Device for writing and capturing images

Abstract

The invention relates to a device (1) for writing and capturing images, comprising: - a pen body (2) extending along a central axis (20) and having two lateral finger positioning zones (21) located on either side of a median sagittal plane (PSM) of the pen body (2) passing through the central axis (20), the body (2) also having a ventral region (22) intended to be oriented towards a writing medium; - writing means (3) accommodated in the body, and comprising a writing tip (31) emerging from the body (2), the tip (31) being coaxial with the central axis (20); - a camera (4) inserted into a recess (24), and fixedly mounted with respect to the tip (31), the camera (4) comprising a front lens (41) located near the lateral finger positioning zones (21), towards the end of the tip (31).

Description

Image writing and capture device

[0001] The field of the invention is that of the design and manufacture of handwriting devices, and of the acquisition of digital images of this handwriting.

[0002] The invention relates more particularly to a pen incorporating a camera to directly acquire digital images of handwriting made using the pen. State of the art

[0003] In the field of the invention, the document published under number CN218675994U is known.

[0004] This device comprises a pen body that houses a writing instrument with a writing tip, such as a lead. The pen body is equipped with a capture camera positioned at a distance from the tip of the lead. The camera is configured to rotate around an axis perpendicular to the axis of the lead, with its axis intersecting the axis of the lead, in order to optimize the capture angle.

[0005] Such a design of a writing device has the disadvantages of providing images that are not satisfactory for handwriting recognition by software, particularly due to the obstruction of the camera's optical field by the user's hand, and of not presenting a harmonious integration of this camera.

[0006] The device described in the document published under number CN209869835U is also known.

[0007] This device comprises a pen body that houses writing means and features a writing tip. The pen body is equipped with a camera positioned near the tip of the nib. The pen body has recesses on its surface forming finger placement zones. The camera is configured to acquire images of text and transmit them to a text identification module. The camera is configured to pivot about an axis perpendicular to the axis of the nib and is mounted to pivot relative to the axis of the nib, allowing it to be retracted inside the pen body and extended to achieve an optimal imaging angle.

[0008] Thanks to its placement near the tip, the camera's field of view is not obstructed by the user's hand when grasping the pen. However, this pen design has the drawback of a deployable camera, hindering its seamless integration and presenting a risk of structural weakness. This weakness is present both at the hinge that allows the camera to move relative to the pen body and at the camera connector, which must withstand repeated deployment and retraction.

[0009] The patent document published under number US11301063B2 is also known. This document discloses a device comprising a pen body that receives writing means having a writing tip of the type employing a ball fed by ink contained in a tube. The pen body is equipped with several cameras arranged near the ball. The axis of the camera and the axis of the pen body lie in the same plane, and the axis of the camera is inclined relative to the axis of the pen body. The cameras are oriented away from, and not toward, the tip.

[0010] This device features seamless integration of its cameras, even during use, as the cameras are contained within the pen's body. However, this device has the drawback of requiring the implementation of multiple sensors, including at least two cameras.

[0011] He is also known from patent documents published under numbers US 2023 / 125465 A1, and EP 1 405 168 B1 which disclose writing and image-capturing devices.

[0012] Finally, there is also a known device with three outward-facing cameras positioned around the periphery of a pen tip, behind it. This pen allows for a comfortable grip that does not obstruct the cameras near the tip. The three cameras detect the movement of the tip and are linked to a sensor that detects pressure on the tip. Detecting this pressure and movement allows the pen to deduce the content of what is written.

[0013] This design implies having at least two cameras and a pressure sensor for the mine, which is a disadvantage in terms of the number of sensors to manage. Technical problem

[0014] The invention aims in particular to overcome these drawbacks of the prior art.

[0015] More specifically, the invention aims to provide a handwriting and image capture device for the writing produced with the device, for the purpose of optical character recognition, which has a shape that most closely resembles that of a classic pen, and does not involve the implementation of multiple capture means.

[0016] The invention also aims to provide such a device which optimizes the acquisition images obtained for analysis for optical character recognition.

[0017] These objectives, as well as others which will appear subsequently, are achieved thanks to the invention which relates to a writing and image capture device, comprising: - a pen body extending along a central axis, and having two lateral finger positioning zones located on either side of a median sagittal plane of the pen body passing through the central axis, the body also having a ventral region intended to be oriented towards a writing support, and a dorsal region opposite to the ventral region with respect to the central axis; - writing means received in the body, and comprising a writing tip emerging from the body, the tip being coaxial with the central axis;- a camera inserted in a housing provided in the dorsal region of the body, and mounted fixed relative to the tip, the camera comprising a front lens defining an optical axis, the front lens being located near the lateral finger positioning areas, in the direction of the tip; characterized in that the optical axis and the central axis are non-coplanar, and in that the camera presents an optical field in which the tip is located.

[0018] The device according to the invention captures images of handwriting produced with the device for the purpose of optical character recognition. This device has a shape closely resembling that of a conventional pen and requires only a single acquisition camera.

[0019] Thanks to its design, the images obtained using the device tend to be particularly suitable for analysis by a computer system for processing optical character recognition data.

[0020] The relative positioning of the front lens between the lateral finger positioning zones and the tip prevents a user's grip from interfering with the camera's optical field.

[0021] Furthermore, the positioning of the tip of the pen within the optical field serves as a particularly beneficial reference point for computer analysis of optical character recognition. Finally, the relative orientation of the optical axis with respect to the central axis—that is, the non-coplanar aspect of the optical axis and the central axis—helps to optimize the camera's optical field's ability to capture sufficient information about what a user has just written for computer analysis of optical character recognition, regardless of the different ways a pen is held.

[0022] According to a preferred embodiment, the writing means comprise an ink storage reservoir coupled to the writing tip, the reservoir having a flexible tubular shape, and the pen body has a passage for receiving the writing means, the passage having: - an open terminal portion from which the writing tip emerges, the terminal portion extending longitudinally and being centered on the central axis; - at least one portion offset from the central axis extending in line with the terminal portion, the housing being provided in the pen body opposite the portion offset from the central axis.

[0023] Thanks to the open end and the tip, which are centered on the central axis, writing with the device is a natural experience for the user. The offset section(s) of the ink receptacle optimize the available space within the pen body for housing the camera. Tests have demonstrated that the twisting of the flexible tubular ink reservoir, imposed by its insertion into the offset section(s), does not impede ink flow to the tip for writing.

[0024] Preferably, according to an orthogonal projection onto the median sagittal plane, the optical axis is oriented to move away from the central axis towards the tip of the point from the body, in a direction going from the ventral region 22 towards the dorsal region.

[0025] According to a preferred characteristic, according to an orthogonal projection onto the median sagittal plane, the optical axis forms an angle A1 with the central axis, with 0° ≤ A1 ≤ 18°, preferably with 6° ≤ A1 ≤ 14°, even more preferably with A1 = 11°.

[0026] At 0° or above 0° for A1, the characters closest to the tip are partially legible. The characters furthest away are only very partially legible.

[0027] At 6° or above 6° for A1, the characters closest to the tip are partially legible and the characters furthest away are also partially legible.

[0028] At 18° or below 18° for A1, the character closest to the tip is partially visible, characters near the tip are legible. Characters furthest from the tip are legible.

[0029] At 14° or below 14° for A1, the characters closest to the tip are legible. The characters furthest from the tip are partially legible.

[0030] According to one embodiment, according to an orthogonal projection onto a median transverse plane passing through the central axis and extending orthogonally to the median sagittal plane, the optical axis is oriented to cross and then move away from the central axis towards the tip of the point, from the body.

[0031] This variant is particularly suitable for right-handed people.

[0032] According to another embodiment, according to an orthogonal projection onto a median transverse plane passing through the central axis and extending orthogonally to the median sagittal plane, the optical axis is oriented to cross and then move away from the central axis towards the tip of the point, from the body, and in a direction from right to left in a top view with the point oriented downwards.

[0033] This variant is particularly suitable for left-handed people.

[0034] Advantageously characterized in that, according to an orthogonal projection onto the median transverse plane, the optical axis forms an angle A2 with the central axis, with 0° ≤ A2 ≤ 30°, preferably with 5° ≤ A2 ≤ 25°, preferably A2 = 22°.

[0035] At 0° or above 0° for A2, the character closest to the tip is completely identifiable, the other characters closest to the tip are partially legible and the characters furthest away are very partially legible.

[0036] At 5° or above 5° for A2, the characters closest to the tip are completely identifiable and the characters furthest away are legible or partially legible.

[0037] At 30° or below 30° for A2, some characters far from the tip are partially identifiable, the characters closest to the tip are not legible.

[0038] At 25° or below 25° for A2, the characters closest to the tip are completely identifiable and the characters furthest away are legible or partially legible.

[0039] According to a preferred characteristic, in an orthogonal projection onto the median transverse plane, the center of the front lens is offset by a distance of 0.5 mm to 1 mm from the central axis, preferably by 0.8 mm, and in that, in an orthogonal projection onto the median sagittal plane, the center of the front lens is offset by a distance of 1 mm to 1.75 mm from the central axis, preferably by 1.4 mm.

[0040] According to an advantageous design, the pen body has, along the central axis: - a main part substantially cylindrical of revolution, having the two lateral finger positioning zones, and extending towards the end of the body from which the tip emerges to an opening leading to the housing in which the camera is inserted; - an end part extending from the main part thinning out to the end of the body from which the tip emerges, the end part having a recess around the optical axis.

[0041] This design promotes the freest possible optical field for the camera while allowing good integration of the tip into this optical field.

[0042] Preferably, according to an orthogonal projection onto the central axis, the center of the front lens and the end of the body from which the tip emerges are spaced at a distance of 8 to 24 mm.

[0043] These values ​​allow for the optimization of handwriting capture using the camera; too small a distance tends to prevent the capture of a large number of characters needed for optical character recognition, and too great a distance requires the device to be gripped by the fingers at the lateral positioning areas too far from the tip of the device.

[0044] Other features and advantages of the invention will become more apparent upon reading the following description of various preferred embodiments of the invention, given by way of illustrative and non-limiting examples, and the accompanying drawings, among which: a is a schematic representation in a top front perspective view of a device according to the invention; a is a schematic representation in a front view of a pen body of the device according to the invention; a is a schematic representation of the pen body in a side view; a is a schematic representation of the pen body as positioned on the, with the internal contour lines visible; a is a schematic view of the pen body in a top view; a is a schematic representation of the pen body as positioned on the, with the internal contour lines visible; a is a schematic illustration of the device in use;la is a schematic representation of the relative positioning of the device with respect to a writing surface, of writing produced with the device, and of the scoring associated with the relative positioning; la is a graph illustrating scores assigned according to the value of an angle A2; la is a graph illustrating scores assigned according to the value of an angle A1; la is a graph illustrating scores assigned according to the value of a distance D3; la is a table listing images of a text acquired using one of the camera types of the device according to the invention, with specific parameters; la is a table listing images of a text acquired using two types of camera for two embodiments of the device according to the invention, with specific parameters;laest a table listing images of a text acquired using two types of camera for two embodiments of the device according to the invention, with specific parameters; laest a table listing images of a text acquired using two types of camera for two embodiments of the device according to the invention, with specific parameters; laest a table listing images of a text acquired using two types of camera for two embodiments of the device according to the invention, with specific parameters; laest a table listing images of a text acquired using two types of camera for two embodiments of the device according to the invention, with specific parameters; laest a table listing images of a text acquired using two types of camera for two embodiments of the device according to the invention, with specific parameters;This is a table listing images of a text acquired using two types of camera for two embodiments of the device according to the invention, with specific parameters; this is a table listing images of a text acquired using two types of camera for two embodiments of the device according to the invention, with specific parameters; this is a table listing images of a text acquired using two types of camera for two embodiments of the device according to the invention, with specific parameters; this is a table listing images of a text acquired using two types of camera for two embodiments of the device according to the invention, with specific parameters. Detailed description

[0045] With reference to figures 1 and 7, a writing and image capture device 1, according to the invention, is shown.

[0046] This device 1 includes: - a pen body 2; - writing means 3; - a camera 4 designed to capture images of writing made using device 1.

[0047] As it subsequently appears, the camera 4 is inserted into a housing 24 presented by the pen body 2.

[0048] With reference to figures 1 to 6, the pen body 2 has a longitudinal shape.

[0049] According to the present embodiment, this body 2 is a tip intended to be coupled to a base to form an assembly of dimensions similar to those of a classic pen.

[0050] According to one possible embodiment, the body 2 can extend to have dimensions similar to those of a conventional pen.

[0051] The pen body 2 extends along a central axis 20.

[0052] Writing methods 3 are received in body 2.

[0053] These writing means 3 include a writing tip 31 which emerges from the body 2.

[0054] This point 31 could correspond to a mine.

[0055] Alternatively, this tip 31 may include a writing ball.

[0056] The tip 31 can also be formed into a porous material intended to be soaked in ink.

[0057] This tip 31 is coaxial with the central axis 20. Tests have shown that aligning this tip 31 with the central axis 20 improves the user experience.

[0058] As will subsequently appear, and according to the present embodiment, the writing means 3 comprise an ink storage reservoir coupled to the writing tip 31. This reservoir is designed to supply the tip 31 with ink.

[0059] According to the present embodiment, the reservoir has a flexible tubular shape.

[0060] The pen body 2 has, along the central axis 20: - a main part 201 substantially cylindrical of revolution, intended to be grasped by a user to write using the device 1; - an end part 202 extending from the main part 201 thinning out to one end of the body 2 from which emerges the writing tip 31.

[0061] The body 2 has two lateral finger positioning zones 21. More specifically, the main part 201 of the pen body 2 has the two lateral finger positioning zones 21.

[0062] These two lateral finger positioning zones 21 are essentially diametrically opposed to each other on the body 2.

[0063] In other words, the two lateral finger positioning zones 21 are located on either side of a median sagittal plane PSM of the pen body 2 passing through the central axis 20.

[0064] As a reminder, a median sagittal plane is a vertical plane that divides a body into two roughly equal lateral parts.

[0065] Each lateral zone 21 is formed by a recess.

[0066] This prompts the device user to grasp body 2 in the correct orientation.

[0067] The main part 201 extends longitudinally, along the central axis 20, towards the end of the body 2 from which the tip 31 emerges, and up to an opening in the housing 24 into which the camera 4 is inserted.

[0068] The end part 202, meanwhile, extends from the main part 201, thinning out to the end of the body 2 from which the tip 31 emerges.

[0069] With reference to figures 1 to 6, the body 2 of the pen also presents: - a ventral region 22; - a dorsal region 23.

[0070] When writing with device 1, the ventral region 22 is designed to be oriented towards a writing support, such as a sheet of paper.

[0071] The dorsal region is opposite the ventral region 22 with respect to the central axis 20. When grasping the device 1, the user must naturally position their middle finger, and / or their ring and little finger on the side of the ventral region 22 of the body 2.

[0072] Body 2 has a median transverse plane PTM which passes through the central axis 20, and which extends orthogonally to the median sagittal plane PSM.

[0073] The ventral region 22 and the dorsal region 23 are located on either side of the median transverse plane PTM.

[0074] As mentioned previously, device 1 includes a camera 4, and this camera 4 is inserted into a housing 24.

[0075] Housing 24 is located in the dorsal region 23 of body 2.

[0076] Camera 4 is fixed relative to tip 31, in housing 24.

[0077] This housing 24 has an open end allowing the camera to capture images in front of the device 1.

[0078] The camera 4 includes a front lens 41 which is the optical element of the camera 4 exposed to the external volume of the device 1.

[0079] Camera 4 also includes a photographic sensor.

[0080] According to the present embodiment, the front lens 41 is directly coupled to the photographic sensor.

[0081] The assembly formed by the front lens 41 and the photographic sensor has an external shape that is substantially cylindrical in revolution.

[0082] The front lens 41 defines an optical axis 40. This optical axis 40 passes through the optical center of the front lens 41.

[0083] Camera 4 has an optical field. This optical field corresponds to the portion of space located in front of the front lens 41, and which is captured by the photographic sensor.

[0084] With more specific reference to Figures 4 and 6, the camera 4, and in particular its front lens 41 and its image sensor, have a very specific orientation relative to the pen body 2. These orientations are defined by: - ​​an angle A2 formed between an orthogonal projection of the optical axis 40 onto the median transverse plane PTM and the central axis 20; - an angle A1 formed between an orthogonal projection of the optical axis 40 onto the median sagittal plane PMS and the central axis 20; - a distance D3, measured between an orthogonal projection onto the central axis 20 of the center of the front lens 41 and the end of the body 2 from which the tip 31 emerges.

[0085] Camera 4 includes additional elements to the assembly described above, such as connectors, however these elements do not necessarily assume a fixed position relative to the substantially cylindrical external shape of revolution of the assembly.

[0086] As illustrated in Figures 4 and 6, the front lens 41 is located along the central axis 20 near the lateral finger positioning areas 21, towards the tip of the point 31. The expression "located along" does not imply that the front lens is positioned directly on the central axis 20.

[0087] The housing 24 provided in the dorsal region 23 has two portions, including: - a front portion 241 which accommodates the front lens 41, and thus also the photographic sensor; - a rear portion 242 which accommodates, for example, the additional elements of the camera 4.

[0088] The front portion 241 has a substantially cylindrical shape of revolution, adapted to the shape of the assembly formed by the front lens 41 and the photographic sensor.

[0089] The front portion 241 has an axis of revolution which extends coaxially with the optical axis 40 of the front lens 41.

[0090] The rear portion 242, for its part, has a modified orientation compared to that of the front portion 241. More specifically, the rear portion 242 forms an elbow with the front portion 241. This is possible thanks to the complementary elements of the camera 4 which do not necessarily have to be located in the extension of the assembly previously described.

[0091] Camera 4 is specifically of the "endoscopic camera" type.

[0092] An "endoscopic camera" is a miniaturized imaging device designed to capture images in confined spaces. Camera 4 consists of an optical lens, a rectangular image sensor, and a flexible ribbon.

[0093] For example, camera 4 of the "endoscopic camera" type has a diameter between 3.5 and 5 mm.

[0094] As can be seen in figures 1 to 4, the end part 202 of the pen body 2 has a recess 203 around the optical axis 40.

[0095] More specifically, the end part 202 includes a cylindrical front subpart 2021 of revolution having the opening from which the tip 31 emerges, and a rear subpart 2022 joining the front subpart 2021 to the main part 201.

[0096] The rear sub-part 2022 has a truncated conical shape of revolution, tapering from the main part 201 towards the tip 31. This rear sub-part 2022 thus presents the recess 203.

[0097] This allows camera 4 to capture images incorporating tip 31, as detailed later, without involving the production of bulk by integrating camera 4 on the pen body 2.

[0098] In addition to this recess 203, according to the present embodiment, the sub-part before 2021 has a flat 2031 aligned with the recess 203, having the same technical effect as that of the recess 203.

[0099] Preferably, the recesses forming the lateral areas 21 extend further on the ventral region 22 than on the dorsal region 23. This allows to optimize the grip of the body 2 by a user to prevent his fingers from coming into the optical field of the camera 4.

[0100] As mentioned previously, and with reference to figures 1, 2, 4, and 6, the writing means 3 are received in the body 2 of the pen.

[0101] For this purpose, the pen body 2 has a passage 25 for receiving the writing means 3.

[0102] This passage 25 presents: - a terminal portion 251 opening from which emerges the writing point 31; - at least one off-center portion 252.

[0103] According to the present embodiment, the passage 25 has two offset portions 252. It is conceivable embodiments in which the passage 25 would have one or more than two offset portions 252.

[0104] The terminal portion 251 extends longitudinally while being centered on the central axis 20. The terminal portion 251 is notably cylindrical of revolution and its axis of revolution extends coaxially with the central axis 20.

[0105] The two offset portions 252 extend in line with the terminal portion 251. More precisely, a first offset portion 252 extends from the terminal portion 251, with an axis of extension intersecting the axis of revolution of the terminal portion 251. A second offset portion 252 extends from the first offset portion 252, again with an axis of extension offset from the axis of revolution of the terminal portion 251.

[0106] The terminal portion 251 is located in the front sub-part 2021 of the end part 202 of the body 2, while the first offset portion 252 is located, at least in part, in the rear sub-part 2022 of the end part 202 of the body 2.

[0107] The ink storage reservoir, which has a flexible tubular shape, is housed in these offset portions 252. Tests have validated that the bends formed by the offsets of these portions do not limit the ink supply to the tip 31.

[0108] In addition, the offset portion 252 is provided in the ventral region 22 of the body 2 of the pen, which allows space to be provided in the body 2 to house the camera 4.

[0109] In other words, the housing 24 is provided in the body 2 of the pen in a manner opposite to the offset portion 252 with respect to the central axis 20.

[0110] With reference to the, the device 1 previously described is represented held in a user's hand M, and used to write a text T.

[0111] As mentioned previously, device 1 must be held in a grip which tends to be standardized thanks to the presence of lateral finger positioning zones 21.

[0112] Traditionally, a pen tends to be held at an angle of less than 90° to the writing surface.

[0113] Device 1 is thus designed so that the ventral region 22 is oriented towards the writing support, while the dorsal region 23 is designed to be oriented in the opposite direction to the writing support relative to the ventral region 22 of the pen body 2.

[0114] In this way, the positioning of camera 4 in the dorsal region 23 tends to optimize the number of characters of text T that can be captured by camera 4.

[0115] In addition to this tilt, different orientations of a pen are possible depending on the habits of the person using it.

[0116] The illustration shows three ways of holding the pen body 2 of the device associated with scores, this view corresponding to a top view of a writing support, and orientations of the central axis 20 of the pen body 2 relative to the written text T.

[0117] The following can be observed: - a score i, in which the device is held inwards (with a slight tilt); - a score m, in which the device is held facing the writing surface (with a slight tilt); - a score e, in which the device is held outwards (with a slight tilt).

[0118] In order to optimize the number of characters of the text T that are collected in the images captured by the camera 4, the orientation and positioning of the camera 4, and of its optical axis 40 in relation to the body 2 of the pen and the tip 31 were the subject of a plurality of tests.

[0119] First, the optical axis 40 and the central axis 20 are non-coplanar. This tends to optimize the number of characters of the text T that tend to be captured in an image.

[0120] Furthermore, camera 4 has an optical field in which the tip of the stylus 31 is located. This information is particularly important since it serves as a reference point to enable subsequent optical recognition of the text in the images captured by camera 4 using software.

[0121] The presence of the tip of point 31 is necessary, however, efforts are also made to minimize it.

[0122] Preferably, the camera 4 is oriented around the central axis of the housing 24 so that the tip 31 is located in a corner of the optical field which is rectangular in shape (rectangular shape defined by the photographic sensor).

[0123] The tip 31 may be located in an area in the right third of the image, and / or the lower third of the image. Preferably, the tip 31 is located in an area in the right quarter of the image, and / or the lower quarter of the image. Even more preferably, the tip 31 is located in an area in the right fifth of the image, and / or the lower fifth of the image.

[0124] The tables in Figures 12 to 22 illustrate the images captured in the three orientations, with, from left to right, the orientations i (held inwards), m (held towards the support - middle), and e (held outwards). Each row of three images corresponds to the images captured either by sensor C1, which is an endoscopic sensor with a resolution of 640 pixels by 480 pixels, or by sensor C2, which is an endoscopic sensor with a resolution of 416 pixels by 416 pixels.

[0125] For each table, at least one of the parameters described below was modified in order to measure its impact on the i / m / e scores, these scores then being reported and translated into the graphs in Figures 9, 10, and 11.

[0126] The calculation of a score is carried out as follows: - The most degraded image between sensor C1 and C2 is systematically chosen for the evaluation; - The position of the lead is noted from 0 to 2 points: 2 points if visible and well positioned, 1 point if visible but poorly positioned, 0 points if not visible or very poorly positioned; - The surrounding letters are evaluated individually: 'e' from 0 to 1 point, 's' from 0 to 2 points, and 't' from 0 to 3 points, according to their degree of visibility; - The groups of letters 'ce' and 'ci' are valued up to 1 point each, with intermediate scores for partial visibility; - The weighting of the letters increases with their proximity to the lead, reflecting their relative importance in the evaluation.

[0127] As an example, for the angle A1 = 21° illustrated in the figure, the analysis of the most degraded images from the sensor C2 gives the following results: - A score i = 2.5 is obtained, composed of 0 points for the non-visible lead, 2 points for the identification of 'this', and 0.5 points for 'e' partially visible; - A score m = 3 is calculated, comprising 0 points for the non-visible lead, 2 points for the identification of 'this', and 1 point for 'e' fully visible; - A score e = 1 is assigned, resulting from 0 points for the non-visible lead and 1 point for the unique identification of the character 'e'.

[0128] As an example, for the distance D3 = 8mm illustrated in the image, the analysis of the most degraded images from the C2 sensor gives the following results: - A score i = 6.5 is obtained, composed of 2 points for the lead visible and well positioned, 0 points for 't', 2 points for 's', 1 point for 'e', ​​1 point for 'ci' and 0.5 points for 'ce' partially visible; - A score m = 7 is obtained, composed of 2 points for the lead visible and well positioned, 2 points for 't' partially readable, 2 points for 's' and 1 point for 'e' fully visible; - A score e = 7.5 is obtained, composed of 2 points for the lead visible and well positioned, 3 points for 't' fully readable, 2 points for 's' and 0.5 points for 'e' partially visible.

[0129] For each table, we find the following parameters: - the angle A2 formed between an orthogonal projection of the optical axis 40 in the median transverse plane PTM and the central axis 20; - the angle A1 formed between an orthogonal projection of the optical axis 40 in the median sagittal plane PMS and the central axis 20; - the distance D3, measured between an orthogonal projection on the central axis 20 of the center of the front lens 41 and the end of the body 2 from which the tip 31 emerges.

[0130] For the table, the parameters are as follows: - angle A2 = 22°; - angle A1 = 6°; - distance D3 = 20.5 mm.

[0131] In these tests where the influence of angle A1 is studied more particularly, the results are slightly degraded because the tip takes up too much space on the image, which prevents the capture of certain characters.

[0132] For the table, the parameters are as follows: - angle A2 = 22°; - angle A1 = 13°; - distance D3 = 20.5 mm.

[0133] In these tests where the influence of angle A1 is studied more specifically, the results are slightly degraded because it is difficult to identify the last character of the word written by the user.

[0134] For the table, the parameters are as follows: - angle A2 = 22°; - angle A1 = 21°; - distance D3 = 20.5 mm.

[0135] In these tests, where the influence of angle A1 is studied in particular, the results are degraded because the lens and sensor are no longer sufficiently oriented towards the text and the tip, preventing the capture of a large number of characters. It is also observed that the tip is no longer visible in the image.

[0136] For the table, the parameters are as follows: - angle A2 = 22°; - angle A1 = 25°; - distance D3 = 20.5 mm.

[0137] In these tests, where the influence of angle A1 is studied in particular, the results are very poor because the lens and camera sensor are no longer oriented towards the text and the tip. Very few characters are visible, the most important characters of the word 'is' are not visible, and the tip is no longer visible.

[0138] For the table, the parameters are as follows: - angle A2 = 5°; - angle A1 = 11°; - distance D3 = 20.5 mm.

[0139] In these tests, where the influence of angle A2 is studied in particular, the results are satisfactory because the point can be identified in the lower right corner of the image. Furthermore, the three most important characters, as well as other characters, can be identified. However, when the device is rotated inwards (i), the point almost overlaps the last character (here, the character 't'), which could prove problematic.

[0140] For the table, the parameters are as follows: - angle A2 = -10° ; - angle A1 = 11° ; - distance D3 = 20.5 mm.

[0141] In these tests where the influence of angle A2 is studied more particularly, the results are degraded because the lens and camera sensor are too eccentric relative to the text, which prevents the capture of a number of characters, particularly when the device is held facing the sheet (m) and outwards (e) on the sheet.

[0142] For the table, the parameters are as follows: - angle A2 = 22°; - angle A1 = 11°; - distance D3 = 27 mm.

[0143] In these tests where the influence of the D3 distance is studied more particularly, the results are degraded because the lens and the camera sensor are too far away from the text, which prevents the capture of a number of characters.

[0144] For the table, the parameters are as follows: - angle A2 = 22°; - angle A1 = 11°; - distance D3 = 8 mm.

[0145] In these tests, where the influence of the D3 distance is studied in particular, the results are degraded because the lens and camera sensor are slightly too close to the user's handwriting. The focal length is correctly maintained and there is no optical blur, but the last character written by the user is difficult or impossible to identify.

[0146] For the table, the parameters are as follows: - angle A2 = 22°; - angle A1 = 11°; - distance D3 = 20.5 mm.

[0147] In these tests, the results are satisfactory because the point can be identified in the lower right corner of the image. Furthermore, the three most important characters, as well as other additional characters, can be identified.

[0148] For the table, the parameters are as follows: - angle A2 = 22°; - angle A1 = 11°; - distance D3 = 11.5 mm.

[0149] In these tests, where the influence of the D3 distance is studied in particular, the results are slightly degraded because in almost all cases it is possible to identify the point in the lower right corner of the image as well as the three most important characters. However, it can be difficult in some cases to identify the last letter written by the user.

[0150] For the table, the parameters are as follows: - angle A2 = 35°; - angle A1 = 11°; - distance D3 = 11.5 mm.

[0151] In these tests, where the influence of angle A2 is studied in particular, the results are very degraded because the lens and camera sensor are too far off-center from the text, which prevents the capture of a large number of characters.

[0152] With reference to the graph, the impact of the value of angle A2 is studied.

[0153] The design described below relates to embodiments applicable to a writing device 1 intended to be used by a right-handed person, but which can also be used by left-handed people depending on how they hold a pen.

[0154] A possible functional range for A2 is as follows: 0° ≤ A2 ≤ 30°.

[0155] The optimal operating range for this value of angle A2 is from 5 to 25°.

[0156] The closer the angle is to 90°, the more the sensor is off-center, capturing an image to the left where the user hasn't yet written. This significantly degrades the image quality, obscuring the tip or words. The closer the angle is to -90°, the more the image quality degrades, obscuring the tip or characters, because the sensor is too far off-center.

[0157] It follows from the above that, according to an orthogonal projection onto a median transverse plane PTM passing through the central axis 20 and extending orthogonally to the median sagittal plane PSM, the optical axis 40 is oriented to cross and then move away from the central axis 20 towards the tip of the point 31, from the body 2, and in a direction going from left to right in a top view with the point oriented downwards as illustrated on the.

[0158] This left-to-right direction can also be likened to a direction from a right lateral side to a left lateral side of the pen body 2.

[0159] Furthermore, within the range 5° ≤ A2 ≤ 25°, the angle A2 = 22° emerges as an optimal value.

[0160] According to an alternative, unrepresented design of writing device 1 intended for use by a left-handed person, the values ​​of angle A2 are also applicable.

[0161] However, in this situation, camera 4 has an orientation contrary to that of the device adapted for right-handed people.

[0162] More specifically, in this left-handed variant, according to an orthogonal projection onto a median transverse plane PTM passing through the central axis 20 and extending orthogonally to the median sagittal plane PSM, the optical axis 40 is oriented to cross and then move away from the central axis 20 towards the tip of the point 31, from the body 2, and in a direction from right to left according to a top view with the point oriented downwards.

[0163] This right-to-left direction can also be likened to a direction from a left lateral side to a right lateral side of the pen body 2.

[0164] With reference to the graph, the impact of the value of angle A1 is studied.

[0165] A possible functional range for A1 is: 0° ≤ A1 ≤ 18°.

[0166] The optimal operating range for this value is from 6° to 14°.

[0167] The closer the angle is to 0°, the more the image quality degrades because the tip dominates the image (taking up too much space) and prevents the camera sensor from correctly capturing certain characters when the device is held facing inwards (i) or outwards (e). The closer the angle is to 25°, the more pronounced the degradation becomes, as the tip disappears from the image, and only a few characters, or even none at all, are captured compared to the tip.

[0168] It follows from the above that, according to an orthogonal projection onto the median sagittal plane PSM, the optical axis 40 is oriented to move away from the central axis 20 towards the tip of the point 31 from the body 2, in a direction going from the ventral region 22 towards the dorsal region 23.

[0169] Furthermore, within the range 6° ≤ A1 ≤ 14°, the angle A1 = 11° emerges as an optimal value.

[0170] With reference to the graph, we study the impact of the distance D3.

[0171] The optimal operating range for this D3 distance is from 8 mm to 24 mm.

[0172] As the image approaches 0 mm, the result degrades rapidly, as characters are missing and the point of the sensor becomes indistinguishable. Conversely, as the image approaches 30 mm, experiments with 50 testers revealed that all users placed their fingers in front of the sensor, which degraded the result.

[0173] In reference to the, other tests have determined that a shift in the position of the lens relative to the central axis 20, and in a frontal plane orthogonal to the median sagittal plane and the median transverse plane is desirable, in particular to reduce the bulk of the pen body 2 and to provide volume for the ink reserve of the writing instruments.

[0174] Thus, according to an orthogonal projection onto the median sagittal plane PSM, the center of the front lens 41 is offset by a distance D1 of 1 to 1.75 mm from the central axis 20, preferably by 1.4 mm.

[0175] Furthermore, according to an orthogonal projection onto the median transverse plane PTM, the center of the front lens 41 is offset by a distance D2 of 0.5 to 1 mm from the central axis 20, preferably by 0.8 mm.

Claims

A writing and image capture device (1) comprising: - a pen body (2) extending along a central axis (20), and having two lateral finger positioning zones (21) located on either side of a median sagittal plane (MSP) of the pen body (2) passing through the central axis (20), the body (2) also having a ventral region (22) intended to be oriented towards a writing support, and a dorsal region (23) opposite to the ventral region (22) with respect to the central axis (20); - writing means (3) received in the body, and comprising a writing tip (31) emerging from the body (2), the tip (31) being coaxial with the central axis (20);- a camera (4) inserted in a housing (24) formed in the dorsal region (23) of the body (2), and fixedly mounted relative to the tip (31), the camera (4) comprising a front lens (41) defining an optical axis (40), the front lens (41) being located near the lateral finger positioning areas (21), in the direction of the tip (31); characterized in that the optical axis (40) and the central axis (20) are non-coplanar, and in that the camera (4) presents an optical field in which the tip (31) is located. Device (1) according to the preceding claim, characterized in that the writing means (3) comprise an ink storage reservoir coupled to the writing tip (31), the reservoir having a flexible tubular shape, and in that the pen body (2) has a passage (25) for receiving the writing means (3), the passage (25) having: - an open terminal portion (251) from which the writing tip (31) emerges, the terminal portion (251) extending longitudinally and being centered on the central axis (20); - at least one offset portion (252) from the central axis (20) extending in line with the terminal portion (251), the housing (24) being provided in the pen body (2) opposite the offset portion (252) with respect to the central axis (20). Device (1) according to any one of the preceding claims, characterized in that, according to an orthogonal projection onto the median sagittal plane (MSP), the optical axis (40) is oriented to move away from the central axis (20) towards the tip end (31) from the body (2), in a direction going from the ventral region (22) towards the dorsal region (23). Device (1) according to the preceding claim, characterized in that, according to an orthogonal projection onto the median sagittal plane (MSP), the optical axis (40) forms an angle A1 with the central axis (20), with 0° ≤ A1 ≤ 18°, preferably with 6° ≤ A1 ≤ 14°, even more preferably with A1 = 11°. Device (1) according to any one of the preceding claims, characterized in that, according to an orthogonal projection onto a median transverse plane (MTP) passing through the central axis (20) and extending orthogonally to the median sagittal plane (MSP), the optical axis (40) is oriented to cross and then move away from the central axis (20) towards the tip of the point (31), from the body (2), and in a direction from left to right according to a top view with the point oriented downwards. Device (1) according to any one of claims 1 to 4, characterized in that, according to an orthogonal projection onto a median transverse plane (MTP) passing through the central axis (20) and extending orthogonally to the median sagittal plane (MSP), the optical axis (40) is oriented to cross and then move away from the central axis (20) towards the tip of the point (31), from the body (2), and in a direction from right to left according to a top view with the point oriented downwards. Device (1) according to claim 5 or 6, characterized in that, according to an orthogonal projection onto the median transverse plane (MTP), the optical axis (40) forms an angle A2 with the central axis (20), with 0° ≤ A2 ≤ 30°, preferably with 5° ≤ A2 ≤ 25°, even more preferably A2 = 22°. Device (1) according to any one of claims 5 to 7, characterized in that, according to an orthogonal projection onto the median transverse plane (MTP), the center of the front lens (41) is offset by a distance (D2) of 0.5 to 1 mm from the central axis (20), preferably by 0.8 mm, and in that, according to an orthogonal projection onto the median sagittal plane (MSP), the center of the front lens (41) is offset by a distance (D1) of 1 to 1.75 mm from the central axis (20), preferably by 1.4 mm. Device (1) according to any one of the preceding claims, characterized in that the pen body (2) has, along the central axis (20): - a main part (201) substantially cylindrical of revolution, having the two lateral finger positioning zones (21), and extending towards the end of the body (2) from which the tip (31) emerges to an opening through the housing (24) into which the camera (4) is inserted; - an end part (202) extending from the main part (201) thinning out to the end of the body (2) from which the tip (31) emerges, the end part (202) having a recess (203) around the optical axis (40). Device (1) according to any one of the preceding claims, characterized in that according to an orthogonal projection on the central axis (20), the center of the front lens (41) and the end of the body (2) from which the tip (31) emerges are separated by a distance (D3) of 8 to 24 mm.

Images