Optics: measuring and testing – Lens or reflective image former testing – For optical transfer function
Reexamination Certificate
2000-11-13
2002-12-10
Pham, Hoa Q. (Department: 2877)
Optics: measuring and testing
Lens or reflective image former testing
For optical transfer function
C359S212100, C359S900000, C355S055000, C355S077000
Reexamination Certificate
active
06493075
ABSTRACT:
FIELD OF THE INVENTION
A Method to adjust the Ranging of the Modulation Transfer Function, MTF, starting with the preparation of a Testing Chart for the Modulation Transfer Function, MTF, of a standard specification, a plurality of Testing Chart of different Resolutions may be run to obtain an applicable ranging of picture depths.
BACKGROUND OF THE INVENTION
Along with brisk growth of the computer industry in our times, almost at shooting speeds, peripheral industries have progressed and are prospering in like measures, taking scanners, for example, just a few years ago it was still a peripheral product of prohibitive price, yet, due to phenomenal advances in technologic breakthrough and consistent downgrading of the prices of electronic parts and components, nowadays one who is a user of a computer, PC, in particular, can purchase a scanner at very affordable prices, a scanner serving to sweep manuscript or graphic files of routine use to enterprises or individuals into the computer for storage and ultimate usage, in mass application, can save much of the time otherwise needed to produce or prepare graphic files, in addition, scanner can be used to run, that is, to produce web pages of an INTERNET, with plenty of graphic presentation on the web page more people would be allured to run access to the pages, whereby an entrepreneurial goodwill is conveyed leading eventually to unlimited business opportunities, to be fair and frank, the ongoing popularity of INTERNET, going on stronger from day to day, owes a lot to what scanner has played in the process, yet the working quality of a scanner is by and large dictated by factors like resolution capability, focal distance, among others, and these determine the quality feature of a scanner, and it goes without saying as to the importance of adjustments of focal distance and of resolution in the course of production.
Generally, in the procedure of either design or production of a workshop of graphic or video scanners, focal adjustment is always a key processing phase, because there lies the crucial point for a graphic file eventually appearing on a computer display screen to be clear enough or not once the scanner that is being produced in the workshop, duly mounted and assembled, available for operation, executes its duty in use. Referring to
FIG. 1
, a side view of a process-in-action of focal adjustment with the Test Chart being supported by two Holders, pursuant to a prior art, more specifically, it is seen that the Test Chart
10
is supported on both sides below, either side on a holder
11
which in turn bears against a scanning bearing face
12
, of light permeable substance, down said scanning bearing face
12
are provided, on suitable locations; one or more reflector
21
, one lens
22
and one video sensor
23
(CCD), in the focusing procedure as executed conventionally, a Test Chart
10
is set on the upper surface of the scanning bearing surface
12
, and, following a scanning test run with a Video Detector
23
, the holder
11
will be replaced with one which stands higher one by one continually, with the result in each execution recorded on completion of scanning performed with the Video Sensor
23
, so as to draw a Distribution Curve of the Modulation Transfer Function, MTF, in the long run.
With the framework and methodology used to test the Modulation Transfer Function, MTF, in a conventional production procedure, summarized in the foregoing, it is a pity to note that in productive adjusting and testing procedures using a scanner, constrained by the fact that the height of each supporting holder is fixed, only one unique, acceptable Modulation Transfer Function, MTF, can be achieved, and that is by far not the optimum accurate value, moreover, with a conventional approach, whatever the art, multiple runs must be made in view of replacements of precision holders of different heights, if only it matters to obtain different Modulation Transfer Function, MTF, and that will cost much precious time while there is still a long way to go arriving at a linear distribution curve of the MTFs, and that is awfully disadvantageous in so far as judgment on focal adjustment in a production procedure is concerned, and there lies a target demanding immediate improvement for professionals engaged in the art.
The Method to adjust the Modulation Transfer Function, MTF, of a Sensing System, as taught according to the invention is aimed at achieving predetermined adjustment of the ranging of Modulation Transfer Function, MTF, in a single execution, thus eradicating once for all, the complicated procedures in previous arts which were common in that, throughout the procedure of adjustment of Modulation Transfer Function, the value obtained as the outcome of the adjustment makes but for a specific point in the ranging of acceptable MTF, there being no assuring as to whether the ranging of the adjustment lies within a predetermined and accepted limit, so the invention is introduced to bring the value of the MTF within an acceptable ranging, the method being controllable, thanks to the creation of Test Charts designed for that MTF ranging and the novel design of Testing Instruments covered under the invention; while on the other hand, as ordinarily a scanner must be matched with a machine console available with permeable light sources, and the focal side for scanning reflection and that for permeation are usually not the same one side, which can often result in a value of reflective Modulation Transfer Function that is accepted not being acceptable to the Permeation Modulation Transfer Function, and that is due to the fact that the ranging acceptable respecting the Modulating Transfer Function has come to an extent smaller than Reflection/Permeation Side by side Differential compounded by the inability to control the ranging while the adjustment is in progress, in view of such problems the invention provides a method to adjust the Ranging of the Modulation Transfer Function, MTF, of a Sensing System.
SUMMARY OF THE INVENTION
As a method to adjust the ranging of the Modulation Transfer Function of a Sensing System, the invention serves to prepare the Test Chart to test the Modulation Transfer Function, MTF, for a standard value, on different resolution parameters, next, testing conditions such as location of the Test Chart, Density of the Line Pair are changed to obtain Modulation Transfer Functions per positions differing in picture depth, in order for the Modulation Transfer Functions thus realized to comply with standard product specifications.
Technically, the principle of operation of the invention is that an incident light beam, on passage through a dielectric in an ambience of air, will incur a focal displacement, so by the intervention of a dielectric in an optic path followed by varying the thickness, location of the dielectric, it is possible to detect a Modulation Transfer Function, MTF.
For a preferred execution, have the machine console of a scanner laid on the Modulation Platform, as pursuant to the invention, run an analysis using computer data to pass an adjudgement as to whether an adjustment to an optimum setting for the ranging of Modulation Transfer Function has been reached, in the negative case run a successive scanning test by means of a simple control system, until a controllable range of Modulation Transfer Function is obtained.
For still another preferred execution, let the position of the focus be changed by taking into account differences in deflection rates, of given dielectrics, such as: thick glass, plasticized resin, etc., to incident beams, concurrently with Test Chart for MTF for Libe Pair, laid on different positions, so as to obtain an optimum ranging for Modulation Transfer Function.
For still another preferred execution, by the size of the Line Pair on the Test Chart, determine an optimum value for the Modulation Transfer Function and the Ranging acceptable for the product, so as to obtain an optimum ranging of Modulation Transfer Function.
Once applied, the invention Method to adjust the Ranging of the M
Huang Chih-Wen
Huang Yin-Chun
Pham Hoa Q.
Umax Data Systems Inc.
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