Instrument for measuring the softness of light

Abstract

The present invention relates to an instrument (1) for objectively measuring the dispersion of light, which is useful in the cinematography and audiovisual sector. The invention overcomes the lack of precise tools, eliminating the relativity of the concept. The instrument of the invention consists of a semi-sphere (2) made of a matte material and having a known size, serving as a constant subject. When the instrument is oriented toward a light source, an external device captures an image of the dispersion of light over the semi-sphere (2), providing an objective measurement of the dispersion. The instrument can include marks (3) for orientation, a mirrored semi-ellipsoid (5) for complementary analysis of the source, and sight holes (6, 7) for alignment. The primary use of the instrument is for evaluating and standardising the measurement of the dispersion of light on a known and constant object that takes the place of a subject.

Description

[0001] DESCRIPTIVE MEMORANDUM

[0002] I. TITLE OF THE INVENTION:

[0003] Instrument for measuring the softness of light.

[0004] II. TECHNICAL SECTOR

[0005] The present invention falls within the technical field of instruments for measuring light characteristics. Its primary use is in the film and audiovisual sector, including professions such as cinematography, cinematography, gaffer, visual effects, virtual production, and all professions related to cinematography and the use of light. It may also find applications in sectors such as architecture and medicine, where light quality is a relevant factor.

[0006] III. BACKGROUND OF THE INVENTION

[0007] Currently, there is no known instrument that can objectively and accurately measure the softness of light, due to the inherently relative nature of this property and the predominantly subjective evaluation of this quality of light within the industry. The "softness" of light, a crucial concept for image professionals, depends on factors such as the relative size of the light source compared to the illuminated subject and the way in which the light envelops the subject. The lack of a standard and an objective methodology hinders the replicability and accurate communication of desired lighting conditions.

[0008] Therefore, the invention in question incorporates the necessary elements to generate a new known standard of size, position, and direction. This standard allows an image capture device (such as a photographic or video camera) to record a valid image of the instrument under incident light, and subsequently measure and quantitatively evaluate the softness of that light.

[0009] In short, the instrument seeks to eliminate the relativity inherent in the evaluation of light softness. Traditionally, it is understood that: “Light softness depends on the relative size of the light source with respect to the subject upon which it is projected.” The present invention proposes to make the “subject” a known and constant element. Furthermore, it defines a specific position and direction to take advantage of another fundamental property of light related to softness: “light travels in a straight line in all directions,” and how this property affects the illumination of an element with a known geometric shape, in this case, spherical. With this instrument, it will be possible to precisely measure how incident light envelops and interacts with the different elements that make up the instrument itself.

[0010] IV. EXPLANATION OF THE INVENTION

[0011] The present invention, as described herein, relates to an instrument (1) designed for the objective measurement of light softness. This instrument has been conceived to meet a technical need not currently satisfied by any other instrument or device known to the applicant.

[0012] The instrument is provided with the necessary elements so that, through the capture of an image of it by an external device (not part of the invention), the softness of the light falling on said instrument can be accurately evaluated and measured.

[0013] The main object of the invention is to provide a method and device that allow for the standardization of light softness measurement, offering objective and replicable results. This is achieved through the interaction of incident light with a key reference element, a semi-sphere (2) of matte material and known dimensions, which acts as the constant "subject." By orienting the instrument towards the light source to be evaluated, the way in which the light scatters and envelops the surface of this semi-sphere (2) is captured by an external imaging device. Analysis of this image allows for the quantification of light softness.

[0014] The instrument may also incorporate auxiliary elements such as identification marks (3) to facilitate correct orientation and determination of the direction of the light, a mirrored semi-ellipsoid element (5) that allows a complementary analysis of the size and shape of the light source by reflecting it, and sight glasses (6, 7) for precise alignment of the instrument with respect to the light source.

[0015] V. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] To complement the description being made and in order to help a better understanding of the characteristics of the invention, a set of drawings is included as an integral part of said description, in which, for illustrative and non-limiting purposes, the following has been represented:

[0017] • Figure 1.- Shows a front view of the instrument that is the subject of the invention. The main elements necessary for measurement are visible. This will be the main view used by the image capture devices.

[0018] • Figure 2.- Shows a lower view of the instrument, allowing the volumes of its main components to be appreciated.

[0019] • Figure 3.- Shows a left side view of the instrument. The sight glass element (7) is highlighted, which, in conjunction with the sight glass on the right side (6), is used to direct the instrument towards the light source to be measured.

[0020] • Figure 4.- Shows a right side view of the instrument. The inclined part of the base is visible, which houses a mirrored semi-ellipsoid (4) (identified as element (5) in the detailed description and claims) and the sight (6) for aiming.

[0021] VI. DETAILED DESCRIPTION OF THE INVENTION (PREFERRED EMBODIMENT)

[0022] As shown in the figures, and in particular Figure 1 and Figure 2, the instrument (1) consists of a main base upon which all the necessary components are mounted. This base (1) is a rigid support with a flat main surface and a secondary section, usually on one side, angled towards the direction of the light source to be measured.

[0023] Integrated onto the main flat surface of the base (1) is the fundamental element of the invention, element (2), which is a light incidence hemisphere. This hemisphere (2) is made of a matte material to prevent direct specular reflections and ensure diffuse light dispersion. It functions as the practical equivalent of the visible half of a full sphere from the perspective of the image capture device and can be of any size, provided that this size is known and constant to establish a standard. By receiving incident light from a source, the hemisphere (2) allows an external image capture device to record how the light disperses and envelops its surface, thus providing a basis for an objective measurement of the softness of that light.

[0024] Around the semi-spherical element (2) a series of identifying marks (3) can be arranged, visible in Figure 1. These marks (3) serve to identify the orientation and direction of the instrument with respect to the light source being measured, allowing a more precise evaluation of the softness of the light based on its angular and positional incidence on the semi-sphere (2).

[0025] The instrument may also include a component called a contrast ramp (4), visible in Figure 1 and Figure 4, which may be located on the base (1) or adjacent to the hemisphere (2). This component (4) is designed to add light contrast measurement functionalities to the environment where the instrument is located, providing additional and complementary information to the softness measurement.

[0026] In a preferred embodiment, the base (1) has a surface extending to one side (preferably the right side in the front view, Figure 1 and Figure 4) with an inclined portion. Element (5), a semi-ellipsoid of mirrored material, is located on this inclined portion. This element (5) is oriented so that it reflects the light source being measured, allowing the image capture device to obtain a reflected view of the source from the front of the instrument. Analysis of this reflected image can provide additional and more precise information about the size and shape of the light source, complementing the smoothness measurement obtained through the semi-ellipsoid (2).

[0027] To facilitate the correct orientation of the instrument (1) towards the light source to be measured, sights are included. As shown in Figure 1, Figure 3, and Figure 4, there is a sight (6) on the right-hand angled side and a corresponding sight (7) on the left side of the instrument. The user aims and aligns these two sights (6, 7) with the light source, thus ensuring that the instrument is correctly oriented for measurement.

[0028] The measurement method with this instrument consists of orienting the instrument (1) towards the light source to be evaluated, using the sights (6, 7) for precise alignment. The hemisphere (2) then receives the incident light. An external image capture device (not part of the invention) is used to take a photograph or video of the front face of the instrument, recording the appearance of the hemisphere (2) under that illumination and, if present, the reflection of the light source on the mirrored semi-ellipsoid element (5). The analysis of the light scattering on the hemisphere (2) and the information obtained from element (5) allow for an objective and quantitative evaluation of the light softness.

[0029] The instrument, as a whole, is designed with sufficient space on its surfaces, both front and inclined, to optionally include new graphic elements or sensors that allow adding secondary measurement functionalities to the main purpose of measuring the softness of light, without deviating from the main inventive concept.

Claims

AMENDED CLAIMS received by the International Bureau on 7 November 2025 (07.11.2025)

1. METHOD for the objective measurement of the softness of a light source, characterized in that it comprises the following steps: a. providing a reference instrument (1) that includes a curved surface element (2) of known geometry and matte finish, oriented towards said light source; b. capturing, by means of an external imaging device, a digital image of the light scattering on the surface of said element (2); c. computationally processing said digital image to analyze the luminance profile through the transition zone between highlights and shadows on the surface of the element (2); and d. calculating, from the gradient of said luminance profile, a numerical index that provides a quantitative measure of the softness of the light.

2. SYSTEM for the objective measurement of the softness of a light source, characterized in that it comprises: a. a reference instrument (1) including a curved surface element (2), of known geometry and matte finish; and b. an image processing module that is configured to receive a digital image of said illuminated instrument and execute the analysis steps c) and d) of the method according to claim 1.

3. The method or system according to claim 1 or 2, characterized in that the curved surface element (2) is a hemisphere, which functions as a known standard of size and shape for measurement.

4. The method or system according to any of the preceding claims, characterized in that the reference instrument (1) further includes a series of identifying marks (3) arranged around the element (2) to facilitate the identification of the orientation and incidence of light during the processing step (c).

5. The method or system according to any of the preceding claims, characterized in that the reference instrument (1) further includes a mirrored semi-ellipsoid element (5), oriented to reflect the light source and allow a complementary analysis of the size and shape of said source.

6. The method or system according to any of the preceding claims, characterized in that the arrangement step (a) comprises the precise alignment of the instrument (1) with the light source by means of sight glasses (6, 7) integrated into the instrument.

7. The method or system according to any of the preceding claims, characterized in that the reference instrument (1) further includes a contrast ramp element (4) to provide a complementary measure of the light contrast in the environment. [0001] [0002]EXPLANATORY STATEMENT OF THE MODIFICATIONS (ARTICLE 19(1)) [0003]A new set of claims (1 to 7) is presented, replacing the one originally presented, to overcome the objections made in the Written Opinion and to better define the object of protection. [0004]The modifications are based on the original descriptive report, which already stated that the objective of the invention is "to measure and quantitatively evaluate the softness of said light" (page 1), and that "The analysis of this image allows the softness of the light to be quantified" (page 2). The amended claims make explicit the technical method by which said quantification is achieved, which was implicit in the original disclosure. [0005]The new claims 1 (method) and 2 (system) now focus the invention on the method of image analysis to obtain a technical result that the state of the art does not teach: an objective numerical index of the softness of the light. [0006]With respect to D01 ("LightColor Meter"), this device measures intensity and color, but not the spatial quality of light diffusion. The new claims focus on the analysis of the luminance profile gradient at the light-shadow transition, a technical concept foreign to D01. [0007]With respect to D02 (US 10302485 B2), this system solves the problem of spectral color evaluation, a completely different technical field. Measuring the spectrum (wavelength) does not provide information about softness (spatial diffusion). Therefore, D02 does not offer any insight that a person skilled in the art could combine with D01 to arrive at the present invention. [0008]In conclusion, the amended claims define an invention with inventive step, since it solves a technical problem not addressed by the state of the art, by means of a method that is not obvious from the cited documents.

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