JPS6173468A - Picture reader - Google Patents

Abstract

PURPOSE:To remove the variation of a distribution ratio generated due to the difference of a polarized surface of a beam including picture information or an incident angle and to hold a wide dynamic range by dividing the beam at its section into plural parts and distributing the divided beams to respective detectors. CONSTITUTION:A laser beam radiated from a light source scans the surface of a film 6 linearly through respective parts 2-4. The whole surface of the film 6 can be scanned with the laser beam by carrying the film 6 in the shown arrow direction and its transmitted light becmoes the laser beam including the picture information. Since two photodiodes are dividedly arranged as shown in the drawing, the laser beam is distributed into two light flux. In this case, the laser beams are made incident upon the surfaces 7 from the same direction (vertical direction). In the dividing method, the distribution ratio based upon the polarizing surfaces of the laser beam incident upon the surfaces 7 is not changed. Then, obtained optical current is inputted to amplifiers 8a, 8b.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an image reading device, and is particularly suitable for configuring an image reading device with a wide width.
This concerns the method of the optical system.

[Background of the invention]

Conventional image reading devices with a wide dynamic angle split the transmitted light or reflected light using a beam splitter, but differences in the polarization plane and angle of incidence of the beams cause variations in the distribution ratio, which makes it difficult to combine signals. No consideration was given to the possibility of deficiencies.

[Purpose of the invention]

An object of the present invention is to provide an image reading device that has a wide dynamic V/G, eliminates defects in signal synthesis due to optical factors such as the polarization plane of the beam and the angle of incidence, and is capable of good word synthesis. [F] to do it.

[Summary of the invention]

The feature of this invention is that by dividing the beam into multiple parts according to the beam cross section and distributing them to each detector, fluctuations in the distribution ratio caused by differences in the polarization plane and incidence angle of the beam containing image information are eliminated, and the beam is passed through the preamplifier. By outputting it, it becomes an electrical signal with a constant gain ratio, and by selecting and synthesizing it, it has a wide Guinamino range.

[Embodiments of the invention]

An embodiment of the present invention will be described with reference to FIG.

1 is a laser light source. 2 is a galvanometer and a photographing mirror. 3 focuses the V-laser beam on a plane at a certain distance (on the film surface) using an fθ lens, and scans the laser beam with a small spot diameter on the plane. 4 is a plane mirror. 5 is laser 6 is film. 7 is a split photodiode (or photomultiplier) that converts incident light into an electrical signal. 8a and 8b are preamplifiers. 9a
.

9b is a sample holder. 10a and 10b are AD converters. 11 is an IF image processing device.

In the above configuration, the laser beam emitted from the light source linearly scans the film 6 through 2, 3, and 4. By feeding the film in the direction of the arrow in the figure, it becomes possible to scan the entire surface of the film with a laser beam, and the transmitted light becomes a laser beam containing image information. The sensor beam is focused on the outside of detector 7 by all 5 spherical mirrors, and enters 7.

At this time, by dividing the first photodiode into two and arranging them as shown in A in Fig. 2, the V-laser beam is distributed as two luminous fluxes to the photodiodes 12a and 12b. Ru.

At this time, the laser beam is incident on the plane of 7 in the same direction (perpendicular direction).
'c The distribution ratio does not vary depending on the polarization plane of the incident laser beam.

In this way, a laser beam is incident on each photodiode, and the resulting photocurrents i8a and 8bK are inputted to make the gain ratio of amplifier a and amplifier b 1100:1. Then, output signals output from up a and a/b b to pull holders (9a, 9bl) and AD converters (10a, 10).
Enter it into 11 through b).

In the above example, firstly, when the entire laser beam is extracted, there is no influence due to the plane of polarization or the angle of incidence. Second, by selecting and adjusting two signals according to the dynamic range of the light transmitted through the film, it is possible to read images over a wide dynamic range.

Furthermore, an example of the shape of the detector for receiving and detecting the laser beam is shown in FIG. Figure 3 shows a system in which the laser beam is distributed to all two amplifiers. In this example, the photodiode type is subdivided into smaller parts than the detector shown in Figure 2, and it covers the whole area, so it is able to withstand vibrations that are external to the device during signal synthesis. Defects are unlikely to occur.

Is Figure 4 a detector? In this example, the beam is further divided into multiple parts to cover the whole area, but an amplifier is attached to each detector for detection, and the movement of the beam by the vibrating mirror is determined from 11. Correcting υC when manually applying power to the amplifier. Each amplifier can provide a gain ratio.

Also, the detector is not limited to a photodiode, but can also be a photomultiplier or CCD.

〔Effect of the invention〕

According to the present invention, variations in the distribution ratio and inconsistencies in signal synthesis caused by differences in the polarization plane or angle of incidence of the beams containing image information can be eliminated. Furthermore, the number of divisions into which the beam is divided can be determined arbitrarily, and thereby the image signal can be read with an arbitrary dynamic range.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a film reading device according to an embodiment of the present invention, FIG. 2 is an explanatory diagram showing the entire beam incident on the detector, and FIG.
The figure is an explanatory diagram of the photodiode of a multi-division detector in which there are two amplifiers in total.

Claims (1)

[Claims] 1. In an image reading device comprising a light source, a scanning system that scans the output light of the light source so as to cover each pixel constituting the image, and a photometry system that receives a beam containing image information, the photometry system is A function that distributes the beam to multiple photodetectors by dividing the beam cross section, a preamplifier that gives a certain gain ratio to the electrical signal obtained from each detector, and a function that distributes the beam to multiple photodetectors by dividing the beam cross section. An image reading device comprising a signal synthesis function that selects an output according to the light intensity of the beam and connects the selected signals.