JPH0472430B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a film image reading device that reads images recorded on a film.

(Prior Art) Images recorded on a film, for example, an X-ray film, have conventionally been directly visually diagnosed by a doctor or the like by placing the images on a shear caster or the like.

However, it is difficult to extract information that is useful for medical diagnosis using this method, so in recent years, it has become possible to convert images recorded on film into electrical signals and then perform various processing to extract information that is useful for medical diagnosis. An image processing system that emphasizes and then reproduces images has been developed and is used for medical diagnosis.

FIG. 4 is a block diagram showing an example of such an image processing system.

The image processing system shown in this figure
a film image reading device 2 that scans the surface of the film 1 with a laser beam, detects the amount of transmitted light at that time, reads the image recorded on the film 1, and converts this image into a digital quantity and outputs the image; A data processing device 3 performs data processing such as frequency enhancement and edge enhancement on the image data output from the film image reading device 2 to create an image that is easy to diagnose, and displays the processing results of this data processing device 3. A display device 4 is provided to display the processing results of the image recorded on the film 1 on the display device 4 for diagnosis by a doctor or the like.

FIG. 5A shows the film image reading device 2 described above.
It is a front view showing the mechanical part of.

The device shown in this figure includes a laser oscillator 5, a beam expander 6, a high-speed angular velocity changing mirror 7, and an f.
θ lens 8 and film feed rollers 9A, 9B
, a condenser 11, and a detector 12.
While conveying the film 1 in the sub-scanning direction, a laser beam is scanned in the main-scanning direction to read the image recorded on the film 1 line by line.

The laser oscillator 5 includes a laser oscillation section that generates a laser beam, a drive circuit that drives this laser oscillation section, etc. When an oscillation command signal is supplied, the laser oscillator 5 generates a laser beam and sends it to beam excitation. Supply to panda 6.

The beam expander 6 is connected to the laser oscillator 5.
The aperture of the laser beam supplied from the laser beam is expanded to an arbitrary size to reduce the spread angle of the laser beam, and this is supplied to the high-speed angular velocity changing mirror 7. In this case, if the beam diameter of the laser beam is expanded five times, the spread angle of the laser beam will be reduced to one-fifth.

The high-speed angular velocity changing mirror 7 is composed of a galvanometer, a polygon mirror, etc., and rotates its reflecting surface at a constant angular velocity in the main scanning direction to direct the laser beam supplied from the beam expander 6 in the main scanning direction. This is supplied to the f/θ lens 8 while being swung.

The f/theta lens 8 is a lens that emits the laser light supplied from the high-speed angular velocity change mirror 7 while keeping the linear velocity constant in the main scanning direction and focuses it on the same plane. The film 1 is irradiated with a laser beam.

Then, the laser beam is transmitted to the condenser 11 by an amount corresponding to the film density of the irradiated area.
supplied to

At least one of the film feed rollers 9A and 9B is configured to be driven by a motor or the like, and when the film 1 is inserted, the film feed rollers 9A and 9B are held at a predetermined speed while holding the film 1 therethrough. to carry out step transport in the sub-scanning direction.

The condenser 11 may be a condenser lens, or an optical fiber bundle consisting of a large number of fibers bundled to form a flat plate when viewed from the side as shown in FIG. As shown, the output end portion is provided with a processed transparent acrylic resin or the like, and the laser beam transmitted through the film 1 is guided to the detector 12.

The detector 12 is equipped with an optical/electrical converter that converts the supplied laser light into an electrical signal, and has a size corresponding to the intensity of the laser light supplied from the condenser 11. generates a detection signal of
This is supplied to the processing circuit 21.

The processing circuit 21 is configured to process this detection signal to generate density data of the film 1, and performs the processing described below to generate the density data.

First, in the image obtained by such a film image reading device 2, even when there is no film 1, the amount of light on the peripheral edge side is insufficient due to the shading effect as shown in FIG. Furthermore, the density of one line is not uniform due to fluctuations in the laser light emitted from the laser oscillator 5, nonuniform optical characteristics of the condenser 11, and the like.

Therefore, in the processing circuit 21 of this film image reading apparatus, the density of the film is measured by the method described below.

First, determine the reference amount of light incident on the detector 12.
I ₀ , and when there is no film 1, detector 1
If the amount of light incident on 2 is I ₁ and the amount of light incident on detector 12 when film 1 is present is I ₂ , then
Density D 1 without film ₁ and film 1
The concentration D ₂ when there is can be expressed by the following equation.

D ₁ = −logI ₁ /I ₀ …(1) D ₂ = −logI ₂ /I ₀ …(2) However, each of these concentrations D ₁ and D ₂ is affected by the shedding effect, etc., so that the starting point of one line is It becomes a large value on the side and the end point side.

Therefore, in this processing circuit 21, the detector 1
After determining each concentration D ₁ and D ₂ based on the output of step 2,
These differences (density data) D ₃ are calculated using the following equation, and the influence of the shading effect contained in each density D ₁ and D ₂ is canceled out.

D ₃ = D ₂ − D ₁ = (−logI ₂ /I ₀ )−(−logI ₁ /I ₀ ) =−(logI ₂ −logI ₁ ) =−logI ₂ /I ₁ …(3) In other words, film 1 The density D ₁ when there is no film 1 is measured and stored in advance, and then the density D ₂ of the film 1 is measured, the difference between these is determined, and this is output as film density data D ₃ .

(Problems to be Solved by the Invention) By the way, such a film image reading device 2
The film 1 that is handled by the operator is susceptible to dirt and dust adhering to it due to the electrification phenomenon.

Therefore, even if you are careful, dirt and dust may adhere to the film 1.
When the film 1 is inserted into the film image reading device 2, dirt and dust attached to the film 1 fall onto the light incident end surface of the condenser 11, and the laser light transmitted through the film 1 is constantly blocked by these dirt and dust. Sometimes I get lost.

In such a state, when the film 1 is scanned with a laser beam, the laser beam is blocked at a specific position during one scan, that is, a position where dirt or dust is present, and the laser beam is not supplied to the detector 12. It disappears.

As a result, a specific pixel portion of each line signal constituting the signal output from the detector 12 is omitted, so-called bit omission occurs, and a black line extending in the sub-scanning direction is displayed on the display device 4 that displays the processing result of this signal. I had a problem with lines appearing.

SUMMARY OF THE INVENTION In view of the above circumstances, it is an object of the present invention to provide a film image reading device that can detect and notify when dust or the like adheres to the light input end face of a condenser.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, a film image reading device according to the present invention scans a film surface placed on a film mounting surface with a laser beam. and a film image reading device that reads an image on the film surface by detecting the amount of transmitted light at that time,
an image reading section that scans the film mounting surface with a laser beam when no film is placed on the film mounting surface, detects the amount of light at that time, and outputs the image pixel by pixel; A difference extraction section extracts the difference between signals obtained from adjacent pixels among each pixel signal output from the image reading section, and a predetermined value of the difference signal output from this difference extraction section. The present invention is characterized by comprising a determination unit that compares the values with the values and determines whether an image capture error has occurred based on the comparison result.

(Operation) With such a configuration, when pixel signals are output from the image reading section, the difference extraction section extracts the difference between them. Then, when the value of this difference exceeds the set value, the determining section determines that there is an image capture error.

(Embodiment) FIG. 1 is a block diagram showing an embodiment of a film image reading apparatus according to the present invention. In this embodiment, the mechanical part, that is, the detector 12
The part that supplies laser light to the laser beam is the same as before.

The device shown in this figure includes a photoelectric conversion section 50, a difference extraction section 51, an output section 52, a determination section 53, and a display 54, and a film (not shown) is inserted through this device. When the calibration mode is set in a state where the Based on the line data, it is determined whether dust or the like is attached to the light incident end face of the condenser. If dust or the like is attached to this light incident end face, this is displayed to inform the operator or the like.

Further, when the measurement mode is set with a film inserted into this device, the intensity of the laser light transmitted through the film and collected by the condenser is measured and memorized. Then, when data for one line is obtained, the difference between this data and the data obtained in the calibration mode is extracted, and the extraction result is supplied to a data processing device (not shown).

The photoelectric conversion unit 50 includes a detector 22, a log amplifier 23, an S/H circuit 24, and an A/D converter 25, and converts the intensity of the laser beam collected by the condenser into The measurement result is output as a digital signal.

The detector 22 includes a photo/electrical conversion element and the like, and outputs a light amount detection signal (analog signal) having a value corresponding to the intensity of the laser light collected by the condenser.
is generated and supplied to the log amplifier 23.

The log amplifier 23 is an amplifier that logarithmically converts the light amount detection signal, and converts the result of this conversion (density signal).
is supplied to the S/H circuit (sample/hold circuit) 24.

In this case, if the value of the light amount detection signal is "I" and the value of the density signal is "D", then the relationship expressed by the following equation holds true: D=logI (4).

The S/H circuit 24 is configured to take in the output of the log amplifier 23 and hold it when a clock signal is received from a controller (not shown) that controls the entire device. , supplies this holding result to the A/D converter 25.

The A/D converter 25 is configured to perform A/D conversion (analog/digital conversion) on the output of the S/H circuit 24 to generate concentration data. The density data is supplied to the difference extraction section 51.

In this case, since the controller outputs a clock signal at a rate corresponding to the angular velocity of a high-speed angular velocity changing mirror (not shown), the A/D converter 25
Each density data outputted from the main scanning direction indicates the density of each pixel in the main scanning direction.

The difference extraction section 51 includes a switch 26, a calibration buffer 27, a line buffer 28, a switch 31, and a difference calculation circuit 29, and a film (not shown) is inserted through this device. If the calibration mode is set in a state where the calibration mode is not set, when density data is supplied from the photoelectric conversion section 50, this density data is stored for one line, and the adjacent density data is The data difference is extracted and supplied as difference data to the output section 52 and the determination section 53.

Further, when the measurement mode is set with a film inserted into this device, when density data is supplied from the photoelectric conversion section 50, it is stored, and this density data and the The difference from the density data obtained in the calibration mode is extracted and supplied as difference data to the output unit 52 and the determination unit 53.

The switch 26 takes in the density data output from the A/D converter 25, and also supplies the taken density data to the calibration buffer 27 or to the line buffer based on the command from the controller. 28.

In this case, if no film is inserted into this device, the switch 26 supplies the acquired density data to the calibration buffer 27. If a film is inserted into this device, the switch 26 supplies the taken-in density data to the line buffer 28.

The calibration buffer 27 is a memory having a capacity sufficient to store one line of density data, and each time a clock signal is supplied from the controller, the calibration buffer 27 takes in the density data and stores it in the memory. are stored sequentially starting from the first address. Then, each time a clock signal is supplied from the controller, the density data already stored is read out sequentially from the first address and is supplied to the switch 31. Then, when a clear command is supplied from the controller, the data in the memory is cleared.

The line buffer 28 is also constructed in the same manner as the calibration buffer 27, and each time a clock signal is supplied from the controller, the line buffer 28 takes in the density data and sequentially stores it from the first address of the memory. Make me remember. Then, each time a clock signal is supplied from the controller, the density data already stored is read out sequentially from the first address and is supplied to the switch 31. Then, when the density data stored at the final address is read out and output, the data in the memory is cleared.

As shown in FIG. 2, the switch 31 includes gate circuits 40, 41, and 42 whose opening and closing are controlled by signals from the controller, and each gate circuit 4.
1 and 42, and when the calibration mode is set with no film inserted into this device, the The gate circuit 42 is closed by this signal, and the gate circuits 40 and 41 are alternately opened and closed in synchronization with the clock signal from the controller.

Thereby, the concentration data sequentially outputted from the calibration buffer 27 is supplied to the corresponding input terminal of the difference calculation circuit 29 via the gate circuit 40, the gate circuit 41, and the OR circuit 43. .

In addition, when the measurement mode is set with a film inserted into this device, the gate circuit 4 is activated by a signal from the controller.
0 and 42 are opened.

As a result, from the calibration buffer 27 and the line buffer 28,
The output concentration data is supplied to the corresponding input terminal of the difference calculation circuit 29 via the gate circuit 40, the gate circuit 42, and the OR circuit 43.

The difference calculation circuit 29 includes a buffer for each input terminal that takes in the concentration data supplied to each input terminal and temporarily stores the data, and calculates the difference between the concentration data held in each of these buffers. The output unit 52 outputs this as difference data.
and the determination unit 53.

In this case, if no film is inserted into this device, the calibration buffer 2
The density data output from 7 is sent to the difference calculation circuit 29.
The difference data obtained by the difference calculation circuit 29 indicates the density difference between adjacent pixels.

Therefore, dirt and dust may adhere to the light incident end face of the condenser, causing the photoelectric conversion unit 50 to be damaged as shown in FIG.
When the output of shading noise N is multiplied by the shading noise N, this shading noise N is extracted as difference data.

In addition, when the measurement mode is set with a film inserted into this device, the concentration data sequentially output from the calibration buffer 27 is supplied to one input terminal of the difference calculation circuit 29. Along with that, Line Batsuhua 2
Since the density data sequentially output from 8 is supplied to the other input terminal of the difference calculation circuit 29, the difference data obtained by this difference calculation circuit 29 is based on the density data of each pixel when the film is not inserted. It shows the difference between the density and the density of each pixel on the film inserted through this device.

The output unit 52 includes a gate circuit 32 whose opening/closing is controlled by a signal from the controller, and an interface (not shown) that transmits differential data to a data processing device (not shown) when differential data is output from the gate circuit 32. I/F) 30,
When the device is in the measurement mode, the gate circuit 32 is opened to take in the difference data output from the difference extraction section 51 and supply it to the data processing device via the interface 30. .

Further, the determination section 53 includes a gate circuit 33, a setting device 35, a comparator 34, and a flip-flop (F/F) circuit 36. When the difference extraction mode is set, the size of the difference data supplied from the difference extraction section 51 is a predetermined value (set value).
determine whether the difference data exceeds a set value, determine that dust or the like is attached to the light incident end surface of the condenser, and generate an image capture error signal; This is supplied to the display 54.

The gate circuit 33 is a circuit whose opening and closing are controlled by signals from the controller, and when the calibration mode is set with no film inserted into this device, it is in an open state and the gate circuit 33 is opened and closed. The difference data output from the difference extraction section 51 is taken in and is supplied to one input terminal of the comparator 34.

Further, the setting device 35 is composed of a data setting switch, etc., and the value set by the data setting switch is transferred to the comparator 34.
to the other input terminal.

The comparator 34 compares the values of the data supplied to each input terminal, and detects an error if the value of the difference data supplied from the gate circuit 33 is larger than the value set in the setter 35. A signal is generated and applied to flip-flop circuit 36.

The flip-flop circuit 36 is an RS type,
Alternatively, it is constituted by an F/F such as a JK type, and is set by the error detection signal to generate an image capture error signal, which is supplied to the display 54.

The indicator 54 is equipped with a light emitting diode, a lamp, etc., and lights up when the image capture error signal is supplied to indicate to the operator that dust or the like is attached to the light incident end surface of the condenser. etc., and have the operator clean the light incident end face of the condenser.

As described above, in this embodiment, when the calibration mode is set with no film inserted into the device, the density data output from the photoelectric conversion section 50 is converted into one line of density data.
At the same time, among these density data, the difference between adjacent data is extracted, and when this extraction result (difference data) becomes larger than the set value, it is determined that there is dust or the like on the light incidence end face of the condenser. Since it is determined that there is adhesion and this is displayed, the operator etc. can be informed of this.

[Effects of the Invention] As described above, according to the present invention, when dust or the like adheres to the light incident end face of the condenser, it is possible to notify an operator or the like of this. As a result, when dust or the like adheres to the light incident end face of the condenser, it can be quickly removed, and it is possible to prevent the occurrence of extremely harmful vertical stripes in image diagnosis.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the film image reading device according to the present invention, FIG. 2 is a detailed block diagram of the switch 31 shown in FIG. 1, and FIG. Waveform diagram showing an example of a signal when dirt or dust adheres to the light input end face, No. 4
The figure is a block diagram showing an example of an image processing system.
5A is a front view showing the mechanical portion of the film image reading device shown in FIG. 4, FIG. 5B is a side view showing the mechanical portion of the film image reading device, and FIG. 6 is a front view showing the mechanical portion of the film image reading device shown in FIG. FIG. 3 is a waveform diagram showing an example of a signal. 50... Image reading section (photoelectric conversion section), 51...
Difference extraction section, 53...determination section.

Claims (1)

[Scope of Claims] 1. A film image reading device that scans a film surface placed on a film mounting surface with a laser beam, detects the amount of transmitted light at that time, and reads an image on the film surface, comprising: an image reading section that scans the film mounting surface with a laser beam when no film is placed on the mounting surface, detects the amount of light at that time, and outputs the image in pixel units; a difference extractor that extracts the difference between signals obtained from adjacent pixels among each pixel signal output from the pixel signal; 1. A film image reading device comprising: a determination unit that compares the images and determines whether or not an image capture error has occurred based on the comparison result.