JPS625770A - Image reader - Google Patents

Abstract

PURPOSE:To decide an appropriate light quantity fitted for a film without being influenced by the local soil or flaw of the film and to perform a good reading of an image by detecting transmission light at a non-image area on a film and controlling the light quantity based on a detecting result. CONSTITUTION:In a state that the film is not positioned at a reading position, a lamp 1 is lightened with a reference light quantity and the peak value of the output of a licensor 2 at a peak value detector 4 is calculated, and a histo gram for the peak value is generated and a light quantity level X3 at the point of the maximum frequency is detected. With inserting a film F and setting the empty part of the film to the reading position, the histogram of the peak value of the output of the licensor 2 is generated and X3' is detected. When X3>X3', the light quantity of the lamp is increased at a lamp light quantity control circuit 16, and the light quantity at a time when X3<=X'3 becomes the light quantity possible to perform the reading of high resolution.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an image reading device that exposes a film on which an image is recorded and reads the image using transmitted light of the exposed film.

(Prior Art) Conventionally, a device has been proposed that records a large amount of information such as documents generated at high density on microfilm, and reads the recorded image of the microfilm and records it on recording paper as necessary. There is.

In such a device, the microfilm is exposed to light by a light source, and the brightness and darkness of the light transmitted through the microfilm is determined by COD.
It is detected by an image sensor such as , and output as an electrical image signal.

Therefore, the output image signal is affected by the intensity of the light amount of the light source for exposing the microfilm. Therefore, it is conceivable to control the amount of light so that it is always kept constant. However, the il+ light of the microfilm depends on the base density of the microfilm, and furthermore, the base density of the microfilm varies depending on the type of film, development state, etc. Therefore, it is not possible to ensure good image reading for various films simply by keeping the amount of light constant.

Therefore, it is conceivable to detect the transmitted light i of the film to be read, and increase or decrease the transmitted light quantity so that the transmitted light quantity becomes a desired value, thereby obtaining the optimum transmitted light quantity even if the base density is different. However, there were local stains, scratches, etc. on the film, and when the light amount was controlled based on the light transmitted through that portion, the light amount could not be controlled appropriately.

(, 11) The uninvented invention was made in view of one or more points, and when reading an image recorded on a film such as a microfilm, the amount of light used to expose the film is appropriate, and good image reading is achieved. It is possible. That is, the present invention is an image reading device that exposes a film on which an image is recorded and reads the image using the transmitted light of the exposed film, and detects the transmitted light over a predetermined width of the non-image area of the film,
The present invention provides an image reading device that controls the amount of light for reading one image based on the detection result.

〔Example〕

The present invention will be explained in detail below based on preferred embodiments.

FIG. 1 is a schematic diagram of a microfilm reading device to which the present invention is applied.

In the figure, frames 31a and 31b of film F are
It is illuminated by light emitted from a halogen lamp 32 and focused by a condensing lens 33. Each image of the frames 31a and 31b of the film F thus illuminated is scanned by a one-dimensional licensor 36 composed of a COD (charge coupled device) or the like via an optical system composed of an imaging lens 34 and a fixed mirror 35. Image is formed on a surface. This one-dimensional licensor 36 is fixed to a carriage 39 that can reciprocate while being guided by a pair of parallel guides 37 and 38. Furthermore, since the carriage 39 is fixed to a wire 40 that makes the rotation from the motor 41 a linear motion, the one-dimensional line sensor 36 is driven by the motor 41.
moves in the sub-scanning direction that is direct to the main scanning direction,
Read image information. The image signal obtained by reading the image in this manner is binarized and output.

A photo-interrupter 43 that detects the start of reading scanning is arranged on the main body side of the N-mounter. When a light-shielding plate 44 fixed to the carriage 39 blocks the light from the photo-interrupter 43 as the carriage 39 moves, the photo-interrupter 43 detects the start of reading scanning. Interrupter 43 generates a read scan start timing signal.

On the other hand, a switching mirror 45 is arranged between the imaging lens 34 and the fixed mirror 35, and a switching mirror 45 is arranged between the imaging lens 34 and the fixed mirror 35.
and 4b, the switching mirror 45 and the projection lens 4
The image is also enlarged and formed on a screen 47 as a display means via a display device 6 or the like. On this screen 47, a reading frame 1 for a half-size image and a reading frame 2 for a full-size image are printed.

If the recording paper set in a laser beam printer (not shown) that forms an image on the recording paper using the read image signal is vertically long, the laser beam printer reads the half-size area surrounded by the reading frame 1 and prints the image. output,
On the other hand, if the recording paper is horizontally long, the laser beam printer reads the full size area surrounded by the reading frame 2 and prints it out.

FIG. 2 shows a block diagram of a circuit for setting a threshold value used to binarize the analog image signal of the line sensor.

In this embodiment, the image set at the reading position of the reading device is read twice. Then, the threshold value for binarizing the image signal is determined using the data obtained from the line sensor during the first reading, and the image information output from the line sensor during the second reading is determined using the first reading data. Binarize using the set threshold.

In FIG. 2, reference numeral 1 denotes a lamp, which exposes the object (microfilm) F. Reference numeral 2 denotes a line sensor made of COD or the like, which reads an image of the subject using light transmitted through the microfilm F. The amount of light emitted from the lamp 1 is controlled in accordance with the base density of the film to be read by controlling its passage by the lamp light sewing control circuit 16, thereby allowing the line sensor 2 to read the subject image in an optimal state.

3 is an analog-digital converter, and line sensor 2
The analog image signal of Nb1t represents the density of each pixel.
into a digital signal.

4 is a peak value detection circuit that detects the peak value of the bright level of the image signal. This peak detection circuit 4 divides the image signal obtained by one scan into a plurality of blocks, and detects the peak value of the image signal of each block.

The image signal obtained by one scan is sent to the block setting circuit 5.
The image is divided into blocks by a predetermined number of pixels.

The block setting circuit 4 is a circuit that divides one scanning line into several blocks, and uses horizontal synchronization signals H and 5YNC synchronized with each reading scan of the line sensor 2 as synchronization signals to start counting. It is a circuit. Then, by setting the middle block to be N bits, one scanning line is divided into an arbitrary number of blocks each having N bits.

FIG. 6 shows the operation of dividing one scanning line by this block setting circuit 4. In FIG. 6, (1) is the vertical synchronization signal V
SYNC, and this VSYNC is a signal synchronized with the start of reading one screen by the line sensor 2. (2) is a water synchronization signal H3YN, and this H3YNC is a signal synchronized with each main scan of the line sensor 2. The block setting circuit 4 has an N-bit counter frequency divider circuit that is cleared by H3YNC, counts the clock CLKI from the clock control circuit 11, and receives a reset signal R every N counts.
5I is output to the peak value detection circuit 4 as shown in FIG. 6 (4). Therefore, as shown in FIG. 6(5), the period of two adjacent H3YNCs, that is, the lifetime scanning period is within block B.
It is divided into m blocks such as LI to BLm. The number of divisions m is appropriately set in consideration of the size of characters, symbols, etc. of the recorded image on the microfilm.

As described above, by using the output of the block setting circuit 4 as the reset signal RSI of the peak value detection circuit 4, the peak value detection circuit 4 always detects the peak value of each block.

6 is a line address setting circuit, which is a circuit for setting an address area in the sub-scanning direction.

Further, 7 is a block address setting circuit, which is a circuit for setting the block area being scanned. CpulO to line address setting circuit 6 and block address setting circuit 7
By presetting n-bit data (Do-Dn) and m-bit data (Do-Dm), an image area as shown in Fig. 3 necessary to find the threshold for binarizing the image signal is created. (Threshold value determination area). In FIG. 3, 51 indicates the entire reading range of the line sensor, and 52 indicates the threshold determination area. In this way, in order to determine the threshold, six areas are defined, and only the peak values obtained from these areas are used as valid peak values for determining the threshold. .This makes the peak value obtained from the film part other than the image invalid even if the image size or image position on the film is uneven.This area is always the size where the image would exist. , of course it can be set in the position.

An embodiment of the line address setting circuit 6 is shown in FIG. 4, which includes a counter 21, two comparators 22, 23 and an AND gate 24. The counter 21 is composed of an inverter 25, and counts the H, 5YNC signal using the V, 5YNC signal indicating the reading period of one screen of images as a synchronization signal for starting counting. The count output of the counter 21 is Cpul
The comparator 22 compares the address (Do-Dm') representing the start point of the area in the sub-scanning direction outputted from O, and the address (Dno'+1 to Dm) representing the end point of the area.
and is compared by the comparator 23, and each comparator outputs one signal from when they match. The AND of the outputs of comparators 22 and 23 (the output of comparator 23 is inverted) is
・By taking 24, a line gate signal (L, GT) which becomes a single value from the start point of the area to the closing point is generated.

Thereby, the area in the sub-scanning direction can be defined by the line gate signal.

Next, an embodiment of the block address setting circuit 7 is shown in FIG. This consists of a counter 26, two comparators 27, 28, an AND gate 29, and an input 30. The counter 26 uses the H, 5YNC signal as a synchronization signal to start counting, and uses the output of the block setting circuit 5. A certain RS
Count I signals. The count output is compared by the Lt comparator 27 with the first address (Do to Dn') of the block area in the main scanning direction output from CpulO, and the last address (Dn'+1 to Dn) of the block area.
and is compared by the comparator 28, and each comparator outputs a 1-value code when they match. By taking the logical product of the outputs of the comparators 27 and 28 (the output of the comparator 28 is inverted) from the AND gate 294, a block area signal (B, GT) having a single value from the start point to the end point of the area is obtained. Set.

As described above, the area in the main scanning direction can be defined by the block area signal.

In FIG. 2, 8 is a gate circuit which creates a two-dimensional area 52 as shown in FIG. 3 by the block area determined by the block address setting circuit 7 and the line area determined by the line address setting circuit 6. This circuit passes only the signal peak values within the area 52 among the peak values detected by the peak value detection circuit 4.

FIG. 7 shows the operation of capturing peak values using block area signals (B, GT). In FIG. 7, (1) is an image signal, (2) is a block area signal, (3) is a clock CLK2 that determines the latch timing of the latch circuit 9, which will be described later, (4) is a reset signal R3I, and (5) is the peak data. The block address setting circuit sets the block area signal to high level when the count value of the reset signal R5I reaches data (Do to Dn') indicating the starting point of the threshold value determination area. As a result, the gate circuit 8
makes the peak value detected by the peak value detection circuit 4 valid.

Note that this threshold value determination area is appropriately set in consideration of the recording position and size of the image on the microfilm.

Reference numeral 9 denotes a latch circuit for setting the timing for taking in the peak value data into the CPU10 using CLK2.

IO is a microcomputer unit (CPU) for controlling the operation of the device. CPUl0 is latch 9
and 15 latch data respectively as clock signals %CLK2,
Capture in synchronization with CLK3 input. Reference numeral 11 denotes a clock control circuit, which is a circuit that creates various timing clocks that serve as operating standards for the device.

Reference numeral 12 denotes a comparator for obtaining a binary image signal by comparing the image signal with a threshold value formed by a predetermined procedure.

13 is the output of the base density detection circuit 14, which will be described later, and the CPU 1.
This is an adder that adds the threshold information TLI (Do to Dp) starting from 0 and supplies the threshold value to the comparator 13.

An embodiment of the base concentration detection circuit 14 is shown in FIG. As shown in the figure, it consists of an up/down counter 51 and a comparator 52.The output of the up/down counter 51 (BA
O) is compared with the digital image signal sig from the AD converter 3, and the value P preset by CPUl0 is determined.
Add/subtract RISET. That is, BAO>Sig(7)
At times, the count of the up/down counter 51 is decreased, and when BAO<sig, the count is increased.

These situations will be explained with reference to FIG. Figure 9 shows the base level BAO (counter output), threshold level and sig (A
/D output), and in the region (I), that is, the region where BAO>sig, up / d o
The w n counter 51 counts down. (II)
In the region where threshold level ≧sig>BAO,
The p/down counter 51 detects the state i'! of the output of the comparator 52. '+ (counts down when BAO > s ig, counts up when BAO < sig). The p/down counter 51 stops counting and holds the previous count value.

By operating in this way, the digital image signal s
A value near the lowest level of iH can be obtained, and this value near the lowest level is used as the approximate base concentration. CLK3 is a sampling clock that provides the timing to take in the approximate base concentration to CPU10, and can be set arbitrarily. 15 is a sampling clock C for the approximate base concentration signal.
This is a latch circuit for loading into CPU10 by LK3.

Reference numeral 16 denotes a lamp light amount control circuit, which receives instructions from the CPU 10 (
Do-DJI) controls the amount of electricity supplied to the lamp 1 in order to control the amount of light from the lamp.

The operation of the second circuit configuration will be explained below. Figure 14 shows the CPU
It is a flowchart diagram showing the operating procedure of CPUl0, and the program shown in this flowchart is stored in advance in the built-in memory ROM of CPUl0.

When the image frame to be read on the microfilm is set at the predetermined reading position and ready for reading operation, the CPU10 receives data Xo, which is the reference signal for the base density.
That is, a reading operation of the line sensor is performed without exposing the line sensor to light (si), and the output xO at that time is fetched (S2). Thereafter, in order to start the first image reading for determining the threshold value for binarizing the image data, the lamp 1 is turned on (S3) and the line sensor 2 starts moving forward (S4).

Then, the peak value data of the digital image signal (S i g) and the approximate base density data are taken in from the CPU10 in the dark value determination area set in advance as described above (S
5. S7).

For example, as shown in FIG. 10, the start and end points of the dark value determination area in the main scanning direction are
(Dm' to Dm), and the starting point and end point of the threshold determination area in the sub-scanning direction are set to y2 (DO to Dn') and yl (Dn' to Dn). As a result, out of the entire reading range 53 shown by the solid line, three frames 54 are shown by the dashed line.
The data within is taken in as data for threshold determination.

When the first image reading is completed in this way (S9), the lamp 1 is turned off and the line sensor 1 is moved back (S12).

Then, using each of the captured data, the CPU 10 determines the threshold value for binarizing the image signal, with the density level on the X axis and the Y
Create a histogram with frequency as the axis (S6.S8)
. In FIG. 5, histograms obtained from two types of films are shown by solid lines and dotted lines, respectively.

FIG. 5(1) is a histogram of the approximate base density component, and is a graph obtained by sampling the vicinity of the lowest level of the image signal by the base density detection circuit 14 as described above.

Further, (II) is a graph obtained by sampling the peak value data within the above-mentioned threshold value determination area in the image signal, that is, in the case of a negative film, the data of the portion where the amount of light transmitted is the largest.

By the way, if you calculate the peak value for each scanning line, you will find that when large characters (characters consisting of components with low spatial frequencies) and small characters (characters consisting of components with high spatial frequencies) coexist in the same image. In this case, the peak values of large characters become sample data, and small characters become blurred or do not appear at all. Therefore, as described above, by dividing one scanning line into a plurality of blocks and using the peak value of each block, it is possible to sample the peak value corresponding to each character even if large characters and small characters are mixed.

Furthermore, the graph (II) has bimodal characteristics; the peak on the lower side of the density level indicates the base density part, the peak on the higher side indicates the peak value part of the image signal, and the density level X2 is the first base density part. This is the location where the peak value level of the signal is greatest in the sample image area of the density film.

In the graph (I), xl is a density level showing a value close to the base density in the sample image area (referred to as approximate base density), and is the density level that is the most common density in the sample data obtained by the base density detection circuit 14. level. x1'
is the base density of the film with the second base density, which is lighter in base density than the film with the first base density for which Xl was determined, and is the density level at which the sample data is most common.

Generally, the base density of a film is not the same depending on the finished state of the film, and the density level differs from film to film. In the graph (II) as well, the second base density shown by the dotted line is lighter than the first base density shown by the solid line.

In the solid line histogram obtained in this way, the approximate base density representative value X1 and the peak value density representative value x2 of the image signal are detected (S L 3), and these two
The difference between the two values, that is, the value of X2-X1 is set as a contrast value XCT (S14). This contrast value
Like the base density, the CT varies depending on the finishing condition of the film, so even characters having the same spatial frequency do not necessarily have the same value. Therefore, as a darkness value for binarizing one image signal, simply dividing the above-mentioned contrast value According to the base density, the contrast value XCT (X2-X1) is corrected.

The graph shown in FIG. 12 shows a correction curve used for this correction operation. The Y-axis shows the coefficient value P for multiplying the contrast value XCT, and the X-axis shows the base density level. As the zero point (origin) moves to the right of the pitch black film through which no light passes, the film base density becomes lighter. On the X axis, D
= 1. The position O is film base density D = 1.
This is the level when the contrast value is 0, and in this case, the contrast value
The threshold value information is obtained by dividing CT by 50%, that is, by dividing the contrast value XCT into two.

FIG. 13 is a graph in which contrast is plotted on the Y axis, spatial frequency is plotted on the X axis, and base density is used as a parameter.

・N is the characteristic of a film with a high base density, and ■ is a characteristic of a film with a light base density. Generally, the main text of a newspaper is located in the spatial frequency band of range a in FIG. 13, and in this range a, the darker the base density, the lower the contrast value tends to be. Therefore, the standard value on the correction curve in FIG. 12 is set as D=1. Base concentration set to O>
By decreasing the correction coefficient P multiplied by the contrast in the case of the standard value, and increasing the correction coefficient P in the case of the base density standard value, by increasing or decreasing the threshold value during binarization,
The densities on copies due to differences in base densities are assumed to be the same density.

However, the value of the maximum frequency approximate base density x1 shown in FIG. 11 is not always a constant value for a particular film due to variations in light intensity settings, product variations, variations due to temperature fluctuations in electric circuits, etc. Therefore, in order to correct these, the above-mentioned value of XQ (FIG. 11(I)) is used.

The value of XQ is a data value obtained as an output of the line sensor 2 when the line sensor 2 is not irradiated with light as described above. By reading this at regular time intervals and using it as a reference value for the histogram, it is possible to absorb variations due to products, electrical circuits, temperature fluctuations, etc., and to always perform arithmetic processing from sample data with high precision.

That is, in FIG. 11 (I), the value obtained by subtracting the correction value XQ from the approximate base density x1, that is, BLX = The corrected base density is the approximate base density
The value obtained by subtracting the correction value XQ from 1, that is, BLX'=X'
t-x.

is the corrected base density of the film having a second base density that is lighter than the film having the first base density. These corrected base densities B LX (
BLX') (7) Calculate the value and make it correspond to the correction curve shown in FIG. 12D to determine the correction coefficient P (an appropriate threshold value for binarization of Slm can be determined).

Based on the histogram created in this way, cpuio
The above processing is executed and threshold information TLI, which serves as a reference for the threshold for binarizing the image signal, is supplied to the adder 13 (518
).

As described above, the adder 13 adds the base intensity value from the base density detection circuit 14 to the threshold information TL■ to form a threshold, and applies the threshold to the comparator 12. In this way, a threshold value is formed that takes into account the image recorded on the film and the base density of the film, and when the image is read a second time using this threshold value, the digital image signal from the AD converter 3 is converted to 2 by the comparator 12. It is digitized and output as a binary code.

That is, the lamp 1 is turned on again (S i 9), the line sensor 2 is moved forward (S 20), and the image is read.

The analog image signal outputted by the line sensor 2 is converted into a digital image signal by the AD converter 3, and further compared with the threshold value obtained by adding the base density to the threshold value information TLI outputted by the CPU10 in the comparator 12, Based on this magnitude relationship, the z-value is converted.

When the desired image has been read (S21), the lamp 1 is turned off (522), and the line sensor 2 is moved back again to the reading start position. This completes the reading of the desired image.

Incidentally, FIG. 11 (III) is a graph obtained by dynamically determining the amount of transmitted light through the film base. The value x3 is the light intensity level at the point of maximum frequency on the histogram when the lamp 1 is turned on without pushing the film into the reading position and the light intensity is measured based on the output of the line sensor 2 at this time. However, by pushing the film into the reading position, the light intensity decreases by the amount of transmission weight of the film base (x3' light intensity level)
, the relative resolution of the image signal decreases. Therefore, while pushing the film in and moving the line sensor, in the area where there is no image (
For example, a reading operation is performed in a non-image area such as a leader section of a film), and the amount of light is set to set the light amount level to X3, thereby maximizing the resolution of the image signal.

By doing this, the data for setting the light amount is sampled from the transmitted light in a predetermined range rather than from the transmitted light at one point on the film, so it is possible to prevent the light amount from decreasing due to variations in the light amount of the lamp, local dirt on the film, etc. It becomes possible to make corrections. Furthermore, since an image with a small contrast value has a low relative resolution with respect to the signal, a good copy density can be obtained by increasing the amount of light, finding the necessary contrast value, and binarizing the image.

FIG. 15 shows the operating procedure for setting the light amount using a histogram. The program of this flowchart is also stored in the internal memory ROM Lm-%l- of the CPU10. Further, this light amount setting operation is executed, for example, before the image reading operation shown in FIG. 14.

First, in a state where the film is not in the reading position, for example, before the film is loaded, or if the film is loaded, after the film has been rewound, the lamp 1 is turned on at the standard light intensity (S31); , line sensor 2
to start reading (532), calculate the peak value of the output of line sensor 2 (S33), create a histogram of this peak value (S34), and when the reading operation for a predetermined time is completed (S35). ), the line sensor reading is stopped (336), and X3 (■ in FIG. 11) is detected from the created histogram (S37).

Thereafter, the film is pushed in and, for example, a blank area of the film is set at the reading position (338).

Then, the line sensor 2 is driven again to start reading and move the line sensor 2 forward (S39).
. The peak value of the output of the line sensor 2 at this time is captured (S40), and a histogram of the peak values is created (
541). When the reading for the predetermined time is completed (S 4
2) Stop reading and move the line sensor back (S
43). X3' (■ in FIG. 11) is detected from the created histogram (S44).

Next, the magnitude relationship between the values of x3 and

Then, the line sensor 2 is read with the increased amount of light (S39), and the peak value at that time is detected (540).
), create a histogram (S41), and
After reading for a predetermined time (S42), the reading is stopped (543), and X3' is detected again from the histogram (S44), X3. ! :Compare X3' (54
6). This operation is repeated until x3≦x3', and when x3≦X3', the amount of light at that time is stored. This amount of light is the amount of light that enables the above-mentioned high-resolution reading, and the film image is read using this light 15. Note that when detecting the amount of light transmitted through the film, the film may be moved instead of moving the line sensor.

As mentioned in ``2'' below, when reading images recorded on microfilm, the threshold for binarizing the image signal is determined according to the image density to be read and the base density. A good binary image signal can always be obtained regardless of the state or the like.

Furthermore, since a sample area of image density for determining the threshold value is defined and data of non-image areas of the film are invalidated, the threshold value is not influenced by anything other than the image.

Furthermore, since the image density sample is obtained from each block by dividing one scanning line into a plurality of blocks, it is possible to determine a good threshold value even for an image containing a mixture of large and different characters, symbols, etc.

Furthermore, since the transmitted light of the microfilm to be read is set to a predetermined value, it is not affected by the type of film, etc.
Film exposure is always performed with the appropriate amount of light.

Incidentally, although Kinoshio's explanation has been given using the reading of microfilm as an example, the present invention can be similarly applied to reading images of other films such as 35 mm film. In addition, the read image signal is not only binarized, but may also be multi-valued using, for example, a plurality of threshold values. can be executed. Furthermore, a two-dimensional image sensor can be used instead of the line sensor for reading.

Note that this threshold value determination operation may be performed every time each frame of microfilm is read, or, for example, when reading multiple frames of the same film in succession, the threshold value may be determined using the first frame. , the same threshold value may be used for reading subsequent frames.

(Effects) As explained above, according to the present invention, transmitted light is detected over a predetermined width of the non-image area of the film, and the amount of light is controlled based on the detection result, so that the amount of light suitable for the film is controlled. This can be determined without being affected by local dirt, scratches, etc.

[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 a circuit that processes a read image signal, Fig. 3 is a diagram showing a threshold value determination area, and Fig. 4 is a block diagram of the line address setting circuit, FIG. 5 is a block diagram of the block address setting circuit, FIG. 6 is a diagram showing the division operation of one scanning line, FIG. 7 is a diagram showing the peak value capture operation, and FIG. is a block diagram of the base concentration detection circuit, FIG. 9 is a diagram showing the operation of the base concentration detection circuit, FIG. 10 is a diagram showing data acquisition from the threshold value determination area, and FIGS. 11 (1), (II), ( III)
12 is a diagram showing an example of a histogram, FIG. 12 is a diagram showing the relationship between base density and correction coefficient, FIG. 13 is a diagram showing the relationship between spatial frequency and contrast, and FIG. 14 is a flowchart diagram showing the operation procedure for threshold value determination. , FIG. 15 is a flowchart showing the operation procedure for determining the amount of light, in which 1 is a lamp, 2 is a line sensor, 4 is a peak value detection circuit, 6 is a line address setting circuit, 7 is a block address setting circuit, and 10 is a CPU. , 12 is a comparator, and 14 is a base concentration detection circuit.

Claims (1)

[Claims] In an image reading device that exposes a film on which an image is recorded and reads the image using the transmitted light of the exposed film, the transmitted light is detected over a predetermined width of the non-image area of the film, and based on the detection result, An image reading device characterized by controlling the amount of light for reading an image.