JP2001275979A - Instrument and method for imaging ocular image, setting device, recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rapidly and suitably reflect past imaging conditions in imaging an ocular image. SOLUTION: The method for imaging the ocular image comprises the steps of setting a lesion part in the ocular image as an area of interest (a frame of a broken line) in the ocular image imaged in the past, and setting a position, a size, an exposure and the like of the area of the interest corresponding to the ocular image imaged this time by referring to past ocular image data at this time imaging time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to photographing of an eye image performed in an ophthalmic hospital or the like.

[0002]

2. Description of the Related Art Conventionally, there has been known an ophthalmologic photographing apparatus in which an image of an eye to be inspected is imaged using an image pickup device such as a CCD instead of a silver halide film and recorded in a recording means. Imaging devices with very high resolution are being developed one after another.

In medical equipment such as an eye image photographing apparatus,
It is known that there is a lesion part to be noted by a doctor, and there are many opportunities to follow-up the lesion part. In such follow-up observation, it is necessary to set the imaging conditions in consideration of the past imaging conditions in order to know the properties of the lesion in detail.

[0004]

However, it is time-consuming to set the imaging conditions by examining past imaging conditions one by one at the time of diagnosis, and it may be painful for the subject.

In this case, in order to easily refer to the past photographing conditions, data indicating the photographing conditions is created at the time of follow-up observation,
A method of storing this in association with the eye image data may be considered, but there is a possibility that an error such as a mismatch between the two may occur.

Accordingly, it is an object of the present invention to provide an eye image photographing apparatus, an eye image photographing method, a setting apparatus, and a recording medium which can quickly and appropriately reflect past photographing conditions.

[0007]

According to the present invention, there is provided an eye image photographing apparatus for photographing an eye image of a subject under predetermined photographing conditions, comprising: setting means for setting the photographing conditions; Recording means for recording an eye image in which a predetermined area in the eye image is set in advance, wherein the setting means is configured to output the eye image recorded in the recording means. An eye image photographing apparatus is provided, wherein the photographing condition is set based on information included in an area.

Further, according to the present invention, there is provided an eye image photographing apparatus for causing a subject to look at a predetermined index and photograph an eye image of the subject, wherein the position setting means sets the position of the index. Recording means for recording an eye image which has been taken in the past and in which a predetermined area in the eye image is set in advance, wherein the position setting means is recorded in the recording means. An eye image photographing apparatus, wherein the position of the index is set such that the region is located at a predetermined position of the eye image to be photographed based on the position of the region of the eye image. .

According to the present invention, there is provided an eye image photographing apparatus capable of photographing an eye image of a subject at a predetermined photographing magnification,
Magnification setting means for setting a photographing magnification of an eye image to be photographed;
Recording means for recording an eye image taken in the past, wherein an eye image in which a certain area in the eye image is set in advance, the magnification setting means, the magnification setting means recorded in the recording means An eye image photographing apparatus is provided, wherein a photographing magnification of an eye image to be photographed is set based on the size of the region of the eye image.

Further, according to the present invention, there is provided an eye image photographing apparatus for photographing an eye image of a subject by irradiating a predetermined amount of illumination, the light amount setting means for setting the light amount, Recording means for recording an eye image that has been photographed in the past, and an eye image in which a predetermined area in the eye image is set in advance, wherein the light amount setting means includes An eye image photographing apparatus is provided, wherein the light amount is set based on the luminance of an image in the region of the eye image.

Further, according to the present invention, there is provided a setting device connected to an eye image photographing device for photographing an eye image of a subject under predetermined photographing conditions, wherein a setting means for setting the photographing conditions is provided. Recording means for recording an eye image in which a predetermined area in the eye image is set in advance, wherein the setting means comprises: an eye image recorded in the recording means. A setting device for setting the photographing condition based on the information of the area.

Further, according to the present invention, there is provided an eye image photographing method for photographing an eye image of a subject under predetermined photographing conditions, wherein the setting step of setting the photographing conditions includes the steps of: Recording a predetermined area in the eye image to record an eye image set in advance, wherein the setting step is based on the information of the area of the eye image recorded in the recording step. Thus, there is provided an eye image photographing method characterized by setting the photographing conditions.

Further, according to the present invention, there is provided an eye image photographing method for causing a subject to look at a predetermined index and photographing an eye image of the subject, the position setting step of setting the position of the index. And a recording step of recording an eye image taken in the past, in which a predetermined area in the eye image is set in advance, wherein the position setting step includes recording in the recording step. An eye image photographing method is provided, wherein the position of the index is set based on the position of the region of the eye image such that the region is located at a predetermined position of the eye image to be photographed.

Further, according to the present invention, there is provided an eye image photographing method capable of photographing an eye image of a subject at a predetermined photographing magnification,
A magnification setting step of setting a photographing magnification of an eye image to be photographed;
Recording an eye image taken in the past, wherein a predetermined area in the eye image records an eye image set in advance, wherein the magnification setting step includes the step of recording the eye recorded in the recording step. An eye image photographing method is provided, wherein a photographing magnification of an eye image to be photographed is set based on the size of the region of the image.

Further, according to the present invention, there is provided an eye image photographing method for photographing an eye image of a subject by irradiating a predetermined amount of illumination, the light amount setting step for setting the light amount, A recording step of recording an eye image photographed in the past, wherein a predetermined area in the eye image is set in advance.
Wherein, in the light amount setting step, the light amount is set based on luminance of an image in the region of the eye image recorded in the recording step.

Further, according to the present invention, in order to photograph an eye image of a subject under predetermined photographing conditions, a computer is provided with setting means for setting the photographing conditions; A recording medium that records a program that functions as a recording unit that records an eye image in which a predetermined area in the eye image is set in advance, wherein the setting unit includes the eye image recorded in the recording unit. Wherein the photographing condition is set based on the information of the area.

Further, according to the present invention, in order to make a subject look at a predetermined index and to photograph an eye image of the subject, a computer is provided with position setting means for setting the position of the index. An eye image photographed in, a recording medium in which a predetermined area in the eye image is recorded as an eye image that is set in advance, a recording medium recording a program to function as the position setting means, A recording medium that sets the position of the index based on the position of the region of the eye image recorded in the recording unit so that the region is located at a predetermined position of the eye image to be captured. Is provided.

According to the present invention, in order to photograph an eye image of a subject at a predetermined photographing magnification, a computer is provided with magnification setting means for setting a photographing magnification of an eye image to be photographed; A recording medium for recording an image, wherein a predetermined area in the eye image is recorded as an eye image in which a predetermined area is set in advance, wherein the magnification setting means includes: A recording medium is provided, wherein a photographing magnification of an eye image to be photographed is set based on a size of the region of the recorded eye image.

Further, according to the present invention, in order to photograph an eye image of a subject by irradiating a predetermined amount of illumination, a computer is provided with light amount setting means for setting the amount of light.
A recording medium that records a program that functions as an eye image captured in the past, and a recording unit that records an eye image in which a predetermined area in the eye image is set in advance,
A recording medium is provided, wherein the light quantity setting means sets the light quantity based on luminance of an image in the area of the eye image recorded in the recording means.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described.

FIG. 1 is a configuration diagram of an eye image photographing apparatus according to one embodiment of the present invention.

In this apparatus, a condenser lens 3, a photographing strobe light source 4, a ring slit 5, a mirror 6, a relay lens 7, and a condenser lens 3 are provided on an optical path from the observation light source 1 to the objective lens 2 facing the eye E. Perforated mirrors 8 are sequentially arranged.

On the optical path behind the perforated mirror 8, a focus lens 9, a zoom lens 10 composed of a plurality of lens groups, a half mirror 11, a switching mirror 12, a field stop 13, and an eyepiece 14 are arranged.

In the optical path on the reflection side of the half mirror 11, a fixation target presenting unit 15, which comprises a backlight and a liquid crystal dot matrix and presents an index for the subject to watch at the time of photographing, is arranged. In the reflection direction of the switching mirror 12 when it is at the position of the dotted line on the road,
An imaging field stop 16, a field lens 17, an imaging lens 18, and an imaging unit 19 are sequentially arranged.

The output of the imaging unit 19 is an A / D converter 20, a memory 21 for storing the result of the A / D conversion, and a D / A converter 2 for displaying the contents of the memory 21 in analog form.
2. Connected to the monitor 23. A / D converter 20,
The memory 21 and the D / A conversion means 22 are connected to a video signal control unit 24 for controlling respective timings and operations, and the image data of the memory 21 is transferred to a magneto-optical disk or the like via an image processing unit 25. Is connected to the recording unit 26.

The image processing unit 25 is connected to a CPU 27. The CPU 27 also includes a memory 21, a video signal control unit 24, a fixation target control unit 28 for controlling the fixation target presentation unit 15, A strobe control unit 29 for controlling the strobe light source 4, a photographing switch 30, and a region of interest setting device 3 which is a pointing device such as a mouse.
1 respectively.

Next, the observation operation will be described.

The light beam emitted from the observation light source 1 passes through the condenser lens 3 and the ring slit 5, is reflected by the mirror 6, passes through the relay lens 7, is reflected around the perforated mirror 8, and is reflected by the objective lens 2. Then, the eye E passes through the pupil Ep of the eye E and illuminates the fundus Er of the eye E.

The fundus image illuminated in this way has a pupil Ep,
The light passes through the objective lens 2, the hole of the perforated mirror 8, the focus lens 9, the zoom lens 10, and the half mirror 11,
It is guided to the field stop 13 and the eyepiece 14. The operator
Positioning is performed using this optical path for observation. Also,
At this time, the subject examines the subject by the fixation target presentation unit 15.
Is in a fixation state by looking at the index presented by.

Next, the photographing operation will be described.

When the photographing switch 30 is depressed when the alignment is completed, the CPU 27 detects the depression, and the optical path switching mirror 12 is flipped up to the dotted line portion 12 'in FIG. It instructs the control unit 24 to start preparation for the process.

Next, after the flip-up of the switching mirror 12 is completed, the flash controller 29 is instructed to start emitting light. The strobe control unit 29 supplies the strobe light source 4 with a light emission trigger, so that the energy stored in the main condenser (not shown) is supplied to the strobe light source 4 and light emission is started.

The photographing light beam illuminates the fundus Er of the eye E through a similar optical path after the ring slit 5, and the reflected light is reflected by the optical path switching mirror 12 jumped up into the optical path. A fundus image (eye image) is formed on the imaging unit 19 via the field lens 17 and the imaging lens 18. The video signal obtained from the imaging unit 19 is digitized by the A / D converter 20 and is simultaneously written into the memory 21.

When the A / D conversion and the writing to the memory 21 are completed, the CPU 27 sends a D signal to the video signal control unit 24.
/ A conversion instruction is issued. The D / A conversion unit 22 that has received the instruction from the video signal control unit 24 outputs the data to the monitor 23 while sequentially reading the data from the memory 21.

FIG. 2A shows a fundus image of the eye to be inspected output to the monitor 23, in which a cross indicates a macula, and a star indicates a lesion that the operator is paying attention to.

Next, the operator sets the region of interest setting device 3
An operation of setting a target part is performed by using No. 1. The region-of-interest setting device 31 may be, for example, a pointing device such as a mouse.
27, and transmits, for example, the detected coordinate information and click information to the video signal control unit 24.
Mixes the input from the region-of-interest setting device 31 with the data D / A converted by the D / A conversion means 22, and synthesizes the data as a character.

FIG. 2B shows a display state after the operator sets the region of interest using the region-of-interest setting device 31, and a portion surrounded by a dotted line indicates the region of interest set by the operator. When the region of interest is determined, the CPU 27 stores the coordinate information of the determined region of interest in a storage medium (not shown). At the same time, a parameter corresponding to the entire image quality (compression ratio) and a parameter indicating a difference between the image quality of the region of interest and the image quality of the non-interest region are received and stored by means not shown. In the present embodiment, an example in which the region of interest is set as a square region has been described, but it is needless to say that the region of interest need not be limited to a square.

Next, an example of the configuration of the image processing section 25 will be described with reference to FIG.

Here, an improvement in the spatial resolution and the resolution in the density direction of the image sensor can provide a high-quality image, but on the other hand, the amount of data is enormous, and the display speed at the time of diagnosis is reduced. Management and operation after diagnosis may be hindered. In this case, a method of using image compression processing to eliminate the adverse effect of the enormous amount of data can be considered. However, if the compression processing also exceeds the limit, remarkable deterioration of the image quality may be caused, and if the image quality of the diseased part to be noted by the doctor deteriorates, accurate diagnosis may be hindered. Therefore, in the present embodiment, image compression processing that can solve such a problem is adopted.

The dotted line in FIG. 3 shows the configuration related to encoding among the internal configuration of the image processing unit 25.
1 shows a path for encoding one image data. 2
5A is an image input unit, 25B is a discrete wavelet transform unit, 25C is a quantization unit, 25D is an entropy encoding unit,
25E is a code output unit, and 25F is an area designating unit.

First, the memory 2 is input to the image input unit 25A.
One image data is input in the raster scan order, and the output is input to the discrete wavelet transform unit 25B.
In the following description, for convenience, the image signal represents a monochrome multi-valued image used in fluorescence imaging or the like, but in the case of a normal color image, the RGB color components may be compressed as the single color components.

The discrete wavelet transform unit 25B performs a two-dimensional discrete wavelet transform process on the input image signal, and calculates and outputs a transform coefficient.
FIG. 4A shows a basic configuration of the discrete wavelet transform unit 25B.
01, are sequentially read out by the processing unit 102, are subjected to conversion processing, and are written into the memory 101 again. FIG. 4B is a diagram illustrating a configuration of the processing unit 102.

In FIG. 4B, an input image signal is converted by a combination of a delay element and a downsampler.
The signals are separated into the signals of the even address and the odd address, and are filtered by the two filters p and u.
FIGS. S and d show low-pass coefficients and high-pass coefficients when one-level decomposition is performed on a one-dimensional image signal, and the discrete wavelet transform for the image data sequence x (n) is expressed by the following equation. It shall be calculated by

D (n) = x (2 * n + 1) -floor ((x (2 * n) + x (2 * n + 2)) / 2) (Equation 1) s (n) = x (2 *) + floor ((d (n-1) + d (n)) / 4) (Equation 2) In the above equation, floor {X} indicates the maximum integer value not exceeding X.

With the above processing, one-dimensional discrete wavelet transform processing is performed on the image signal. In the two-dimensional discrete wavelet transform, one-dimensional transform is sequentially performed in the horizontal and vertical directions of an image, and details thereof are publicly known, and thus description thereof is omitted here. FIG. 4 (c)
This is a configuration example of a two-level transform coefficient group obtained by a two-dimensional transform process, in which an image signal is decomposed into coefficient sequences HH1, HL1, LH1,..., LL in different frequency bands. In the following description, these coefficient sequences are called subbands. The coefficients of each subband are output to the subsequent quantization unit 25C.

The region specifying section 25F determines a region (ROI: region of interesting) to be decoded with higher image quality compared to the surrounding portion in the image to be encoded. The region specifying unit 25F receives the coordinate information of the region of interest set by the operator from the above-described operation from the CPU 27, and outputs mask information indicating which coefficient belongs to the region of interest when the subject eye image is subjected to the discrete wavelet transform. Generate.

FIG. 5A shows an example of generating mask information. FIG. 5A is a diagram on the left side of FIG.
When the region of interest set in (b) is specified, the region specifying unit 25F calculates a portion that the region of interest occupies in each subband when an image including the region of interest is subjected to discrete wavelet transform. The area indicated by the mask information is a range including surrounding transform coefficients necessary for restoring the image signal on the boundary of the region of interest.

The figure on the right side of FIG. 5A is an example of the mask information calculated in this way. In this example, mask information when a two-level discrete wavelet transform is performed on the image on the left side of the figure is calculated as shown in the figure. In the figure, the portion indicated by the dotted line is the region of interest, and the bits of the mask information in this region are 1 and the bits of the other mask information are 0. Since the entire mask information is the same as the configuration of the transform coefficient by the two-dimensional discrete wavelet transform, it is possible to identify whether or not the coefficient at the corresponding position belongs to the region of interest by inspecting the bits in the mask information. it can. The mask information generated in this way is output to the quantization unit 25C.

Further, the area specifying section 25F receives from the CPU 27 a parameter for specifying the image quality for the area of interest. The parameter indicating the difference between the image quality of the region of interest and the image quality of the region of non-interest corresponds to this. The region specifying unit 25F calculates the bit shift amount B for the coefficient in the region of interest from the parameters, and outputs the calculated amount to the quantization unit 25C together with the mask.

The quantization unit 25C quantizes the input coefficient by a predetermined quantization step, and outputs an index for the quantized value. Here, the quantization is performed by the following equation.

Q = sign (c) floor (abs (c) / Δ) (expression 3) sign (c) = 1; c> = 0 (expression 4) sign (c) = − 1; c <0 (Equation 5) Here, c is a coefficient to be quantized. In the present embodiment, it is assumed that the value of Δ includes 1.
In this case, no quantization is actually performed. In addition, C
The parameter indicating the overall image quality received from the PU 27 corresponds to Δ in the above equation. Next, based on the mask and the shift amount B input from the area specifying unit 25F, the quantization unit 25C
The quantization index is changed by the following equation.

Q ′ = q * 2 ^ B; m = 1 (Equation 6) q ′ = q; m = 0 (Equation 7) Here, m is the value of the mask at the position of the quantization index. . By the above processing, the area specifying unit 25F
In, only the quantization index belonging to the region of interest specified by the CPU 27 is shifted up by B bits.

FIGS. 5B and 5C show the change of the quantization index due to the shift up. In (b), three quantization indices exist in each of the three subbands, and the mask value in the networked quantization index is 1 and the shift number B is 2
In the case of, the quantized index after the shift is as shown in FIG. The changed quantization index is output to the entropy encoding unit 25D that follows.

The entropy coding unit 25D decomposes the input quantization index into bit planes, performs binary arithmetic coding on a bit plane basis, and outputs a code stream.

FIG. 6 is a diagram for explaining the operation of the entropy coding unit 25D. In FIG. 6 (a), three non-zero quantization indices are present in a region within a subband having a size of 4 × 4. Exist, +13, + respectively
It has values of 6, +3. The entropy encoding unit 4 scans this area to find the maximum value M, and calculates the number of bits S required to represent the maximum quantization index by the following equation.

S = ceil (log2 (abs (M))) (Equation 8) where ceil (x) represents the smallest integer value among integers equal to or greater than x.

In FIG. 6A, the maximum coefficient value is 1
Since it is 3, S is 4, and the 16 quantization indexes in the sequence are processed in units of four bit planes as shown in FIG. 6B. First, the entropy coding unit 25D outputs the most significant bit plane (LS
B) (binary arithmetic coding) and output as a bit stream.

Next, the bit plane is lowered by one level, and similarly, the respective bits in the bit plane are encoded and output to the code output unit 25E until the target bit plane reaches the least significant bit plane (represented by LSB in the figure). I do. At this time, the code of each quantization index is entropy-encoded immediately after the first non-zero bit is detected in the bit plane scanning.

FIG. 7 is a schematic diagram showing the structure of a code string generated and output in this way. FIG. 1A shows the entire structure of a code string, where MH is a main header, TH is a tile header, and BS is a bit stream. As shown in FIG. 3B, the main header MH includes the size of the image to be encoded (the number of pixels in the horizontal and vertical directions), the size when the image is divided into a plurality of rectangular tiles, and each color component. It is composed of the number of components representing the number, the size of each component, and component information representing the bit precision. In the present embodiment, since the image is not divided into tiles, the tile size and the image size take the same value, and the number of components is 1 when the target image is a monochrome multivalued image.

Next, the structure of the tile header TH is shown in FIG.
It is shown in (c). The tile header TH includes a tile length including a bit stream length and a header length of the tile, an encoding parameter for the tile, a mask indicating a region of interest, and a bit shift number for a coefficient belonging to the region. The encoding parameters include the level of the discrete wavelet transform, the type of filter, and the like. FIG. 7D shows the configuration of the bit stream according to the present embodiment. In the figure, bit streams are grouped for each sub-band, and are arranged in order of increasing resolution starting with the sub-band having the smaller resolution. Further, in each subband, codes are arranged in units of bit planes from the upper bit plane to the lower bit plane.

In such a series of processing, as described above, the image quality of the entire image to be encoded can be controlled by changing the quantization step Δ.

The image quality can be controlled by restricting (discarding) lower bits of the bit plane to be encoded in the entropy encoding unit 25D as necessary. In this case, all the bit planes are not encoded, and the bit planes from the upper bit plane to the number of bit planes corresponding to the desired image quality are encoded and included in the final code sequence. If the function of limiting the bit plane is used, only bits corresponding to the above-described region of interest are included in the coded sequence, and only the region of interest can be coded as a high-quality image. The data encoded by the above method is output from the code output unit 25E and recorded in the recording unit 26.

Next, a method of reversely decoding the bit stream generated by such encoding processing will be described.

The dotted line in FIG. 8 shows a decoding-related configuration of the internal configuration of the image processing unit 25, and shows a path for decoding the image data stored in the recording unit 26.
25E 'is a code input unit, 25D' is an entropy decoding unit, 25C 'is an inverse quantization unit, 25B' is an inverse discrete wavelet transform unit, 25A 'is an image output unit, and 25F' is an area extraction unit.

A code string is input to the code input section 25F ', and a header included in the code string is analyzed to extract parameters necessary for subsequent processing, and the flow of processing is controlled as necessary. Also, the corresponding parameter is sent to the subsequent processing unit. The bit stream included in the code string is output to the entropy decoding unit 25D '.

The entropy decoding unit 25D 'decodes and outputs the bit stream in bit plane units. The decoding procedure at this time follows the reverse path of FIG.
Decoding is started in bit plane units in order from the MSB of the bit plane shown in (b), and the quantization index restored in the form of FIG. 6A is output to the inverse quantizer 25C ′.

The inverse quantizer 25D 'restores discrete wavelet transform coefficients from the input quantization index based on the following equation.

C ′ = Δ * q / 2 ＾ U; q ≠ 0 (formula 9) c ′ = 0; q = 0 (formula 10) U = B; m = 1 (formula 11) U = 0 M = 0 (Equation 12) Here, q is a quantization index, Δ is a quantization step, and Δ is the same value used at the time of encoding.

B is the number of bit shifts read from the tile header, and m is the value of the mask at the position of the quantization index. Further, c ′ is a restored transform coefficient, which is a restored coefficient represented by s or d at the time of encoding.

The transform coefficient c 'is output to the subsequent inverse discrete wavelet transform unit 25B'. Area extraction unit 25F '
Extracts the mask value m at the position of the quantization index from the above numerical value and outputs to the CPU 27 coordinate data of the region of interest embedded in the image.

FIG. 9 is a block diagram showing the configuration and processing of the inverse discrete wavelet transform unit 9. In FIG. 9A, the input transform coefficients are stored in the memory 201. The processing unit 202 performs a two-dimensional inverse discrete wavelet transform by performing a one-dimensional inverse discrete wavelet transform, sequentially reading out transform coefficients from the memory 201 and performing processing. The two-dimensional inverse discrete wavelet transform is performed in a procedure reverse to that of the forward transform. Also, FIG.
2 shows a processing block No. 02, in which input transform coefficients are subjected to two filter processes of u and p, and after being upsampled, superimposed to output an image signal x ′. These processes are performed by the following equations.

X ′ (2 * n) = s ′ (n) −floor ((d ′ (n−1) + d ′ (n)) / 4) (Expression 13) x ′ (2 * n + 1 ) = d ′ (n) + floor ((x ′ (2 * n) + x ′ (2 * n + 2)) / 2) (Expression 14) Here, (Expression 1), (Expression 2), (Equation 12), (Equation 13)
Since the forward and backward discrete wavelet transforms satisfy the perfect reconstruction condition, if the above-described quantization step Δ is 1 and all the bit planes have been decoded in the bit plane decoding, the The image signal x ′ matches the signal x of the original image, and means lossless conversion (lossless compression) in encoding and decoding.

The image is restored by the above processing, output to the image output unit 25 A ′, and output to the memory 21, so that the subject's eye image data can be output to the monitor 23.

The above is the content of the image compression / decompression processing in the present embodiment.

Next, based on the eye images taken in the past,
The procedure for setting the current shooting conditions will be described. In the present embodiment, in particular, the imaging conditions are set based on the information of the above-described region of interest. Hereinafter, setting examples of the shooting conditions will be described, but it is needless to say that the present invention is not limited thereto. In the following example, the above-described compression / decompression processing is assumed, but it goes without saying that other compression / decompression processing may be adopted. <First Example> As a first example, a method will be described in which a region of interest corresponding to a region of interest set by an operator in the past is located at the center of an eye image captured from the region of interest.

In this case, for example, when a past eye image as shown in FIG. 2A is read from the recording unit 26, the region extracting unit 25F 'performs the above-described decoding by the dotted line in FIG. The region of interest shown in the section is extracted from the image data and output to the CPU 27. At the same time, the image shown in FIG.

Next, the CPU 27 detects the nipple position and the macula position from the image information of the eye image developed in the memory 21. The detection method is, for example, P- in FIG.
The luminance information of the scanning line indicated by P 'is detected, and FIG.
The luminance information corresponding to the position shown in FIG. By moving PP ′ up and down, the nipple Q having the highest luminance and the macula R having the lowest luminance are detected. Next, as shown in FIG. 3C, a distance d1 between the macula R and the center coordinates of the region of interest extracted by the region specifying unit 25F 'and a distance d2 between the macula R and the image center are calculated.

The CPU 27 moves to the target position by d1 with the macula as a fulcrum and further obtains the coordinate s shifted by d2, and calculates the amount of movement on the image data by the fixation target presentation unit 15
And issues a movement instruction for the fixation target presentation unit 15 to the fixation target control unit 28. In this way, the index provided by the fixation target presentation unit 15 is positioned, and when the subject gazes at the index,
The macula is fixed at the coordinates S.

When the preparation for the photographing is completed, the operator presses the photographing switch 30 to store the image of the eye to be examined in the memory 21 in the same manner as in the above-described photographing sequence, as shown in FIG. It is possible to obtain an image in which the region of interest is the center of the image. In the first example, moving the region of interest set in the past to the center of the image has been described. However, moving the region of interest to any part other than the center of the image, for example, under the same conditions as the past fixation position, Photographing can be performed by the same procedure. <Second Example> As a second example, a method of moving the region of interest to the center of the image and setting a photographing magnification of the region of interest as in the first example (magnification photographing in this case) will be described.

As in the first example, at the time of the above-described decoding, the region extracting unit 25F ′ extracts the region of interest indicated by the dotted line in FIG. 2B from the image data and outputs it to the CPU 27. At the same time, the image shown in FIG.

Here, the CPU 27 obtains the diagonal length d3 of the region of interest as shown in FIG. next,
After performing the same calculation as in the first example, the fixation target is moved, and the extracted region of interest is moved to the center of the screen to promote fixation.

Here, the CPU 27 sets d in the image data.
The conversion into the moving amount of the zoom lens 10 is performed so that 3 is assigned to the maximum of the photographable range. The zoom lens 10 is moved by instructing movement by the movement amount obtained by conversion using a zoom lens driving unit (not shown). Zoom lens 1
When the operator presses the photographing switch 30 at the time when the movement of 0 is completed, the eye image to be inspected is stored in the memory 21 in the same manner as in the above-described photographing sequence.
It is possible to obtain an image in which the region of interest shown in FIG.

In the second example, the method of enlarging the region of interest set in the past to the entire screen has been described. Similarly, an arbitrary magnification can be set, and photographing is performed under the same conditions as the past magnification. Of course it is also possible. Further, in the above description, it is assumed that the region of interest is moved to the center of the image as in the first example, but this is not always necessary. <Third Example> As a third example, a method of photographing a region of interest set by the operator in the past with the same exposure will be described. As in the first example, the region extraction unit 25F '
Extracts the region of interest indicated by the dotted line in FIG. 2B from the image data and outputs it to the CPU 27. At the same time, the image shown in FIG.

The CPU 27 reads the luminance information of the image in the region of interest from the memory 21, divides the sum of the luminance information in the region of interest by the number of pixels in the region of interest, and obtains an average value of the luminance information. Next, it is detected whether or not the papilla and the macula are included in the region of interest by the same method as in the first example (see FIGS. 10A and 10B).

Here, the CPU 27 is provided with a table for converting the average luminance in the region of interest into a photographing light amount in advance. Since luminance information greatly differs between the nipple and the macula, several types of tables are provided depending on whether or not the nipple and the macula are included. For example, in the eye image of FIG. 2B, since the region of interest does not include the nipple or the macula, the calculation is performed using a conversion table that does not include both of them, the light emission amount is determined, and the flash control unit 29 is set.

When the preparation for the photographing is completed, the operator presses the photographing switch 30 to store the eye image illuminated with the optimum light amount in the memory 21 in the same manner as in the above-described photographing sequence. It is possible to obtain a fundus image of the eye to be inspected equal to the exposure amount in the region of interest set in the last time and in the past. As another method, the amount of exposure may be adjusted using a region of interest as a photometric point using partial photometry and direct dimming known by a camera or the like.

As described above, according to the present embodiment, the region of interest set at the time of photographing can be quickly extracted from the image data without leaving troublesome history information in the image data photographed in the past. The photographing conditions can be set based on the settings at that time, thereby improving operability and reliability.

Further, particularly at the time of follow-up observation of a lesion,
Based on eye images taken in the past, it is possible to position the region of interest at the center of the image, enlarge the region of interest over the entire screen, or shoot under the same exposure conditions as the region of interest, Operability at the time is improved.

In the first to third examples described above, the example in which the decoded data in the memory 21 is used as the image data has been described. However, the image data in the decoding process shown in FIG. Even if it is used, it is possible to perform higher-speed processing.

In this embodiment, the image processing unit 25 and the like are arranged in the eye photographing apparatus.
For example, a system configuration for connecting an eye image photographing apparatus and a PC (Personal Computer) can be adopted. In this case, the function of the image processing unit 25 may be provided to the PC, and the photographing conditions of the eye image photographing apparatus may be determined using a communication command or the like according to the extracted region of interest information.

Further, in the present embodiment, an example in which an image captured in the past is read from the recording unit 26 has been described, but other devices such as a database server can be used via a network such as Ethernet using a communication device. You may make it read.

The preferred embodiment of the present invention has been described above. However, an object of the present invention is to provide a storage medium (or a recording medium) on which a program code of software for realizing the functions of the above-described embodiment is recorded by using a system. Alternatively, it is needless to say that this can be achieved by supplying the program code to the device and causing the computer (or CPU or MPU) of the system or device to read and execute the program code stored in the storage medium. In this case, the program code itself read from the storage medium implements the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention. When the computer executes the readout program codes, not only the functions of the above-described embodiments are realized, but also an operating system (OS) running on the computer based on the instructions of the program codes. It goes without saying that a case where some or all of the actual processing is performed and the functions of the above-described embodiments are realized by the processing is also included.

Further, after the program code read from the storage medium is written into the memory provided in the function expansion card inserted into the computer or the function expansion unit connected to the computer, the program code is read based on the instruction of the program code. , The CPU provided in the function expansion card or the function expansion unit performs part or all of the actual processing,
It goes without saying that a case where the function of the above-described embodiment is realized by the processing is also included.

[0094]

As described above, according to the present invention, past photographing conditions can be promptly and appropriately reflected.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an eye image photographing apparatus according to an embodiment of the present invention.

FIG. 2A is a diagram illustrating a fundus image of a subject's eye output to a monitor 23; FIG. 3B is a diagram illustrating a fundus image of the eye to be examined in which a region of interest is set.

FIG. 3 is a diagram showing a configuration related to encoding in an image processing unit 25;

FIG. 4A is a diagram illustrating a basic configuration of a discrete wavelet transform unit 25B. FIG. 2B is a diagram illustrating a configuration of the processing unit 102. (C) is a diagram showing a configuration example of a two-level transform coefficient group obtained by a two-dimensional discrete wavelet transform process.

FIG. 5A is a diagram illustrating an example when mask information is generated. (B) and (c) are diagrams showing a change in quantization index due to shift-up.

FIGS. 6A and 6B are diagrams showing an entropy coding unit 25;
It is a figure explaining operation of D.

FIGS. 7A to 7D are diagrams illustrating a configuration of a code string generated by an image processing unit 25. FIGS.

FIG. 8 is a diagram showing a configuration related to decoding in the image processing unit 25.

FIG. 9A is a diagram illustrating a configuration of an inverse discrete wavelet transform unit 9; (B) is a diagram showing a configuration of the processing unit 202.

FIG. 10A is a diagram illustrating a mode of detecting a nipple position and a macula position from an eye image. FIG. 4B is a diagram illustrating luminance information of an eye image. (C) is a diagram illustrating a mode of calculating a distance between a macula R and a center of a region of interest.

FIG. 11 is a diagram illustrating an example of an eye image in which a region of interest is the center of an image.

FIG. 12A is a diagram illustrating a mode of obtaining a diagonal length d2 of a region of interest. (B) is a figure which shows the eye image which image | photographed by enlarging the region of interest.

Claims (28)

[Claims] 1. An eye image photographing apparatus for photographing an eye image of a subject under predetermined photographing conditions, comprising: setting means for setting the photographing conditions; Recording means for recording an eye image in which a certain area inside is set in advance, wherein the setting means performs the photographing based on the information of the area of the eye image recorded in the recording means. An eye image photographing apparatus characterized by setting conditions. 2. An eye image photographing apparatus for causing a subject to look at a predetermined index and photograph an eye image of the subject, wherein: a position setting means for setting a position of the index; Recording means for recording an eye image in which a predetermined area in the eye image is set in advance, wherein the position setting means is configured to: An eye image photographing apparatus, wherein the position of the index is set based on the position of the region so that the region is located at a predetermined position of an eye image to be photographed. 3. The eye image photographing apparatus according to claim 2, wherein the position setting unit sets the position of the index so that the region is located substantially at the center of the eye image to be photographed. 4. An eye image photographing apparatus capable of photographing an eye image of a subject at a predetermined photographing magnification, comprising: magnification setting means for setting a photographing magnification of an eye image to be photographed; Recording means for recording an eye image in which a predetermined area in the eye image is set in advance, wherein the magnification setting means is configured to determine a size of the area of the eye image recorded in the recording means. An eye image photographing apparatus, wherein a photographing magnification of an eye image to be photographed is set based on the image magnification. 5. An eye image photographing apparatus for photographing an eye image of a subject by irradiating a predetermined amount of illumination, the light amount setting means for setting the light amount, and an eye image photographed in the past. Recording means for recording an eye image in which a predetermined area in the eye image is set in advance, wherein the light amount setting means is provided in the area of the eye image recorded in the recording means. An eye image photographing apparatus, wherein the light amount is set based on the luminance of an image. 6. The light amount setting unit according to claim 5, wherein the light amount setting unit sets the different light amounts depending on whether or not the image related to the nipple or macula of the eye is included in the region. Eye imaging device. 7. The light amount setting means has a plurality of tables for setting the light amount, wherein the table includes a case where an image related to a nipple of an eye is included in the region, a macula of the eye, 7. The eye image photographing apparatus according to claim 6, wherein a case where an image relating to a part is included and a case where none of these are included are set. 8. An eye image photographing apparatus according to claim 1, further comprising means for setting said area. 9. An encoding device for encoding the eye image and recording the encoded image on the recording device, wherein the encoding device performs encoding including a discrete wavelet transform on the eye image, and 9. The eye image photographing apparatus according to claim 1, wherein encoding is performed on the region such that an image at the time of decoding is decoded with higher image quality than an image of another region. apparatus. 10. A setting device connected to an eye image photographing device for photographing an eye image of a subject under predetermined photographing conditions, comprising: setting means for setting the photographing conditions; Recording means for recording an eye image in which a predetermined area in the eye image is set in advance, wherein the setting means includes information which the area of the eye image recorded in the recording means has A setting device for setting the photographing condition based on the setting. 11. An eye image photographing method for photographing an eye image of a subject under predetermined photographing conditions, comprising: a setting step of setting the photographing conditions; and an eye image photographed in the past; And a recording step of recording an eye image in which a certain area is set in advance.In the setting step, the imaging condition is set based on information of the area of the eye image recorded in the recording step. An eye image photographing method characterized by setting. 12. An eye image photographing method for causing a subject to look at a predetermined index and photographing an eye image of the subject, wherein: a position setting step of setting the position of the index; A recording step of recording an eye image in which a certain area in the eye image is set in advance, wherein in the position setting step, the area of the eye image recorded in the recording step is included. An eye image photographing method, wherein the position of the index is set such that the region is located at a predetermined position of the eye image to be photographed based on the position of the eye image. 13. In the position setting step, the area is:
The eye image photographing method according to claim 12, wherein the position of the index is set so as to be located substantially at the center of the eye image to be photographed. 14. An eye image photographing method capable of photographing an eye image of a subject at a predetermined photographing magnification, comprising: a magnification setting step of setting a photographing magnification of an eye image to be photographed; Recording a predetermined area in the eye image to record an eye image set in advance; and in the magnification setting step, the size of the area of the eye image recorded in the recording step An eye image photographing method characterized by setting a photographing magnification of an eye image to be photographed on the basis of the following. 15. An eye image photographing method for photographing an eye image of a subject by illuminating a predetermined amount of light, comprising: a light amount setting step for setting the light amount; And a recording step of recording an eye image in which a predetermined area in the eye image is set in advance. In the light amount setting step, an image in the area of the eye image recorded in the recording step is included. And setting the light amount based on the luminance of the eye image. 16. The light amount setting step according to claim 15, wherein in the light amount setting step, a different light amount is set depending on whether or not an image related to a papilla or a macula of the eye is included in the region. Eye imaging method. 17. In the light amount setting step, the light amount is set using a plurality of tables, and the table includes a case where an image related to a papilla of an eye is included in the region and a case where a macula portion of the eye is included. 17. The eye image photographing method according to claim 16, wherein the case where such images are included and the case where none of these images are included are separately set. 18. The method according to claim 11, further comprising the step of setting the region. 19. The recording step includes, when recording the eye image, an encoding step of encoding the eye image, wherein the encoding step includes a discrete wavelet transform on the eye image. 19. The method according to claim 11, wherein encoding is performed on the region such that an image at the time of decoding is decoded with higher image quality than images in other regions. An eye image capturing method according to any one of the above. 20. A computer, comprising: a setting unit configured to set the photographing conditions in order to photograph an eye image of a subject under predetermined photographing conditions; A recording medium for recording a program that functions as a recording unit that records an eye image in which an area of the eye image is set in advance, wherein the setting unit includes information that the area of the eye image recorded in the recording unit has A recording medium, wherein the photographing condition is set based on the following. 21. A computer, comprising: a position setting means for setting a position of the index, in order to cause the subject to look at a predetermined index and capture an eye image of the subject; A recording medium that records a program that functions as an eye image in which a predetermined area in the eye image is recorded in advance, wherein the position setting means is recorded in the recording means. A recording medium configured to set the position of the index based on the position of the region of the eye image so that the region is located at a predetermined position of the eye image to be captured. 22. The recording medium according to claim 21, wherein said position setting means sets the position of said index so that said area is located substantially at the center of a captured eye image. 23. Magnification setting means for setting a photographing magnification of an eye image to be photographed in order to photograph an eye image of a subject at a predetermined photographing magnification; A recording medium that records a program that functions as a recording unit that records an eye image in which a predetermined area in the eye image is set in advance, wherein the magnification setting unit includes the eye image recorded in the recording unit. A photographing magnification of an eye image to be photographed is set based on the size of the region. 24. A computer, comprising: a light amount setting unit for setting the light amount, for photographing an eye image of the subject by illuminating a predetermined amount of light; A recording medium on which a predetermined area in the eye image is recorded as a recording unit that records an eye image in which a predetermined area is set in advance, wherein the light amount setting unit is configured to record the light amount recorded on the recording unit A recording medium, wherein the light amount is set based on luminance of an image in the area of an eye image. 25. The light quantity setting device according to claim 24, wherein the light quantity setting means sets the different light quantity depending on whether or not the image related to the nipple or macula of the eye is included in the area. recoding media. 26. The light quantity setting means has a plurality of tables for setting the light quantity, wherein the table includes a case where the area includes an image related to a nipple of an eye, 26. The recording medium according to claim 25, wherein the recording medium is set separately when an image related to a copy is included and when none of these images is included. 27. The program according to claim 27, wherein
27. The recording medium according to claim 20, further comprising a program that functions as means for setting said area. 28. The computer-readable storage medium storing a program that causes a computer to function as an encoding unit that encodes the eye image and records the image in the recording unit, wherein the encoding unit includes a discrete wavelet for the eye image. The coding including conversion is performed, and the coding is performed so that an image at the time of decoding of the region is decoded with higher image quality than an image of another region. 28. The recording medium according to any one of 20 to 27.