JP2001045294A - Method for correcting temperature of film scanner and film scanner for executing the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a film scanner temperature correction method for securing high scanning quality even when environmental temperature fluctuates and to obtain a film scanner for executing the method. SOLUTION: The film scanner 3 is provided with an illuminating optical system 30 for projecting irradiation light to a picture film, a photoelectric conversion element 51 for photoelectrically converting a film image obtained by the irradiation light and a digitizing processing part 50a for digitizing a signal transferred from the element 51. The environmental temperature of the scanner 3 is measured and the operation parameter of the processing part 50a is readjusted in accordance with the measured temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination optical system for projecting irradiation light onto a photographic film, a photoelectric conversion element for photoelectrically converting an image of a film image by the irradiation light, and a signal transferred from the photoelectric conversion element. A temperature correction method for a film scanner including a digitization processing unit for performing digitization processing;
And a film scanner for performing the method.

[0002]

2. Description of the Related Art In the field of photographic DP, in which an image picked up on a photographic film is printed on photographic paper, a digital image obtained by photoelectrically converting light transmitted through a photographic film instead of a projection exposure type image exposure apparatus recently. A so-called digital exposure type image exposure apparatus has been developed in which print data is generated by performing appropriate image processing on image data, and a digital exposure head exposes photographic paper based on the print data. In such a digital exposure type image exposure apparatus, the resolution of a film scanner as an input unit is particularly important. For this reason, a photographed image frame of a photographic film to be conveyed is converted using a photoelectric conversion means such as a line CCD sensor. A method of sequentially reading is adopted.

[0003]

SUMMARY OF THE INVENTION A film scanner is
Although a photoelectric conversion element such as a CCD is used as a core, a digitization processing unit generally including a CDS circuit, an AGC circuit, and an A / D converter is provided to digitize a signal transferred from the photoelectric conversion element. In addition, due to the temperature dependence of the operation characteristics of the photoelectric conversion element or the circuit components, characteristic fluctuations due to heat cannot be avoided. For this reason, when used in areas with high temperatures during the day, the characteristics of electronic circuits will fluctuate due to changes in environmental temperature, even if they are adjusted sufficiently at the time of shipment or installation. Worsens the reproducibility of In view of the above circumstances, an object of the present invention is to provide a film scanner temperature correction method for ensuring good scanning quality despite fluctuations in environmental temperature, and a film scanner for implementing the method.

[0004]

According to the present invention, there is provided an illumination optical system for projecting irradiation light on a photographic film, a photoelectric conversion element for photoelectrically converting an image of a film image by the irradiation light, and A temperature correction method for a film scanner, comprising: a digitization processing unit for digitizing a signal transferred from a photoelectric conversion element; measuring an environmental temperature of the film scanner; and operating the digitization processing unit in accordance with the measured temperature. It is proposed to readjust the parameters.

In this method, the environmental temperature of the film scanner is measured, and the operating parameters of the digitizing processing unit are readjusted in accordance with the measured temperature so as to compensate only for the thermal fluctuation. Nevertheless, a stable digital image signal can be obtained, and scanning quality can always be ensured.

[0006] One of the specific methods of readjusting the operating parameters
For example, when the measured environmental temperature reaches a predetermined value, based on a signal obtained by irradiating the photoelectric conversion element with standard irradiation light, the digitalization is performed so that the output signal becomes a set value. There is a method of re-adjusting the operation parameters of the processing unit. That is, when the temperature changes by a predetermined amount, the setup filter is interposed in the propagation path of the irradiation light, or the setup film is inserted, and the photoelectric conversion element receives the standard light serving as the reference, and thereby the digitizing processing unit. Is analyzed and the operating parameters of the digitizing processor are readjusted so that the temperature can be compensated. Preferably, by repeating this readjustment operation several times, the scanning quality can be highly stabilized.

As another specific method of re-adjusting the operating parameters, when the measured environmental temperature reaches a predetermined value, the above-described method is performed based on a look-up table including a preset environmental temperature and operating parameters. There is also a method of re-adjusting the operation parameters of the digitization processing unit. This is because if the relationship between the environmental temperature and the thermal fluctuation of the digitizing unit can be grasped experimentally and empirically, a look-up table that stores the relationship between the environmental temperature and operating parameters for temperature compensation in advance is created. By using this lookup table, stable scanning quality can be ensured despite temperature fluctuations.

[0008] The most common digitizing processing section is composed of a CDS circuit, an AGC circuit and an A / D converter. In this case, the operating parameters handled are A
The gain of the GC circuit is preferable, and the AGC control terminal for ensuring that the signal amplitude falls within the A / D conversion voltage range, and the OPB (optical black level) set the lower limit of the A / D conversion voltage range. An offset terminal is used to prevent the terminal from coming off.

In order to solve the above problems, in a film scanner according to the present invention, an illumination optical system for projecting irradiation light onto a photographic film, a photoelectric conversion element for photoelectrically converting an image of a film image by the irradiation light, and the photoelectric conversion element A digitization processing unit that digitizes the signal transferred from the control unit, a control unit that controls the photoelectric conversion element and the digitization processing unit, and a temperature sensor that measures the environmental temperature of the film scanner are provided. The control unit re-adjusts the operation parameters of the digitizing unit according to the measured value. by this,
When the ambient temperature of the film scanner changes, the operating parameters of the digitizing unit are readjusted to compensate for only the resulting fluctuation, so that a stable digital image signal can be obtained despite the fluctuation of the environmental temperature. And stable scanning quality can be obtained. Other features and advantages according to the present invention will become apparent from the following description of embodiments with reference to the drawings.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Film scanner 3 according to the present invention
FIG. 1 is a schematic block diagram of a printer processor which employs the above-mentioned printer and is known as a so-called digital minilab. The digital minilab employs a digital exposure system, and a film scanner 3 for reading a photographed image from an image frame of a photographic film (hereinafter simply referred to as a film) 1 developed by a film developing machine (not shown); A controller 7 for processing digital image data read through the film scanner 3 to create print data; a digital print unit 5 for exposing an image corresponding to a frame image to the photographic paper 2 based on the print data; And a developing section 6 for developing the photographic paper 2. The photographic paper 2 developed by the development processing section 6 is discharged as a finished print through a drying process.

The film scanner 3 includes, as main components, an illumination optical system 30, an imaging optical system 40, a photoelectric conversion unit 50 using a line CCD sensor 51 as a photoelectric conversion element,
An automatic film mask 10 is provided for determining the irradiation range of the film 1 and for transporting the film 1 in the sub-scanning direction for scanning by a line CCD sensor.

The illumination optical system 30 includes a halogen lamp 31 as a white light source, a light control filter 32, and a mirror tunnel 3.
3 irradiates the film 1 with the color distribution and intensity distribution of the light beam from the light source adjusted. An imaging optical system 40 for processing a transmitted light beam from the film 2 includes a lens unit 41 and a mirror 42 for changing the direction of light. The light control filter 32 is provided with a setup filter 32a used for adjustment.
The setup filter 32a can be set on the optical axis by a command from the controller 7.

The photoelectric conversion unit 50 that photoelectrically converts the light beam guided by the imaging optical system 40 includes three CCD sensors 51a, 51b, and 51c assigned to detect each color of RGB as a line CCD sensor 51. Each CCD sensor has a large number (for example, 5000) of C
CD elements are arranged in the main scanning direction, that is, in the width direction of the film 1. A color filter that allows only the red component of the light transmitted through the film 1 to pass through the imaging surface of the red CCD sensor 51a, and allows only the green component of the light that has passed through the film 1 to pass through the imaging surface of the green CCD sensor 51b. A color filter is provided on the imaging surface of the blue CCD sensor 51c so as to pass only the blue component of the light transmitted through the film 1, and performs photoelectric conversion of only the blue, red, and green components, respectively. .

When the frame image of the film 1 is positioned at the scan position set on the auto film mask 10, the reading process of the frame image is started, and the transmitted light of the frame image is transmitted by the film transport mechanism 9 to the film 1. By the feeding, three CCD sensors 51a, 51b, and 51c sequentially read, but since each CCD sensor is arranged at intervals of several pixels along the transport direction of the film 1, R, R There is a time difference between the detection timings of the G and G component colors. This is due to the signal processing at the subsequent stage of the photoelectric conversion unit 50.
The image signals are stored in a predetermined memory of the controller 7 in association with each other. Such control of the illumination optical system 30, the imaging optical system 40, and the photoelectric conversion unit 50 of the film scanner 3 is performed by the controller 7.

In this embodiment, the digital print section 5 employs a PLZT shutter system. That is, a shutter array including a PLZT element is employed as the exposure head 5a. The shutter array composed of this PLZT element is made of a transparent ferroelectric ceramic material obtained by adding lanthanum to lead zirconate titanate, and utilizes the electro-optic effect of the material. Light of each color of R, G, and B is introduced from the light source 5b via many optical fibers. The shutter array extends in the width direction of the photographic paper 2, that is, in the transverse direction of the transport direction. When a predetermined level of voltage is applied to each shutter, it enters a light transmitting state,
When the application of the voltage is stopped, the light is cut off. Therefore, when a drive voltage is applied to the shutter corresponding to each pixel from the controller 7 based on the print data, the shutter is opened and light of the color introduced from the light source is irradiated on the printing paper 2. The light source 5b has R, G, B
A rotation filter composed of color optical filters is provided, and by controlling the rotation phase of this rotation filter,
One of R, G, and B selectively faces the light source, and light of the selected color is sent to the shutter through an optical fiber through a filter of that color. In addition to the PLZT shutter method, a liquid crystal shutter method, a fluorescent beam method, a FOCRT method, and the like are known as a method of the digital printing unit, and can be arbitrarily selected according to an exposure specification.

Since the digital printing section 5 can simultaneously expose each of the cut photographic papers 2 arranged in two rows,
The photographic paper transport mechanism 8 is divided into a photographic paper supply line 8A that transports the cut photographic paper 2 in a single row, an exposure transport line 8B that can transport the cut photographic paper 2 in two rows, and a development transport line 8C. Paper supply line 8A and exposure transport line 8B
A sorting device 4 for sorting the printing paper 2 sequentially sent from the printing paper supply line 8A to each row of the exposure conveyance line 8B is provided.

The photographic paper supply line 8A is selectively provided from either one of the two photographic paper magazines 2A and 2B which house the photographic paper 2 in a roll shape with the emulsion side facing out.
And a pre-distribution transport unit that transfers the photographic paper 2 to the distribution device 4.

At the upstream end of the pre-sorting transport section, a paper cutter 12 for cutting the photographic paper 2 drawn from the photographic paper magazine 2A or 2B according to the print size is provided. Is provided. The back print section 13 is provided on the back side (non-emulsion side) of the photographic paper 2.
It prints a film ID, a frame number, and correction information indicating image processing performed at the time of print data creation, and a dot-in-packed printer is usually used.

The exposure transport line 8B is arranged in the transport direction
An intermediate transport roller unit 80A constituting two rows of carry-in areas of the exposure transport line 8B, a first exposure transport roller unit 80B on the entrance side arranged to sandwich the exposure head 5a of the digital print unit 5, and a second exposure roller unit 80B on the exit side. An exposure transport roller unit 80C is provided, each of which is a set of a driving roller and a pressure roller that can be displaced in a distance from the driving roller.

The sorting device 4 includes a paper cutter 11
The photographic paper 2 cut by the above is received, and is constituted by a chucker-type XY moving mechanism that alternately transfers the photographic paper 2 to the left and right row positions of the intermediate transport roller unit 80A. Of course, when handling a wide large photographic paper 2, exposure is performed in one row, so the photographic paper 2 received from the photographic paper supply line 8A is simply used as the intermediate transport roller unit 80A.
Just hand it over.

Next, the photoelectric conversion unit 5 of the film scanner 3
About the temperature correction control of 0 and the function of the controller 7. This will be described with reference to FIG. The photoelectric conversion unit 50 is the same as the CC described above.
D sensor 51, CCD during main scanning of the film scanner 3
A CCD driver 52 for controlling the charge accumulation operation and charge accumulation time of the sensor 51, a CDS circuit 53 for clamping a voltage signal output from the CCD sensor 51, an AGC circuit 54 for amplifying the held signal, and an AGC circuit 54 A / D converting the voltage signal converted into the A / D input voltage into a digital signal having a predetermined number of bits (for example, 12 bits)
A D converter 55 is provided. The CDS circuit 53 and the AGC circuit 54 are usually formed of a one-chip module.
AGC control terminal 54a for ensuring that the amplitude of the signal falls within the D conversion voltage range, and for preventing OPB (optical black level) from falling below the lower limit of the A / D conversion voltage range. Offset terminal 54b is provided. In this application, the CDS circuit 53 and the AGC
The circuit 54 and the A / D converter 55 are collectively called a digitizing unit 50a.

Further, in order to measure the environmental temperature, the film scanner 3 has a photographing optical system 4 in this embodiment.
A temperature sensor 60 is provided in a region between 0 and the photoelectric conversion unit 50, and a detection signal thereof is taken into the controller 7. The controller 7 to which a monitor 7a for displaying various processing information and an operation console 7b for inputting various processing instructions are connected uses a microcomputer system including a CPU, a ROM, a RAM, an I / O interface 70 and the like as a core member. The various functions necessary for controlling the photographic processing apparatus as described above are realized by hardware and / or software. The control unit as a main functional element related to the present invention realized here is obtained by the film transport control unit 71 for controlling the film transport mechanism 9, the scanner control unit 72 for controlling the film scanner 3, and the film scanner 3. An image processing unit 73 that performs various image processing such as white balance, negative / positive inversion, and edge enhancement on the processed image data to generate print data, and displays the image data processed by the image processing unit on the monitor 7a. A video processing unit 74 that generates a video signal, a temperature correction unit 75 that generates a correction signal to the digitizing processing unit 50a based on a detection signal from the temperature sensor 60 using an LUT (lookup table) 75a, and a digital printing unit 5 And the like, which controls the print control. Of course, the control of the photographic paper transport mechanism 8 can also be performed by the controller 7. The controller 7 is usually a multi-CP composed of a main computer and a sub computer.
Built with U system.

Digitization processing unit 5 by temperature control unit 75
The mechanism of the temperature correction of 0a will be described with reference to the flowchart of FIG. A temperature correction routine is started to check the environmental temperature by the temperature sensor 60 regularly or irregularly. First, as an initial setting, a previous measured value is set as a reference temperature value (# 10). Then, the measured value measured by the temperature sensor 60 is taken in (# 12),
When the fluctuation width is equal to or larger than the predetermined threshold value as compared with the reference temperature value, the control enters the adjustment mode # 16 or lower.
4). When the adjustment mode is entered, the setup filter 32a having an appropriate gray value of the illumination optical system 30 is set on the optical axis (# 16), and the CCD sensor 5 receives the reference light.
1 is irradiated (# 18). The temperature correction unit 75 accesses the image processing unit 73 and compares the density value of each dot obtained based on the reference light with the reference value stored in the LUT 75a (# 22), and the difference can be ignored. If so, the process exits the temperature correction routine. If the difference cannot be ignored, a control signal for temperature correction to the control terminal of the digitizing processing unit 50a is determined according to the difference (# 24). In this embodiment, an AGC control terminal 54a, an offset terminal 54b, or both are employed as control terminals of the digitization processing unit 50a. The determination of the control signal according to the above-mentioned difference pattern is performed by a conditional expression set in advance by data obtained by experimentally and empirically evaluating the thermal fluctuation of the electronic circuit. When the control signal for temperature correction is determined, the digitizing processor 50a is readjusted with the control signal (# 26), and the process returns to # 18 to repeat the adjustment operation. By executing such a temperature correction routine, the film scanner 3 can ensure good scanning quality despite the fluctuation of the environmental temperature.

In the above-described embodiment, in the adjustment mode, the adjustment of the photoelectric conversion unit is performed using the setup filter. However, if the control signal for ensuring a good scanning quality with respect to the environmental temperature is experimentally and empirically obtained. When the relationship of the values is obtained, the temperature correction unit 75 can calculate the LUT 75 from the measured value from the temperature sensor 60 by storing the environmental temperature-control signal value characteristic in a table and storing it in the LUT 75a.
Since the control signal value can be obtained by accessing “a”, the digitizing processing unit is automatically adjusted without performing the test scanning, and a good scanning quality is ensured despite the fluctuation of the environmental temperature. be able to.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of a digital minilab system employing a film scanner according to the present invention.

FIG. 2 is a block diagram of a film scanner and a controller according to the present invention.

FIG. 3 is a flowchart showing a temperature correction routine.

[Explanation of symbols]

 Reference Signs List 3 film scanner 7 controller 9 film transport mechanism 10 auto film mask 30 illumination optical system 40 imaging optical system 50 photoelectric conversion unit 50a digitization processing unit 51 CCD sensor (photoelectric conversion element) 52 CCD driver 53 CDS circuit 54 AGC circuit 55 A / D converter 60 Temperature sensor 72 Scanner control unit 73 Image processing unit 75 Temperature correction unit 75a LUT

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H106 AA41 BH00 5C062 AA05 AB03 AB17 AC02 AC21 AC27 AC58 AE03 5C072 AA01 BA12 BA19 CA02 CA11 EA05 RA13 RA15 UA01 UA05 UA06 UA11 VA03 5C077 MM03 MM30 MP08 PP11 PP12 PP11 PP12 PP11 PP12

Claims (5)

[Claims] 1. An illumination optical system for projecting irradiation light onto a photographic film, a photoelectric conversion element for photoelectrically converting an image of a film image by the irradiation light, and a digitization for digitizing a signal transferred from the photoelectric conversion element. A temperature correction method for a film scanner comprising a processing unit, comprising: measuring an environmental temperature of the film scanner; and re-adjusting an operation parameter of the digitizing processing unit according to the measured temperature. Method. 2. When the measured temperature reaches a predetermined value, the output signal of the digitizing unit becomes a set value based on a signal obtained by irradiating a photoelectric conversion element with standard irradiation light. 2. The method according to claim 1, wherein the operation parameters are readjusted. 3. When the measured temperature reaches a predetermined value, the operating parameters of the digitizing unit are readjusted based on a look-up table including preset environmental temperatures and operating parameters. Claim 1
3. The temperature correction method for a film scanner according to item 1. 4. The method according to claim 1, wherein the digitizing processing section includes a CDS circuit and an AG.
The temperature correction of a film scanner according to any one of claims 1 to 3, comprising a C circuit and an A / D converter, wherein the gain of the AGC circuit is readjusted as the operation parameter. Method. 5. An illumination optical system for projecting irradiation light on a photographic film, a photoelectric conversion element for photoelectrically converting an image of a film image by the irradiation light, and a digitization for digitizing a signal transferred from the photoelectric conversion element. And a control unit for controlling the photoelectric conversion element and the digitizing processing unit. The temperature sensor measures an environmental temperature of the film scanner. The film scanner according to claim 1, wherein the control unit re-adjusts an operation parameter of the digitizing unit.