JP4338416B2 - Automatic focus adjustment device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an automatic focus adjustment device particularly suitable for an electronic endoscope.
[0002]
[Prior art and its problems]
In recent years, various electronic endoscopes having an autofocus (AF) function in which the position of the focus lens is automatically adjusted according to the position of the distal end of the insertion portion of the endoscope have been proposed. Such an automatic focus adjustment apparatus provided in an electronic endoscope generally adjusts the position of a focus lens based on image data from an image sensor (CCD) provided at the distal end of an insertion portion of the endoscope. Specifically, a predetermined calculation is performed using the high-frequency component of the image data (luminance information of the image data), an evaluation value indicating the focus state of the subject is calculated, and the focus lens is positioned at the position where the evaluation value is maximum. Is moved (see Patent Document).
[0003]
By the way, in endoscopy, observation may be performed using a coloring agent for the purpose of obtaining more detailed findings than normal observation or obtaining findings that cannot be obtained by normal observation. In such a dye endoscopy (pigment method), the subject is dyed or colored in a specific color by the coloring agent, so that the luminance change tends to be smaller than in normal observation without the coloring agent. Are known.
[0004]
However, in the conventional method as described above, since the AF evaluation value is calculated based on the luminance information of the image data, there is a possibility that an accurate AF evaluation value may not be obtained during dye observation, and high-precision focus adjustment is realized. It was difficult to do.
[0005]
[Patent Literature]
Japanese Patent Laid-Open No. 2001-154085
OBJECT OF THE INVENTION
An object of the present invention is to obtain an automatic focus adjustment device capable of high-precision focus adjustment in a mode suitable for the color state (colored, dyed or discolored state) of a subject.
[0007]
Summary of the Invention
The reason for the present invention is that the AF evaluation value is calculated by the same calculation method regardless of whether or not the subject is colored or discolored as a factor that the accurate AF evaluation value cannot be obtained during dye observation in the conventional method. In particular, it focuses on it.
[0008]
That is, the present invention provides an image acquisition unit for obtaining an image data group from a pixel group of an imaging unit, and an image data group in an automatic focus adjustment apparatus that moves a focus lens based on an AF evaluation value calculated by a predetermined calculation. A data conversion means for converting the image data group into an HSI data group, an HSI conversion of the average value of the image data group to calculate a hue reference value, and a hue difference between the hue reference value and the hue data H is calculated as a variation in the hue data H When the variation in the hue data H is less than a predetermined threshold, the AF evaluation value is calculated using the brightness data I of the HSI data group, and when the hue data H is greater than the predetermined threshold, It includes an evaluation value calculation means for using one or both of the degrees data S calculates an AF evaluation value, and the threshold value, normal observation mode and a dye agent without using a dye agent Value to determine which of dye observation mode using is characterized in that it is set.
[0010]
The evaluation value calculation means uses both the hue data H and the saturation data S for AF evaluation value calculation when the variation of the hue data H is equal to or greater than a predetermined threshold, and the hue data H and the saturation data S are weighted with a predetermined weight. The accumulated value can be used as an AF evaluation value.
[0011]
The above automatic focusing device is particularly suitable for an electronic endoscope device. When mounted on an electronic endoscope apparatus , AF evaluation values in the normal observation mode in which the subject is not colored, stained, or discolored with the coloring agent and in the dye observation mode in which the subject is colored, stained, or discolored with the coloring agent The calculation method of is switched.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a block diagram showing a main configuration of a medical endoscope apparatus provided with an automatic focusing apparatus according to the present invention. The endoscope apparatus 100 includes an electronic endoscope 10 that images a patient's body cavity, a processor 30 that processes a captured image of the electronic endoscope 10, and a TV monitor 60 that displays a video signal output from the processor 30. Has been.
[0013]
The electronic endoscope 10 is extended to a flexible insertion portion 11 that is inserted into a body cavity of a patient, a grip operation portion 12 that is held by an operator of the electronic endoscope 10, and a side portion of the grip operation portion 12. The universal tube 13 and a connector portion 14 provided at the tip of the universal tube 13 are detachable from the processor 30 via the connector portion 14.
[0014]
As shown in FIG. 2, an objective lens 15, a pair of illumination lenses 16, an air / water supply nozzle 17, and a treatment instrument insertion channel outlet 18 a are disposed at the distal end 11 a of the insertion portion 11. A focus lens L and a CCD 20 that are movable along the optical axis direction of the objective lens 15 are disposed behind the objective lens 15. The focus lens L moves upon receiving a driving force from the AF motor 19 provided in the connector unit 14. In the present embodiment, a plurality of step positions are provided in the movable region from the infinity end to the close end, and the focus lens L is moved in units of this step position. An image formed by the objective lens 15 and the focus lens L is picked up by a CCD (image pickup device) 20 and can be observed on the TV monitor 60 via the processor 30. Illumination light from a lamp light source 33 provided in the processor 30 is given to the illumination lens 16 via the light guide LG1 passing from the universal tube 13 through the grip operation unit 12 and the insertion unit 11. The grip operation unit 12 is provided with various operation switches including an AF start switch SWAF for starting an AF operation, and a treatment instrument insertion channel is provided at a connecting portion positioned between the grip operation unit 12 and the insertion unit 11. A treatment instrument insertion port 18 leading to the outlet portion 18a is provided.
[0015]
The processor 30 includes a CCD drive circuit 21 that outputs a synchronization signal to the CCD 20 and the CCD process circuit 22 and scans the CCD 20 based on the synchronization signal. The CCD 20 is a so-called primary color CCD and outputs RGB image signals. The CCD process circuit 22 is a circuit that reads the RGB image signal of the CCD 20 in synchronization with the synchronization signal input from the CCD drive circuit 21 and preprocesses the read signal (signal amplification processing, noise removal processing, etc.). The signal output from the CCD process circuit 22 is converted into a digital signal by the A / D conversion circuit 23, and after various image processing such as white balance and gamma correction is performed by the video signal processing circuit 24, The analog signal is converted by the / A conversion circuit 25 and output to the TV monitor 60. The RGB image signal of the CCD 20 is also input to the color separation conversion circuit 26 via the CCD process circuit 22 and the A / D conversion circuit 23. The color separation conversion circuit 26 performs color separation for each pixel on the input RGB image signal to generate an RGB (red, green, blue) data array (RGB image data group). The RGB image data group RGB [x] [y] (x, y; natural numbers) output from the color separation conversion circuit 26 passes through the RGB matrix circuit 27, and the R data group R [x] [y], G data group. G [x] [y] and B data group B [x] [y] are divided and output to the microcomputer 28 independently. In the present embodiment, the CCD process circuit 22, the A / D conversion circuit 23, the color separation conversion circuit 26, and the RGB matrix circuit 27 constitute an image acquisition unit.
[0016]
The microcomputer 28 converts the input R data group R [x] [y], G data group G [x] [y], and B data group B [x] [y] into the HSI data group HSI [x] [y] ( Hue H, Saturation S, Lightness I). For conversion from RGB to HSI, a conversion formula of a hexagonal pyramid color model can be used as is well known. Further, the microcomputer 28 performs a predetermined calculation based on the HSI data group H [x] [y], S [x] [y], I [x] [y], and indicates an AF evaluation value indicating the focus state of the subject. Is calculated. The AF evaluation value is output to the motor control circuit 31. The motor control circuit 31 calculates the driving amount of the AF motor 19 provided in the electronic endoscope 10 based on the AF evaluation value input from the microcomputer 28, and the motor driving circuit 32 is calculated by the calculated driving amount. Then, the AF motor 19 is driven to move the focus lens L. The RGB image data group input and the AF evaluation value calculation are executed at each step position of the focus lens L while moving the focus lens L. Then, the focus lens L is finally moved to the step position (focus position) where the AF evaluation value is maximized.
[0017]
The processor 30 further includes a lamp light source 33. The illumination light emitted from the lamp light source 33 is adjusted to an optimum light amount by a diaphragm (not shown), and then supplied to the illumination lens 16 via the condenser lens 34 and the light guide LG2.
[0018]
In the endoscope apparatus 100 having the overall configuration described above, the microcomputer 29 performs the focus adjustment operation while switching the AF evaluation value calculation method according to the image state input from the electronic endoscope 10. In other words, based on the image data group input from the electronic endoscope 10, it is determined whether or not the subject is colored, stained or discolored by the coloring agent, and observation is performed without using the coloring agent (the subject is colored). AF evaluation values are calculated for a normal mode (first mode) that is not dyed or discolored) and a dye mode (second mode) in which observation is performed using a coloring agent (subject is colored, stained, or discolored). The method switches.
[0019]
Specifically, the microcomputer 29 calculates the variation of the hue data group H [x] [y], and switches to the normal mode when the calculation result is less than a predetermined threshold, and switches to the dye mode when the calculation result is equal to or greater than the predetermined threshold. Switch. In the normal mode, since the luminance difference of the subject can be sufficiently detected, the AF evaluation value is calculated using the brightness data group I [x] [y] corresponding to the luminance of the subject. On the other hand, in the dye mode, since the subject is colored, dyed, or discolored by the coloring agent, there is little difference in luminance. Therefore, the hue data group H [x] [y] and the saturation data group S [x] [y ] Is used to calculate the AF evaluation value. By switching the AF evaluation value calculation method in accordance with the image state of the electronic endoscope 10 in this way, an accurate AF evaluation value can be calculated regardless of whether or not a coloring agent is used. Based on this, it is possible to realize a highly accurate AF operation.
[0020]
Next, the AF operation of the endoscope apparatus 100 will be described in more detail with reference to FIG. FIG. 3 is a flowchart regarding the AF operation of the endoscope apparatus 100. This AF operation is started when the AF start switch SWAF is turned on and is controlled by the microcomputer 28.
[0021]
When the AF operation is started, first, a variable Cmax indicating the maximum AF evaluation value is set to 0 (S1), the AF motor 19 is driven via the motor control circuit 31 and the motor drive circuit 32, and the focus lens L is moved to the infinity end. (S3). Next, it is checked whether or not the focus lens L has reached the closest end (S5). The position of the focus lens L is detected, for example, by converting the driving amount of the AF motor 19, or the focus lens L is provided with position detection means (position detection sensor, code plate, etc.) and output from the position detection means. Detect based on signal.
[0022]
If the focus lens L has not reached the closest end (S5; N), the RGB matrix data 27 from the RGB matrix circuit 27 R [x] [y], G [x] [y], B [x] [y] Are input independently (S7), and mode recognition processing is executed (S9). In the mode recognition process, the presence / absence of hue variation is checked based on the RGB image data groups R [x] [y], G [x] [y], and B [x] [y] input in S7. For example, the AF evaluation value calculation method is switched to the normal mode, and if there is variation, the AF evaluation value calculation method is switched to the dye mode.
[0023]
Subsequently, in S9, it is checked whether or not it is the dye mode (S11). If it is the dye mode, an AF evaluation value is calculated according to the algorithm for the dye mode (S11; Y, S13). On the other hand, if it is not the dye mode, the AF evaluation value is calculated according to the algorithm for the normal mode (S11; N, S15). The calculated AF evaluation value and the lens position where the AF evaluation value is obtained are held in the microcomputer 28.
[0024]
After calculating the AF evaluation value, it is checked whether the AF evaluation value is larger than the variable Cmax (S17). If it is larger than the variable Cmax (S17; Y), the AF evaluation value calculated in S13 or S15 is overwritten in the variable Cmax (S19), and the focus lens L is moved one step toward the closest side (S21). Return to S5. On the other hand, when the AF evaluation value calculated in S11 or S13 is not larger than the variable Cmax (S17; N), the focus lens L is moved one step toward the closest side without changing the variable Cmax (S21). Return to S5.
[0025]
The processes of S5 to S21 are repeatedly executed until the focus lens L reaches the close end (until it reaches the close end and can no longer move to the close side). That is, the AF evaluation values are calculated at all step positions (including the infinity end and the close end) of the focus lens L, and the AF evaluation value is compared with the variable Cmax to update the variable Cmax to a larger value. Finally, the value stored in the variable Cmax becomes the maximum AF evaluation value. If the focus lens L has reached the closest end (S5; Y), the AF motor 19 is driven via the motor control circuit 31 and the motor drive circuit 32, and the AF evaluation value stored in the variable Cmax is stored. The focus lens L is moved to the lens position where the lens is obtained (S23).
[0026]
Next, the mode recognition process executed in S9 of FIG. 3 will be described in detail with reference to FIG. When entering this process, first, hue variation determination is performed (S31). In the hue variation determination, the RGB image data groups R [x] [y], G [x] [y], and B [x] [y] input in S7 of FIG. 3 are used as the hue data group H [x] [y]. And the variation of the hue data group H [x] [y] is calculated. When the variance value exceeds a predetermined threshold, it is determined that there is a variation in hue. If there is a hue variation, the mode is switched to the dye mode (S33; Y, S35), and if there is no hue variation, the mode is switched to the normal mode (S33; N, S37).
[0027]
Next, the hue variation determination process executed in S31 of FIG. 4 will be described in detail with reference to FIG. When entering this process, first, the average values Rm, Gm of all the pixels of the RGB image data groups R [x] [y], G [x] [y], B [x] [y] inputted in S7 of FIG. , Bm are respectively calculated (S41), and the average values Rm, Gm, Bm are subjected to HSI conversion to obtain a hue reference Hm (S43), and the determination result is reset to “no variation” (S45). The hue reference Hm is a reference value for comparing hue variations.
[0028]
Subsequently, the processing of S49 and S51 is performed for each pixel on the RGB image data group R [x] [y], G [x] [y], and B [x] [y] input in S7 of FIG. (S47 to S51). In S47, it is checked whether or not the processing in S49 and S51 has been completed for all the pixels of the RGB image data groups R [x] [y], G [x] [y], and B [x] [y]. . If not completed (S47; N), the RGB image data R [x] [y], G [x] [y], B [x] of the pixel [x] [y] specified by the variables x and y ] [y] is subjected to HSI conversion to calculate hue data H [x] [y] (S49), and the difference between the calculated hue data H [x] [y] and the hue reference Hm has a predetermined threshold value. It is checked whether or not it exceeds (S51), and if the difference between the hue data H [x] [y] and the hue reference Hm does not exceed a predetermined threshold, the process returns to S47 (S51; N). Then, when the processing of S49 and S51 is completed for all the pixels (S47; Y), the processing exits from this processing and proceeds to S33 in FIG. As described above, when it is determined No in S47, there is no pixel in which the difference between the hue data H [x] [y] and the hue reference Hm exceeds the threshold value, and the determination result is set in S45. Return with no variation. On the other hand, if the difference between the hue data H [x] [y] and the hue reference Hm exceeds a predetermined threshold (S51; Y), the determination result is set to “with variation” (S53), and this process is performed. The process proceeds to S33 in FIG.
[0029]
In the hue variation determination, it is ideal to compare the dispersion value of the hue data H [x] [y] with a predetermined threshold and determine the presence or absence of hue variation based on the comparison result. However, in actuality, since a complex operation is required to calculate the average value of the hue data H [x] [y], the variance value of the hue data H [x] [y] should be calculated numerically. Is not easy. Therefore, in the present embodiment, as described above, the difference between the hue reference Hm that is an average value and the individual hue data H [x] [y] is calculated, and the hue variation is determined based on this difference.
[0030]
Next, the dye mode AF evaluation value calculation process executed in S13 of FIG. 3 will be described in detail with reference to FIG. In the AF evaluation value calculation process for the dye mode, the input RGB image data group RGB [x] [y] is converted into the HSI data group HSI [x] [y], and the hue data group H [x of this HSI data group is converted. ] [y] and saturation data group S [x] [y] are used to calculate an AF evaluation value.
[0031]
In this process, first, a variable C for storing the AF evaluation value is set to 0 (S61), and a variable y (1) for designating a row (vertical direction position) of the RGB image data group RGB [x] [y]. 1 is set to ≦ y ≦ IH-2) (S63). Next, whether or not the variable y exceeds the specified maximum vertical position IH-2 is checked based on whether or not the variable y is less than (IH-1) (S65). When the variable y is less than (IH-1) (S65; Y), the variable x (1 ≦ x ≦ IW−) that designates a column (horizontal position) of the RGB image data group RGB [x] [y]. 2 is set to 1 (S67), and it is checked whether or not the specified maximum horizontal position IW-2 has been exceeded (S69) depending on whether or not the variable x is less than (IW-1). If the variable x is less than (IW-1), the RGB pixel data of the pixel adjacent to the pixel [x] [y] specified by the variables x and y is converted into HSI data (S71). That is, pixels [x] [y + 1] and [x] [y-1] adjacent in the vertical direction and pixels [x-1] [y] and [x + 1] [y] adjacent in the horizontal direction RGB image data is converted into HSI data for a total of four pixels.
[0032]
Then, hue data H [x] [y + 1], H [x] [y-1], H [x-1] [y], H [x + 1] [y for four pixels converted in S71. ], A hue difference H ′ for the pixel [x] [y] is calculated (S73). The hue difference H ′ is an integrated value of the hue difference | ΔHx | in the horizontal direction with respect to the pixel [x] [y] and the hue difference | ΔHy | in the vertical direction with respect to the pixel [x] [y]. Here, the hue difference | ΔHx | in the horizontal direction is calculated from the equation; | ΔHx | = | H [x + 1] [y] −H [x−1] [y] |, and the hue difference in the vertical direction | ΔHy | Is calculated by the equation: | ΔHy | = | H [x] [y + 1] −H [x] [y−1] | When the hue difference H ′ calculated by the above formula is 360 or more, conversion is performed so that 0 ≦ H ′ <360.
[0033]
When the hue difference H ′ is calculated, the saturation data S [x] [y + 1], S [x] [y−1], S [x−1] [y], S for four pixels converted in S71. Using [x + 1] [y], the saturation difference S ′ in the vertical direction of the pixel [x] [y] is calculated (S75). The saturation difference S ′ is an integrated value of the horizontal saturation difference | ΔSx | for the pixel [x] [y] and the vertical saturation difference | ΔSy | for the pixel [x] [y]. Here, the saturation difference | ΔSx | in the horizontal direction is calculated from the equation; | ΔSx | = | S [x + 1] [y] −S [x−1] [y] | | ΔSy | is calculated by the equation: | ΔSy | = | S [x] [y + 1] −S [x] [y−1] |
[0034]
Subsequently, the hue difference H ′ and the saturation difference S ′ calculated in S73 and S75 are added to the variable C to be overwritten (S77). If the variable C is updated, 1 is added to the variable x to overwrite the memory, and the process returns to S69 (S79). After returning to S69, the processes from S69 to S79 are repeated until the variable x becomes (IW-1). By executing S69 to S79 once, processing is performed for one row (RGB [1] [y] to RGB [IW-2] [y]) of the RGB image data group RGB [x] [y]. (HSI data conversion and AF evaluation value calculation) are performed.
[0035]
When the variable x is not less than (IW-1) in the check of S69 (S69; N), that is, when the processing of one row of the RGB image data group RGB [x] [y] is completed, 1 is added to the variable y. The overwrite memory is then stored, and the process returns to S65 (S81). When returning to S65, the processes from S65 to S81 are repeatedly executed until the variable y becomes (IH-1). By repeating S65 to S81, HSI data conversion and AF evaluation value calculation are performed on RGB [1] [1] to RGB [IW-2] [IH-2] for all pixels of the RGB image data group. The AF evaluation value at the current position of the focus lens L is stored in the variable C. When the variable y is not less than (IH-1) (S65; N), the process exits from this process and proceeds to S17 in FIG.
[0036]
FIG. 7 is a flowchart relating to the AF evaluation value calculation processing for the normal mode executed in S15 of FIG. In the AF evaluation value calculation processing for the normal mode, the input RGB image data group RGB [x] [y] is converted into the HSI data group HSI [x] [y], and the brightness data I [x] of this HSI data group An AF evaluation value is calculated based on [y]. In other words, the flowchart of FIG. 7 is the same as FIG. 6 except that S74 and S76 are provided instead of S73, S75, and S77 of FIG. That is, in S74, the hue data H [x] [y + 1], H [x] [y-1], H [x-1] [y], H [x + 1] for four pixels converted in S71. ] [y] is used to calculate the brightness difference I ′ for the pixel [x] [y]. Then, the calculated brightness difference I ′ is added to the variable C (S76), and an AF evaluation value is calculated. The brightness difference I ′ is an integrated value of the brightness difference | ΔIx | in the horizontal direction with respect to the pixel [x] [y] and the brightness difference | ΔIy | in the vertical direction with respect to the pixel [x] [y]. The difference | ΔIx | is calculated from the equation; | ΔIx | = | I [x + 1] [y] −I [x−1] [y] |, and the vertical lightness difference | ΔIy | is the equation; = | I [x] [y + 1] -I [x] [y-1] |
[0037]
According to the present embodiment described above, the RGB image data group RGB [x] [y] from the CCD 20 is converted into the HSI data group HSI [x] [y], and the HSI data group HSI [x] [y] The AF evaluation value calculation method is switched between the normal mode and the dye mode according to the variation of the hue data group H [x] [y]. In the normal mode, since the luminance difference of the subject can be sufficiently detected, the AF evaluation value is calculated using the brightness data group I [x] [y]. On the other hand, in the case of the pigment mode, since the luminance difference of the subject is reduced by the pigment, the AF evaluation value using the hue data group H [x] [y] and the saturation data group S [x] [y]. Is calculated. In this way, if the AF evaluation value is calculated by an optimal calculation method corresponding to the image data group from the electronic endoscope 10, an accurate AF evaluation value is obtained, and high-precision AF is obtained based on the AF evaluation value. Operation is feasible.
[0038]
In the present embodiment, the AF evaluation value calculation method is switched according to the variation of the hue data group H [x] [y], but is switched according to the variation of the saturation data group S [x] [y]. Alternatively, switching may be performed according to both variations of the hue data group H [x] [y] and the saturation data group S [x] [y].
[0039]
In the present embodiment, the AF evaluation value is calculated using the hue data group H [x] [y] and the saturation data group S [x] [y] when in the pigment mode, and the brightness data when in the normal mode. The AF evaluation value is calculated using the group I [x] [y], and the AF evaluation value includes the hue data H [x] [y], the saturation data S [x] [y], and the lightness data I [ You may calculate using all of x] [y]. Specifically, specific weights (α, β, γ) are assigned to the hue difference H ′, the saturation difference S ′, and the brightness difference I ′ calculated in S73 and S75 in FIG. 6 and S74 in FIG. The integrated value (α × H ′ + β × S ′ + γ × I ′) is added to the variable C to obtain an AF evaluation value. At this time, in the normal mode, it is preferable to set the weighting coefficient γ of the lightness difference I ′ larger than the weighting coefficient α of the hue difference H ′ and the weighting coefficient β of the saturation difference S ′. On the other hand, in the pigment mode, it is preferable to set the weighting coefficient α of the hue difference H ′ and the weighting coefficient β of the saturation difference S ′ to be larger than the weighting coefficient γ of the brightness difference I ′.
[0040]
In the present embodiment, the microcomputer 28 functions as a data conversion unit, an evaluation value calculation unit, a variation calculation unit, a hue calculation unit, a saturation calculation unit, and a brightness calculation unit. It is also possible to provide the above means. In the above-described embodiment, the primary color CCD is used as the CCD 20, but a complementary color CCD can be used instead of the primary color CCD. When a complementary color CCD is used, an RGB conversion circuit for converting complementary color image data output from the complementary color CCD into RGB image data is provided.
[0041]
【The invention's effect】
According to the present invention, the image data group from the imaging means of the endoscope is subjected to HSI conversion to acquire the hue data group H and the saturation data group S, and at least one of the hue data group H and the saturation data group S. The AF evaluation value is calculated by an optimum method according to the variation of the color, so that it is possible to obtain an accurate AF evaluation value during normal observation without using a coloring agent and during dye observation using a coloring agent, and high-precision AF Operation is feasible.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a main configuration of an endoscope apparatus provided with an automatic focusing apparatus according to a first embodiment of the present invention.
2 is a plan view showing a distal end of an insertion part of the electronic endoscope of FIG. 1. FIG.
FIG. 3 is a flowchart relating to an AF operation of the endoscope apparatus shown in FIG. 1;
FIG. 4 is a flowchart regarding a mode recognition process executed in S9 of FIG.
FIG. 5 is a flowchart regarding hue variation determination processing executed in S31 of FIG.
6 is a flowchart relating to a dye mode AF evaluation value calculation process executed in S13 of FIG. 3;
FIG. 7 is a flowchart related to a normal mode AF evaluation value calculation process executed in S15 of FIG. 3;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Electronic endoscope 11 In-vivo insertion part 12 Grasping operation part 13 Universal tube 14 Connector part 15 Objective lens 16 Illumination lens 17 Air supply / water supply nozzle 18 Treatment tool insertion port 19 AF motor 20 CCD
21 CCD drive circuit 22 CCD process circuit 23 A / D conversion circuit 24 Video signal processing circuit 25 D / A conversion circuit 26 Color separation conversion circuit 27 RGB matrix circuit 28 Microcomputer 30 Processor 31 Motor control circuit 32 Motor drive circuit 33 Lamp light source 34 Condensing lens 60 TV monitor 100 Endoscope device L Focus lens LG1 Light guide (electronic endoscope side)
LG2 Light guide (processor side)

Claims (3)

In an automatic focus adjustment apparatus that moves a focus lens based on an AF evaluation value calculated by a predetermined calculation,
Image acquisition means for obtaining an image data group from a pixel group of the imaging means;
Data conversion means for converting the image data group into an HSI data group;
Variation calculating means for calculating a hue reference value by performing HSI conversion on an average value of the image data group, and calculating a hue difference between the hue reference value and the hue data H as a variation of the hue data H ;
When the variation of the hue data H is less than a predetermined threshold value, an AF evaluation value is calculated using the brightness data I of the HSI data group, and when the variation is greater than the predetermined threshold value, the hue data H and the saturation data S An evaluation value calculation means for calculating an AF evaluation value using one or both ,
An automatic focusing apparatus according to claim 1, wherein the threshold value is set to a value for discriminating between a normal observation mode in which no coloring agent is used and a dye observation mode in which a coloring agent is used . 2. The automatic focus adjustment apparatus according to claim 1, wherein the evaluation value calculation means uses both the hue data H and the saturation data S for calculating the AF evaluation value when the variation of the hue data H is equal to or greater than a predetermined threshold. An automatic focus adjustment device that adds a predetermined weight to the hue data H and the saturation data S, and uses the integrated value as the AF evaluation value. The automatic focusing apparatus according to claim 1 or 2, wherein the automatic focusing apparatus is mounted on an electronic endoscope.

Images