A non-contact pupil measurement application method under random lighting environment

Abstract

The present invention discloses a non-contact pupil measurement application method in a random illumination environment, which relates to the technical field of eyeball image acquisition. The illumination sensor is used to detect the ambient illumination to determine whether it meets the set measurement ambient illumination requirement. If the ambient illumination value is greater than Xb, the measurement is stopped or other algorithms are enabled; if the ambient illumination value is less than Xd, the compensation lighting source Lc is turned on and then the detection is performed again, and the corresponding adjustment coefficient is set according to the ambient illumination result of the re-detection; if the ambient illumination result is in the bright field, the pupil can be directly photographed, measured, and the coefficient is adjusted. The method of the present invention changes the traditional practice that the application of pupil diameter measurement must be implemented in a fixed illumination environment, and has broad prospects in some application fields where it is difficult to achieve a fixed illumination environment.

Description

Technical Field

[0001] The invention relates to the technical field of eyeball image capture, and in particular to an application method for non-contact pupil measurement in a random lighting environment. Background Art

[0002] With the development of modern corneal and lens refractive surgery, pupil size has become an important parameter for preoperative evaluation and surgical design. In excimer laser refractive surgery, the cutting area is generally designed according to the patient's pupil diameter in the dark. If the cutting area is smaller than the pupil diameter in the dark room, it may cause an increase in postoperative spherical aberration, blurred vision and discomfort at night and in dim light, affecting the imaging quality of the human eye. Therefore, it is particularly important to accurately measure the dark room pupil before corneal refractive surgery and design the cutting area size according to the patient's dark room pupil diameter and corneal thickness. The measurement of pupil diameter in dark light has become a necessary step in the preoperative evaluation of corneal refractive surgery. In other pupil measurement applications, such as the diagnosis of diseases, accurate measurement of pupil diameter is also required, otherwise the diagnosis of the disease will be misjudged.

[0003] Pupil diameter is usually in dynamic change, which makes it difficult to measure. In order to accurately measure pupil diameter, pupil diameter measurement before surgery needs to be carried out in a dark room with a special measuring instrument, which undoubtedly increases the cost and measurement difficulty. In some measurement applications in non-fixed lighting environments, due to changes in the lighting environment, the pupil diameter application algorithm needs to be adjusted according to the corresponding environment, such as algorithm 1 is applicable to 100Lux illumination environment, algorithm 2 is applicable to 300Lux, ..., algorithm n is applicable to 800Lux illumination environment, etc. The ambient illumination needs to be detected and identified before use, so as to adjust the pupil diameter application algorithm to the corresponding illumination. However, the ambient illumination is a continuously changing analog quantity, while the several different sets of ambient illumination given in advance are discrete values. Therefore, the ambient illumination application algorithm based on discrete values ​​is difficult to correspond to the actual ambient illumination. For example, when the actual ambient illumination value is 197 Lux, whether Algorithm 1 (100 Lux) or Algorithm 2 (300 Lux) is used, there will be a large error with the actual illumination. Therefore, in this case, the pupil diameter application result given can only be a similar value for reference. Because in some diseases judged by pupil diameter, the same pupil diameter has completely different results under different illumination environments.

[0004] Figure 1It is the projection of the pupil diameter measured when the illuminance ranges from Lux100 to 1100 on the coordinates. The horizontal (X) axis of the coordinates is the illuminance, and the vertical (Y) axis is the pupil diameter. Obviously, Y=f(x). The shaded circle is the pupil diameter measured when the illuminance is Lux100, Lux300, Lux500, Lux800, Lux1000 and Lux1100 respectively. The pupil diameter application algorithm basically selects one or several illuminance values, such as selecting 300Lux or selecting 100Lux, 300Lux, and 500Lux. The former requires that the application illuminance environment be limited to 300Lux, and the latter requires that the application illuminance environment be limited to 100Lux, 300Lux, and 500Lux respectively. They will be called separately according to the actual situation when applied. However, in actual operation, it is difficult to set the illumination environment to be completely consistent with the requirements, and there will always be fluctuations. For example, if the illumination is set to 100 Lux, it is normal to see 90-110 Lux in reality, but we can only use the 100 Lux application algorithm. If the illumination is set to 300 Lux, it is normal to see 280-330 Lux in reality, and we can only use the 300 Lux application algorithm.

[0005] Since illuminance is an analog quantity, there are actually countless f(x) values ​​between 100 Lux and 1100 Lux. Therefore, it is obviously inaccurate to use the pupil diameter application algorithm that sets a certain number of illuminance values ​​in advance to adapt to the pupil diameter actually measured under continuously changing illuminance conditions. Summary of the invention

[0006] In view of the large error in applying the pupil diameter measurement results obtained under a random illumination environment to a fixed illumination environment, the present invention proposes a non-contact pupil measurement application method under a random illumination environment, which solves the application problem of the changing pupil diameter obtained under a random illumination environment. In applications involving pupil diameter, the illumination environment is no longer the key issue to be solved first.

[0007] The present invention proposes a non-contact pupil measurement application method in a random lighting environment. The non-contact measurement system used includes: an infrared eye camera lens module, an illumination sensor, an infrared light compensation lighting lamp and a white light compensation lighting lamp. The infrared eye camera lens module includes a visible light lens and an infrared lens. The illumination sensor is used to detect the brightness of the shooting environment and submit the detection result to the system; the white light compensation lighting lamp is used to increase the brightness when the shooting environment is dark. The specific measurement application method includes the following steps:

[0008] S1. Determine the measurement area. Select the interval consisting of two points Xd and Xb on the X-axis of the pupil diameter-light intensity curve. In this interval, the pupil diameter will change with the change of light intensity. The amplitude of the change is to maintain the constant amount of light entering the pupil. The values ​​of Xd to Xb are between the lighting brightness that people are usually accustomed to, depending on the specific application scenario, which is called the bright vision area. The interval from the origin O to point Xd is the dark vision area. This area requires the rod cells to increase their sensitivity to light to compensate for the lack of light intensity; the interval from point Xb to point X with a larger value is called the highlight area. This area requires the cone cells to reduce their sensitivity to light to protect the visual cells from burns; the measurement and application of the pupil diameter are selected in the bright vision area, that is, the measurement area;

[0009] S2, ambient light illumination detection, the illumination sensor selects a digital illumination sensor, and directly outputs a digital value corresponding to the brightness;

[0010] S3, the ambient light illumination is in the bright vision area, i.e. the measurement area. M and S are different points in the measurement area, and their illumination values ​​are a0 and a1 respectively. The pupil diameters correspond to b0 and b1 respectively. A standard illumination value Ls is set in the measurement area. Under this illumination environment, a normal pupil is measured. The obtained pupil standard diameter value Ds and standard pupil area Ss are obtained, and a standard measurement unit S for this area is obtained. LD , is the product of the standard illumination value and the pupil area under the standard illumination value, that is:

[0011] S LD =Ls·Ss

[0012] Its unit is Lxmm, which means lux millimeter square, and the standard measurement unit S LD , measurement of pupil diameter in the photopic area, in standard units S LD As a standard, the measurement results under different illumination environments are adjusted and converted;

[0013] Standard unit of measurement S LD It is another way to express luminous flux. Its physical meaning is that no matter how the pupil diameter and illumination value change, the luminous flux entering the pupil is constant. That is:

[0014] Φ=E·S

[0015] E=Φ / S

[0016] S=Φ / E

[0017] Φ is the luminous flux, unit (Lm); S is the illuminated area, unit (m 2 );E illumination, unit (Lx or Lux);

[0018] Based on this, the pupil diameter d is obtained:

[0019] S=π·r 2

[0020] S / π=r 2

[0021]

[0022]

[0023] According to the luminous flux expression, after transformation, the standard formula for pupil diameter measurement is:

[0024] S LD / Illuminance = Pupil Area

[0025]

[0026] S4, in the standard measurement unit S LD Under certain conditions, correction is required when using a fixed illumination measurement algorithm to judge an application. The correction method is to use the ratio of the instant pupil diameter to the standard pupil diameter Dr / Ds as a coefficient. The pupil diameter value in the application under the original standard fixed illumination environment is multiplied by the coefficient to obtain the judgment parameter of the instant pupil diameter.

[0027] Preferably, the method further includes step S5, in which, when in the dark vision area, the ambient light illuminance is increased by adding compensation lighting, and the compensation light illuminance value is set to Lc, so that the illuminance value after the compensation lighting falls in the bright vision area. The selection of the illuminance value should meet the following requirements:

[0028] Xb>Lc>Xd

[0029] Lc+Xd<Xb.

[0030] The beneficial effects of the present invention are as follows: first, the range of the clear vision area is determined, points Xd and Xb are selected, and the value of the compensation illumination Lc is determined according to Xd and Xb; then the standard illumination value Ls is set, and the standard pupil diameter Ds and the standard measurement unit S are generated under this standard illumination value. LD , where S LD It is the product of the standard illumination value and the pupil area under the standard illumination value, that is:

[0031] S LD =Ls·Ss

[0032] Thus, Ls is determined as the standard illumination value, and the pupil diameter Dr measured in any lighting environment from the dark to the bright area can be used for diagnosis consistent with its actual illumination. The application method is to multiply the ratio of the instantaneous pupil diameter Dr to the standard pupil diameter Ds by the standard pupil diameter to generate a new instantaneous illumination pupil parameter.

[0033] The method of the present invention changes the traditional practice that the pupil diameter measurement application must be implemented in a fixed light intensity environment, and has broad prospects in some application fields where it is difficult to achieve a fixed light intensity environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is the projection diagram of the pupil diameter measured when the illumination ranges from Lux100 to 1100 on the coordinates;

[0035] Figure 2 This is a comparison diagram of the camera aperture and the human eye pupil principle;

[0036] Figure 3 The change pattern of normal human pupil diameter with different light intensity;

[0037] Figure 4 The principle block diagram of the non-contact measurement system applied in the present invention;

[0038] Figure 5 This is a diagram showing the changing rules of the dark vision area, bright vision area and highlight area;

[0039] Figure 6 It is a flow chart of the measuring method of the present invention. DETAILED DESCRIPTION

[0040] The present invention will be further explained below in conjunction with specific embodiments.

[0041] The pupil is a small round hole in the center of the iris in an animal or human eye, which is the channel for light to enter the eye. The pupil can control the amount of light entering the eye by adjusting its size to ensure a clear image on the retina. The diameter of the average human pupil can vary between 1.5-8.0mm. When a person goes from a bright place to a dark place, the pupil diameter will increase so that more light can enter the eyeball; when going from a dark place to a bright place, the pupil diameter will decrease to prevent too much light from entering the eyeball and burning the retina. It can be seen that the change of the pupil has the effect of keeping the amount of light entering the eye constant under different lighting conditions. However, this function of keeping the amount of light entering constant is limited to a certain range, because the intensity of the strong sunlight in the starlight environment is actually reduced by about 1 million times, so the change in pupil size alone is far from enough to keep the amount of light entering the eye constant.

[0042] In the retina, there are cells that can convert light stimulation into nerve impulses - photoreceptors, also known as photoreceptor cells. Photoreceptors are divided into cones and rods, which play different roles in visual activities. Cones are cells that sense strong light and color; the rod system composed of rods is also called the night light perception or scotopic vision system. They can sense weak light stimulation in dim environments and cause scotopic vision, but have no color vision and low ability to distinguish details of the objects being viewed.

[0043] The human eye receives light stimulation by adjusting the sensitivity of the photoreceptor cells in the retina under different brightness conditions. In extremely dark environments, in addition to increasing the pupil diameter, the rod cells are much more sensitive to light than in normal brightness environments; conversely, in extremely bright environments, in addition to reducing the pupil diameter, the cone cells' sensitivity to light will also decrease to avoid burns.

[0044] The light reaction process of the pupil and retinal cells of the human eye is similar to the aperture of a camera and the sensitivity of the film (image sensor). In fact, the principle of the camera aperture is inspired by the pupil of the human eye. Figure 2 As shown. The changes in pupil diameter and aperture size are only to adjust the amount of light entering. When the changes in pupil diameter and aperture size still cannot meet the imaging requirements of the retina or camera film (image sensor), the sensitivity of the rods, cones or film (image sensor) must be changed. For example, when taking pictures outdoors on a sunny day, a film with a sensitivity of ISO100 is usually selected, a film with a higher sensitivity of ISO200 can be selected on a cloudy day, and a film with a higher sensitivity of ISO400 can be used indoors. The ISO sensitivities are 50, 100, 125, ..., 1000, ..., 25600 to adapt to different lighting environments. A film with a higher sensitivity can be selected at night.

[0045] The idiom "work at sunrise and rest at sunset" is a good summary of the daily life of ancient people. People get up to work when the sun rises and rest when the sun sets. In fact, this statement is essentially a description of visual function, because only after sunrise is there enough light intensity, people can see things clearly and carry out normal activities; when the light intensity drops after sunset, objects cannot be seen clearly, work activities are hindered, and people can only go home to rest. Human pupils have evolved in this long-term life mode, that is, normal vision requires specific lighting conditions. Within a certain range of light, if the light intensity is too high, the pupil diameter is reduced to reduce the amount of light entering; if the light intensity is too low, the pupil diameter is expanded to increase the amount of light entering, so as to keep the amount of light entering constant under different light intensity conditions, and then reliable imaging.

[0046] Figure 3 This is the law of change of pupil diameter of normal people with different light intensity. The vertical (Y) axis is pupil diameter, and the horizontal (X) axis is light intensity. The change of pupil diameter with light intensity occurs in the shadow area surrounded by points o, p, and q. Among them, when the light intensity value is small, that is, close to o, the rod cells will increase their sensitivity to light to compensate for the insufficient amount of light caused by the inability of the pupil to continue to increase, so as to form a clear image; when the light intensity value is large, that is, close to q, the cone cells will reduce their sensitivity to light to reduce the overbright image and retinal burns caused by the inability of the pupil to continue to shrink.

[0047] exist Figure 3 There are two points on the X-axis, one point is somewhere close to point o, and the other point is somewhere close to point q. Between these two points is the area where the pupil can change its diameter with the intensity of light to maintain a constant amount of light entering. Therefore, if the application of measuring pupil diameter is kept in this area of ​​light intensity, only one application algorithm can be used without setting several different light intensity algorithms to adapt to the pupil diameter. This solves the problem of inaccurate accuracy of the traditional pupil diameter measurement algorithm.

[0048] The non-contact measurement application method of the pupil in a random lighting environment of this embodiment, the non-contact measurement system used includes: an infrared eye camera lens module, an illumination sensor 3, an infrared light compensation lighting lamp 4 and a white light compensation lighting lamp 5. The infrared eye camera lens module includes a visible light lens 1 and an infrared lens 2. The illumination sensor 3 is used to detect the brightness of the shooting environment and submit the detection result to the system; the white light compensation lighting lamp is used to increase the brightness when the shooting environment is dark; the principle block diagram is as follows Figure 4 shown.

[0049] It should be noted that the measurement unit of the pupil diameter in this embodiment is pixel bit, but how to convert pixel bit into the standard length measurement unit mm is a conventional technical means, which is not the key point of the present invention and is not elaborated here.

[0050] The specific measurement application method includes the following steps:

[0051] S1. Setting of measurement area

[0052] exist Figure 3 There is an interval consisting of two points on the X-axis of , in which the pupil diameter will change with the change of light intensity, and the amplitude of the change is to maintain the constant amount of light entering the pupil. Figure 5 The values ​​of points Xd to Xb in the image are within the lighting brightness that people are usually accustomed to, depending on the specific application scenario, which is called the light vision area; the interval from the origin O to point Xd is the dark vision area, this area requires rod cells to increase their sensitivity to light to compensate for the lack of light intensity; the interval from point Xb to X with larger values ​​is called the highlight area, this area requires cone cells to reduce their sensitivity to light to protect the visual cells from burns.

[0053] In this embodiment, the pupil diameter is measured and applied in the bright vision area, so this area can also be called the measurement area. When the ambient illumination is in the dark vision area and the bright vision area, other solutions are adopted.

[0054] S2. Ambient light intensity detection

[0055] The detection of ambient light illumination can be realized by a special illumination sensor chip. Illuminance sensors are widely used, such as well-known mobile phones, laptops, etc., which can adjust the brightness of the background light according to the brightness of the environment to save energy and improve visibility. There are also power-saving devices such as automatic light control switches. In this embodiment, a digital illumination sensor is selected, which can directly output a digital value corresponding to the brightness, and the measurement range is between 0 and 100,000 Lux.

[0056] S3, for the ambient light illumination in the bright vision area, i.e. the measurement area, such as Figure 5 As shown, if Xd is selected as 300 and Xb is selected as 1200, the measurement area is between the illumination values ​​of 300Lux and 1200Lux. Among them, M and S are different points in the measurement area, and their illumination values ​​are a0 and a1 respectively, and the pupil diameters correspond to b0 and b1 respectively. Set a standard illumination value Ls in the measurement area, if Ls=800Lux is selected; measure a normal pupil (clinically a normal pupil is non-myopia, no eye disease, no eye trauma, no emotional fluctuations, no medication that affects the pupil, etc.) under this illumination environment, and the obtained standard pupil diameter value is Ds=2.6mm, and the corresponding standard pupil area is Ss=5.3091mm 2 , which is located at Figure 5 Measure point N in the area.

[0057] In this way, we can get a standard measurement unit S for this area. LD , which is the product of the standard illumination value and the pupil area under the standard illumination value, that is:

[0058] S LD =Ls·Ss

[0059] S LD =800Lux×5.3091mm 2

[0060] S LD ≈4248Lxmm

[0061] Its unit is Lxmm, which means lux millimeter square. LD The measurement of pupil diameter in the bright vision area can be used as a standard to adjust and convert the measurement results in different light intensity environments.

[0062] This formula is actually another way to express luminous flux. Its physical meaning is that no matter how the pupil diameter and illumination value change, the luminous flux entering the pupil is constant. That is:

[0063] Φ=E·S, E=Φ / S, S=Φ / E

[0064] Where, Φ is the luminous flux, in Lm; S is the illuminated area, in m 2 ); E illumination, unit (Lx or Lux).

[0065] Based on this, the pupil diameter d is obtained:

[0066] S=π·r 2

[0067]

[0068]

[0069] According to the luminous flux expression, after transformation, the standard formula for pupil diameter measurement is:

[0070] 4248Lxmm / illuminance = pupil area

[0071]

[0072] If the ambient light intensity is 400 Lux at a certain time, the instant pupil parameters should be calculated as:

[0073] Sr=4248 / 400=10.62mm 2 (Instant pupil area)

[0074]

[0075] If the ambient light intensity is 900 Lux at a certain time, then the pupil diameter at this time should be:

[0076] Sr=4248 / 900=4.72mm 2

[0077]

[0078] In this example, S LD =4248Lxmm, when using the fixed illumination measurement algorithm to judge the application, corresponding corrections can be made. The correction method is to use the ratio of the instant pupil diameter to the standard pupil diameter Dr / Ds as a coefficient, and multiply the pupil diameter value in the application under the original standard fixed illumination environment by the coefficient to obtain the judgment parameter of the instant pupil diameter.

[0079] For example, some diagnostic conditions for a disease diagnosis application based on pupils are shown in Table 1:

[0080] Table 1

[0081]

[0082] The age groups in Table 1 can be divided into 5-year, 10-year or longer time periods, depending on the specific application; PCA is the pupil contraction amplitude; PID is the pupil diameter; I is the iris diameter; abnormalities 1 to 3 represent different symptoms. It should be noted that the pupil data in this table is measured at an ambient light illumination of 500 Lux, and the diagnosis should also be measured under the same light illumination environment, and then the diagnosis results are given according to this table. However, in the actual measurement process, the ambient light illumination varies with the different places of use, so directly using Table 1 will result in misdiagnosis. If the actual value of the ambient light illumination measured in a certain time is 560 Lux, the measured pupil diameter must be smaller than the data in Table 1, so according to the principle of constant pupil light flux, the adjustment coefficient is set to convert the illumination ratio into the pupil diameter ratio.

[0083] Sr=4248 / 560=7.5857mm 2

[0084]

[0085] Ss=4248 / 500=8.496mm 2

[0086]

[0087] Ambient illumination ratio: 560Lux / 500Lux=1.12

[0088] Pupil diameter ratio: (560 Lux) Dr / Ds (500 Lux) = 0.9449

[0089] Then, based on the judgment parameters in Table 1, a new judgment rule of 560 Lux illumination is generated as shown in Table 2.

[0090] Table 2

[0091]

[0092] For example, if the ambient light intensity during pupil measurement is 300 Lux, the pupil diameter measured must be larger than the data in Table 1 measured at 500 Lux. Therefore, the adjustment coefficient is set according to the same principle as follows:

[0093] Sr=4248 / 300=14.16mm 2

[0094]

[0095] Ss=4248 / 500=8.496mm 2

[0096]

[0097] Ambient illumination ratio: 300Lux / 500Lux=0.6

[0098] Pupil diameter ratio: 300(Lux):(500lux)=Dr / Ds=1.2910

[0099] Then, based on the judgment parameters in Table 1, a new judgment rule of 300 Lux illumination is generated as shown in Table 3.

[0100] Table 3

[0101]

[0102] For another example, the ambient light illuminance for pupil measurement is 498 Lux, which is very close to the standard illuminance of 500 Lux, but the pupil diameter measured should also be larger than the data in Table 1 measured at 500 Lux. Therefore, the adjustment coefficient is set according to the same principle:

[0103] Sr=4248 / 498=8.5301mm 2

[0104]

[0105] Ss=4248 / 500=8.496mm 2

[0106]

[0107] Ambient illumination ratio: 498Lux / 500Lux=0.996

[0108] Pupil diameter ratio: 498 (Lux): (500 lux) = Dr / Ds = 1.0020

[0109] Then, based on the judgment parameters in Table 1, a new judgment rule of 498 Lux illumination is generated as shown in Table 4.

[0110] Table 4

[0111]

[0112]

[0113] According to this principle, the diagnosis of pupil diameter can be achieved with one algorithm in any lighting environment within the "bright vision zone".

[0114] S4. Compensation Light Illumination

[0115] exist Figure 5In the three groups of ambient light illumination areas, the dark vision area and the bright vision area are not suitable for the calculation diagnosis method of the bright vision area. However, in the dark vision area, the ambient light illumination value can be made to fall within the bright vision area by adding compensation lighting. If the compensation light illumination value is set as Lc, the selection of its illumination value should meet the following requirements:

[0116] Xb>Lc>Xd ⑴

[0117] Lc+Xd<Xb ⑵

[0118] Still using the above example, Figure 5 Assume that Xd is 300 Lux and Xb is 1200 Lux. Lc can be set between 300 and 900 Lux. If Lc is set to 450 Lux, when the ambient light is in the dark vision area, the compensation lighting Lc can be turned on to make the light value after compensation lighting fall in the bright vision area. The same algorithm can still be used for measurement and diagnosis.

[0119] For example, when measuring the pupil, the system detects that the ambient light illuminance is 15 Lux. After the compensation lighting is turned on, the ambient light illuminance is 465 Lux, which meets the illuminance setting requirements ⑴ and ⑵. Therefore, the adjustment coefficient is set according to the same principle:

[0120] Sr=4248 / 465=9.1354mm 2

[0121]

[0122] Ss=4248 / 500=8.496mm 2

[0123]

[0124] Ambient illumination ratio: 465Lux / 500Lux=0.93

[0125] Pupil diameter ratio: 465 (Lux): (500 lux) = Dr / Ds = 1.0369

[0126] In this way, when the ambient light intensity is in the dark viewing area, after compensating the illumination, a new judgment rule of 465 Lux illumination is generated based on the judgment parameters in Table 1, as shown in Table 5.

[0127] Table 5

[0128]

[0129] Of course, the compensating lighting can also be designed to be digitally adjustable, so that Lc is not a fixed illuminance value, but this will make its control more flexible.

[0130] The measurement method of this embodiment first determines the range of the clear vision area, that is, Figure 5 Select points Xd and Xb in the figure, and determine the value of the compensation illumination Lc according to Xd and Xb; then set the standard illumination value Ls, and generate the standard pupil diameter Ds and the standard measurement unit SLD under this standard illumination value, where SLD is the product of the standard illumination value and the pupil area under the standard illumination value, that is:

[0131] SLD=Ls·Ss

[0132] Thus, Ls is determined as the standard illumination value, and the pupil diameter Dr measured in any lighting environment from the dark to the bright area can be used for diagnosis consistent with its actual illumination. The application method is to multiply the ratio of the instantaneous pupil diameter Dr to the standard pupil diameter Ds by the standard pupil diameter to generate a new instantaneous illumination pupil diameter parameter.

[0133] like Figure 6 As shown, during operation, the ambient illumination is first detected by the illumination sensor to determine whether it meets the set measurement ambient illumination requirement. If the ambient illumination value is greater than Xb, the measurement is stopped or other algorithms are enabled; if the ambient illumination value is less than Xd, the compensation lighting source Lc is turned on and then detected again, and the corresponding adjustment coefficient is set according to the ambient light illumination result detected again; if the ambient light illumination result is in the bright vision area, the pupil shooting, measurement, coefficient adjustment and other processes can be directly carried out.

[0134] The method of this embodiment changes the traditional practice that pupil diameter measurement must be carried out in a fixed illumination environment, and has broad prospects in some application fields where a fixed illumination environment is difficult to achieve.

[0135] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A non-contact measurement application method of pupils in a random lighting environment, and a non-contact measurement system for the application include: An infrared eye camera lens module, an illumination sensor, an infrared light compensation lamp and a white light compensation lamp, wherein the infrared eye camera lens module includes a visible light lens and an infrared lens, the illumination sensor is used to detect the brightness of the shooting environment and submit the detection result to the system; the white light compensation lamp is used to increase the brightness when the shooting environment is dark, and is characterized in that the specific measurement application method includes the following steps: S1. Determine the measurement area. Select the interval consisting of two points Xd and Xb on the X-axis of the pupil diameter-light intensity curve. In this interval, the pupil diameter will change with the change of light intensity. The amplitude of the change is to maintain the constant amount of light entering the pupil. The values ​​of Xd to Xb are between the lighting brightness that people are usually accustomed to, depending on the specific application scenario, which is called the bright vision area. The interval from the origin O to point Xd is the dark vision area. This area requires the rod cells to increase their sensitivity to light to compensate for the lack of light intensity; the interval from point Xb to point X with a larger value is called the highlight area. This area requires the cone cells to reduce their sensitivity to light to protect the visual cells from burns; the measurement and application of the pupil diameter are selected in the bright vision area, that is, the measurement area; S2, ambient light illumination detection, the illumination sensor selects a digital illumination sensor, and directly outputs a digital value corresponding to the brightness; S3, the ambient light illumination is in the bright vision area, i.e. the measurement area. M and S are different points in the measurement area, and their illumination values ​​are a0 and a1 respectively. The pupil diameters correspond to b0 and b1 respectively. A standard illumination value Ls is set in the measurement area. Under this illumination environment, a normal pupil is measured. The obtained pupil standard diameter value Ds and standard pupil area Ss are obtained, and a standard measurement unit S for this area is obtained. LD , is the product of the standard illumination value and the pupil area under the standard illumination value, that is: S LD =Ls·Ss Its unit is Lxmm, which means lux millimeter square, and the standard measurement unit S LD , measurement of pupil diameter in the photopic area, in standard units S LD As a standard, the measurement results under different illumination environments are adjusted and converted; Standard unit of measurement S LD It is another way to express luminous flux. Its physical meaning is that no matter how the pupil diameter and illumination value change, the luminous flux entering the pupil is constant; that is: Φ=E·S E=Φ / S S=Φ / E Φ is the luminous flux, unit (Lm); S is the illuminated area, unit (㎡); E is the illumination, unit (Lx or Lux); Based on this, the pupil diameter d is obtained: S＝π·r 2 S / π＝r 2 According to the luminous flux expression, after transformation, the standard formula for pupil diameter measurement is: S LD / Illuminance = Pupil Area S4, in the standard measurement unit S LD Under certain conditions, correction is required when using a fixed illumination measurement algorithm to judge an application. The correction method is to use the ratio of the instant pupil diameter to the standard pupil diameter Dr / Ds as a coefficient. The pupil diameter value in the application under the original standard fixed illumination environment is multiplied by the coefficient to obtain the judgment parameter of the instant pupil diameter.

2. According to the non-contact pupil measurement application method in a random illumination environment as described in claim 1, the other is that it also includes step S5, when in the dark vision area, the ambient light illumination is increased by adding compensation lighting, and the compensation light illumination value is set to Lc, so that the illumination value after the compensation lighting falls in the bright vision area, and the selection of the illumination value should meet the following requirements: Xb>Lc>Xd Lc+Xd<Xb.

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