JPS625768A - Film exposure device - Google Patents

Abstract

PURPOSE:To keep a picture on a film to certainly by exposed at a regular exposure position by detecting a picture position on a microfilm using the data distribution of a histogram prepared to decide the threshold for the binary- coding of a picture signal. CONSTITUTION:The picture signal from an image sensor 2 is AD-converted at an AD converter 3 and a peak value is calculated at a peak value detector 4 and a base density detector 14 generates an envelope of low level from a digital picture signal. A CPU10 compares a difference (b) between the maximum value A of a base density histogram and the maximum value at the bright level side of a peak value histogram with a constant (a) regulated in advance, and when (b)<(a), it decides that the picture image is not located at a regular reading position and outputs a picture absence alarm signal and lightens a display device 17. When (b)>(a), the CPU calculates and outputs a density indication value to decide the threshold value and generates the threshold value for the binary-coding on the digital picture signal at a comparator 12 and outputs it to a printer or a CRT.

Description

[Detailed Description of the Invention] [Technical Field] The present invention electrically reads an image recorded on a film such as a microfilm, and transmits the read image information to an image processing section of a laser beam printer, an inkjet printer, etc. The present invention relates to a film exposure device used in an output film image reading device or the like.

[Prior art]

2. Description of the Related Art Conventionally, there has been known an apparatus that records a large amount of information such as documents at a high density on microfilm, reads recorded images on the microfilm each time as necessary, and prints out images in a predetermined size.

In particular, as an image reproducing device that is capable of image information processing such as electronic transmission and editing of image information, it reads images recorded on microfilm using an image sensor such as COD,
A device is known that outputs the read information to a printer or the like that converts the image into a visible image on recording paper.

Conventionally, with this type of device, a person had to monitor the screen and read the microfilm while checking whether the frames on the film were projected in the correct position.

If this is not done, non-image areas between frames of the film may be read.

〔the purpose〕

The present invention has been made in view of the above points.

It is an object of the present invention to provide a film exposure device in which an image on a film to be exposed is reliably exposed at a regular exposure position.

〔Example〕

Hereinafter, the present invention will be explained in detail using preferred embodiments.

FIG. 1 is a schematic configuration diagram of an image reading device to which the unreleased 1-1 is applied.

In the figure, frames 41a and 41b of film F are
It is illuminated by light emitted from a halogen lamp 42 and condensed by a condensing lens 43. Each image of the frames 41a and 41b of the film F illuminated in this way is transmitted to C through an optical system consisting of an imaging lens 44 and a fixed mirror 45.
An image is formed on the scanning surface of a one-dimensional line sensor 46 composed of an 0D (fi coupling element) or the like. This one-dimensional line sensor 46 is fixed to a carriage 49 that can reciprocate while being guided by a pair of parallel guides 47 and 48. Further, since the carriage 49 is fixed to a wire 50 that makes the rotation from the motor 11 a linear motion, the one-dimensional line sensor 4 is driven by the motor 51.
6 moves in the sub-scanning direction substantially perpendicular to the main-scanning direction. As a result, images on the microfilm are sequentially read fin by fin.

On the folded body side, there is a front panel that detects the start of reading scan)
・The interrupter 53 is arranged, and the carriage 49
When the light shielding plate 44 fixed to the carriage 49 blocks the light from the photointerrupter 53 as the carriage 49 moves, the photointerrupter 53 generates a read scan start timing signal.

On the other hand, a switching mirror 55 is arranged between the imaging lens 44 and the fixed mirror 45.
The images a and 41b are also enlarged and formed on a screen 57 as a display means via a switching mirror 55, a projection lens 56, and the like. On this screen 57, a reading frame (■) for a half-size image and a reading frame (2) for a full-size image are printed, respectively. If the recording paper set in a laser beam printer (not shown) is vertically long, the half-size area surrounded by the reading frame ■ is read and output to the laser beam printer; For example, a full-size area surrounded by a reading frame (■) is read and output to a laser beam printer.

FIG. 2 shows a block diagram of a circuit that processes the output of the image sensor.

(2) is a lamp that is a light source for exposing the microfilm; (2) is a one-dimensional line image sensor such as a COD that reads an image using a light image transmitted through the microfilm; (3) is an analog image output by image sensor 2; An AD converter converts the signal into a digital image signal representing the density of each pixel; 4 is a circuit that detects peak values from sequentially input digital image signals; 5 is a circuit that divides each unit pixel, that is, main scanning into a plurality of blocks; , a block setting circuit that resets the peak detection circuit so as to detect the peak value of each block shift, 6 counts the main scanning synchronization signal synchronized with each main scanning of the image sensor 2, and sets the sub-scanning based on the count value. A line address setting circuit 7 for limiting the range of peak value data acquisition in the direction is cleared to each line frame rH by the main scanning synchronization signal, counts the reset signal from the block setting circuit 5, and based on the count value Block address setting circuit for limiting the peak value data acquisition range in the scanning direction, 8
is a gate circuit that outputs peak value data within a required range as a valid peak value in accordance with range limiting signals from the line address setting circuit 6 and block address setting circuit 7.

FIG. 3 shows this line address setting circuit 6. A state in which the capture range of peak value data is limited using the block address setting circuit 7 and the gate circuit 8 is shown. 31 is the entire reading range of the image sensor 2 in one reading operation. now,
The CPU 10 sets the start point statement and end point statement 7 of the sub-scanning direction range in the line address setting circuit 6, and sets the start point b2 and end point b2 of the -L scanning direction range in the block address setting circuit 7, respectively. That is, the desired range 32 surrounded by the dotted line is now set by the CPU 10 as the input range of the peak value data.

When the image sensor 2 starts reading for peak value detection, a reset signal indicating a dividing position at which the main scanning direction is divided into a plurality of blocks is input to the block address setting circuit 7 from the block setting circuit 5. Then, the block address setting circuit 7 counts this set signal,
When the count value reaches b2, the main scanning range limiting signal BA is set to high level, and when the count value reaches b2, the main scanning range limiting signal BA is set to low level.

Therefore, the main scanning range limiting signal BA becomes high level during the period of the range i to b2 in the main scanning direction set by the CPU10. Note that the count value of the block address setting circuit 7 is cleared by the main scanning synchronization signal for each main scanning of the image sensor 2, so the counting operation of the reset signal described above is performed for each main scanning iσ, and all main scanning In the same period, the main scanning range limiting signal BA becomes high level.

On the other hand, the line address setting circuit 6 counts the main scanning synchronizing signal from the start of reading by the image sensor 2, and when the count value reaches 4ul, the sub-scanning range limiting signal LA
is set to high level, and when it becomes 2, the sub-scanning range limiting signal LA is set to low level. Therefore, the range in the sub-scanning direction set by CPU10! Q1~! ; During the period of 12, the sub-scanning range limiting signal LA becomes high level.

In this way, the line address setting circuit 6 and the block address setting circuit 7 each output a high-level range limiting signal over the range set by the CPU10. Therefore, the period during which both of these two range-limiting signals are at high level corresponds to the peak value acquisition range shown by the dotted line in FIG.

Then, the peak value input to the gate circuit 8 during this period is made valid.

The reason for limiting the capture range of peak values in this way is that the size or position of images recorded on microfilm etc. is not necessarily constant, and the peak values obtained from the entire reading range of the image sensor 2 are other than images. (for example, the base), and contains peaks that cannot be said to be accurate image peaks. Therefore, a predetermined range within which an image will necessarily exist within the reading range of the image sensor 2 is defined, and only peak values from this predetermined range are treated as valid. This makes it possible to reliably obtain the peak value of the image.

9 is a latch for reading peak value data into CPU10; 14 is a base density detection circuit that detects the base density of the microfilm from the output of AD converter 3; 15 is a latch for reading base density data into CPU 10;
0 is a CPU that takes in peak value data and base density data, analyzes them, calculates and outputs an appropriate density instruction value used for binarizing the image signal, and 11 controls the timing of each circuit block. Should I output clock control circuit 12 to a printer, etc. to create a lock? A comparator 13 compares the digital image signal from the AD converter 3 with a threshold value to generate a value image signal, and a comparator 13 adds the density instruction value output from the CPU 10 to the base density and compares it with the digital image signal in the comparator 12. An adder 16 is a lamp light amount control circuit that controls energization of the lamp 1 according to a command from the CPU10.

Further, 17 is a display device for indicating to the operator that the image to be read is not at the normal reading position.

First, automatic concentration setting in this circuit configuration will be described. The analog image signal output from the image sensor 2 according to the clock from the clock control circuit 11 is AD converted by the AD converter 3.

For this digital image signal, the peak value of the image signal in each unit block is determined for each predetermined pixel unit in a peak value detection circuit 4. From the plurality of peak value data thus detected for each block, only the peak value data within the data extraction image area is extracted by the gate circuit 8 as described above, and read into the CPU10.

On the other hand, the base density creates a low level envelope from the digital image signal from the AD converter 3. This value corresponds to the base density, and this value represents the image signal level of the area on the microfilm where there is no image information. The base concentration detection circuit 14 is a negative peak hold circuit with a relatively slow response. CPU10 analyzes the occurrence frequency of peak value days and evenings and base concentration data, and determines the concentration indicator value at an appropriate position between the peak value and base concentration value, for example, so that the dark value is in the center of the peak value and base concentration. It is calculated and output to the adder 13.

The adder 13 adds the density instruction value to the base density data to create a darkness value for binarization. Thereafter, the image of the same microfilm is read again as an image by the sensor 2, and using this threshold value, the digital image signal from the AD converter 3 is binarized by the comparator 12. This binary signal is output to a printer, memory, or CRT. In this way, depending on the base density of the microfilm and the recorded image density? Since the threshold value for value conversion is determined, the
A value conversion operation is performed.

Next, the detection of the position of the film image in the circuit configuration shown in FIG. 2 will be described. FIG. 5 shows the operating procedure of this circuit. The procedure shown in FIG. 5 is preprogrammed in the CPU 10. First, the image sensor starts reading for peak value detection, and the CPU 10 takes in a plurality of base density data and peak value data and creates a histogram.

Graphs (1), (2), and (3) in FIG. 4 show examples in which the histograms obtained when negative film is read are compared between normal times and when no images are taken. Figure 4 (1
) indicates that the image to be read is normally located at the normal reading position, while (2) in Figure 4 indicates that the microfilm is not loaded in the device or that the film is loaded but the image is located at the reading position. If not, and light passes through,
FIG. 4 (°3) shows histograms when the film is loaded but there is no image at the reading position and the image is solid black.

In FIG. 4(1), the center position of the maximum value of the base density histogram during normal operation is A, and the center position of the maximum value on the right side (friend level side) of the peak value histogram is B. Then, as b=B-A, this b represents the contrast inherent in the image. The contrast b of a normal image has a sufficient length.

Next, in Figure 4 (2), when the film is not loaded, or even when it is loaded, there is no image at the reading position and light passes through it, that is, for example, when reading the league part or trailer part of the roll film. As shown in the figure, the maximum values in both graphs have moved to the right (bright level). What is important here is that the value of b is extremely small.

Next, in FIG. 4(2), when the film is loaded but there is no image and the image is solid black, the maximum values of both graphs move to the left (dark level) as shown in the figure. And here too b
The value of becomes extremely small.

In other words, when there is no image information (cases (2) and (3)), the contrast b appearing in this histogram will be small in either case, so a no-image warning signal should be output when b is smaller than a certain value. Bye.

Therefore, the maximum value A of the base density histogram and the maximum value B on the light level side of the peak value histogram are determined, and the difference between them is compared with a predetermined constant a. And b<
In case a, it is determined that the image is not at the normal reading position,
Outputs a no-image warning signal and lights up the display 17,
Display this to the operator. Further, reading or printing may be stopped by this no-image warning signal, or if this microfilm reader is used as an online terminal, the signal may be sent to a host computer.

On the other hand, if b>a, it is determined that the image to be read on the microfilm is at the normal reading position, and the density indication value for determining the threshold value is calculated from the detected peak value and base density histogram as described above. The image sensor 2 executes the reading operation again, and the read image signal is binarized using the threshold determined as described above.

As described above, the image position on the microfilm is also detected based on the data distribution of the histogram created for determining the threshold value for binarizing the image signal.

In addition, taking into consideration statistical errors and non-uniformity of the light intensity of the lamp,
This is to increase or decrease the constant a, which is a criterion for determining the presence or absence of an image.

In addition, in this embodiment, an example of reading a negative film was explained, but even in the case of a positive film, a normal histogram has almost the same shape, and the image position can be detected using the same procedure. can be done.

As explained above, it is possible to simultaneously determine whether or not an image is at the reading position in a microfilm reading device, and it is also possible to determine whether there is an abnormality before actually reading the image on the film, thereby eliminating unnecessary image reading. It can be prevented. Furthermore, since abnormality is determined using the output of the image sensor for reading one image, there is no need to provide a sensor or the like exclusively for abnormality determination.

Furthermore, since the image position can be determined not only by the sensor but also by the histogram formed for determining the threshold value for binarization, there is no need to provide a dedicated circuit configuration for abnormality determination.

Although this embodiment has been described using microfilm reading as an example, the present invention can also be applied to an exposure device of a reading device for other films such as 35 mm film.

〔effect〕

As described above, according to the present invention, it is possible to effectively and reliably determine the position of an image exposed by a light source. Therefore, when used to determine an abnormality in the film exposure light source at the image position of the film, it is possible to prevent unnecessary film reading.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of a microfilm reading device to which the present invention is applied, FIG. 2 is a block diagram showing an example of an image signal processing circuit, and FIG. 3 is a diagram showing a peak value detection range.
FIG. 4 is a diagram showing an example of a histogram, and FIG. 5 is a flowchart diagram showing a processing procedure, in which 1 is a lamp, 2 is an image sensor, 4 is a peak value detection circuit, 10 is a CPU, 1
4 is a base concentration detection circuit.

Claims (4)

[Claims] (1) A light source for exposing the film, a first detection means for detecting the base density of the film using the transmitted light from the film exposed by the light source, and a second detection means for detecting the image density using the transmitted light. and means for determining an image position on the film based on the detection outputs of the first detection means and the second detection means. (2) Claim (1) further comprises an image sensor that reads an image using the transmitted light;
A film exposure apparatus characterized in that the second detection means detects the base density and the image density, respectively, based on the output of the image sensor. (3) The film exposure apparatus according to claim (1), wherein the second detection means detects the image density based on the peak value of the image. (4) In claim (2), the above-mentioned first,
A film exposure apparatus comprising means for determining a threshold value for binarizing the output of the image sensor based on the detection output of the second detection means.