US1852784A - Picture scanning system - Google Patents

Description

April 5, 1932. H. LUX

PICTURE SCANNING SYSTEM Filed April 16, 1950 INVENTOR HEINZ LUX ATTORNEY Patented Apr. 5, 1932 UNITED STAirg HEINZ LUX, 0F BERL IN, GEEBEANY, ASSIG-NOR TO TELEFUNKEN GESELLSCI-IAFT FUR DRAHTLOSE TELEGRAPHIE III. E. Ii, 03? BERLIN, GERMANY, A CORPORATION OF GERMANY PICTURE SCAN N11? G SYSTEM".

Application filed. April 16,: 1930, Serial No.

The present invention relates to picture scanning systems and, in particular, to a method and means by which the speed of decomposition and recomposition of the picture transmitted and received may be made substantially constant over the entire picture area.

Scanning or exploring means in picture transmission sets are known both for picture analyzers as well as for picture compositors or re-creators wherein the explorin means are subject to a circular movement of uniform rotation, and in which the explored picture line falls along a chord of the circular path. The exploring means of this type may be multiple and may be provided, for instance, upon a uniformly revolving disk, commonly termed a sun-flower disk; and the exploring means, in accordance with the particular purpose for which they are intended, may be given the form of slits, luminous lines, edges or blades or the like.

If these exploring elements are of rectilinear form as heretofore used, regardless of whether disposed radially or not, then, in the case of uniform rotation thereof, the rela tive exploring speed in reference to a line or row located-in a chord of the circular path is not constant. In fact, the exploring speed in such systems will var I from one pointto the next. Presupposing that transmitter and receiver are built perfectly similar, this exploring speed variance for different points, to be sure, will not result in any distortion of the picture, but it will produce an irregular distribution of the intensity upon the picture, in so far as the zones explored at a higher rate of speed will appear dinnner or fee bler, and the irregularities of the transmitter and the receiver will then be integrated in the same sense. However, if arrangements are so chosen that one of the corresponding apparatus, say, the transmitter, is made to operate at a uniform rate of scanning speed, while the other one, in this instance the receiver, will not so operate, then there will occur a distortion of the picture in addition to irregularities in the distribution of the various light intensities. A situation of this kind will arise, for instance, when the copy 444,665, and in Germany March 13, 1929.

to be sent out is located upon a uniformly revolving drum and if the same is explored by an axially displaced scanning element, for instance, a luminous ray or pencil, while the picture compositor or re-creator means is designed along lines as hereinbefore mentioned. In this case, according to this invention, perfect compensation is insurableboth as regards uniformity of intensity distribution as well as freedom from distortion by" that the explorer means at the receiving end are made so arcuate or curved that the ex ploring speed along a picture line or row becomes constant.

Therefore, among the objects of my inven tion I have sought to provide a means by which the scanning or analyzing speeds may be constant at all times; to provide a system wherein the produced light values shall closely correspond to the time values; and, to provide the utmost simplicity of operation. Other objects and advantages will of course suggest themselves and become apparent from reading the following specification and claims in connection with the accompanying drawings, wherein, Fig. 1 represents a type of picture recorder particularly suited to electrochemical picture reproducing systems; 2 discloses a modification of Fig l and shows a system particularly useful in optical recording; while Fig. 3 discloses a further modification of the system of Fig. 1.

Now, to refer particularly to Fig. 1 disclosing a picture recorder based upon the electrochemical principle of picture recording, there is provided a spindle or axis 1 about which rotates disk 2 comprisin six recorder edges, denoted by numerals 3 t0 8 inclusive. These recorder edges are secured to the disk on radial supports or carrier'elements. The picture line is determined by a stationary edge or blade 9 over which the recorder paper 10 is drawn in any preferred manner as shown by the arrow. The length of a line in this arrangement at most is equal to half the len 'th of the chord over the double centric angle of two neighboring recording edges, and the curvature of the recording edges is so ascertained that inside this range the recording speed will be constant;

The general form of construction shown by the curved recording edges of Fig. 1 is useful also for optical picture scanning as shown by way of example by Fig. 2, wherein a light source 11 illuminates a slit diaphragm 12 from which the issuing light passes toward a uniformly revolving disk 13 which cuts out of the band of light l l an element having the size of a picture pointer unit by means of regularly disposed slits 15. The shape of the slits 15 in the disk 13 is so determined that the opening liberated by the disk will travel across the width of the slit 1?. at a uniform rate of speed. So far as the rest of the path of the rays is concerned, a solution may be found in a mirror polygon 16 having a number of mirrors and a rotational speed such that the picture upon the screen 17 will be explored in a line for line manner.

In case of symmetric disposition of the rotating system in relation to the scanning line, it is necessary to choose another curvature for the scanning elements as Well as simultaneous shifting thereof. This case is illustrated in Fig. 3 for an electrochemical picture recorder. Referring particularly to Fig. 3 of the drawing, the numeral 18 denotes a disk rotating about the indie l9 and having sir; tracing or writing edges designated by numerals 20 to 26 inclusive. These edges are mobile radially, and their shape is such that thereby, and owing to radial displacement, a constant recording speed with respect to the path 9 is obtained. The desired radial movement may be controlled, e. g., by a stationary and conveniently shaped cam or disk 26. The recording edges are secured upon lamination or leaf springs having in addition a guide pin or roller 27 which is made to wipe or roll over the cam surface 26, steady pressure upon the latter being insured, for instance, by tractile springs 28.

While the invention has been above described in only a few of its preferred forms it is of course obvious that many modifications and changes may be made thereto. Therefore, I believe myself to be entitled to make and use any and all of these modifications in so far as they fall fairly within the spirit and scope of the hereinafter appended claims.

Having now described my invention what I claim and desire to secure by Letters Patent is the following:

1. In a picture reproducing apparatus for tracing scanning paths on a line located along the chord of a circular path, a constant speed rotary scanning device, and a plurality of elongated and curved scanning elements, of a curvature such that the linear scanning speed thereof along said chord is uniform carried by said scanning device for producing during the rotation of said device constant speed scanning hroughout the length of each path traced.

2. In picture reproducing apparatus for tracing scanning paths on a line located along the chord of a circular path, a constant speed rotary scanning device, and a plurality of sinusoidal scanning elements carried by said device for producing during the rotation of said device constant speed scanning throughout the entire length of each path traced.

3. In picture reproducing apparatus for tracing scanning paths on a line located along the chord of a circular path, a constant speed rotary scanning device, a plurality of sinusoidally curved scanning elements carried by said device and arranged to extend outwardly therefrom, and means for causing each elemental section of said sinusoidally curved scanning elements to trace during the rotation of said device an elemental section of said path along said chord at substantially constant velocity.

4. In picture reproducing apparatus, a continuously moving record surface, a rotary scanning device, a plurality of curved scanning elements extending outwardly from and carried by said scanning device, said elements being so curved as to trace, at a uniform speed, a scanning path on said record surface extending substantially along the chord of a circular path, and means cooperating with said scanning device for causing each point of the curved scanning elements to scan only a single elemental section of the chord traced thereby at substantially uniform speed.

5. In picture reproducing apparatus, a continuously moving record device, a plurality of sinusoidally curved scanning elements carried by said device and arranged to trace a scanning path on said record surface extending substantially along the chord of a circular path, and means cooperating With said scanning device for causing each point of the sinusoidally curved scanning elements to scan only a single elemental section of the chord traced thereby.

6. In picture reproducing apparatus, a continuously moving record surface, a scanning device, a plurality of sinusoidally curved scanning elements carried from said scanning device and extending radially upwardly therefrom and arranged to scan during the rotation thereof successive lines on said record surface extending along a path corresponding substantially to the chord of a circular path, and a cam surface cooperating with said scanning elements for causing each elemental section of said sinusoidally curved elements to scan only consecutively single elemental sections of the traced path.

7. In picture reproducing apparatus for tracing scanning paths on a line located along the chord of a circular path, a rotary scanning device comprising a plurality of sinusoidal scanning elements.

HEINZ LUX.

surface, a scanning

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