US3751705A - Electron image data processing apparatus - Google Patents

Abstract

Disclosed is an electron image correlation tube adapted to achieve correlation without mechanical or electrical nutation. This eliminates the need for considerable electronic equipment in system complexity. Fundamentally, the invention utilizes an electronic lens in combination with a sectioned anode cooperating with a differencing circuit to achieve the correlation. The outputs of the various sections of the sectioned anode are analyzed by the differencing circuit and the resultant signals are, through a deflection circuit, utilized to control the deflection yokes of the correlation tube and consequently accurately achieve the correlation.

Description

United States Patent 1 Shoemaker 1 1 Aug. 7, 1973 l l ELECTRON IMAGE DATA PROCESSING APPARATUS John R. Shoemaker, Akron, Ohio [22] Filed: Aug. 10, 1971 [21] Appl. No.: 170,656-

Related U.S. Application Data [63] Continuation of Ser. No. 872,677, Aug. 10, 1971,

[75] Inventor:

abandoned.

[52] U.S. Cl. 315/11, 315/12, 315/31 [51] Int. Cl. H0lj 31/48 {58] Field of Search.....- ..3l5/10,1l,12, 31 R [56] 1 References Cited v UNITED STATES PATENTS 2,977,499 3/1961 Bockemuehl 315/10 X 3,054,019 9/1962 'Hendry 3,278,780 10/1966 Carnahan et a1. 315/12 X Sm I2 PRESENT INPUT IMAGE 1 l l8 1 l REFERENCE IMAGE LECTION CIRCUIT 3,476.197 11/1969 Penix et al. 315/11 X 3,496,290 2/1970 Smith 315/11 X 3,555,346 l/l97l McGee et al. 315/12 X Primary Examiner-Carl D. Quarforth Assistant Examiner-P. A. Nelson Att0rneyJ. G. Pere [57] ABSTRACT Disclosed is an electron image correlation tube adapted to achieve correlation without mechanical or electrical nutation. This eliminates the need for considerable electronic equipment in system complexity. Fundamentally, the invention utilizes an electronic lens in combination with a sectionedanode cooperating with a differencing circuit to achieve the correlation. The outputs of the various sections of the sectioned anode are analyzed by the differencing circuit and the resultant signals are, through a deflection circuit, utilized to control the deflection yokes of the correlation tube and consequently accurately achieve the correlation.

TClairiisQiDriivihg Figures DIFFERENCING CIRCUIT Y ERROR SIGNAL PATENIEDAUE 3.151.705

34 mxsi:

PRESENT INPUT 1 0 IMAGE l I w- T I l8 1 ERENCE GE DIFFERENCING CIRCUIT Y ERROR SIGNAL INVENTOR JOHN R. SHOEMAK ER MH'MW ATTORNEYS ELECTRON IMAGE DATA PROCESSING APPARATUS This application is a continuation of Pat. application Ser. No. 872,677, filed Aug..l0, 1,971 and now abandoned.

Heretofore it has been known'that there have been many and various types of electronic correlation tubes which operate to correlate two images, either electronic or optical, or a combination of both. However, all'these prior art systems required some actual nutation between the two images in order to achieve the correlation. Normally a closed loop is utilized so that correlation is rapidly achieved and maintained. The expense for equipment and the complexity of operation is inherent where nutation is necessary. Hence, a need to achieve nutationless correlation is present in the art. It is the general object of the present invention to provide a nutationless correlation tube that operates on a differentiation principle with reduced equipment cost and complexity.

The aforesaid object of the invention and other objects which will become apparent as the description proceeds areachieved in an apparatus to effect electron image data processing which comprises an electron image tube, grid means to store image information as an electronic pattern in the tube, means to project image information as an electron pattern down the tube onto the grid, an anode means to collect the electrons projected down the tube which pass through the grid which is characterized by an electrostatic lens positioned between the grid and the anode means to direct all electrons moving parallel to the axis of the lens to impinge on the center of the anode, the anode divided into at leasttwo separateregions surrounding a central region, means to represent the number of electrons impinging onto the regions of the anode as the voltage, means to differentiate the voltage on the respective re gions and determine 1: and y error signals for the correlation of the stored electron pattern and the projected electron pattern, and means to deflect the projected electron pattern in accordance with the x and y error signals to close the loop on the correlation between the two patterns.

For a better understandingof the invention reference should be had to the accompanying drawings wherein FIG. 1 is a schematic system block diagram illustrating thebasic components in the new system;

FIG. 2 is an enlarged end view of the segmented anode; and

FIG. 3 is an enlarged broken away cross-sectional view of the storage grid-illustrating the principle of the invention.

In many control operations it is desirable to maximize or minimize the integral of a two dimensional function I (x a, y 3) over a'surface which may or may not be connected. Thisbasic problem may be attacked by either evaluating-the integral for many values of a and B and comparing the values this being equivalent to differentiating the functionwith respect to a and B, commonly called nutati'ng'. Also, the gradient of the function can be integrated over the surface. The integrating form possesses the attraction of being conservative of time, but the "computation of vector integral taking account of the directionalna'ture of the derivative is cumbersome. An example of this type of computation is correlation guidance with a two level reference in which case it is desired to maximize or minimize the integral over the white area of the reference. The normal procedure is to cause a and B to vary over some path and control to minimum variation in the integral. This is classical nutation.

The instant invention utilizes an electronic image correlation tube to evaluate directly andco'ntin'uously the derivative of the surface integral without notation and without differentiation of the function.

It is the general purpose of this invention to p'rovde a means whereby an electron image correlation tube can deliver separately and continuously an electrical signal proportional to each of the orthogonal line integrals of dx and dy within a predetermined surface. The invention presupposes the condition that prevails in an electron image correlation tube upon whose storage mesh is stored reference black and white scene signals. It is generally understood by those skilled in the art that in the black areas of the storage mesh 10 of a tube 12 as seen in FIG. 1, when the tube is operated in a read-out mode, the grid wires of the storage mesh 10 and a collector mesh 14 are at a reference potential of 0 volts or greater. The potential at a photocathode 16 is typically a few volts and the insulation in this region is likewise charged to this potential so that an electron entering at a position as seen in FIG. 3, is reduced to 0 velocity before arriving at the storage mesh 10 and returns to the collector 14. Hence, the electron flow is cut off in this region.

Likewise in the white region,- the insulation at cathode 16 is at 0 potential and hence an electron entering at point as seen in FIG. 3 emerges with velocity unchanged. v

However, in the transition region corresponding to the contours around the white regions an electron en. tering at pointv as seen in. FIG. 3, is bent towards the white region and emerges at an angle 6 depending on the spacing of the meshes and the steepness of the transition. I have found that if the electrons with left velocity vectors can be separated from those traveling to the right and straight ahead and each of these separately collected, the following equationsresult:

I I dx i i;

I0 I n d The functions i, and i, are the collected currents with left and right components and i and i, are those with upward and downward components. The requisite separationis achieved by placing an eectrostaticlens 20 behind the storage mesh 10 as it can be seen that all the electrons with velocity vectors oriented in a common direction pass througha common point in the focal plane. The electrons moving parallel to the axis of lens 20 will pass through the focal point of the lens.

Hence, if such a lens 20 has its axis aligned with the axis 18 of the housing 12, and the anode 22 is divided into-a least two separate" areas, although five are indicated in FIG. 2, the current collected onsector as seen in-FIG. 2 will be proportionalto I IdS and (9 12 to either maximize or minimize the surface integral according to the image input being either negative or positive. Typical deflection yokes that could be utilized are illustrated in U.S. Pat. Nos. 3,423,624; 3,424,937;

3,430,092 and 3,476,197. A typical differencing circuit is described at page 753 of The Encyclopedia of Electronics, edited by Charles Suskind, l962.

A differencing circuit which would readily achieve the objects of the instant invention is shown in FIG. 18 in the text Electronic Fundamentals and Applications, Third Edition" by John D. Ryder, and published by Prentice-Hall in 1964. Of course, any of numerous differencing circuits are contemplated to achieve the objects of the invention.

Hence, it is seen that the invention provides a tech nique using an electron correlation tube with an electrostatic lens to evaluate directly and continuously the derivative of the surface integral without nutation. It provides an electrical signal proportional to the orthogonal line integrals which can be utilized through a deflection circuit to control the electronic image passing down the tube representing either an input image or the reference image, depending upon which image, is initially stored upon the storage grid 10, in a manner well understood by those skilled in the art..

The invention also contemplates that a metalized coating 40 is provided on the internal surface of the housing 12 to collect the electrons that veer so much that they wont hit the collector anode 22 and might bounce back to give false readings. A colloidal suspension of graphites in water such as Aqua Dag, as made by Acheson Colloids Company of Port Huron, Mich., would be suitable for this purpose.

While in accordance with the Patent Statutes, only the best known embodiment of the invention has been illustrated and described in detail, it is to be particularly understood that the invention is not limited thereto or thereby, but that the inventive scope is defined in the appended claims.

What is claimed is:

1. Apparatus to effect electron image data processing which comprises:

an electron image tube, grid means for storing image information as an electronic pattern in the tube, means for projecting image information as an electronic pattern down the tube onto the grid means, and an anode to collect the electrons projected down the tube which pass through the grid, the anode being divided into at least two separate regions surrounding a central region, I each region producing an output electrical signal indicative of the number of electrons impinging thereon, which is characterized by: an electrostatic lens positioned between the grid and the anode to direct all electrons having common velocity vectors upon reaching the electronic lens to correspondingly common regions on the anode;

means for determining the differences between the electrical signals of the respective anode regions surrounding the central region, these differences being error signals for the correlation of the stored electronic pattern with the projected electronic pattern; and

means for deflecting the projected electronic pattern in accordance with the error signals so as to close the loop on the correlation between the two patterns. V

2. The apparatus as recited inv claim I wherein the means for projecting information as an electronic pattern comprises a photocathode and means for projecting optical image information onto the photocathode for conversion thereby into an electronic pattern.

3. The apparatus as recited in claim 1 which further includes a conductive layer on the internal surface of the tube for collecting stray electrons.

4. The apparatus as recited in claim 1 wherein the anode is separated into at least four separate and distinct regions surrounding a central region.

* 18 i I i

Claims (4)

1. Apparatus to effect electron image data processing which comprises: an electron image tube, grid means for storing image information as an electronic pattern in the tube, means for projecting image information as an electronic pattern down the tube onto the grid means, and an anode to collect the electrons projected down the tube which pass through the grid, the anode being divided into at least two separate regions surrounding a central region, each region producing an output electrical signal indicative of the number of electrons impinging thereon, which is characterized by: an electrostatic lens positioned between the grid and the anode to direct all electrons having common velocity vectors upon reaching the electronic lens to correspondingly common regions on the anode; means for determining the differences between the electrical signals of the respective anode regions surrounding the central region, these differences being error signals for the correlation of the stored electronic pattern with the projected electronic pattern; and means for deflecting the projected electronic pattern in accordance with the error signals so as to close the loop on the correlation between the two patterns.

2. The apparatus as recited in claim 1 wherein the means for projecting information as an electronic pattern comprises a photocathode and means for projecting optical image information onto the photocathode for conversion thereby into an elecTronic pattern.

3. The apparatus as recited in claim 1 which further includes a conductive layer on the internal surface of the tube for collecting stray electrons.

4. The apparatus as recited in claim 1 wherein the anode is separated into at least four separate and distinct regions surrounding a central region.

Images