JPS63191034A - Visibility measuring apparatus - Google Patents

Abstract

PURPOSE:To determine visibility accurately when an actual object is viewed, by calculating the visibility of the object from the difference between the brightness of the object and that of its background and from a brightness difference threshold. CONSTITUTION:A brightness distribution measuring section 1 measures a brightness distribution object-wise in a field of view containing an object and outputs a signal corresponding to brightness to a brightness difference calculating section 3, which calculates the difference between the brightness of objects and that of its background adjoining thereon. A brightness difference threshold calculating section 6 receives outputs from an equivalent photoscreen brightness measuring section 4 and a center cavity adaptive brightness measuring section 5 to calculate a brightness difference threshold when objects are observed. A visibility calculating section 7 calculates visibility of individual objects from a signal inputted from the brightness difference calculating section 3 and a signal inputted from the brightness difference threshold calculating section 6. Thus, a signal is outputted to a visibility distribution chart display section 8 according to the visibility of the objects.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a device for measuring the visibility of objects within a field of view.

Conventional technology Conventional visibility measurement devices provide a front curtain between the object and the observer's eyes, and change the front curtain brightness to measure the object while keeping the background brightness of the object constant. It was based on the principle that the brightness contrast between an object and its background was changed, and the visibility of the object was expressed by the front curtain brightness at which the object was no longer perceivable.

Problems to be Solved by the Invention Conventional devices measure the visibility of objects placed on a fixed work surface within a field of view. For this reason, when determining the visibility of objects at various positions within the field of view, it is necessary to point the measurement device in that direction and observe each time.

In addition, since there is a limit to the field of view to be observed, when measuring visibility, it is important to consider the effect that the equivalent light curtain brightness caused by the light that enters the eye from the peripheral field of view when actually looking at the object has on visibility. This has the problem of not being able to be reproduced accurately.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a brightness distribution measuring section that measures the brightness distribution, an object condition setting section that sets conditions for the brightness and position of the object, a brightness difference calculation unit that inputs signals from the object condition setting unit and the brightness distribution measurement unit and calculates a brightness difference between the target object and its background; and a brightness difference calculation unit that measures the equivalent light curtain brightness of the eyes of an observer viewing the target object. a foveal adaptation luminance measurement unit that measures the luminance to which the fovea of the observer's eye is adapted; a brightness difference discrimination threshold calculation unit that inputs the signal and calculates a brightness difference discrimination threshold of the observer's eyes;
The luminance difference discrimination threshold calculation section and a visibility calculation section that receives the signal from the brightness difference calculation section and calculates the visibility of the object are provided.

Operation The present invention uses the above-described means to determine the brightness distribution within the visual field, and calculates the difference between the brightness of an object located at an arbitrary position within the visual field and its background from the measured value of this brightness distribution. on the other hand,
A brightness difference discrimination threshold is calculated from the equivalent light curtain brightness and foveal adaptation brightness of the eyes of the observer looking at the object. The visibility of the object is calculated from the difference between the brightness of the object and its background and the brightness difference discrimination threshold.

Embodiment A block diagram of a visibility measuring device according to the present invention is shown in FIG. 1. 1 is a brightness distribution measuring section, 2 is an object condition setting section,
3 is a brightness difference calculation unit, 4 is an equivalent light curtain brightness measurement unit, 5 is a foveal adaptation brightness measurement unit, 6 is a brightness difference discrimination threshold calculation unit, 7 is a visibility calculation unit, and 8 is a visibility distribution map display unit. be.

The operation of the embodiment according to the present invention will be described below with reference to FIG. The brightness distribution measurement unit 1 measures the brightness distribution of a field of view that includes an object whose visibility is to be measured, divides the field of view into grids, calculates the brightness of the area surrounded by each grid, and calculates the brightness of each individual. A signal corresponding to the value is output to the luminance difference calculation section 3. The position and brightness (LO) of each of a plurality of objects whose visibility is to be determined are input to the object condition setting section 2, and signals corresponding to these are output to the n-degree difference calculation section 3. The brightness difference calculation unit 3 calculates the difference (ΔL=ILo−Lb) between the brightness of each object and the brightness (Lb) of the background adjacent to it.
l) is calculated for each object and output to the visibility calculation unit 7. The equivalent light curtain brightness measurement unit 4 measures the equivalent light curtain brightness (Leq) of the observer's eyes when looking at each object, and outputs a signal corresponding to the measured light curtain brightness. The foveal adaptation I1 degree measurement unit 5 measures the brightness to which the fovea of the observer's eye is adapted when looking at each object (foveal adaptation brightness Laf), and outputs a signal corresponding to the brightness. do. The luminance difference discrimination threshold calculation unit 6 inputs a signal corresponding to the equivalent front curtain intensity and a signal corresponding to the foveal adaptation luminance, and calculates a luminance difference discrimination threshold when observing each object from these, Signals corresponding to each are output to the visibility calculation section 7. In this case, the luminance difference discrimination threshold (ΔLmi
n) is obtained from the sum of the luminance difference discrimination threshold (ΔLmin(Leq)) determined by the equivalent light curtain luminance at that time and the luminance difference discrimination threshold (ΔLmin(Laf)) determined by the foveal adaptation luminance. That is, Δ1m1n=ΔLmin(Laf)+ΔI, m1n(L
Figure 2 shows the relationship between the luminance difference discrimination threshold determined by the equivalent light curtain luminance and the equivalent light curtain luminance, and the relationship between the luminance difference discrimination threshold determined by the foveal adaptation luminance and the foveal adaptation luminance. .

The visibility calculation section 7 calculates the visibility (VL) of each object from the signal input from the brightness difference calculation section 3 and the signal input from the brightness difference discrimination threshold calculation section 6, and calculates the visibility (VL) of each object. A signal corresponding to the degree of visibility is output to the visibility distribution chart display section 8.

In this case, the visibility ■L is determined from the ratio of the difference ΔL between the brightness of the object and the brightness of its background and the brightness difference discrimination threshold Δl,min.

That is, visibility: VL=ΔL/ΔLmin The visibility distribution map display unit 8 displays a diagram of the visibility distribution state of an object at an arbitrary position within the field of view.

Note that the brightness distribution measuring section 1 can be configured by combining a brightness meter and a personal computer. Further, the equivalent light curtain brightness measuring section 4 can be constructed by combining a glare lens and a brightness meter, which have the same scattering characteristics as the light scattering characteristics within the human eyeball.

Effects of the Invention According to the present invention, the visibility of objects at various positions within the visual field can be measured at once. In addition, when looking at an object, it is possible to accurately take into account the #reverberation caused by scattered light within the eyeball caused by light that enters the eye from the peripheral field of vision, so the visibility when looking at the actual object can be accurately calculated. You can ask well. Furthermore, even if the object does not actually exist within the field of view, the visibility of the virtual object can be determined by setting the position and brightness conditions, and the visibility can be simulated.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a visibility measuring device according to an embodiment of the present invention, and FIG. 2 is a diagram showing the relationship between equivalent light curtain brightness, foveal adaptation brightness, and a brightness difference discrimination threshold determined by each. 1... Brightness distribution measuring section, 2... Target condition setting section,
3... Brightness difference calculation unit, 4... Equivalent light curtain brightness measurement unit,
5... Foveal adaptation 11 degree measuring unit, 6... Luminance difference discrimination threshold calculation unit, 7... Visibility calculation unit, 8... Visibility distribution map display unit Name of agent Patent attorney Toshio Nakao One idiot! 2 figure

Claims (1)

[Claims] A brightness distribution measurement unit that measures the brightness distribution, a target object condition setting unit that sets conditions for the brightness and position of the target object, and a device that inputs signals from the brightness distribution measurement unit and the target object condition setting unit to determine the target object. A brightness difference calculation unit that calculates the brightness difference of the background, an equivalent light curtain brightness measurement unit that measures the equivalent light curtain brightness of the eye of the observer looking at the object, and the fovea of the observer's eye are adapted. a foveal adaptation luminance measurement section that measures luminance; and a luminance difference discrimination threshold calculation that inputs signals from the equivalent light screen luminance measurement section and the foveal adaptation luminance measurement section and calculates a luminance difference discrimination threshold of the observer's eye. and a visibility calculation unit that receives signals from the brightness difference discrimination threshold calculation unit and the brightness difference calculation unit and calculates visibility of an object.