JPS62249135A - Negative and positive recognizing method for microfilm - Google Patents

Abstract

PURPOSE:To eliminate an error in recognition without being affected by the density variation of a microfilm nor variation in the quantity of image light by calculating the appearance frequency distribution of output levels corresponding to the quantities of transmitted light in respective plurally divided areas of the microfilm. CONSTITUTION:A scanning mirror and optical sensors S1-Sn on a sensor base are exposed to an image on the microfilm by scanning and then image illuminance data obtained by the sensors S1-Sn are passed through an A/D converter 17, and stored in a RAM 19 at prescribed time intervals and at right angles to the axial direction through the microcomputer or divided by arrangement intervals of the sensors S1-Sn and digitized in the axial direction. The illuminance data on the microfilm which is written in the RAM 19 is read out to calculate the output level appearance frequency distribution of respective plurally divided areas of the microfilm by the computer 18. Then, it is decided that the film is a positive from the low illuminance of a character part, etc., and it is also decided similarly that the film is a negative.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for recognizing negative and positive microfilms.

(Prior Art) As is well known, there are two types of microfilms: negative images and positive images.

If you want to always print out positive images with a reader printer, you must change the printing process depending on whether the image on the microfilm is negative or positive. The user has to do this by looking at the film, which hinders labor-saving.

Conventionally, the following methods have been used to solve this problem. In other words, the image of microfilm Fh @f
As shown in Figures 4 and 5, in most cases, a positive image has a large amount of light passing through it, while a negative image has a small amount of light passing through it.Therefore, the amount of light transmitted through the microfilm F is detected by a light detection element. Then, it is determined whether the microfilm is a positive film or a negative film depending on whether the sum of the detected values is larger or smaller than a certain value, that is, whether the microfilm has many parts that transmit light or many parts that block light. That is, if the sum of the light sparrow detection values is larger than a certain value, it is recognized as a positive film, and if it is smaller, it is recognized as a negative film.

(9, Problems that Ming attempts to solve) However, in the case of such conventional technology, the density of the image on the microfilm differs significantly from the standard, and the size of the printed image changes, so the projection When changing lenses,
There is a problem that erroneous recognition occurs. That is, for example,
For negative films with a low density, the total value of illuminance data is too high and it is mistakenly recognized as a positive film.On the other hand, for positive films with a low density, the total value of illuminance data is small and it is mistakenly recognized as a negative film. There may be cases where this is mistakenly recognized. On the other hand, when the projection lens is changed, the optical hardness of the image light that projects the image on the microfilm changes accordingly, causing the same erroneous recognition as described above.

Therefore, the present invention has been made to solve the problems of the prior art described in L.The purpose of the present invention is to solve the problems of the prior art as described in L. light! To provide a method for recognizing negative and positive microfilms that does not cause erroneous recognition even when the film itself changes over a wide range.

(Means for Solving the Problems) In order to solve the problems described in 1-1, the present invention divides the microfilm image into a plurality of regions, and the transmitted light of each region is divided into several regions. Detected by light detection, font, f-.

The light detection is configured to calculate 4J of the frequency of appearance of the output level of f-, and then recognize whether the image on the microfilm is a negative image or a positive image based on the frequency distribution of appearance. There is.

(Example) The present invention will now be explained based on the illustrated embodiments.

FIG. 1 shows a microfilm printer to which a method for recognizing negatives and positives of microfilm related to JI can be applied. In FIG. 1, F is a microfilm as an information recording medium, l is a projection lamp, 2 and 3 are scanning mirrors arranged at 90°, 4 is a photosensitive tram as an image recording medium, 5 is a sensor base disposed on the L side of the photosensitive drum 4 and has a slit 6 along the axial direction; 7 is a primary charger; 8a is a negative/positive reversal developing device; 8b is a positive/positive non-reversing developing device; 9 is a transfer charger, 1
0 is a fixing device.

Therefore, the images on the microfilms F and h can be obtained by moving the scanning mirror 2.3 in the direction of the arrow to move the optical sensor from a to l) with respect to the image f on the microfilm F as shown in FIG. As shown in FIG. 4 or FIG. 5, a positive image f or a negative image f of the microfilm F is scanned by optical sensors 31 to Sn, which will be described later, and is sequentially scanned and exposed onto the photosensitive drum 4. ,
An image is recorded on the reversible material P by one step of the well-known electrophotographic method.

The sensor base 5 is provided with a slit 6 along the axial direction of the photosensitive drum 4, as shown in FIG. Sensors 5l-sn are fixed at predetermined intervals.

FIG. 5 is a block diagram showing a control system. In FIG.
19 is a RAM, and 20 is an image forming section that performs switching control of the developing devices 8a and 8b.

In the configuration described above, in the microfilm negative/positive recognition method according to this embodiment, the microfilm negative/positive recognition is performed in the following manner. That is, prior to exposing the image to the photosensitive drum 4, the scanning mirror 2.3 is pre-scanned, and the image on the microfilm F is scanned and exposed to the optical sensors 31 to So of the sensor base 5k. The image illuminance data detected by the optical sensors S1 to SO during this image scanning is digitized by the A/D converter 17 and then read into the microcomputer 18. Microcomputer 18 stores this data in RAM 19. That is, the image on the microfilm is divided at predetermined time intervals in the direction perpendicular to the axial direction of the photosensitive drum, and according to the arrangement interval of the optical sensors 51 to Sn in the axial direction of the photosensitive drum, and the illuminance of the image in each area is sequentially divided. The microcomputer 18 calculates the appearance frequency distribution (hereinafter referred to as a histogram) of the illuminance data according to the flowchart shown in FIG. 7, which is digitized and stored. That is, one piece of illuminance data is fetched from the RAM 19, and the counter for the number of times the illuminance value appears is incremented by one. This is done for all the illuminance data, and the histogram obtained in this way is shown in FIG. 9 or 10. FIG. 9 shows the case of negative film, and FIG. 1O shows the case of positive film. In the case of microfilm, the histogram h indicates the frequency of the ground part of the subject manuscript,
Two peaks appear depending on the frequency of parts such as letters. When looking at the image of the microfilm F, it can be seen that the area of the ground part of the subject document is larger than the text part, as shown in FIG. 4 or 5. Therefore,
When creating a histogram of illuminance data, in the case of positive film, the illuminance of the background area is higher than that of text (illuminance shown by C in Figure 1Theta), and its appearance frequency (Frequency D in Figure 1Theta) Also, the illuminance of a single character is lower than that of the ground (illuminance E in Figure 1O), and its appearance P! (Power PPK in Figure 1O) is also lower than the background area. Conversely, in the case of negative film, the illuminance of the background area (illuminance C in Figure 9) is lower than the text, etc. , its appearance degree a (frequency D in Figure 9) is higher than that of characters, etc., and the illuminance of parts such as characters (illuminance E in Figure 9) is higher than that of the ground; Frequency (9th
NPK in the figure) is lower than the ground part.

Based on these, the microcomputer 18
Recognize the negatives and positives of the microfilm according to the flowchart shown in the figure. First, find the illuminance that appears most frequently in the histogram L (step), that is,
Find the 0 point in Figure 9 or Figure 1θ. As mentioned above, this is the zero-order illuminance of the ground part of the document, and the value of C above.
Constant Δ2.

By adding Δ4 and subtracting the constants Δ1 and Δ3, the illumination ranges N-AREA and P-AR that can be taken by the character part are determined.
Find EA (gtep2), then the above P-AR
Find the peak of the histogram within the range of EA, that is, the PPK point in Figure 9 or Figure 10 (step 3), and roughly find the peak of the histogram within the range of N-AREA, that is, the PPK point in Figure 9 or Figure 1θ. Find the NPK point (gtep4
) Next, compare the values of these PPK points and NPK points (step 5). If PPK>NPK, the microfilm F is recognized as a positive film, and PPK<
If it is NPK, microfilm F is recognized as a negative film. If the microfilm F is a positive film, positive-positive non-reversal printing is performed (step 6), and if it is a negative film, negative-positive reversal printing is performed (step 7).

That is, as shown in FIG. 12, the photosensitive drum 4 is -
The photosensitive drum 4 is uniformly positively charged by the charger 7.
The surface potential of becomes the dark potential ILo.After that, when the image of the microfilm F is exposed on the photosensitive drum 4,
As shown in FIG. 11, the surface potential of the exposed area becomes the bright area potential ILL and an electrostatic latent image is formed. If it is recognized that this is the case, the positive/non-reversing developing device 8b is moved to a position close to the photosensitive drum 4 by a driving stage R (not shown). Since the negatively charged toner NT is attached to the surface of the developing sleeve SL of the developing device 8b, the negatively charged toner NT is statically deposited on a portion of the surface of the photosensitive drum 4 which has a higher potential fLd than the developing sleeve SL. It is attached by electric power and a non-reversal image is developed with respect to the exposed image. Also, if the image on microfilm F is recognized as a negative film,
A developing device 8a for negative-positive reversal is moved to a position close to the photosensitive drum 4 by a drive stage (not shown). Since the positively charged toner FT is attached to the surface of the developing sleeve SL of the developing device 8a, the lE? fF electric toner F
T is attached by electrostatic force to a portion of the surface of the photosensitive drum 4 that has a lower potential RL than the developing sleeve SL, and an image that is inverse to the exposed image is developed.

The image developed in this way is transferred to the transfer paper PL by the transfer charger 9, and the transferred image is fixed onto the transfer paper Ph by the fixing device 10 and is discharged.

In this example, even if the density of the image differs greatly depending on the microfilm, or if the brightness of the image changes significantly due to lens replacement, it is possible to
Since the histogram shown in FIG. 0 only shifts along the illuminance axis direction and the shape of the histogram does not change, erroneous recognition does not occur.

In addition, as mentioned above, depending on whether the microfilm is a negative film or a positive film, the developing device is visually selected and a positive image is always output. images will not be printed.

In the illustrated embodiment, the developing device is switched based on the negative and positive recognition results. The amount of light, etc. may also be controlled.

Further, in the illustrated embodiment, a case has been described in which the present invention is applied to a device that prints images on microfilm, but it can also be applied to a facsimile or the like that transmits portraits on microfilm.

(Effect of one shot force) The present invention consists of the following structure and operation.

Great for e-filtering microfilm images and replacing lenses.
Even if the light fi of the image light changes over a wide range, erroneous recognition can be reliably prevented.

[Brief explanation of drawings]

Fig. 1fA is a schematic configuration diagram showing one embodiment of the information recording device of the present invention, and Fig. 2 is a schematic diagram showing the scanning state of the optical sensor.
Figure J1 and Figure 3 are perspective views showing the main parts of Figure 1, Figures 4 and 5 are top views showing positive images and negative images respectively, Figure 6 is a block diagram showing the control system, Figure 7 8 and 8 are flowcharts showing the operation of the control system, and FIGS. 9 and 10.
FIG. 11 is a graph showing a histogram, FIG. 11 is a graph showing the upper surface of the photosensitive drum, and FIG. 12 is an explanatory diagram showing the photosensitive drum and the developing device. Explanation of symbols 11 F... Microfilm 51 to Sn... Optical sensor - 18... Microcomputer Patent applicant Canon Corporation, - Figure 1 Figure 2 Figure 4 Figure 5 Figure 6 7 figure 91 concave f envy 1 piece 10th snake

Claims (1)

[Claims] The image of the microfilm is divided into a plurality of regions, the amount of transmitted light in each region is detected by a photodetection element, and the appearance frequency distribution of the output level of the photodetection element is calculated. A method for recognizing negative and positive microfilms, the method comprising recognizing whether an image is a negative image or a positive image.