JPS58106945A - Mtf measuring system for optical reader - Google Patents

Abstract

PURPOSE:To obtain easily and surely MTF in the subscanning direction, by storing only a picture signal corresponding to a line pattern in a waveform storing circuit in the optical reader which reads line patterns. CONSTITUTION:A picture signal is sampled after a required time from the start time of main scanning A, and detected data is stored in a memory 8. This operation is repeated for every scanning; and when the number of times of scanning reaches a prescribed value, the data waveform stored in the memory 8 is reproduced, and this waveform becomes a waveform obtained by reading a sampling line 5 in the subscanning direction B, and thus, MTF is calculated easily.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention is an optical reading device that changes the linear density and is suitable for one-shot feeding force, which is useful for evaluating resolution with an optical reading device that accommodates round wire and cutout.
#1 Includes things related to fixed methods.

(2) Same points as the conventional technology Conventionally, when evaluating the resolution of an optical reading 4L device, MTI
'C modulation 1/transfer 7a/comb 1no) is used. As shown in the first id (a), the line density t
o The changing pattern 1 is printed and the date 2 is read by the optical system and the reading mechanism 3 consisting of various elements p1 The output artist signal 4 is read by an oscilloscope etc. side. In this case, 111Iv! As the 1 degree increases, it is detected, and as the 9 amplitude gradually decreases, a tumor is sure to occur.

The ratio of this amplitude to the standard amplitude is expressed as nMTF.

In other words, if the line butter 71 includes a sufficiently small - one-dense storm line butter 721 and a large line density *0* pattern 22, as shown in Figure 1s1), 11g1 with a large amount of detection
One signal OSm is obtained by the following equation, MTF/Ii and MTF/Ii, respectively.

MTF depth M/his (same-false) Main scanning direction MTF in the main scanning direction of the optical aS
get.

However, the MTF in the sub-scanning direction (@t) perpendicular to the main-scanning direction (2) shown in 2nd #A) is also important as 011 when evaluating the resolution ability of the eccentric position. In this case, chart 2 is set at right angles to the case of H1wJ(a),
Ill1l image signal corresponding to Nampling Twin 5
There must be. However, the optical reading device is basically only capable of one-dimensional OM reading in the main scanning direction, and the image signals that can be read on the side with an oscilloscope etc. are the waveforms shown in (Oka Akebono). , @i.e. pattern 21. That interval, the portion 1. corresponding to the sampler twin 5 for that of the pattern 22. M1゜As we are meeting. However, if things continued as they were, calculating MTF (D) would be extremely difficult.

(3) Purpose of the Invention The purpose of the present invention is to
The method of determining koji easily and reliably is to prepare it.

(4) Structure of the invention m1 purpose 2! ! The MTFllj foot method of the optical reading device of the present invention has changed the pattern from the optical system and the optical reading element. In an optical reading device that performs rounding to measure MTF curvature in a sub-scanning direction perpendicular to the main scanning, sampling of the l1ii image signal is performed after a predetermined time from the beginning of the main scanning, and the composition data is stored in a memory. is repeated once for each main scan f, and at 9 o'clock for a predetermined number of scans, it is stored in the memory, the 9-dimensional wave f# is reproduced, and the MTF is calculated from the cough waveform. There are mountains.

(From @O Example FIG. 5 is a configuration diagram @J4 diagram of an embodiment of the present invention.

In the same figure, the reading mechanism is a CCD (charge coupled device) image sensor, etc.). A scanning clock generation circuit 52 supplies a scanning qts3 and an i*clock start signal 6 to this. It is composed of a and a cylinder 34. The outputs from the reading mechanism 5 are the image signal 4 and the 11111L start compensation signal 6, the image signal 4 is input to the waveform storage circuit 8, and the a filling start signal 6 is input to the sampling pulse generation path 7. The output of the sampling pulse generation circuit 7, the t pre/g pulse 10, is input to the liquid S memory path 8.
The output 15 of the waveform storage circuit 8 is displayed on a display section 9 for binding the waveform I1.

With this configuration, MTFta5 of direct composter w50 thinning direction■
i! Consider a case where As shown in chart 2 for goose measurement, sampling line 5 and main scanning direction 00 waterfall scanning 1
Image signal 4 is read by reading element 31 while moving oxygen and chart 2 in the sub-scanning direction @4CIIjJ so that 825 is at right angle.
m1ii.

Figures 1114) to 1114) A waveform diagram of an example of Ko II Figure 3.

#A (a) shows the O image signal 4 from the reading element 61. This waveform includes a signal A corresponding to the image on the line pattern on the sampling line 5. A pulse (in the figure) is outputted from the running clock generating circuit 62 as the starting signal 6. The pulse shown in FIG. 3(b) indicates that the reading confectionery 31 is d! This represents the point in time when the end point 24 of the bank scan [23] was cut off. In response to this pulse, the sampling pulse generation circuit 7 generates a delayed pulse as shown in FIG. 2(c). The pulse ring T of this fly pulse is set to open when the wire rod 5 scans the end point 24 of the gun retrieval distance [23] to the intersection with the bring line 5. As a method for generating this -IIA extended pulse, a so-called monostable multivibrator or the like is suitable. The sampling pulse generating circuit 7 further generates the sampling pulse 10 shown in FIG. 1IiJ (d) at the falling edge of the delayed pulse. This sampling pulse 10 makes it possible for the waveform storage circuit wI&8 to sample and store the -image symbol 4t in the figure (&). When this image is returned once while moving the chart 2 in the sub-scanning direction (2), the 1lii images on the Templing line 5 are sequentially converted and stored in the waveform trace 8. After all the steps (m-take of the cheat butter y1) are completed, the contents stored in the waveform memory path 8 are reproduced and the waveform is displayed on the display section 9, so that a waveform as shown in mstm is obtained. This is a waveform obtained by cutting the sampling line 5 in one scanning direction (2). Therefore, this wave f#O warehouse.

M') Just like the above-mentioned MTF in the main scanning direction, fj
I4 scanning direction (it is slow due to DMTFt calculation).

``'II''W In the above example, /Pling is running f:1i11111
1 to 9 is monostable! On the other hand, as another embodiment of the present invention, in the figure twin senna 31tJ@-9 line taking mechanism 5, this/plinder tvjA body is constructed using a CCD. In addition to y*yt, it is also possible to count the 17Ii dual-purpose clock signal for a predetermined period of time.

FIG. 16 is a waveform diagram of an embodiment of Hirofu Invention O and others.

piii-false line image value], which is output in synchronization with the clock signal 33 of the same figure). Then, when the clock signal 35 is counted from the scanning start signal 6 in the same figure (-) and reaches a certain number, the figure corresponding to the input point of the ll1i image signal is counted (
Output the sampling pulse 10 of d).

FIG. 7 is an explanatory diagram of the main part of the other embodiment described above.

In the same figure, a sampling pulse generation circuit 7iC counter 71t- is provided, and the initial 1st shift is set at the terminal 72.
Counts down from the running f open #* number 6 using the clock signal 63, and emits a sampling pulse 10 to the # that reaches 0.
jLS let. Although the size of the kakunta 71 needs to be p larger than the number of pixels in one line, this embodiment has the advantage that the sampling timing can be set easily and reliably.

(＠11iO effect As explained above, according to the present invention, since it is difficult to store only the image signal corresponding to the line pattern in the waveform memory 1&!l path, the MTF in the sub-travel direction By simply determining , it is possible to easily and quickly evaluate the resolution of an optical locking device.

[Brief explanation of drawings]

$11ii1(#), 佽), 萖2图false), 佽) are enlarged waveform diagrams of the main scanning embodiment. Figure 117 is an explanatory diagram of the main part O configuration of the same embodiment. In Figure 6p1, 1 is line turn, 2
Hiro chart, 5 is am mechanism, 5 is sampling line,
7 wires/pulling pulse generation circuit, 8 is wave f#1 memory fj
Route A, 9 indicates an oscilloscope. License applicant: Fujitsu Limited 1st generation 1 person: 1) Yoshishige Saka Figure 1 Figure 2 Figure 3 Figure 4 Pulse 10

Claims (1)

[Claims] (t) An optical thread that performs filling in the main scanning direction in the -dimensional direction by a reading mechanism consisting of an optical system and an optical thread by changing *IIIJ [9-patterns] In the device i, rounding is performed to measure the MTF characteristics in the sub-scanning direction orthogonal to the main-scanning, and the main-scanning! After a predetermined period of time from time s#, the image signal is sampled and the detected data is stored in the memory for each main scan, and when the predetermined number of scans has been reached, the data waveform stored in the memory is , and from the scissors waveform M
Optics 11 to calculate TF and Vce mold! MTF measurement method for J4R. (2) m light distribution, the scanning clock signal twM is applied to the single twin sensor by the above-mentioned sampling;
An MTF' measurement method for an optical reader according to claim 1, wherein the nanopulling pulse is made available to the vendor for a predetermined period of time.