CN100556069C - Cis - Google Patents

Abstract

image reader. An image reader includes: an illumination unit that irradiates an object to be read with light; a first optical system that enables first reflected light from the object to be read to travel therein; a second optical system that enables light from the object to be read to the second reflected light of the object to be read can travel therein; the switching unit switches between the first optical system and the second optical system to be used; the imaging unit switches between the first optical system and the second optical system through the switching unit Switch between the two optical systems to form an image of the first reflected light traveling in the first optical system and an image of the second reflected light traveling in the second optical system; and a light receiving unit that receives and forms multiple The first reflected light and the second reflected light of an image, and generate corresponding image signals.

Description

image reader

technical field

The present invention relates to a technique for capturing information on texture of an original and reproducing the information in an image reader.

Background technique

The surfaces of objects each have a "texture". For example, the surface of polished metal gives the viewer a "shine feel", while the surface of cloth or fabric gives the viewer a "matte feel". In order to represent an object more realistically like an actual object, it is necessary to capture information about the texture (texture information) of the actual object such as gloss and feel (appearance and touch) and reproduce the texture information. Therefore, in image readers of scanners, copiers, and the like, attempts have been made to read not only color information of objects but also texture information of objects.

The texture of an object mainly depends on the reflection of light on the surface of the object. Generally, the reflected light on the surface of an object is composed of highly directional specular light and low directional diffuse light, wherein the texture of the object is different according to the ratio of these two lights. For example, the proportion of specularly reflected light is relatively high on a polished metal surface, so the metal surface has a glossy appearance. On the other hand, on the surface of a matte object such as cloth or fabric, the proportion of diffuse light is relatively high. That is, by measuring the reflected light from the surface of the object to obtain the ratio of specular reflected light to diffuse reflected light, so as to faithfully express the texture of the object, more specifically, the glossiness of the object.

In an image reader, objects constituting an original are read using diffuse reflected light. That is, in the image reader, reflected light containing a large amount of diffusely reflected light from an original is received, and color information of an object is generated based on the diffusely reflected light. On the other hand, when the image reader is designed so as to receive reflected light containing a large amount of specularly reflected light from the original, there may be cases where the specularly reflected light component becomes excessively The color reading performance of the original image by reflected light is degraded. Therefore, the imaging optical system is designed so that specularly reflected light from the original is minimized so that reflected light containing as much diffusely reflected light as possible is received.

On the other hand, in order to read the texture of the surface of the original, the image reader can be configured such that it receives diffuse reflection light and specular reflection light from the original, and obtains color information and texture information based on the corresponding reflection light components. For example, there are known techniques in which an image mainly containing diffuse reflection light (diffuse reflection image) is read by light emitted from a light source to an object to be copied (original), and an image is read by light emitted from another light source to an object to be copied. Images mainly containing specular reflection light (specular reflection images) are taken and gloss signals representing gloss are generated based on these image signals. That is, in this technique, color information of an object to be copied is obtained based on diffuse reflection light, and texture information of the object to be copied is obtained based on specular reflection light.

However, using this technique to obtain the texture information of the original surface has the following disadvantages.

In the above technology, the optical system contains two different lighting units, one lighting unit (light source) is used to obtain diffuse reflection light, and the other lighting unit (light source) is used to obtain specular reflection light. Therefore, the structure for irradiating the original becomes large in size and increases in cost. In addition, these illumination units are located at different reading positions, so when obtaining an overlay image from these reflected lights, i.e. when overlaying a diffuse image with a specular image, the same diffuse and specular image must be used. A memory or the like corresponding to the shifted position of the image corrects the position of these image signals.

Furthermore, in the above structure, since the optical path length for reading the reflected light of the diffuse reflection light is different from the optical path length for reading the reflected light of the specular reflection light, unless any measures are taken, at least one of the reflected light will not be correctly reflected. The reflected light is received with the light focused into an image. Therefore, in order for these reflected lights to perform correct imaging, it is necessary to adjust the focus point of the reflected lights every time, and to perform the reading operation of the original twice.

Contents of the invention

The present invention has been made in view of the above circumstances, and provides a technique that makes it possible to obtain texture information more easily and quickly.

According to an aspect of the present invention, an image reader includes: an illumination unit that irradiates an object to be read with light; a first optical system that enables first reflected light from the object to be read to travel therein; a second optical system , which makes the second reflected light from the object to be read travel therein; the switching unit, which switches between the first optical system and the second optical system to be used; the imaging unit, which passes through the switching unit in the first optical system switching between the system and the second optical system to form an image of the first reflected light traveling in the first optical system and an image of the second reflected light traveling in the second optical system; and a light receiving unit that receives The first reflected light and the second reflected light formed into a plurality of images by the imaging unit, and corresponding image signals are generated.

Description of drawings

Multiple embodiments of the present invention will be described in detail based on the following drawings, in which:

FIG. 1 is a diagram showing a device structure of an image reader according to a first exemplary embodiment of the present invention.

FIG. 2 is a diagram showing the structure of a full rate carriage of the same embodiment.

FIG. 3 is a graph showing an example of the intensity distribution of specularly reflected light from the original P. As shown in FIG.

FIG. 4 is a diagram showing the structure of a full-rate module of a second exemplary embodiment of the present invention.

FIG. 5 is a diagram showing the structure of a full-rate module of a third exemplary embodiment of the present invention.

FIG. 6 is a diagram showing the structure of a full-rate module of a fourth exemplary embodiment of the present invention.

FIG. 7 is a diagram showing a structure in which a liquid crystal shutter is mounted on the full rate module shown in FIG. 6. Referring to FIG.

FIG. 8 is a diagram showing the structure of a full-rate module of a fifth exemplary embodiment of the present invention.

Fig. 9 is a diagram schematically showing directions of first reflected light and second reflected light focused to form an image by the full rate component of the third exemplary embodiment.

Fig. 10 is a diagram showing the structure of a full-rate module of a sixth exemplary embodiment of the present invention.

Fig. 11 is a diagram showing the structure of a full-rate module of a seventh exemplary embodiment of the present invention.

Figure 12 is a diagram illustrating a full rate assembly including an exemplary embodiment of a prism.

Detailed ways

Hereinafter, the present invention will be described in detail based on a plurality of embodiments with reference to the drawings.

The image reader of the present invention includes an optical system (a plurality of mirrors) in which the first reflected light and the second reflected light from an original that is irradiated with light from a single lighting unit (light source) are finally guided to On the same optical path, the first reflected light and the second reflected light are received by the same light receiving unit (linear image sensor). Due to this structure, the image reader of the present invention can obtain texture information more easily than conventional image readers. Furthermore, according to the present invention, the above-mentioned first reflected light and second reflected light are captured as synthesized reflected light and read by a single read operation, therefore texture information can be obtained faster than conventional image readers . Hereinafter, the present invention will be described in detail in conjunction with several embodiments.

first embodiment

FIG. 1 is a diagram showing a device structure of an image reader 100 according to a first exemplary embodiment of the present invention. As shown in the figure, the image reader 100 includes a flat-press glass 11 , a flat-press cover 12 , a full-rate carriage 13 , a half-rate carriage 14 , an imaging lens 15 , a linear image sensor 16 , and an operation section 17 .

The flat glass 11 is formed of a transparent glass plate on which the original P to be read is placed. On both surfaces of the flat glass 11 , for example, an antireflection layer formed of a dielectric multilayer coating or the like is formed, thereby reducing reflection of light on the surface of the flat glass 11 . The platen cover 12 is arranged such that the platen cover 12 covers the platen glass 11 and blocks external light for reading the original P placed on the platen glass 11 .

The original P is not limited to paper, but may be formed of a plastic sheet (such as an OHP sheet), a metal sheet, cloth, or fabric.

FIG. 2 shows the structure of the full-rate component 13 of this embodiment. The full rate assembly 13 includes a light source 131 , mirrors 132 , 133 , 134 and a rotatable reflector 135 . The light source 131 is constituted by, for example, a tungsten-halogen lamp or a xenon fluorescent lamp, and irradiates the original P with light. Mirrors 132 , 133 , 134 also reflect reflected light from original P and direct the reflected light to half rate assembly 14 . The rotatable reflector 135 forms a mirror 135m reflecting light on one surface thereof and a light trap 135t absorbing light on the other surface thereof. The light trap 135t is formed, for example, from a black porous polyurethane sheet, the surface of the light trap 135t traps and absorbs most of the light incident on the light trap 135t.

When the rotatable reflector 135 is in the position shown in FIG. Light. The rotatable reflector 135 is rotated around an axis 135a as an axis by a driving portion not shown in the figure, and can be moved to a position indicated by a dotted line (135') in the figure. When rotatable reflector 135 is in such a position, rotatable reflector 135 directs light from mirror 134 to half rate assembly 14 and, on the other hand, absorbs light directed towards mirror 132 .

Therein, the light reflected by the rotatable reflector 135 has an optical path aligned with the optical path of the light reflected on the mirror 134 . By adopting this structure, two different kinds of reflected light can be received using the same light receiving unit (linear image sensor 16).

Here, the reflected light traveling inside the full rate module 13 will be described.

As described above, the specularly reflected light has high directivity and most of the specularly reflected light is reflected at substantially the same angle with respect to the incident angle. FIG. 3 shows an example of the intensity distribution of specularly reflected light from the original P, in which the offset angle from the incident angle is indicated on the horizontal axis (the intensity indicated on the vertical axis is a dimensionless quantity). In contrast, diffuse light has low directionality and is reflected substantially uniformly at all angles.

Then, in the full-rate component 13 of the present embodiment, the incident angle of the light _Lin from the light source 131 is set to about 45°, and the light L _sr reflected at a reflection angle of about 45° relative to the light _Lin is reflected on the mirror 133. For upward reflection, the light L _sr is used as reflected light (second reflected light) for reading specularly reflected light. Although the light L _sr contains not only the specular reflection light but also the diffuse reflection light, the component of the light L _sr corresponding to the diffuse reflection light is canceled out by applying a given mathematical calculation to an image signal generated after receiving the light. On the other hand, in the same manner as a general-purpose image reader that reads only color information, the diffuse reflection light is read based on the light L _dr reflected at a reflection angle of about 0° with respect to the light _Lin , and the light L _dr Set as reflected light (first reflected light) for reading diffuse reflected light. That is, the reflected light L _sr for reading specular reflected light is reflected on the mirrors 133 , 134 and the half-rate component 14 , and is focused into an image by the imaging lens 15 on the linear image sensor 16 . In addition, the reflected light L _dr for reading the diffuse reflected light is reflected on the mirror 132 , the rotatable reflector 135 and the half-rate component 14 , and is focused into an image by the imaging lens 15 on the linear image sensor 16 .

Here, in the following description, the reflected light L _dr used to read diffuse reflected light is referred to as "first reflected light", and the reflected light L _sr used to read specular reflected light is referred to as "second reflected light". ".

Furthermore, in the present embodiment, the plurality of mirrors and the rotatable reflector may be arranged as follows. That is, the optical path length (P-132-135-141) for guiding the reflected light L _dr from the original P to the half-rate component 14 and the optical path length (P-132-135-141) for guiding the reflected light L _sr from the original P to the half-rate component 14 ( P-133-134-141) are equal. In this case, even if the position of the rotatable reflector 135 changes, the focal point of the imaging optical system does not change. Due to this structure, since the focus position does not vary with respect to each reflected light, it is not necessary to adjust the focus position when reading reflected light.

The constituent elements of the above-mentioned full-rate assembly 13 are arranged in a direction perpendicular to the paper surface of FIG. 2 so as to have a width substantially equal to that of the flat-pressed glass 11 as a whole. In addition, the full-velocity assembly 13 is moved at a velocity v in the direction indicated by the arrow C in FIG. 1 by a driving section not shown in the figure. The full-speed assembly 13 can scan the entire surface of the original P by actuating the driving portion to move the full-speed assembly 13 in the direction indicated by the arrow C.

Referring again to FIG. 1 , various parts of the image reader 100 are described below.

Half rate component 14 includes mirrors 141 , 142 and directs light from full rate component 13 to imaging lens 15 . In addition, the half-speed assembly 14 is driven by a driving part not shown in the figure, and makes it to the same direction as the moving direction of the full-speed assembly 13 at a rate (that is, v/2) of half of the speed of the full-speed assembly 13 move.

The imaging lens 15 is arranged on an optical path connecting the mirror 142 and the linear image sensor 16 and forms an image of light from the original P on the surface of the linear image sensor 16 . The linear image sensor 16 is a light receiving element (such as a 3-line color CCD (Charge Coupled Device) image sensor, etc.) color light and perform photoelectric conversion on the light, thereby generating and outputting an image signal corresponding to the amount of received light.

The operation section 17 includes a liquid crystal display, various push button switches, etc., and receives input instructions from the user by displaying information for the user.

The operations of the above-mentioned parts are controlled by a control part not shown in the figure. The control section includes a mathematical operation device such as a CPU (Central Processing Unit) and various memories such as a ROM (Read Only Memory), RAM (Random Access Memory) and the like. The control section provides instructions to the above-mentioned driving section in response to instructions input by a user, thereby instructing the driving section to perform a given operation to read an image. Further, the control section applies various image processing (such as AD conversion, γ conversion, shading correction) to the image signal output from the linear image sensor 16, thereby forming image data. The image signal output from the linear image sensor 16 is composed of an image signal based on the second reflected light and an image signal based on the first reflected light. The control section performs a given mathematical operation using these image signals and generates image data containing information on texture. A mathematical process of canceling the component corresponding to the diffusely reflected light from the above-mentioned second reflected light is performed at this stage of the overall operation.

With the above structure, the image reader 100 of the present embodiment scans the entire surface of the original P by moving the full rate unit 13 in the C direction, and generates an image signal of the original P. In the present embodiment, the image reader 100 performs a reading operation (scanning operation) on the original P twice, and generates an image signal based on the reflected light L _dr and an image based on the reflected light L _sr in the reading operation. Signal. When generating an image signal based on the reflected light _Ldr , the control part moves the rotatable reflector 135 to the position shown in FIG _. Move to the position indicated by 135' in FIG. 2 . Then, the control section obtains gloss information from the image signal based on the reflected light L _sr , and superimposes the gloss information on color information obtained from the image signal based on the reflected light L _dr .

Here, "gloss information" indicates which area of the image data has gloss (hereinafter referred to as "glossy area") and the glossiness of the glossy area. For example, "gloss information" indicates glossiness with respect to a digital signal of 2 to 8 bits based on an RGB color of a pixel corresponding to image data. Each pixel data takes a value close to "black (R=0, G=0, B=0)" corresponding to the decrease in glossiness. Using the gloss information, the control section designates a glossy area on the image data, obtains the degree of gloss in the area, then determines the color of the glossy area (for example, determines gold, silver) and adds the information to the image data. Alternatively, for each pixel, the control section may specify the glossy area based only on the 2 to 8-bit digital signal of the G color, thereby generating image data by adding only the glossiness.

The image data obtained in this way contains information on texture (ie, texture information). For such image data, for example, by applying given processing to glossy areas in an image forming apparatus, an image in which the texture of an object (original) is reproduced can be generated. In the case of an electrophotographic image forming apparatus, a given process on a glossy area refers to, for example, a process in which the usual colors of C (cyan), M (magenta), Y (yellow), and K (black) are used. Toner forms an image on paper, then forms a transparent toner layer on glossy areas, and finally, fixes the image under high temperature and pressure to impart gloss to the surface of the formed image, or a process in which metallic color is used (such as gold, silver, etc.) toner to form a gold or silver metallic image.

second embodiment

Next, a second exemplary embodiment of the present invention will be described. The image reader of this embodiment (hereinafter referred to as "image reader 200") differs from the above-described image reader 100 of the first embodiment only in the structure of the full-rate components. Therefore, only the structure of the full-rate module will be described below, and the same constituent parts as those of the first embodiment will be given the same reference numerals and their descriptions will be omitted.

FIG. 4 shows the structure of the full rate module 23 of this embodiment. As shown, the full rate component 23 includes a light source 131 , a prism 232 and a rotatable light trap 233 .

The prism 232 is a polygonal prism, by coating a mirror layer, a semi-transmissive mirror layer, etc. , an antireflection layer, etc., and by bonding these layers using an optical adhesive material having a refractive index substantially equal to that of the glass material, the polygonal prism is obtained. The prism 232 is arranged to cover a direction perpendicular to the paper surface of FIG. It has vertices A, B, E, F in cross-section) and a quadrangular prism-shaped glass material 232b (which has vertices B, C, D, E in cross-section) is bonded to form prism 232 . Furthermore, for example, a thin aluminum layer is covered to the surface AB of the glass material 232a and the surface BC of the glass material 232b by vapor deposition and these surfaces are used as mirrors. An antireflection layer is formed on the surface CD of the glass material 232b, and in addition, a light trap 232t formed of a black porous polyurethane sheet or the like is laminated on the surface CD, thereby allowing the surface CD to absorb substantially all light incident on the surface CD. An antireflection layer is formed on the surface DE of the glass material 232b and the surfaces EF and FA of the glass material 232a such that the angle formed by the optical axis of incident light with each surface becomes 0°. In addition, a semi-transparent mirror (semi-transparent mirror) layer is formed on the bonding surface BE of the glass material 232a and the glass material 232b to reflect a part of the incident light and allow a part of the incident light to transmit. Due to the structure of the semi-transparent mirror, as the light reflectance of the front side increases, the light transmittance of the back side decreases. Therefore, when designing the full-rate component 23 of this embodiment, it is possible to properly select a semi-transparent mirror that allows each reflected light to be read in an appropriate ratio.

The above-mentioned light trapping members are laminated on both surfaces of the rotatable light trap 233, and the rotatable light trap 233 is rotated by a driving unit not shown in the figure using the shaft 233a as an axis. When the rotatable light trap 233 is located at a position along the surface EF of the prism 232, the rotatable light trap 233 absorbs the diffusely reflected light from the original P, and when the rotatable light trap 233 is located along the surface DE of the prism 232 position, the rotatable light trap 233 absorbs specularly reflected light from the original P.

Wherein, in this embodiment, the optical path length for reading diffuse reflection light and the optical path length for reading specular reflection light may also be set to be equal. That is, assuming that the length of the optical path from the original P to the surface EF of the prism 232 along the optical axis is _l11 , the length of the optical path from the surface EF of the prism 232 to the surface FA along the optical axis is _l12 , and the length of the optical path from the original P to the prism 232 along the optical axis is l11. The optical path length of the surface DE of the prism 232 is l ₂₁ , the optical path length from the surface DE of the prism 232 to the surface FA along the optical axis is l ₂₂ , and the refractive index of the prism is n, then the relationship expressed by the following formula 1 can be satisfied:

l ₁₁ +nl ₁₂ = l ₂₁ +nl ₂₂ ... (Formula 1)

This relationship is satisfied by adopting a structure in which the cross-sectional shapes of the glass material 232a and the glass material 232b are line-symmetric with respect to the extension line of the surface BE.

By using the above structure, the image reader 200 of the present embodiment can perform substantially the same operations as the image reader 100 of the first embodiment. In the image reader 200, when generating an image signal based on the first reflected light, the control portion moves the rotatable light trap 233 to a position along the surface DE of the prism 232, and when generating an image signal based on the second reflected light signal, the control part moves the rotatable light trap 233 to a position along the surface EF of the prism 232 .

third embodiment

Next, a third exemplary embodiment of the present invention will be described. The image reader of this embodiment (hereinafter referred to as "image reader 300") is different from the image readers of the first and second embodiments described above in that the first reflection can be read by a single scanning operation. light and the second reflected light. In addition, the image reader 300 of this embodiment differs from the image reader 100 of the first embodiment only in the structure of the full-rate components, so only the structure of the full-rate components will be described below, and the The same constituent parts as those of the first and second embodiments are given the same reference numerals and their descriptions are omitted.

FIG. 5 is a diagram showing the structure of the full-rate module 33 of the present embodiment. As shown, the full rate component 33 includes a light source 131 , mirrors 332 , 333 and a semi-transmissive mirror 334 . The semi-transmissive mirror 334 reflects a part of the reflected light L _dr from the mirror 332 without transmitting the reflected light L _dr and allows a part of the reflected light L _sr to transmit without reflecting a part of the reflected light L _sr from the mirror 333 .

In the image reader 300 of the present embodiment, the length of the optical path along which the reflected light L _dr from the original P is reflected on the mirror 332 and reaches the surface AB of the semi-transmissive mirror 334 is different from that of the reflected light L _sr from the original P. The length of the optical path along which the mirror 333 is reflected and reaches the semi-transmissive mirror 334 is designed to be equal, and the reflected light L _dr and the reflected light L _sr are synthesized by the semi-transparent mirror 334 and output as synthesized light. By making the full-rate component 33 have such a structure, diffuse reflection light and specular reflection light reflected from the same position of the original P can be received at the same time. Therefore, image data having texture information can be easily formed without performing complicated mathematical operations.

Here, the angle _θ2 formed by the reflected light L _sr incident on the mirror 333 with respect to the normal to the original P can be set to a value that differs by ±5° from the incident angle _θ1 of the light L _in from the light source 131. The reason for this will be explained below.

Here, it will be described with reference to the above-mentioned FIG. 3 . As shown, specular light is generally very directional, and the peak of specular light becomes steeper as the surface gloss increases. Therefore, when an object having a high-gloss surface is used as the original P, when there is a relationship of θ ₂ = θ ₁ between the angle θ ₂ and the angle of incidence θ ₁ , there is a possibility that the synthetic light received by the linear image sensor 16 The intensity exceeds the readable limit of the linear image sensor 16 . In this case, the intensity of the image signal output from the linear image sensor 16 has a saturation value, and therefore, it is difficult to correctly read diffuse reflection light and specular reflection light from such a signal. In order to prevent the intensity of the signal output from the linear image sensor 16 from reaching saturation when receiving the synthesized light, the mirror 333 may receive the reflected light L _sr at an angle such that the signal intensity is less than the maximum intensity, so as to receive the light having a readable signal not exceeding the linear image sensor 16. Synthetic light with extreme intensity. By deviating the angle θ ₂ formed by the reflected light L _sr with respect to the normal to the original P from the incident angle θ ₁ of the light L _in from the light source 131 by about ±5°, the intensity of the image signal generated by the synthesized light can be made smaller than the maximum strength.

Due to this structure, the image reader 300 of the present embodiment can read the first reflected light and the second reflected light by a single scanning operation, and can obtain an image with texture information without increasing the scanning time for the original data. For example, by using the image reader 300 of this embodiment to perform reading of an original in which only a specific area of an image has strong gloss and other areas have weak gloss, it is possible to obtain (Non-glossy area) is an image signal with high intensity. The image data obtained from this image signal shows a color value larger than the maximum value of the color value (ie, the color value of "white") considered to be color information based on the first reflected light in the above-mentioned glossy area. Therefore, by performing determination of a glossy area with respect to image data using the above-mentioned "white" color value as a threshold, given processing can be applied to the glossy area. For example, in an electrophotographic image forming apparatus, an application is considered in which an image is formed on paper using general color toners of C, M, Y, K for non-glossy areas and metallic toners are used for glossy areas. A metal image is formed on the area.

Alternatively, the image reader 300 of the present embodiment can be suitably applied to a case where reflection of specularly reflected light from the surface of an original can be predicted to some extent, for example, the original is glossy The case of the printing paper or the original are basically dull cloth.

Fourth embodiment

Next, a fourth exemplary embodiment of the present invention will be described. The image reader of this embodiment (hereinafter referred to as "image reader 400") can read the first reflected light and the second reflected light by a single scanning operation in the same manner as the image reader 300 of the third embodiment described above. reflected light.

The arrangement of mirrors and the like inside the full-rate module is not limited to that of the above-described embodiment, and various modifications can be conceived. The arrangement of the present embodiment is directed to one example of these modifications.

FIG. 6 shows the structure of the full rate module 43 of the image reader 400 of the present embodiment. As shown, the full rate assembly 43 includes a light source 131 , mirrors 432 , 433 , 434 , 435 and a semi-transmissive mirror 436 . With this structure, the first reflected light (diffuse reflected light) is reflected on the mirrors 432, 433 and the semi-transmissive mirror 436 and received by the line sensor 16, while the second reflected light (specular reflected light) is reflected on the mirrors 434 and 435. , through the semi-transmissive mirror 436 and received by the linear image sensor 16 . However, in this case also, it is necessary to make the optical path length of the first reflected light equal to the optical path length of the second reflected light.

Due to this structure, the image reader 400 can read the first reflected light and the second reflected light through a single scanning operation.

Here, as described above in connection with the third embodiment, when the image reader 400 receives the first reflected light and the second reflected light at the same time, it is necessary to prevent the image generated by the combined light of the first reflected light and the second reflected light The signal is saturated. However, as has been described in connection with the third embodiment, when the second reflected light is reflected on the mirror at an angle slightly larger or smaller than the angle at which the maximum intensity can be obtained, there is a disadvantage as follows: When an object (ie, an object in which the ratio of the specularly reflected light component contained in the synthesized light is small) is the original P, it is impossible to obtain accurate texture information. Therefore, the use of the above method is limited to the case where the glossiness of the original P can be preliminarily predicted to some extent.

As a countermeasure against this disadvantage, for example, a liquid crystal light valve can be used. A liquid crystal light valve is a device that can change the transmittance of light by controlling an applied voltage.

FIG. 7 is a diagram showing a structural example in which a liquid crystal light valve 437 is provided in the full rate module 43 shown in FIG. 6 . In this figure, the first reflected light travels in a region 437 a inside the liquid crystal light valve 437 , and the second reflected light travels in a region 437 b inside the liquid crystal light valve 437 . In the liquid crystal light valve 437, the transmittances of the regions 437a and 437b are independently controlled by applying different voltages.

Due to this configuration, the user who operates the image reader 400 can input an instruction to decrease the transmittance of the area 437b and increase the transmittance of the area 437a when performing reading of an original P having a high glossiness, for example, or to An instruction to increase the transmittance of the area 437b and decrease the transmittance of the area 437a may be input when reading of the original P having low glossiness is performed.

Here, the above description has been made for the liquid crystal light valve 437 that can independently change the transmittance of each of the first reflected light and the second reflected light. However, a structure in which only the transmittance of the second reflected light can be changed can also obtain an advantageous effect to some extent. In addition, the liquid crystal light valve can be applied to other image readers than the image reader 400 of the present embodiment.

fifth embodiment

Next, a fifth exemplary embodiment of the present invention will be described. According to the image reader of this embodiment (hereinafter referred to as "image reader 500"), it is possible to read the first reflected light and the second reflected light by a single scanning operation, while having The structure of the extractor 200 is basically the same structure.

FIG. 8 shows the structure of the full-rate component 53 of this embodiment. As shown, the full rate assembly 53 includes a light source 131 and a prism 232 . That is, the full rate assembly 53 of the present embodiment is constructed by removing the rotatable light trap 233 from the full rate assembly 23 of the second embodiment. Here, in this embodiment, the optical path length of the first reflected light must be equal to the optical path length of the second reflected light.

Due to this structure, the image reader 500 can receive the image from the The first reflected light and the second reflected light reflected at the same position of the original P. Therefore, image data with texture information can be easily formed without performing complicated mathematical operations.

Furthermore, the full-rate assembly 53 of the image reader 500 can be constructed only by removing the rotatable light trap 233 from the full-rate assembly 23 of the second embodiment. That is, when the image reader 500 further includes the rotatable light trap 233, the image reader 500 can receive the first reflected light and the second reflected light individually in the same manner as the second embodiment described above, and at the same time can The combined light of the first reflected light and the second reflected light is received. Wherein, when receiving the combined light of the first reflected light and the second reflected light, the rotatable light trap 233 can be arranged at a position where the rotatable light trap 233 neither blocks the first reflected light nor blocks the second reflected light place.

Sixth embodiment

Next, a sixth exemplary embodiment of the present invention will be described. The image reader of this embodiment (hereinafter referred to as "image reader 600") can also employ substantially the same basic structure and operation as the image reader of the third embodiment described above. However, the image reader 600 of the present embodiment differs from the image reader of the third embodiment in the number of mirrors and the arrangement of the mirrors. That is, the present embodiment is characterized by the number of reflections of the first reflected light and the second reflected light on the plurality of mirrors.

FIG. 9 is a diagram schematically showing reflection directions of first reflected light and second reflected light formed as an image by the full rate component 33 of the third embodiment. In this figure, each arrow shown on the optical path indicates the vertical direction of the original P, where the direction of these arrows indicates the upward direction of the original P.

As shown in the figure, the first reflected light is reflected on the mirror 332 and the semi-transmissive mirror 334, that is, reflected twice in total, so when the first reflected light is output from the full rate assembly 33, the upper direction of the original P is downward . On the other hand, the second reflected light is reflected only once by the mirror 333, and therefore, when the second reflected light is output from the full rate assembly 33, the upper direction of the original P faces upward. That is, it can be understood that the image directions of the first reflected light and the second reflected light are opposite. When the two reflected lights are read simultaneously in this case, the resolution of the image formed on the linear image sensor 16 deteriorates, thereby becoming a cause of lowering the quality of the read image.

In order to make the image directions of the first reflected light and the second reflected light the same, the number of reflections of the first reflected light by the plurality of mirrors and the number of reflections of the second reflected light by the plurality of mirrors may be set to be equal. For example, assuming that both the first reflected light and the second reflected light are reflected twice by multiple mirrors, when the first reflected light and the second reflected light are output from the full rate component, for the first reflected light and the second reflected light, the original The up directions of P all face down, so the image directions become the same.

In the same way, it can be understood that even if the first reflected light is reflected three times on a plurality of mirrors and the second reflected light is reflected once on the mirrors, the upper direction of the original P is upward for both the first reflected light and the second reflected light , therefore, the orientation of each image becomes the same. That is, it can be understood that when both the number of reflections of the first reflected light and the number of reflections of the second reflected light become odd or even, the respective image directions become the same.

Here, in the above description of the manner of operation, only the optical path before outputting each reflected light from the full rate component has been described. However, in an actual operation mode, it must be based on the number of reflections of the first reflected light generated from the original P before the first reflected light is received by the linear image sensor 16 and the number of reflections from the original P before the second reflected light is received by the linear image sensor 16. The number of reflections of the second reflected light generated is used to determine whether the image orientation becomes the same. However, the light output from the full-rate components is the combined light of the first reflected light and the second reflected light and their optical paths are the same, therefore, the number of reflections in the subsequent full-rate components is naturally equal. Therefore, if the number of reflections of the first reflected light and the second reflected light before they are output from the full-rate component becomes the same, the number of reflections of each reflected light before being received by the linear image sensor 16 also becomes the same. got the same.

In view of the above description, the full-rate components of the image reader 600 of the present embodiment will be described.

FIG. 10 is a diagram showing the structure of the full-rate module 63 of the present exemplary embodiment. As shown, the full rate assembly 63 includes a light source 131 , mirrors 632 , 633 , 634 and a semi-transmissive mirror 635 . In this full-rate component 63, the first reflected light is reflected on the mirrors 632, 633 and the semi-transmissive mirror 635, so the number of reflections becomes three times in total. On the other hand, the second reflected light is reflected on the mirror 634, so the number of reflections thereof is one. That is, both the number of reflections of the first reflected light and the number of reflections of the second reflected light are odd numbers, and therefore, it can be understood that the image directions of the respective reflected lights received by the linear image sensor 16 become the same.

In other embodiments, the optical system may also be designed so that the image directions of the first reflected light and the second reflected light become the same, but not limited to this embodiment.

Seventh embodiment

Next, a seventh exemplary embodiment of the present invention will be described. Also in the image reader of this embodiment (hereinafter referred to as "image reader 700"), the first image received by the linear image sensor 16 is made The image direction of the reflected light is the same as that of the second reflected light. The present embodiment shows a modified example of the case where the image directions of the first reflected light and the second reflected light become the same.

FIG. 11 is a diagram showing one example of the structure of the full rate module 73 of the present embodiment. The full rate component 73 includes a light source 131 , mirrors 732 , 733 , 734 , a semi-transmissive mirror 735 and a light trap 736 . In full rate component 73 , the first reflected light is reflected on mirror 732 and semi-transmissive mirror 735 , while the second reflected light is reflected on mirrors 733 and 734 . That is, the number of reflections of each reflected light is two, that is, both are even numbers, so it can be understood that the image direction of each reflected light received by the linear image sensor 16 becomes the same.

Here, in the same manner as the above-described second embodiment, a structure including a prism may be provided instead of the mirror and the semi-transmissive mirror provided for the full rate module 73 .

Fig. 12 is a diagram showing a full rate assembly 73' including a prism in this embodiment. In this figure, full rate assembly 73' includes light source 131 and prism 737. The cross-section of the prism 737 is a heptagon with vertices A, B, C, D, E, F, G, where an aluminum thin film having a mirror function is vapor-deposited on the surfaces AB, CD, DE. In addition, an anti-reflection layer is formed on a portion corresponding to 736 in the drawing of the surface DE and a light trap 736 is bonded thereto. Due to the above-mentioned structure, the full-rate module 73' can obtain substantially the same advantages as the full-rate module 73 described above.

As noted above, some aspects of the invention are summarized below.

According to an aspect of the present invention, an image reader includes: an illumination unit that irradiates an object to be read with light; a first optical system that allows first reflected light from the object to be read to travel therein; Two optical systems, which allow the second reflected light from the object to be read to travel therein; a switching unit, which switches between the first optical system and the second optical system to be used; switching between the first optical system and the second optical system to form an image of the first reflected light traveling in the first optical system and an image of the second reflected light traveling in the second optical system; and a light receiving unit, It receives first reflected light and second reflected light formed into a plurality of images and generates corresponding image signals.

Such an image reader can generate first reflected light (from which diffuse reflected light is read) and second reflected light (from which specular reflected light is read) based on light irradiated from the same lighting unit, and can pass the same light The receiving unit receives the first reflected light and the second reflected light. Therefore, the image reader can perform reading of texture information with a simpler structure than the related art. In addition, the image reader performs two reading operations and calculates color information and texture information based on two kinds of image information, and therefore, can obtain color information and texture information more accurately.

In this image reader, the optical path length of the first reflected light traveling in the first optical system until being received by the light receiving unit can be compared with the optical path length of the first reflected light traveling in the second optical system until being received by the light receiving unit. The optical path lengths of the second reflected light are set to be equal.

Due to this structure, there is no possibility that the focal position of the first reflected light (from which the diffuse reflected light is read) is shifted from the focused position of the second reflected light (from which the specular reflected light is read). A mechanism for adjusting the focus position is provided on the side of the light receiving unit.

According to another aspect of the present invention, an image reader includes: an illumination unit that irradiates an object to be read with light; a first optical system that allows first reflected light from the object to be read to travel therein; A second optical system that allows the second reflected light from the object to be read to travel therein; a reflected light combining unit that combines the first reflected light that travels in the first optical system with the second reflected light that travels in the second optical system The reflected light is output as combined light; an imaging unit that forms an image of the combined light output from the reflected light combining unit; and a light receiving unit that receives the combined light formed as an image by the imaging unit and generates an image signal.

Such an image reader can generate diffuse reflection light and specular reflection light based on light generated from the same lighting unit, and can receive the diffuse reflection light and specular reflection light by the same light receiving unit. Therefore, the image reader can obtain texture information with a simpler structure than the prior art. In addition, the image reader can receive synthesized light of diffuse reflection light and specular reflection light with a single reading operation, so the image reader can obtain texture information faster than the prior art.

Wherein, in the above aspects, the image reader may include a variable transmission unit that changes the light on at least one of the optical paths of the first reflected light and the second reflected light transmittance.

Due to this structure, even if the intensities of the first and second reflected lights from which the diffuse reflection and specular reflection light are read are strong, it is possible to prevent the combined light from exceeding the reading limit, which is formed by the constituent light. This is caused by the saturation of the signal output of the photoelectric conversion element, etc. of the receiving unit. Furthermore, according to this configuration, the light amount ratio of the first reflected light to the second reflected light can be adjusted arbitrarily, and therefore, glossiness can be adjusted, thereby allowing input of information suitable for reproducing a more desirable texture.

Furthermore, in the above-described aspects, the number of reflections of light before receiving the first reflected light from the original by the light receiving unit and the number of reflections of light before receiving the second reflected light from the original by the light receiving unit may be equal. be even or odd.

Due to this structure, the image direction of image light obtained by diffuse reflection light and the image direction of image light obtained by specular reflection light can be aligned with each other, and therefore, information on the original can be input more accurately.

The foregoing description of various embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to explain the principles of the invention and its practical application, thereby enabling others skilled in the art to understand it in various embodiments and with various modifications as are suited to the particular use contemplated. this invention. The scope of the invention is defined by the appended claims and their equivalents.

The entire disclosure of Japanese Patent Application No. 2004-316763 filed on October 29, 2004 including specification, claims, drawings and abstract is incorporated herein by reference.

Claims (11)

1, a kind of cis, it comprises:

Lighting unit, it uses rayed object to be read;

First optical system, it makes and can advance therein from first reverberation of described object to be read;

Second optical system, it makes and can advance therein from second reverberation of described object to be read;

Switch unit, it switches between described first optical system that will use and described second optical system;

Image-generating unit, it switches between described first optical system and described second optical system by utilizing described switch unit, is formed on first catoptrical image of advancing in described first optical system and the second catoptrical image of advancing in described second optical system; And

Light receiving unit, its reception forms described first reverberation and described second reverberation of a plurality of images and generates image signals corresponding by described image-generating unit.

2, cis according to claim 1, wherein, described light receiving unit catoptrically diffuses and generates image signals corresponding from the described second catoptrical specular light by reading from described first.

3, cis according to claim 1, wherein, each in described first optical system and described second optical system all comprises mirror.

4, cis according to claim 1, wherein, each in described first optical system and described second optical system all comprises mirror and half-transmitting mirror.

5, cis according to claim 1, wherein, each in described first optical system and described second optical system all comprises the surface of prism.

6, cis according to claim 1, wherein, will in described first optical system, advance, the described first catoptrical optical path length before being received by described light receiving unit with in described second optical system, advance, up to being arranged to equate by the described second catoptrical optical path length before the described light receiving unit.

7, cis according to claim 1 wherein, is arranged at the variable transmission unit that changes the optical transmission rate at least one light path in the described first catoptrical light path and the described second catoptrical light path.

8, cis according to claim 1, wherein, number of times that this first reverberation is reflected before receiving from described first reverberation of described object to be read by described light receiving unit and this second reverberation is reflected before receiving from described second reverberation of described object to be read by described light receiving unit inferior number average are set to even number or odd number.

9, cis according to claim 1, wherein, described first reverberation has with respect to the angle of reflection from 0 ° of the incidence angle of the irradiates light of described lighting unit, and described second reverberation has with respect to the angle of reflection from 45 ° of the incidence angles of the irradiates light of described lighting unit.

10, cis according to claim 1 also comprises output unit, and the picture signal that this output unit utilizes described light receiving unit to generate is exported based on the first catoptrical information with based on the second catoptrical information.

11, cis according to claim 10, wherein, described output unit utilizes described picture signal output based on the described first catoptrical colouring information with based on the described second catoptrical texture information.

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