen in Fi~. 4, conductors 186 and 188 are con-Y¦ nected to power supplies designated as +A and -A, respectively.

10¦ The designator ~A is to be understood herein to represent the 11¦ positive terminal of an unre~ulated 15 volt direct current 12¦ power su~ply; and the desi~nator -A is to be understood herein 13 to represent the negative terminal of an unregulated 15 volt 14 I direct current power supply. Further, the designator L is to be understood herein to represent the positive terminal of a 16 regulated 5 volt direct current power supply. Referxing again 17¦ to Fig. 4, it is to be understood that in the preferred embodi-~¦ ment of the present invention the following components have 19¦ the indica-ted values: capacitor 190, 0.01 microfarads; capaci-201 tor 192, 100 picofarads; resistor 194, 2.4 megohms; capacitor 21¦ 196, 100 picofarads, resistor 198, 1 kilohm; capacitor 200, 22¦ 0.1 microfarads; resistor 202, 500 kiiohms; potentiometer 204, 231 20 kilohms; resistor 206, 150 kilohms; resistor 208, 1 kilohm;
24¦ resi~tor 210, 500 kilohms; and resistor 212, 100 ohms. Photo-2sl diode 52 is a Vactec VTS-5076 photodiode. Integrated circui-t 26l operational amplifiers 216, 218, 220 and 222 are LM319-type 27 inte~rated circuit operational amplifiers. Diode 224 is a 28¦ lN914 diode, as is diode 226. Zener diode 228 is a 5.6 volt 291 Zener diode.

30 ¦ During the manufacture of devices constructed in ac-31 ¦ cordance with the preferred embodiment of the present inven-32 ¦ tion, potentiometers 204 and 214 are adjusted as follows.

1 21~8765 1 ¦ The light output of monitor screen 54 is measured by 2 ¦ a ~ektronix J-16 digital photometer or its equivalent, using a 3 I Tektronix J6523 one degree narrow angle luminance probe. Using 4 ¦ a pro~ramed test mode which is available in device 30, the ~ ¦ MsDAc and MCDAC (Fig. 15) are set directly, using displays 40 6 ¦ and 42 and switches 18 and 20, and setting DIP SWITCHES 1, 6, 7 j 7, 9, and 10 to their ON positions, and all of the other DIP
8 ¦ SWITC~l~S to their OFF positions, so that the mGnitOr light 9 output equals 102.4 foot-lamberts as measured by the Tektronix 10 ¦ photometer. (~ith the DIP SWITCHES set as noted above, the 11 I M~DAC se-tting appears on the indicator 40, and the MCDAC
12 ¦ setting appears on the indicator 42.) Potentiometers 204 and 13 ¦ 214 are then manipulated until the full scale output of ~41 analog-to-digital light output converter 60 (Fig. lA)I i.e., 15 ¦ FF in hexadecimal, corresponds to 102.4 foot-lamberts, as 16 ¦ read on said J-16 digital photometer. The MBDAC setting is 17~ then adjusted until the spot photometer reads 0.4 foot-lam-18¦ berts. The~E~otentiometer settings are then further adjusted 19¦ until a reading of 0.1 hexadecimal at the output of converter 20¦ 60 is obtained. For convenience in using this programmed 21¦ manual test mode, the output of convertPr 60 in hexadecimal 22¦ is displayed on indicator 44 when the DIP SWITCHES are set as ~31 indicated above. The above DAC and potentiometer adjustments 241 are reiterated until the converter output of FF in hexadecimal 2sl corresE)onds to a spot photometer reading of 102.4 foot-lam-27 I berts and a converter ou-tput of 0.1 in hexadecimal corresponds 28 I to a spot photometer reading of 0.4 foot~lamberts.
l Referring now to Fig. 5A, it is to be understood 291 that all of the resistors 230 through 244 and 246 through 260 l are 4.7 kilohm resistors. Gate 262 is a 74LS~2 integrated 321 circuit gate. Integrated circuits 264 and 260 are 74LS253 ¦ integrated circuits. Switch 26~, which is denoted as DIP
~3 ~ ~2~76S

1 SWITCH l0 in the computer program listing portion of the 2 present speci~ication, is the internal channel image polarity 3l swi~ch for input channel 4 of device 30. As indicated in the 41 com~uter program listing portion of the present specification, 51 page l, any input video Bignal carried by channel 4 is re-61 versed in image polarity when switch 268 (DIP SWITCH l0) is ON, 7¦ i.e., clos~d.
8 Similarly, switch 270 is the internal channel image 9 polarity switch for input video channel 3; switch 272 is the internal channel image polarity switch for input video channel 11 2; and switch 274 is the internal channel image polarity switch 12 for input video channel l.
13 The parenthetical expression following certain switch 14 reference numerals in the drawings indicates their correspond-ing clenotations in the program listin~, e.g., 268(DS l0) 16 indicates that dip switch 268 is also called DIP SWITCH l0.
17 Terminals 276, 278, and 280 shown in Fig. 5A are de-1B /~ _ 1~ ~// , 20 ~ /// t ~4 I ///

26 ~

28 I /~/
~9 ///

31 ~

~I L/~

~Z(~37~i5 I
1¦ noted in the computer pro~ram listing portion of the present 21 speci~ication as E9, E10, and Ell, res~ectively. See page 1, 31 lines 32 through ~4. As there taught, the number of exposures 4I made on any photoplate in device 30 can be predetermined by sl the proper strappin~ of these terminals.
61 Referring now to Fig. 5B, it is to he understood that 7 ¦ all of the resist~.rs 284 through 314 are 4.7 kilohm resistors.
8¦ Integrated circuits 316 and 310 are ?4LS253 integrated circuits.
9¦ Switch 320, which is denoted as DIP SWITCH 5 in the 10¦ computer program listing portion of the present specification 11 ¦ serves when closed to disenable the tracking mode of the Auto-,21 Comp program function of device 30.

131 Switch 322, which is denoted as DIP SWITCH 4 in 14 ¦ the computer program listing ~ortion of the presen~ specifi-15 ¦ cation, page 1, serves to prevent the operation of the Auto-16 I Con~p portion of the program of device ~0 when closed.
17 ExposL~re control terminals 324, 326, 328, 3~0 and 18 332, also r~spectively denoted as E~, E7, E~, E4J and E5, are 19 referred to in the computer program listing portion of the present specification, where the result of strapping, i.e., 21 directly, conductively connectin~ certain ones of them is 22 explained.
23 Further, switch 336 (Fig. SA), also called DIP
24 S~ITCH 2, makes it possible to change the exposure time values stored in Nitron 70, one of each image polari~y of each input 2b channel. When switch 336 is closed the stored exposure time 27 value ~or the then selected input channel (switch 16) and image 28 polarity (switch 14~ is displayed on LDDI indicator 40. This 29 value can be changed to a new, desired value by manipulation of switch 18, and this new value can be made to replace the ~1 previous stored value by raising the handle of switch 22 to its 32 STOR~ position. In this mode, indicator 40 reads from 1 to ~ (15 l ~ '7~S

1¦ 128 in vertical video synchronizin~ pulse intervals.
21 Referring now to Fig. 6, it is to be understood that 3l in the preferred embodi~ent of the present invention integrated 41 circuit 340 is a type 721BB eight-character, seven-segment sl decoder/driver circuit, and the OR gate 342 is an integrated 61 circuit gate of the kind commercially designated as 74LS32.
71 Referring now to Fig. 7, it is to be understood tha ~¦ in the preferred em~odiment of the present invention circuit 91 component 344 is a temperature controlled reference diode of 10¦ the kind referred to by the commercial designatlon LM399Z.
11¦ Amplifier 346 is a unity gain amplifier, and the 12¦ selection of sui~able values for the components thereof is 13 within the scope of one having ordinary skill in the art, in- ¦
14l fonned by the present discLosure. Operational amplifier 348 15¦ is a type LF347 integrated circuit operational amplifier.
16¦ The gain of amplifier 350 is adjustable by means of 17¦ potentiometer 352, which during the manufacture of device 30 181 is adjusted~so that the gain of amplifier 350 is 10. The 191 selection of suitable values for the components of amplifier 201 350 lies within the scope of those having ordinary skill in 221 the art, informed by the present disclosure. Operational am-l plifier 354 is a type LF3~7 integrated circuit operational 231 amplifier.
24 Zener diode 356 is a type lN4732 Zener diode.
In accordance with a particular feature of the present 26 invention, a sample of the line voltage supplied ~o device 30, ~uitably proportionally reduced, is applied to pin 28 of in 2~ tegrated circuit 358, and thus device 30 is rendered inopera-¦ tive whenever the line volta~e supplied there~o is too low to

33 ¦ pe~nit the production of video images which conorm to the 32 video image quality standard~ for the realization of which de-vice 30 was designed.
~.6 1 Gates 360 and 362 are commercially available inte-2 grated circuit gates.
3 Referring now to Fig. 8, it is to be noted that in-4 tegrated circuit 364 is a type 8035 microprocessor integrated circuit.
6 Crystal 366 is a 6 megahertz crystal, and capacitors 7 368 and 370 are 20 picofarad capacitors. The upper terminal 8 372 of the coil of solenoid 374 is connected to the positive 9 terminal of a 23 volt, unregulated direct current power supply (not shown). Solenoid 374 serves to operate the mechanical I shutter which is a feature of the present invention embodied 12 in device 30. Solenoid 374 opens said mechanical shutter when 13 it is energized via transistor 376. Said mechanical shutter 14 is shown in Fig. 16, and there identified by the reference number 380.
16 Referring now to Fig. 9, it is to be understood that 17 integrated circuit 382 is an Intel type 8243 l/O ~xpander in-18 tegrated circuit. 386 is a 2N3904 transistor which drives 19 the monitor CRT TTL blanking input. The unmarked resistor in its base (Fig. 9) is resistor 384 and has a value of 100 kilohms.
21 Referring now to Fig. lOA, it is to be understood 22 that integrated circuit 388 is a type 74S188 integrated 23 circuit, and that integrated circuit 390 is a type 74LS74 24 integrated circuit. Resistors 392 through 406 are all 4.7 kilohm resistors. Capacitors 408 and 409 are 0.1 microfarad 26 capacitors.
27 Referring now to Fig. lOB, it is to be understood 28 that resistors 410 and 412 are 100 ohm resistors, that resis-2~ tors 414 through 420 are 75 ohm resistors, and that resistors 422 through 428 are 4.7 kilohm bleeder resistors.
31 Manually o~erable switches 430 through 436 serve to 32 individually shunt the bleeder resistors 422 through 428, 33 respectively. Thus, it will be seen those having ordinary

34 skill in the art, informed by the present disclosure, that ~ ~ZC~765 1¦ video input line 146 may be terminated in a large impedance, 2 ca. 4800 ohms, or in a characteristic impedance, i.e., 75 3 ohms, depending upon the position (open or closed) of switch 4 430. Each o~ the other switches 432 throu~h 4~6 serves to provide the same choice of line termination impedances for an 6 associated video input line, i.e., lines 144, 142, and 140, 7 respectively.
8 As noted in Fig. lOB, integrated circuit 114 is an 9 LF13201 analog multiplexer integrated circuit.
As further seen in Fig. lOB, resistors 442, 444, 446, Il and ~48 are all 100 ohm resistors, and conductor 134 inter-12¦ connects pins 2, 7, 10 and 15 of multiplexer 114. Capacitor 13¦ 450 is a 10 microfarad capacitor and resistor 452 is a 22 14¦ kilo~lm resistor. Resistor 454 is a 33 kilohm resistor, and ~sl capacitor 456 is a 0.1 microfarad capacitor. Resistors 458 16 and 460 are both 1 kilohm resistors, and ca~acitor 462 is a 17¦ 0.1 microfarad capacitor. The selection of suitable tran-1~¦ sistors for~ use as transistors 464, 466, and 468 is within the .91 scope of one having ordinary skill in the art, informed by the 20¦ present disclosure_ 21 ¦ Re~erring now to Fig. lOC, there are shown the PWISS
?2 l sample-and-hold circuit 120 and the BPISS sample-and-hold cir-231 cuit 122, both of which are represented s~hemakically in Fig.
241 1~. Also shown in Fi~. lOC is the monitor video input buffer 2s ¦ 129, which is shown schematically in Fig. lD.
26¦ ~s seen in Fi~. lOC, the ~IISS-LISS network comprises 271 300 ohm resistor 124, 56 ohm resistor 126, and ~ ohm resistor 2~I 128.
291 Resistors 470 and 472 are 100 ohm resistors, and 301 capacitors 474 and 476 are 0.1 microfarad capacitors.
Monitor video input buffer 129 comprises 100 ohm re-~21 sistors ~78, 480 and 482, 0.1 microfarad capacitors 484 and ~8 , I

1;Z~37~

1¦ 486, 4.7 oh~ resistor 4~u, and an ~10002 integrated circuit 2¦ ~ideo buffer 490.
31 sPIss sa~ple-and-hold circuit 122 comprises a 100 41 ~l resistox 492, a 0.1 microfarad capacitor 494, a 3.3 kilohm 5¦ resistor 496, a 0.1 mi~rofarad storage capacitor 498, and a ~¦ I~353 inte~rated circuit operational amplifier 5~0 The net-71 work comprising switch 502, 1 kilohm resistor 504, and lN914 Bl diode 506 serves to permit the selection of the drop across 91 diode 506 as the reference value for the BPISS sample-and-hold ~ol circuit 122, in lieu of the monitor video input signal on con-11¦ ductor 125 at the output of analog multiplexer 116. .
12¦ PWISS sample-and-hold circuit 120 comprises 1~0 ohm 13¦ resistors 510, 512, and 514, 0.1 microfarad capacitors 516, ]4l 518, 520, and 522, capacitor 5~0 being a Mylar c~pacitor, tran-1~¦ ~istor 524, 100 kilohm resistor 526, 33 kilohm resistor 528, 16¦ 10 kilohm resistor 530, 10 ~egohm resistor 532, LM319 integrated 17¦ circuit operational amplifier 534, and LF353 integrated circuit 18¦ operational- amplifier 536.
~9¦ In accordance with a principal feature of the pre 2~1 sent invention, video switch ~ is direct-current coupled 21¦ substantially throughout.
22 ¦ It is to be understood that the present invention is 23 1 not limited to the employment of the particular HISS-LISS net-241 work 124, 1~6, 128 shown in Fig. lOC.
25j To the contrary, certain preferred e~bodiments 271 of the present invention will be substantially identical to ¦ device 30 of the preferred embodiment shown and described in 2~ ¦ detail herein except for the substitution of particular forms l of HISS~LISS network which will now be described in detail.

31 ~ Referring now to Fi~. lOD, there is shown the HISS-32 LISS network 540 of a ~irst alternative preferred embodiment of the present invention, which first alternative preferred .. ~ ~c~/r.~l.
. I

~ ZQ8765 I ¦ em~odimeAt is otherwise subst~ntially identical to device 30 2 ¦ As may be seen by comparison of Fi~s. lOC and lOD, 3 ¦ the four termir-als o~ network 540 are connected, respectively, ~ I ///
s ~

81 /// .
. 9 I /// .
10 1 /// ' .
11 I /// ' ' 12 ~

1~ I ///
1~ 1 ///

17 I /// .
lB ¦ ///
~91 ///
201 /~ .

~21 ///

: 2 3~
32 I /~/
I . .
~.0 . .

~ ~120~7~iS

to the correspondingly numbered leads o~ circult points of the .
21 circuit of Fig. lOC, in place of the network 124, 126, 128 of 3 ~ . lOC.
4 Thus, terminal 542 of network 540 is connected direct- .
ly to the lead or circuit point 542 of Fig,. lOC, to receive the BPISS si-~nal; terminal 544 of network 540 is connected 7 directly to point 544 of Fig. lOC, to .receive the PWISS signal;
terminal 546 of network 540 is connected directly to point 9 546 of Fig. lOC, to supply the HISS signal to pin 14 of analog multiplexer 116; ~tc.
11 Referring now to Fig. lOD, it will be seen that net-1~ work 590 comprises a potPntiometer 550 having a sliding ~on-13 tact or slider 552, and a potentiometer 554 having a slidiny 14 contact or slider 556. The terminal of slider 552 is terminal 1~ 546 of network 540, and the terminal of slider 556 is terminal 16 5~8 of network 540. Terminal 5~2 of network 540 is connected 17 directly to a ~irst end terminal of each potentiometer 550, 18 55~, and t~rminal 544 oE network 540 i5 conne¢ted directly to 14 a second end terminal of each potentiometer 5$0, 554.
It is to,be particularly noted that slider 552 i9 21 provided with a mechanical stop 558, and that slider 556 is 22 provided with a mechanical stop 560. Stops 558 and 560 are 23 50 constructed and arranged that the HISS signal produced at 24 terminal 54~ of network 540 can be equal to but never exceed the LISS sicJnal produced at terminal 548 of network 540, and 26 so that the LISS signal produced at terminal 548 can be equal 27 to but never be smaller than the ~ISS signal produced at 28 terminal 546.
29 ¦ ~s also seen in Fig. lUD, the respective end terminals 30 ¦ of potentiometer 550 are marked with their corresponding HISS
31 ¦ levels, and the respective end terminals of potentiometer 554 32 I are marked with their correspondin~ LISS levels.

1¦ As will now ~e obvious to those having ordinary skill 21 in tl~e art, informed by the present disclosure, HISS-LISS net-3 work 540 is in some ways an optimally flexible HISS-LISS net-4 ¦ work, whereby any desired combination of HISS and LISS levels sl may ~e set. It is contemplated as part of the present inven-61 tion that in some embodiments thereof the manual controls for 71 552 and 556 will be made directly accessible tu the 8¦ operator of the device of that embodiment, while in other em-91 bodiments the manual controls for sliders 552 and 556 will be 10¦ located internally of the devices of those embodiments, and 11¦ thus will be accessible only to the installation or maintenance 12¦ technician.
13¦ ~eferring now to Fig. lOE, there is shown the III5S-14¦ LISS netw~rk 570 of a seco~d alternative preferred embodiment 15¦ of the present invention. ~his second alternative preferred 16 embodiment of the present invention will be substantially 17 ¦ identical to device 30 except for the elimination of HISS-LISS
lB ¦ network 1~9~ 126, 128 of E'ig. lOC and the substitution there-19 ¦ for o~ network 570. As will be apparent to those having or-20 ¦ ~inary skill in t~e art, informed by the present disclosure, 21¦ each terminal of network 570 identified by a particular ref-22 I erence numeral will be directly connected to the point of the 23 ¦ circuit of Fig. lOC which is itself identified by the same 24 I numeral. Thus, terminal 542 of networ~ 570 will be directly 25 ¦ connected to point 542 of the circuit of Fig. lOC, terminal 26 ¦ 544 of network 570 will be directly connected to point 544 of 27 ¦ th~ circuit oE Fig. lOC, etc.
28 Referring again to Fig. lOE, it will be seen that 29 network 570 consists of a potentiometer 572, a resistor 574 having one of its terminals connected to the slider terminal 31 ~f potentiQmet~r 572, a resistor 576 having one of its ter-32 minal~ connected to one end terminal of potentiometer 572, and .
5"

1~876~5 ~

1 a resistor 579 connected in the slider circuit as shown.
21 As will be obvious to those having ordinary skill in 31 the art, info~med by the present disclosure, ~IISS-LISS network I 570 is particularly advantageous for the reason that it makes 51 possible sel~ction of the desired HISS-LISS difference or 6¦ lma~e siynal sample span tISSS~ by means of only one manual 7¦ control, viz., the manual control means for positioning the 8 slider of potentiometer 572.
9¦ As will be obvious to those having ordinary skill in 10¦ the art, informed by the present disclosure, the image signal 11¦ sample spans (ISSS's) will be symmetrical about ~he half-12¦ range image signal sample level, i.e., half way between BPISS
,31 and PWISS, if the value of resistor 574 is equal to the value ~4¦ of resistor 576.
15¦ It i~ to be understood, however, that the present 16¦ invention is not limited to such symmetrical HISS-LISS net-,71 works. Thus, in some versions of this second alternative pre-18¦ ferred embodiment o~ the present invention, resistors 574 and ~9¦ 576 may he unequal in value, and thus the ISSS provided may be 20¦ dissymetrical with ~espect to the half-range ima~e signal sam-211 ple level by a deslred amount.
221 It is further to be understood that the present in-231 vention embraces embodiments in which resistors 574 and 576 241 are themselves adjustable potentiometers, whereby the position 2sl of the ISSS in the full ima~e signal sample range may be de-2b ¦ ///
27 ~

32 ~//
S;~ . .

il.~08~65 1 1 termined as desired.
21 ReferrincJ now to Fig. ll, there is shown a part 620 31 of the circuit of monitor 56, ~onitor 56 is a Tektro~ix Model 41 No. 634 Video ~5Onitor, and partial ci~cuit 620 is taken direct-51 ly from a ~anual supplied by the manufacturer thereof. In Fig.
61 ll there are shown the points 622, 624, 626 of the circuit of 71 the Tektronix No. 634 Video Monitor from which the direct cur-81 rent restore (DCR) pulse signal, the vertical synchronizing 91 pul~e signal, the vertical synchronizing pulse signal, and the 10¦ hori~ontal synchronizing signal pulse signal utilized in other 11¦ parts of device 30 are derived. As also seen in Fig. ll~ point 12¦ 622 is directly, conductively connected to sheet terminal llRl, ;
13¦ pOillt 624 is directly, conductively connected to sheet terminal 14¦ llR2, and poin~ 626 i5 directly, conductively connected to 1~¦ sheet terminal llR3.
16¦ As further seen in Fi~. ll, sheet terminal llLl is 17¦ directly, conductivvely connected to the input terminal of mon-lB¦ itor 56 whi~h i9 identified as its brightness or ~ri te~ninal, 19¦ sheet terminal llL2 iS directly conductively connected to the 20¦ input terminal of ~onitor 56 which is identified as its contrast 21¦ or con ter~inal, sheet ter~inal llL3 is directly, conductively 22¦ connected to the input terminal of monitor 56 which is identi-231 fied as its external synchronizing signal or EXT SYNC terminal, 241 sheet terminal llL4 is directly, conductively connected to the input terminal of monitor 56 which is identified as its TTL
261 Bh~NKING terminal, and sheet terminal llL5 is directly, con-~71 ductively connected to the input terminal of monitor 56 which 28 is identified as its VIDEO INPUT terminal.
~91 Referring now to Fig. 12, there are shown the two 301 two-kilobyte programmable read-only memory units or PROMS
3~1 630, 632, which toge-ther, along with inverter 634, constitute 321 the program memory 64 associated with microprocessor 60, as 5~

. , .

1~08765 I shown schematically in ~i~. lB. .
21 Both PROM 630 and PROM 632 are progralr~able read-only 3¦ memory units of the type sold under the conunercial designation 41 2716.
s¦ In device 30 inverter 6~4 is an integrated circuit ~¦ inverter of the type sold under the con~ercial designation 7¦ 74I.S04.
81 Referring now to Fig. 13, there is shown the non-91 volatile random~access me,nory device 640 of.device 30, which is identified in Fi~. lB of the schematic diagram as non~vola- .
~¦ tile memory unit 70. In device 30 random~access memory devlce ;
12¦ 640 is a commercially available integrated circuit, non-vola-13¦ tile RAM sold under the commercial designation Nitron 7033.
14¦ Going now to Fig. 14, there is shown the integrated 15¦ circuit address latch bank 644 which is identified in Fi~. lB
16¦ of the schematic diagram of device 30 as address latch unit 66.
17¦ In device 30 address la~ch bank 644 is an integrated circuit 18¦ device of the type sold commercially under the designation 19¦ 41LS363.
20¦ Referring now to Fig. 15, there is shown the combina- .
21¦ tion o~ circuit elements which constitutes the digital-~o-- 22¦ analog converters 80 and 82 of Fig. iC of the schema~ic diagram ~31 f device 30.
24 ¦ Digital-to-analog converter 80, which is also desig- .
: 2s¦ nated as th~ MsDAc or monitor brightness digi~al-to-analog : 26¦ converter herein, serves to produce the MBCS or monitor bright-27 ¦ ness control signal which is discussed hereinbelow under the28 ¦ heading "Method of Operation". MBDAC ao comprises an inte-2'? ¦ grated circuit digital~to-analog converter of the type sold 30 ¦ under the conunercial designation D~C1006, and an integrated 31 I circuit operational amplifier of the type sold under the com- .
32 ~ mercial designation 347.

.5~ . ~

1~0Z3765 l .
1 ¦ Digital-to-analog converter 82, which is also desig-2 ¦ nated as th~ MCD~C or monitor contrast di~ital-to-analog con-3l verter herein, serves to produce the MCCS or monitor contrast I control signal which is discussed hereinbelow under the headln~
51 "Method of Operation". MCDAC 82 comprises an integrated cir-~1 cuit digital-to-analog converter 654 of the type sold under 71 the commercial designation D~Cl006, and a~ integrated circuit ~1 operational amplifier 656 of the type sold under the co~nercial 91 designation LF347.
~ol The (analog) monitor contrast control signal MCCS
11¦ is ei~her positive or negative, i.e., covers a positive rang2 12¦ from 0 to +l0 volts, or a negative range from 0 to -l0 volts, ;
13¦ depending upon the most significant bit (MSB) latched in its ~41 la~ch, which most significant bit is determined by the settings 15¦ of the iMa~Je polarity switch 14, the channel selection switch 16¦ 16, and the corresponding channal polarity switch, acting 17¦ through the microprocessor of device 30 and its stored program.
When said MSs is 0 the MCCS is in its negative range, and, 19¦ due to the design o~ monitor 56, the polarity of the image ~ol displayed on monitor scr~en 54 is not inverted with respect to 21 ¦ the polarity of the image borne by the selected video input 22¦ siynal. When said MS~ is 1 the MCCS-is in its positive range, 231 and, due to the design of monitor 56, the polarity of the image 241 displayed on monitor screen 54 i5 inverted with respect to the 25 ¦ polarity of the image borne by the selected video input signal.
~61 In the circuit of Fig. 15 the resistors 660, 662, 271 669, and 666 are all 18.2 kilohm resistors; the resistors 668 28¦ and 670 are 2.43 kilo~n resistors; the resis~ors 672 and 674 291 are 133 kilohm resistors; and the resistor5 676 and 67B are 301 l00 ohm resistors. The capacitors 680 and 682 are 0.l micro-¦ farad capacitors. In the n~twork co~non to MBDAC 80 and M~DAC
32 ¦ 82, capacitor 684 is a l0 microEarad capacitor, capacitor 686 . I ..
I .
' -1 is a 0.1 microfarad capacitor, xesistor 638 is a ~20 ohm re-2 sistor, and Zener diode 69n is an LM336Z Zener dio~. The re-3 sistor 692 and the capacitor 694 of the biasin~ network of 4 ¦ operatiollal amplifier 656 can be provided by -those havin~
S ¦ ordinary skill in the art without the exercise of invention.
Simil~rly, the resistor 693 and the capacitor 695 of ~he bias-7 in~ ne~work of operational amplifier 652 may be provided by B¦ those having ordinary skill in the art without the exercise of 91 inverltion.
10¦ The parts oE device 30 shown in Figs. 16 and 17 are 11¦ described in detail elsewhere in the present specification, and 12 the detaile~ description of the same will not be repeated here~

14 l~ethod of O~eration 16¦ For ease o understanding of the ~ethods of operation 17¦ carried ou-t by certain devices embodying the prasent invention, 18 and the op~rators thereof, the terms and corresponding symbol~
19 used herein to denote certain particular features and aspects o~ the present invention should be considered in detail. These terms and symbols are discussed directly below.
LISS. The term ~low image si~nal sample" or LISS
23 is defined in the Glossary, su~ra.
24 IIISS. The term "high image signal sample" or HISS
is defilled in the Glossary, su~ra. -26 LISS Level. The term '9LISS level" is defined in the 27 Glossary, su~ra.
28 IIISS Level. The term "HISS level is defined in the 29 Glossary, ~ .
In accordanca with the principles of ~he present in-31 vention, the I~ISS and -th~ LISS in a ~hotoqraphic video image 32 recordin~ device embodying the p~esent invention are taken . ' ., 1¦ substantially directly from the input vi.deo signal from which 2 ¦ images are to be recorded, so that the HISS level and the LISS
3¦ level are substantially unaffected by component value drift, 41 line vol~age variation, and other factors which produce record-s¦ ed image drift in video image recording devices of the prior ~¦ art.
7l For example, it m~y be seen in Fig. lD that in the 81 device 30 of -the preferred embodiment of the present invention 9 ¦ the particular input video signal selected by analog multiplexer 10¦ 114 passes only through buffer 118 before being sampled by the 11¦ peak-white-~ample-and-hold subcircuit 120; and that that same 12¦ video input signal passes only through buffer 118 and analog 13¦ multiplexer 116 before being sampled by the back-porch~sample-14¦ and-hold subcircuit 122. Analog multiplexers 114 and 116 and 15¦ buffer 118 are preferably selected for their ability to pass 16 ¦ the selected video input signals substantially without change.
17 ¦ Further, as also seen in Fig. lD, the HISS and the LISS obtain-18 ing at any ~articular time in device 30 are derived directly 19¦ from the PWISS and khe sPIss, supplied by sample-and-hold 201 subcircuits 120 an~ 122, respec~ively, by means of a simple 21¦ resistive network 124, 126, 128, the ~IISS level and LISS level 22¦ of which remain substantially the same over the entire op~
231 erating range of device 30.
241 Thus, it may be seen that in accordance with the 25 ¦ principles of the present invention the HISS and the LISS in 26¦ device 30 are taken substantially directly from the input 27 ¦ video signal from which images are to be recorded, and are 28¦ substantially unaffected by component value drift, line voltage 291 variation, host video signal amplitude, and the other factors 301 wl~ich produce recorded image drift in the photographic video 31¦ image recording devices of the prior art.

3~1 LISSLllM. The term "l~ image signal s~mple l~nina.ce"

~2~ iS

1 ~r LIS5LU~I is used herein to denote a monitor screen luminance ~ ///

7 //~

10 ~//

///

22 /~/
2~ ///

///
.26 ///

28 i//

3? //f ~ .

Q8Y65i 1¦ value corres~ondin~ to a p~r~icular L~SS value. The term 21 "actual low image s,ignal sample luminance~ or actual LISSLU~
31 is used herein to denote the value measured by the monitor 41 display screen output photometer o~ a video image recording S1 device embodying the present invention when a s~nthetic video 61 ima~e si~nal is supplied to the monitor the image signal por-71 tion of which is constant and equal to the LISS ("LISS video 81 signal~'). The term "desired low ima~e signal sample lumi-91 nance" or desired LISSLUM as used 1~erein denotes a desired or 10¦ tar~et LISSLUM, i.e., a desired or taryet luminance value 11¦ corresponding to a particular LISS value. The term ~low image 12¦ si~nal sample luminance ratio" or LISSLUM ratio as used herein 13¦ denotes the ratio between the ~ISS and the corresponding 14¦ desired or tar~et LISSLUM obtaining in a particular video 15¦ image recording device en~bodyin~ the present invention at a 16¦ particular moment o~ its operation. LISSLUM ratio may, e.g.,, 17¦ be expressed in volts per foot-lambert.
1~¦ E3~SSLU~. The term "high image signal sample lU'Mi-19¦ nance" or l-lISSLUM is used herein to deno~e a monitor screen 20¦ luminance value corresponding to a particular HISS value. The 21¦ term "actual high image signal sample luminance" or actual 22¦ HISSLUM is used herein to ~enote the luminance value ~easured 231 ~y the monitor display screen output photometer of a video 241 imaye recording device embodying the present invention when 251 a synt}letic video image signal is supplied to the monitor 26 ¦ the image signal portion of which is constant and equal to the 27 ¦ 11ISS ["HISS video signal"). The term "desired hi~h image 2~1 signal sample luminance" or desired HISSLUM as used herein ~91 denotes a desired or tar~et HISSLUM/ i.e., a desired or tar~et 301 luminance value corresponding to a particular 11ISS value. The 311 term "high image si~nal sample luminanc~ ratio" or HISSLUM
32 ratio as used here1n denotes the ratio between the 11ISS and l ¦ the corresponding desired or tar~et HISSLUM obtaining in a 21 particular video ima~e recordin~ device embodylng the preqent 31 invention a-t a particular moment o~ its operation, ilIS5LUM
41 ratio may, e.g., be~expressed in volts per foot-la~bert.
51 The term "monitor briyhtness control signal" or MBCS
61 as used herein denotes the signal supplied by the servosystem 71 portion of a video image recordlng device embodying the present B ¦ invention to the monitor of that device to control the bright-9 ¦ ness of the monitor display, the term "brightness~' being used ~¦ here in the sense in which it is ordinarily used in the video 11 ¦ monitor art. In the device 30 of the preferred embodiment of 1~¦ the present invention the monitor brightness control signal or 13¦ MBCS is supplied to monitQr 56 via brightness signal terminal 14 ¦ lO0 (Fi~. lD).
15¦ The term "nlonitor contrast control si~nal" or MCCS
16 as used herein denotes the signal supplied by the servosystem 17 portion of a video image recorAing device embodyin~ the present 18¦ invention ~o the monitor of that device ~o control the contrast ~91 of the monitor display, the terln "contrast" bein~ used here in 201 the sense in which it is ordinaril~v used in the vldeo monitor 21¦ art. In the device 30 o~ the preferred embodiment of the 22¦ present invention the monitor contrast control signal or MCCS
231 is supplied to monitor 56 via contrast signal terminal 102 241 (Fi~. lD).
2S¦ LDDI. As taught hereinabove, the term "low Dunn 261 density index" or LDDI as used herein denotes an index n~nber 28 which may be conveniently employed in utilizing a partioular 291 device embodying the present invention for photographically l recordin~ video images. ~s also taught hereinabove, certain 301 particular preferred embodiments of the present invention are 311 provided with externally accessible image parameter controls~

¦ e.g., 18~ 40, Fig. 17, which are calibrated in terms of the .' '~ '' `.

0~7~iS

1¦ low Dunn Density Inde~ ~ LDDI o~ that ~rticula~ embodiment.
21 It is to be understo~ that the pre~ent invention i5 not linl-31 ited to devices having externally accessible controls cali-4 ¦ brated in terms o~ the LDDI of the particular device. It is 51 also to be understood that in certain embodiments of the pre-sent invention particular value~ of the index number LDDI
7 ¦ may not have the same significance as in other embodiments 81 o~ the present invention. The term "indicated low Dunn density 91 index" or indicated LDDI will sometimes be used herein to de-10¦ note the particular value of LDDI appearin~ on ~he LDDI indica-11¦ tor of a particular embodiment o the present invention at a 12 1 particular time.
13 ¦ It is of particular importance to note tha-t ever~
14 ¦ LDDI value which can be indicated on the LDDI indicator of a 15 I particular video image recording device embodying the present 16 ¦ invention at a particular time is directly related -to a cor-17 1 responding desired LISSLVM value in that particular device.
1~ ¦ For examp]e~ in the device 30 of the preferred embodiment of 19 ¦ the present invention the relationship between any indicated 20 I LDDI value and its~c~rresponding desired LISSLUM value is the 21 ¦ identi-ty relationship. In o-ther words, any particular LDDI
2231 value indicated on LDDI indicator 40 of device 30 (cf., Fi~.
l 17) is also the value of the desired LISSLUM then obtaining in 241 device 30. It is to be understood, however, that this identity 251 relationship between LDDI and desired ~ISSLUM will not ne-271 cessarily obtain in every device embodying ~he present in-281 vention. ~s pointed out hereinabove, the term LDDI i5 syn 29 onomous with -the term LDN or "low Dunn number".
1 HDDI. ~s taught hereinabove, term "hi~h Dunn density 301 index" or IIDDI as used herein denotes an index number which 321 may be convenien-tly employed in utilizing a devics embodying I the present invention for photograph1cally recording video 6~ ~

l ¦ images. As also taught hereinabove, certain particular pre-2 ¦ ferred embodiments of the p~esent invention are provided with 3 ¦ e~ternally accessible i~a~e para~eter controls, e.g., 20, 42, 41 ~i~. 17, which are calibrated in terms of the high Dunn density 5 ¦ index or 11DDI of that particular embodiment. It is to be ~¦ understood that the present invention is not limited to de-7 ¦ vices having externally accessible controls calibrated in a ¦ terms of the ~IDDI of that particular device. It is also to 91 be understood that in certain embodiments ~f the present in-vention particular values o~ the index number HDDI may not 11¦ have the same significance as in other embodiments of the pre-12 ¦ sent invention. The -term "indicated high Dunn density index"
13¦ or indicated ~IDDI will sometimes be used herein to denote the 14 ¦ particuldr value of HDDI appearing on the ~DDI indicator of a 1~ ¦ particular embodiment of the present invention at a particular 16 time.
17 ¦ It is of par-ticular importance to note that every 18 ¦ IIDDI value which can be indicated on the HDDI indicator of a 1~¦ particular video i~age recording device embod~in~ the present 201 invention at a particular time is directly related to ~ cor-21 ¦ res~ondiny desired ~IISSLU~ value in that particular device.
22¦ For example~ in the device 30 of the preferred embodiment o~
2~ the present invention the relationship between an~ indicated 24 ¦ HDDI value and its corresponding desired HISSLUM value is the 2sl iclentity relationship. In other words, any particular HDDI
26¦ value indicated on IIDDI indicator 42 of device 30 tcf., Fig.
27¦ 17) is also the value of the desired l-lISSLUM then obtaining in 2~1 device 30. It is to be understoodj however, that this iden-29 ¦ tity rela-tionship between ~IDDI and desired ~IISSLUM will not 301 necessarily obtain in ever~ device e~bodying the present inven-311 tion. As pointed out above, the term ~IDDI is synonomous with 32 the term llDN or "high Dunn number".

63 .

~ 12(18~65 1 Reference should be had -to Fig. lD, which shows the 21 implementation o~ the relationship between the quantities de-31 noted by the terms deEined above and o-ther ~asic terms defined 41 herein in the device 3~ of the preferred embodiment of the pre-51 sent invention.

71 A computer program of device 30 includes a subprogram 8 ¦ . or set of inter-related routines, called Auto-Comp herein, 91 whereby the MsCS and MCCS are repeatedly v'aried in systematic ¦ fashion to make the actual LISSLUM measured by the monitor screen 11¦ output photometer system 50, 60 equal to the indicated LISS, and 12¦ to make the actual HISSLUM measured by the monitor screen output 14 photometer system 50, 60 equal to the indicated HISS.
~51 17¦ Before desc~ibin~ in detail the method of servocontrol 18 ¦ operation which is automatically and repeatedly carried out by the ~uto-Comp portion of the program of device 30, preliminary l steps of the me~hod o~ operation of device 30 carried out by 21¦ and under control of the operator of device 30 will be consid-23 ered.
l Going to Fig. l6, i-t will be seen that a film cas-2~1 sette 180 has been loaded into device 30 through port 600, 251 and its dark slide removed7 Port 600 is provided with suitable 26¦ light leaka~e preventing means in the well-known manner. The 281 housin~ of clevice 30 provides a light-tight enclosure contain-291 lng cassette 180, monitor 56, the monitor optical system 602, I comprising mirror~ 604, 606, 608, lens 610, and mechanical shu-tter 3B0, whereby the irna~es appearin~ on monitor display 332 screen 54 are ima~ed upon selected areas of the ilm in cas-sette 180. ~onitor 56 and the elements of its optical system 6~ .

lZ~B~ S

1 602 are joined toyether into a unitary asse~bly by mechanical 2¦ means (not shown), and electrical servopositioning méans of 31 well known type (also not shown) are provided for s-teppin~ this 41 unitary assembly, seriatim, through a predetermined plurality 5 ¦ of predeterm.ined jux~apositions to the film in cassette 180, 6¦ whereby a predetermined array of exposures can be made on the 7 ¦ film in cassette 180, each exposure representing one image 8¦ which was presented on monitor screen 54. A viewing port for 91 viewin~ monitor screen 54 is provided, which is covered by a 10¦ viewing door 182. As explained hereinabove, the images dis-11¦ played on monitor screen 54 are derived from video signals 12¦ which may be selected from among the set of video signals sup 13¦ plied by the four host video devices 160 through 166.
14¦ It is assumed that the operator of device 30 has se-15¦ lected the host video device which is to be used as the source 16 of video signals for monitor 56, which is a normal image po-17 larity host video device~ by means of channel switch 16 (Fig.I~¦ 17), in which case the corresponding channel polarity swi~ch 91 is set to its Normal (Open) setting, and that the desired 20¦ expos~lre time for ~he particular film in cassette 180 is the 21 exposure time preset in device 3~. (It will be remembered 22¦ from the discussion above, however, that desired values of 23 ¦ exposure time can be s.et by suitable manipulation of switches 241 336, ~0 and 22. It is further assumed that the desired LDDI
2~ ¦ and ~DDI previously stored .in the manner described above, are 26¦ now automaticalJ.y recalled from memory 70 to processor 60.
271 ~ddit.ionally, it is assumed for the preliminary part of this 28 discussion of the operation of device 30 that the operator 29 ¦ thereof has set image polarity switch 14 to its POS position.
At this time, and so long as an unexposed image area remains 31 ¦ availahle on the film in cassette 180, the polarity inverse 32~ of any desired image appearing on monitor screen 54 can be ~2~l~'7~5 1 recorded on the film in cassette 180 by simply depressing 2 exposure switch 12. It is to be understood, however, that 3 the selection of the desired image to be recorded must be 4 determined fr~m the monitor viewing screen of the host video device supplying,the video signal to monitor 56, since device 6 30 will not operate while.viewing door 182 is open.
7 Auto-Comp. As pointed out above, ~he Auto-Comp '8 portion of the program of device 30 serves to automatically 9 and repeatedly.vary the monitor brightness control signal (MBCS) and the monitor.contrast control signal (MCCS) in 11 systematic fashion to make ~he actual LISSLUM measured by 12 the monitor screen output photometer system 50 9 60 equal 13 to the indicated LDDI, and to make the actual HISSLUM
14 measured by the monitor screen output photometer system 50, 60 equal to the indicated HDDI.
16 The Auto-Comp subprogram comprises two different 17 routines or methods of operation, viz., the successive ' 18 approximation Auto-Comp mode or routine (SAM) and the track-19 ing Auto-Comp mode or routine (TAM).
In accordance with the program of device 30, stored ,21 .in program memory 64'(Fig.'lB~, the SAM routine is invoked ~nd 22 carried out whenever one of certain predetermined SAM-- 23 triggering events takes place, such as the operating of any 24 front panel switch excepting the downward operation of switch , ,25 '22, or the moving of monitor 56 to its initial exposure ~:.26 position with respect to the film in cassette 180.' 27 In accordance.with a further feature of the program 28 of device 30, the completion of each SAM routine automatic~lly 29 triggers a TAM routine, so that one complete TAM operation 30 - is carried out, unless exposure of a film area is taking place 31 or monitor 56 is in motion, in which events the TAM operation 32 is delayed until the exposure is completed or the monitor comes :

~ 1:~01 3';'65 1 to rest.
21 Assuming for the moment that the polarity awitch fac-31 tor product, ~, infra, is -l~ each SAM operation carried 41 out under the control of the SAM routihe of the program of device 30 will be a series of successive approximation~ during 6 which the MBCS and MCCS are varied to cause the actual LISSLUM
71 to approach and ultimately reach the desired LISSLUM~ i.e., 81 the indicated LDDI value, and to cause the actual HISSLUM to 91 approach and ultimately reach the desired HISSLUM, i.e., the 10¦ indicated ~JDDI value. Somewhat similar routines are used in 11¦ microprocessor-based analog-to-digital conver~ers, and are 12 ¦ well-known to those having ordinary skill in the art~ and 13 thus this S~M routine will not be described in detail here.
~41 ~1 16 Before further considering the S~M routinel the fol-17 lowing particular details of the operation of device 30 should 18¦ be noted. ~n the carrying out of each SAM routine the M~CS

19¦ is ~irst adjusted, then the MCCS is adjusted, then the MBCS, 201 etc. The most significan~ bit stored in the MCDAC (82, Fig.

21¦ lC) is used as a ~ign (~, -) indicator; and thus only 9 nu-22 merical or monitor display polarity bits are stored in the 231 MCDAZ. Thus, the term MS~B or most significant numerical bit 241 as used herein refers to the actual most significant bit but 2sl one in the MCDAC, etc.

26 In accordance with the SAM routine corresponding to 271 the polarity switch factor product stated immediately above~

281 i.e., -l, called the L/B SAM routine herein, the monitor screen 2 contrast value latched in latching digital-to-analog converter 311 82 (MCDAC) (Fig. lC) is first set to 256, the monitor screen 32 briyhtness value latched in latching digital-to-analog con-/// ' '~.-67 . ~
.. ~. ,f Il I lZ08~65 l verter 8~ (MBDAC) ~Fi~. lC) iS initially set to ~id-span, i.e,, 2 hal~ of ~ull scale, or 512, and the monitor is supplied with 31 the LISS video signal.
41 Further carr~ing out the L~s ~AM routine, the actual Sl LISSLUM is then read by the photometer sy~te~ 50, 60, and com-61 pared with the desired LISSLUM. If the actual LISSLUM exceeds 7 the desired LISSLU~, the most significant bit latched in the 81 MsDAc is cleared, and the next three mo~ significant bits used 91 as the MBDAC~setting, as in the well known successive approxi-~¦ mation technique referred to above. (S~e, e.g., Microcomputer 11¦ Interfacin~ by Bruce A. Artwick, Prentice-Hall, Inc., 1980, 12¦ pages 224 and 225.) This adjustment is then carried out for 13¦ each of the next three most significant bits.
14 Immediately thereafter, while the just determlned 15 ¦ value is latched in the MBDAC, a similar procedueure is followed 16 ¦ in carrying out an initial adjustment of the valu~ latched in 17 the ~CDAC, i.e~, adjusting the first four most significant 18 numerical bi~s therein.
19 Following these first approximation adjustments of 20¦ the values latched ln the MDAC and the MsDAC, these adjustment 21¦ procedures are repeated for the six most significant numerical 22¦ bits in each DAC, and then for the eight most significant nu-~31 merical bits in each DAC. Finally, these adjustment procedures are repeated for all of the most significant numerical bits ¦ in each DAC, i.e., the M~DAC and the MCDAC.
~ I At this point a truncated L/B or -1 SAM routine is 27 performed, and the results of the two routines are compared.
28¦ If these results differ only in their least significant bits, 2~1 or do not differ at all, the results of the full L/B SAM routine 31 are accepted as valid/ and, e.g., a corresponding (-1) T~M routine, l q.v., is commenced. This truncated test routine and comparison is 68 1 : ~

~ 876S
I
1 otherwise repeated until agreement is achieved, although other ~1 condition responsive routines may be provided.
31 In the L/C type o~ S~M routine, the sUccesSiYe ad-41 justment procedures followed are subfi~antially the same as 51 those just described, except that thè initial value latched in 61 the MCDAC is 768, the ~CCS i8 adjusted in accordance with the 71 LISSLUM difference, rather than -the HISSLVM difference, to equal ~ -31 LDDI, and the M~CS is adjusted in accordance with the HISSLUM
91 differencie rather than the LISSLUM difference, to equal HDDI.
10¦ As will ~e seen fro~ the above by those having ordin-11¦ ary skill in the art, informed by the present disclosure, there 12¦ are two types of SAM routine embodied in the Auto-Comp subpro-13 gram, i.e., the SAM routine in which the difference between ~41 the actual LISSLUM and the desired LlSSLUM, i.e., the LISSLUM
15¦ difference, is eliminated by varying the MBCS, and the S~M
1~ routine in which the LISSLUM diff~xence is eliminated by vary-17¦ ing the MCCS. The first ~ype of SAM routine, i.eO ~ in which 18¦ the ~scS i~ varied to eliminate the LISSLUM difference, will 19 be called the LJB tyye of SAM routine herein. The other type 20¦ of SAM routine wiLl be called the L~C herein.
21 In accordance with the program of device 30, the ~ype 2~1 of S~M rou-tine carried out at any particular time will be de-23 termined by the existing se~tings of ~l) the image polarity 241 ~witch 14 and (2) the channel polarity switch (268, 270, 272, 251 or 274, ~ig. SA~ of the channel then indicated on channel 26 selection switch 16.
271 For ease in determining the type of SAM routine which 281 will be invoked during any particular combination of image po-291 larity switch setting and channel polarity switch setting, the 301 following numbers 7 called "mode factorsl', may be employed.
311 The "image polarity switch factor" or IPF is +l when 32 image polarity swtich 14 is in its POS position, and otherwise l 69 . ,.

, 1 i9 -1.
2 The "channel polarity switch factor" or CHPF is +l 3 when the currently selected channel polari~y swi~ch (268, 270, 4 272, or 274) is in its Normal, open or off position, and otherwise is -l.
6 The algebraic product of these two factors obtaining 7 at any time is called the "polarity switch factor product", and 8 these Eactors are individually called the "polarity switch 9 factors".
The "film image polarity factor" or FPF is -~l when 11 the developed film ima~e is of -the same image polarity as ~le 12 corresponding host vide~ device viewing monitor image, and 13 otherwise is -l.
14 The "SAM type factor", cf. infra., is ~l for the L/C
type ~AM, and -l for the L/B -type SAM.
lb The "TAM type f~ctor", cf. infra., is +l for the H/B
17 type TAM, and -l for the L/B type TAM.
I8 Given these made factors, the S~l type factor obtain-19 ing at any time will be the same as the polarity switch factor product obtaining at that time.
21 For example, if switch 14 is set to POS (IPF = ~l), 22 the selected channel polarity switch, e.g., 270, is set to its 23 Closed or Reversed Video position (CHPF = -l), the polarity 24 switch factor product of the corresponding SAM routine type, ~5 i.e., the SAM type factor, can be readily computed as -l, and 26 thus the S~M routine type then carried out will ~e seen from 27 the above mode factor definitions to be the L/B type, in which 2~ the LISSLUM differenc0 is eliminated by varying the MBCS. In 29 carrying out this type of S~M routine the ~ISSLUM differenc~, i.e., the difference between the actual HISSLUM and the desired 31 I{ISSLUM, will, of course, be eliminated by varying the MCCS.
32 On the other hand, the IIISSLUM difference will be eliminated ~
' , ~ZVI~'76S `

. by varying the ~BCS du~in~ the L~C (or ~1) type of SAM routine.
2 I t is to be noted that in accordance with the program 3 /~/

S ///

7 /// .
8 /~/

10 //~ . .

12 ~//

16 //~
17 //~
1~' /~/ _ , .
19 //~
20 /~/
21 /~/

25 /i/
2~ //~

2 //~

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~Z087~5 'I l 1 ¦ of device 3n any readin~ o photo~eter sySte~ 50~ 60 i5 ac-21 cepted as valid when three succe~isive ~eadin~s ~re identical 31 or 20 vertical synchronization times of the video input signal 41 have elapsed.
51 In accordance with the pro~ram of device 30 only the 61 MBCS is adjusted durin~ the carryin~ out of the T~M routines~
71 It will now be assumed that the polarity s~itch fac-81 tor product, and the the TA~ type factor, is ~l. In accordance 91 with the H/B TAM routine, then, which is automatically inyoked 10¦ by the proqram of device 30 once an L/C SAM routine has been 11¦ co~pleted, the M~DAC is continuously adjusted in one bit in-121 crements, as necessary. During an H/B TA~ routine interval~
13¦ except when an image is being recorded, the HISS video signal ~41 is applied to monitor 56, and after each twentieth vertical 15¦ synchronization time of the selected inpuk vldeo signal the 16 actual ~1ISSLUM is read by the photometer syst~ 50, 60 and com-17 pared with the desired 11ISSLUM (the indicated LDDI). If the 18¦ actual HISSLUM exceeds the desired HISSLVM, the value latched 19¦ in the M~DAC is incremented by l. If the actual HISSLUM equals the desired I~ISSLUM the value latched in the MBD~C is not 21 changed. :~
22 In accordance with the L~B TAM routine, which is 23 carried out when the polarity switch factor product is -l, the 24 successive M~D~C adjustments are made in accordance with the difference between the actual LISSLUM and the desired LISSLUM.
26 During each per~ormanoe of this L/B TAM routine, the value ~s 2a latched in the MBDAC is incremented or decremented by one bit per adjustment, or left unchanged, in accordance with the dif-29 erence, if any, between the actual LISSLUM read hy the photo-meter system 50, 60 and the desired LISSLUM stored in the LDDI

32 storage location correspondinq to the existinq setting of the channel selection switch 16.
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~ 87~5 While the best mode contemplated by the inventors for 2 carrying out their invention is shown and described in the present 3 specification and drawings, it is to be particularly noted that 4 the scope of the invention is not limited to apparatus and methods S of operation involving two separate index value display devices 6 and corresponding separate manually operablf~ disF~lay~d.'index value.
7 control devices. Rather, it is to be particulariy noted that this 8 invention embraces embodiments comprising, e.g., but one index value 9 display device which is switchably used for displaying selected 10 values of a plurality of di:Eferent indexes. Further, these same 11 display devices may also be employed for displaying other values, 12 such as values of open device operating parameters, film types or 13 characteristics, etc., including but not limited to color balance, 14 tint, shade, hue, chroma, video signal luminance, chrominance and 15 color. burst amplitude. In addition, devices embodying the present 16 invention may be provided which accept non-composite color video 17 signals, which signals comprise plural separate signals, each 18 carrying the information relating to a primary color component 19 o:~ the video images carried thereby. Further, it is to be parti-20 cularly understood that while, in the embodiments shown and des-,21 cribed herein the film-impingent light image is controlled by 22 varying the monitor brightness and contrast, the invention embraces , 23 the use of any means to servocontrol the film-impingmen~ Lght 24 image, including but not limited to servomotor driven lens aper-25 ture defining means, servomotor driven polarizing meanst Kerr cell 26 means, and the like. Additionally, this invention embraces in its 27 scope embodiments in which, e.g., monitor display screen brightness 28 and contrast are fixed b~ electronic regulation and the film-29 impingent light image brightness is controlled by, e.g., servo-30 otor driven lens aperture defining means.

~ ' 73

Claims (5)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. In a system for recording images generated by a video display monitor, said monitor including a video signal input receiving a video signal, and having separate brightness and contrast control inputs, apparatus for maintaining said image brightness within a range to produce a desired exposure of a photographic recording film emulsion comprising:

a user-programmable memory for receiving first and second index values corresponding to a maximum and minimum image intensity level for producing a known exposure of said photographic film;

means for sampling and holding first and second amplitude levels of said video signal corresponding to a first and second fraction of said video signal amplitude excursion;

means for measuring said video monitor image brightness;

processor means connected to said means for measuring, to said video monitor brightness and contrast control inputs, to said means for sampling, and to said memory, said processor being programmed to apply said sampled amplitude levels in succession to said video monitor input, and to compare the image brightness produced in response to said applied input voltages with a brightness level represented by said index values, and to generate a signal for said video monitor brightness and contrast inputs which reduces the difference between said measured brightness levels and said represented brightness level whereby said video signal amplitude excursion produces a desired exposure of said film emulsion.

2. An apparatus of claim 1 further comprising means for selecting the polarity of an image to be displayed on said monitor.

3. The apparatus of claim 2 further comprising an input multiplexer for selecting one of a plurality of video signals for display on said monitor.

4. The apparatus of claim 2 wherein said user-prgrammable memory includes indices for each displayed image polarity.

5. The apparatus of claim 4 wherein said memory is user-programmable.