DEVICE FOR TAKING MULTIPLE IMAGES EACH WITH DIFFERENT LIGHT ILLUMINATION

Description

Field of invention

[0001] The present invention relates to a multiple image capturing device. Prior art

[0002] As is known, a device for capturing multiple images of the same object with multiple different light exposures is operated under the trade name TAC7 Scanner. The device described is dome-shaped inside which several LED light emitters and several monochromatic cameras are placed.

[0003] As is known, a device for capturing multiple images of the same object with multiple different light exposures is the subject of patent US6654013, which describes a graphics system for highlighting the perception of shapes. The graphics system relates to a technique for creating interactive display images of objects exposed to different light conditions in order to reveal surface phenomena.

[0004] The device used to create the interactive display is a dome with several light emitters and a hole at the top to accommodate an image capture unit.

[0005] However, these solutions do not give complete satisfaction.

[0006] Dome construction is difficult to achieve, and its shape makes automation difficult, making production costs high. In addition, a dome is bulky, which poses several disadvantages, particularly during transportation.

[0007] Documents US 2014 / 340572A1 and US 2004 / 233421A1 describe relevant prior art examples.

[0008] The present invention aims to resolve all or part of the drawbacks mentioned above. Statement of the invention

[0009] To this end, the present invention relates to a device for capturing multiple images of an object arranged in a reference position, each image having a different light exposure, the device comprising: a light emitting assembly comprising at least one light emitting unit, the light emitting assembly being arranged on a flat surface; at least one image capture unit; a control unit configured to trigger a plurality of successive image captures from a shooting position, and at each image capture, control a light emitting unit of the light emitting assembly, so as to obtain at least one light characteristic of the light emitted by the light emitting unit determined as a function of the distance between a lighting position of the light emitting unit and the reference position, the intensity of the light emitted from the lighting positions depending on the distance separating them from the reference position in order to obtain, for each of the lighting positions, an equivalent received light intensity on the reference position.

[0010] In a system where the different positions of the light source are distributed over a hemisphere, the distance from the source to the target is constant.

[0011] In the system described here, the simplified construction of positioning the light source at different points on a plane results in a variation in the distance from the source to the target.

[0012] The consequence of this variation in distance is an unwanted variation in the light intensity received by the target.

[0013] The system described integrates an algorithm compensating within an acceptable approximation this unwanted lighting variation by modulating the light intensity of the source inversely to the variation caused by this non-constant distance.

[0014] Thus, light sources placed close to a location will generate much less illumination than those placed on the periphery of the system.

[0015] Thanks to these provisions, the invention provides a solution whose automation is simplified, whose production cost is low and whose footprint is minimal.

[0016] According to one aspect of the invention, the light characteristic considered corresponds to a light intensity of the emitting unit.

[0017] According to one possibility, the luminous intensity of the light emitted by the light emitting units can thus be calculated as a function of a ratio between the distance between an illumination position of an emitting unit and the reference position.

[0018] In particular, the light intensity controlled for a light emitting unit can be modulated according to a ratio: d d max

[0019] The value d corresponds to the distance between the lighting position of the emitting unit and the reference position. The value d max corresponds to the distance between the lighting position of a emitting unit farthest from the reference position among the plurality of lighting positions of the emitting unit assembly and the reference position.

[0020] Thus, the luminous intensity I can be determined as a function f of the ratio described above and a maximum luminous intensity I max available or determined for an emitting unit: I = f d d max I max

[0021] According to one possibility, the light intensity controlled for a light emitting unit can be modulated according to the square of the ratio described above, that is to say according to a quantity: d d max 2

[0022] Thus, the luminous intensity I can be determined as a function f of the square of the ratio described above and a maximum luminous intensity I max available or determined for an emitting unit: I = f d d max 2 I max

[0023] According to a particular non-limiting example of expression of the function f, the luminous intensity can be determined as follows: I = d d max 2 I max

[0024] Of course, an approximate calculation of the function f can be used to facilitate the implementation of the determination.

[0025] The control unit is thus configured to control the lighting intensity for each of the emitting units by modulating the intensity using the above function.

[0026] According to one aspect of the invention, the light emitting units may be of any kind such as light emitting diodes and / or xenon lamps for example.

[0027] According to one aspect of the invention, the planar surface on which the light emitting units are arranged has at least one location so as to allow the insertion of at least one image capture unit.

[0028] According to one aspect of the invention, the at least one image capture unit may be of any type such as a digital camera or a film camera for example.

[0029] According to one embodiment, the at least one image capture unit is controlled by the control unit.

[0030] The invention also relates to a method of capturing multiple images each having a different light exposure, comprising the following steps: positioning an object to be photographed in a reference position; triggering a plurality of successive image captures from a shooting position; for each image capture, performing lighting from a respective lighting position, during the image capture, the plurality of image captures being associated respectively with a plurality of lighting positions included in a lighting plane; and for each image capture, controlling the lighting performed from the respective lighting position to obtain at least one light characteristic of the lighting determined as a function of the distance between the lighting position and the reference position, the intensity of the light emitted from the lighting positions depending on the distance separating them from the reference position in order to obtain, for each of the lighting positions, an equivalent received light intensity at the reference position.

[0031] According to one embodiment, the triggering of the lighting at each image sensor is carried out according to different light characteristics depending on the distance between the reference position and the lighting position corresponding to the image capture.

[0032] The definition of the function f detailed previously can be used.

[0033] According to one aspect of the invention, triggering the light emitting units according to different light characteristics depending on the distance separating them from the reference position makes it possible to simulate natural lighting.

[0034] According to the invention, the intensity of the light emitted by the light emitting units depends on the distance separating them from the reference position in order to obtain, for each of the light emitting units, an equivalent received light intensity at the reference position.

[0035] According to one aspect of the invention, the characteristics of the light emitted by the light emitting units may vary such that the spectrum of the emitted light varies, for example.

[0036] According to one aspect of the invention, the variation of the light spectrum emitted by the light emitting units makes it possible to highlight certain aspects of the object whose image is to be captured.

[0037] According to one embodiment, the triggering of the lighting from the lighting positions and the corresponding image captures is carried out synchronously.

[0038] According to one aspect of the invention, the synchronized triggering of the light emitting units and the at least one image capture unit makes it possible to obtain as many light exposures as there are light emitting units.

[0039] Thus, it is notably possible to produce a set of image captures in which each image capture of the set is synchronized with the lighting control of a unit of the set of lighting units.

[0040] The different aspects defined above, which are not incompatible, can be combined. Brief description of the figures

[0041] The invention will be further understood with the aid of the detailed description set out below with reference to the attached drawing in which: there figure 1 represents a multiple image capture device in accordance with the present invention; and the figure 2 represents a planar support for light emitting units in accordance with the present invention. Description with reference to figures

[0042] The invention will be better understood with the aid of the detailed description which is set out below with reference to the appended drawing in which: As illustrated in the figure 1, the device 11 captures multiple images of an object arranged at a reference position PR, each image having a different light exposure.

[0043] The device comprises in particular a set of light emitting units 51 arranged on a flat surface 31 as well as at least one image capture unit 41.

[0044] The at least one image capture unit 41 may be of any kind such as a digital camera or video camera or CMOS / CCD digital sensor or a film camera for example. In the embodiment of the invention illustrated in the Figures 1 and 2 , the image capture unit 41 is a digital camera.

[0045] The light emitting units 51 may be of any kind such as light emitting diodes and / or xenon lamps for example. In the embodiment of the invention illustrated in the Figures 1 and 2, the light emitting units 51 are light emitting diodes.

[0046] As illustrated in the figure 2 , by way of non-limiting example, the set of light emitting units 51 arranged on a flat surface 31 consists of 64 light emitting units.

[0047] Advantageously, the set of light emitting units 51 comprises at least one light emitting unit 51.

[0048] The flat surface 31 on which the light emitting units 51 are arranged has at least one location 36 so as to allow the insertion of at least one image capture unit 41.

[0049] In order to control all of the light emitting units 51 to obtain at least one light characteristic determined as a function of the distance between an illumination position of the light emitting unit and the reference position PR, as well as to control the triggering of the at least one image capture unit 41 and the light emitting units 51, the device also comprises a control unit 21.

[0050] The luminous intensity of the light emitted by the light emitting units can thus be calculated and controlled based on a ratio between the distance between a lighting position of an emitting unit and the reference position.

[0051] The luminous intensity I for an emitting unit can be determined as a function f of the ratio described above and a maximum luminous intensity I max available or determined for an emitting unit: I = f d d max I max

[0052] The value d corresponds to the distance between the lighting position of the emitting unit and the reference position. The value d max corresponds to the distance between the lighting position of a emitting unit farthest from the reference position among the plurality of lighting positions of the emitting unit assembly and the reference position.

[0053] According to a particular mode of expression of the function f, the luminous intensity can be determined as follows: I = d d max 2 I max

[0054] Of course, an approximate calculation of the function f can be used to facilitate the implementation of the determination. According to one embodiment, the distance between the reference position PR and the image capture unit 41 does not vary. Only the distance between each light-emitting unit 51 and the reference position PR changes. Indeed, the light-emitting units 51 are arranged on the flat surface 31 at different distances from the reference position PR in order to obtain a more homogeneous rendering.

[0055] According to one embodiment, the triggering of the at least one image capture unit 41 and the light emitting units 51 is carried out by the image capture unit 41.

[0056] Such an arrangement makes it possible to obtain permanent lighting, in fact, each light emitting unit 51 is lit in turn so that there is always a light emitting unit 51 lit. Such an arrangement saves time in capturing multiple images.

[0057] A method in accordance with the present invention will be described below.

[0058] In order to capture multiple images, each with a different light exposure, several steps are performed.

[0059] The first step is to position an object to be photographed on a PR reference position.

[0060] The second step is capturing a plurality of images from a PPV shooting position using the image capturing unit 41.

[0061] During this second step, for each captured image, lighting is carried out, from a lighting position, using the light emitting units 51. The plurality of image captures is associated with a plurality of lighting positions included in a lighting plane PE.

[0062] Illumination is carried out from the plurality of lighting positions PE using the light emitting units 51 with at least one intensity determined as a function of the distance between the lighting position PE and the reference position PR.

[0063] The control unit 21 synchronously triggers the light emitting units 51 and the at least one image capturing unit 41 in order to obtain as many light exposures as there are light emitting units.

[0064] Advantageously, the greater the number of light-emitting units 51, the greater the number of images captured. This allows for a rendering close to reality.

[0065] According to a non-shown embodiment, the multiple image capture device comprises a single light emitting unit 51 moving on a plane defined by the flat surface 31 using a movement unit such as a two-axis motorized rail system for example. Advantageously, a multiple image capture device comprising a single light emitting unit 51 makes it possible to reduce the weight, size and cost of said device.

[0066] According to a non-represented embodiment, the multiple image capture device comprises a subset of light emitting units 51 comprising several light emitting units 51, said subset moving on a plane defined by the flat surface 31 using a movement unit such as a two-axis motorized rail system for example. Advantageously, a multiple image capture device comprising a subset of light emitting units 51 makes it possible to reduce the weight, size and cost of said device.

[0067] Of course, the invention is not limited to the embodiments shown and described above, but on the contrary covers all variants thereof.

Claims

1. A device for capturing multiple images of an object arranged in a reference position (PR), each image having a different light exposure (11), the device comprising: • a light emitting assembly comprising at least one light emitting unit (51), the light emitting assembly being arranged on a flat surface (31); • at least one image capturing unit (41); • a control unit (21) configured to trigger a plurality of successive image captures from a shooting position (PPV), and at each image capture, control a light emitting unit (51) of the light emitting assembly, so as to obtain at least one luminous characteristic of the light emitted by the light emitting unit determined as a function of the distance between a lighting position of the light emitting unit and the reference position (PR), the intensity of the light emitted from the lighting positions depending on the distance separating them from the reference position in order to obtain, for each of the lighting positions, an equivalent received light intensity at the reference position.

2. The device according to claim 1, wherein the at least one image capture unit (41) is controlled by the control unit (21).

3. A method for capturing multiple images, each having a different light exposure, including the following steps: • positioning an object to be photographed in a reference position (PR); • triggering a plurality of successive image captures from a shooting position (PPV): • for each image capture, performing lighting from a respective lighting position, during the image capture, the plurality of image captures being respectively associated with a plurality of lighting positions included in a lighting plane (PE); and • for each image capture, controlling the lighting performed from the respective lighting position to obtain at least one luminous characteristic of the lighting determined as a function of the distance between the lighting position and the reference position, the intensity of the light emitted from the lighting positions depending on the distance separating them from the reference position in order to obtain, for each of the lighting positions, an equivalent received light intensity at the reference position.

4. The method according to claim 3, wherein the lighting at each image capture is performed according to different luminous characteristics as a function of the distance between the reference position (PR) and the lighting position corresponding to the image capture.

5. The method according to any one of claims 3 and 4, wherein the triggering of the lighting from the lighting positions and the corresponding image captures is performed synchronously.