OPTICAL PROCESSING APPARATUS AND LIGHT SOURCE LUMINANCE ADJUSTMENT METHOD THEREOF

• US 20170139489A1
• Filed: 01/27/2017
• Published: 05/18/2017
• Est. Priority Date: 02/04/2013
• Status: Active Grant

• Current Assignee: PixArt Imaging Incorporated
• Original Assignee: PixArt Imaging Incorporated
• Inventors: CHUNG, Ching-Lin, CHEN, Chun-Wei
• Granted Patent: US 10,241,593 B2
• Time in Patent Office: Days
• CPC Class Codes: G04G 21/00 Input or output devices integrated in time-pieces
• CPC Class Codes: G04G 21/025 for measuring physiological data
• CPC Class Codes: G06F 1/163 Wearable computers, e.g. on a belt
• CPC Class Codes: G06F 1/169 the I/O peripheral being an integrated pointing device, e.g. trackball in the palm rest area, mini-joystick integrated between keyboard keys, touch pads or touch stripes G06F1/1643 takes precedence; constructional details of pointing devices G06F3/033
• CPC Class Codes: G06F 3/0304 Detection arrangements using opto-electronic means constructional details of pointing devices not related to the detection arrangement using opto-electronic means G06F3/033; optical digitisers G06F3/042
• CPC Class Codes: G06F 3/0312 for tracking the rotation of a spherical or circular member, e.g. optical rotary encoders used in mice or trackballs using a tracking ball or in mouse scroll wheels tracking relative movement in co-operation with a regularly or irregularly patterned surface, e.g. as in optical mice G06F3/0317; constructional details of scroll or thumb-wheels G06F3/0362; optical rotary encoders G01D5/3473
• CPC Class Codes: G06F 3/0362 with detection of 1D translations or rotations of an operating part of the device, e.g. scroll wheels, sliders, knobs, rollers or belts
• CPC Class Codes: G06T 2207/10144 Varying exposure
• CPC Class Codes: G06T 2207/30168 Image quality inspection
• CPC Class Codes: G06T 7/0002 Inspection of images, e.g. flaw detection
• CPC Class Codes: H04N 23/71 Circuitry for evaluating the brightness variation
• CPC Class Codes: H04N 23/73 by influencing the exposure time
• CPC Class Codes: H04N 23/74 by influencing the scene brightness using illuminating means
• CPC Class Codes: H04N 23/743 Bracketing, i.e. taking a series of images with varying exposure conditions

Abstract

An optical processing apparatus and a light source luminance adjustment method adapted to detect a rotational displacement and a pressing state are provided. The optical processing apparatus includes a light source unit, a processing unit, and an image sensing unit, wherein the processing unit is electrically connected to the light source unit and the image sensing unit. The light source unit provides a beam of light. The processing unit defines a frame rate, defines a plurality of time instants within a time interval, and sets the light source unit to a luminance value at each of the time instants. A length of the time interval is shorter than the reciprocal of the frame rate. The luminance values are different and are within a range. The image sensing unit captures an image by an exposure time length at each of the time instants, wherein the exposure time lengths are the same.

Claims

1. An optical processing apparatus, adapted to detect a pressing state and a rotational displacement of a button, the optical processing apparatus comprising:

a light source unit configured to provide a beam of light to a surface of the button facing the light source unit;

a processing unit, electrically connected to the light source unit, and configured to

define a frame rate,

define a plurality of first time instants within a first time interval, and

set the beam of light provided by the light source unit to a luminance value at each of the first time instants, wherein a length of the first time interval is shorter than a reciprocal of the frame rate, and the luminance values are different and within a first range; and

an image sensing unit, electrically connected to the processing unit, and configured to capture a first image of the surface of the button by an exposure time length at each of the first time instants, wherein the exposure time lengths are the same,

wherein the processing unit is further configured to

calculate an image quality index of each of the first images,

compare the image quality index of one of the first images with at least one first press threshold to identify the pressing state of the button within the first time interval,

compare the image quality indices of each of the first images with at least one quality threshold, and

select more than one of the first images as a plurality of first temporary images to calculate the rotational displacement of the button when the image quality indices do not meet the at least one quality threshold.

2. The optical processing apparatus of claim 1, wherein the processing unit is further configured to derive an averaged image by averaging the first temporary images and set the averaged image as a first selected image representing the first time interval.

3. The optical processing apparatus of claim 1, wherein the processing unit is further configured to

decide a second range corresponding to a second time interval according to a comparison result of comparing the image quality indices with the at least one quality threshold, wherein the second time interval occurs later than the first time interval, a length of the second time interval is shorter than the reciprocal of the frame rate, and the second range is different from the first range,

define a plurality of second time instants within the second time interval, and

set the beam of light provided by the light source unit to a luminance value at each of the second time instants, wherein the luminance values corresponding to the second time interval are different and within the second range, and

wherein the image sensing unit is further configured to capture a second image by the exposure time length at each of the second time instants.

4. The optical processing apparatus of claim 3, wherein the processing unit is further configured to

calculate an image quality index of each of the second images, and

compare the image quality index of one of the second images with at least one second press threshold to identify the pressing state of the button within the second time interval, wherein the one of the second images corresponds to a minimum luminance value or a maximum luminance value of the light source unit among the second time instants.

5. The optical processing apparatus of claim 1, wherein each image quality index is one of a feature value and image intensity of the corresponding first image.

6. The optical processing apparatus of claim 1, wherein the button is a watch crown.

7. The optical processing apparatus of claim 1, wherein the one of the first images corresponds to a minimum luminance value or a maximum luminance value of the light source unit among the first time instants.

8. A light source luminance adjustment method, being adapted for use in an optical processing apparatus which is adapted to detect a pressing state and a rotational displacement of a button, the optical processing apparatus comprising a light source unit, a processing unit, and an image sensing unit, the light source unit providing a beam of light to a surface of the button facing the light source unit, the processing unit defining a frame rate, the image sensing unit receiving light reflected from the surface of the button, and the light source luminance adjustment method comprising:

defining, by the processing unit, a plurality of first time instants within a first time interval, wherein a length of the first time interval is shorter than a reciprocal of the frame rate;

setting, by the processing unit, the beam of light provided by the light source unit to a luminance value at each of the first time instants, wherein the luminance values are different and within a first range;

capturing, by the image sensing unit, a first image of the surface of the button by an exposure time length at each of the first time instants, wherein the exposure time lengths are the same;

calculating, by the processing unit, an image quality index of each of the first images;

comparing, by the processing unit, the image quality index of one of the first images with at least one first press threshold to identify the pressing state of the button within the first time interval,

comparing, by the processing unit, the image quality indices of each of the first images with at least one quality threshold; and

selecting, by the processing unit, more than one of the first images as a plurality of first temporary images to calculate the rotational displacement of the button when the image quality indices do not meet the at least one quality threshold.

9. The light source luminance adjustment method of claim 8, further comprising:

deriving, by the processing unit, an averaged image by averaging the first temporary images; and

setting, by the processing unit, the averaged image as a first selected image representing the first time interval.

10. The light source luminance adjustment method of claim 8, further comprising:

deciding, by the processing unit, a second range corresponding to a second time interval according to a comparison result of comparing the image quality indices with the at least one quality threshold, wherein the second time interval occurs later than the first time interval, a length of the second time interval is shorter than the reciprocal of the frame rate, and the second range is different from the first range;

defining, by the processing unit, a plurality of second time instants within the second time interval;

setting, by the processing unit, the beam of light provided by the light source unit to a luminance value at each of the second time instants, wherein the luminance values corresponding to the second time interval are different and within the second range; and

capturing, by the image sensing unit, a second image by the exposure time length at each of the second time instants.

11. The light source luminance adjustment method of claim 10, further comprising:

calculating an image quality index of each of the second images, and

comparing the image quality index of one of the second images with at least one second press threshold to identify the pressing state of the button within the second time interval, wherein the one of the second images corresponds to a minimum luminance value or a maximum luminance value of the light source unit among the second time instants.

12. The light source luminance adjustment method of claim 8, wherein each image quality index is one of a feature value and image intensity of the corresponding first image.

13. The light source luminance adjustment method of claim 8, wherein the one of the first images corresponds to a minimum luminance value or a maximum luminance value of the light source unit among the first time instants.

14. An optical processing apparatus, adapted to detect a pressing state and a rotational displacement of a button, the optical processing apparatus comprising:

a light source unit configured to provide a beam of light to a surface of the button facing the light source unit;

a processing unit, electrically connected to the light source unit, and configured to

define successive frame capturing periods,

define a plurality of time instants within a time interval in each frame capturing period, wherein a length of the time interval is shorter than the frame capturing period, and

set the beam of light provided by the light source unit to a luminance value at each of the plurality of time instants within each time interval; and

an image sensing unit, electrically connected to the processing unit, and configured to capture an image of the surface of the button by an exposure time length and a gain value at each of the plurality of time instants within the each time interval,

wherein the processing unit is further configured to

set an image capture parameter, which includes at least one of the luminance value, the exposure time length and the gain value, at each of the plurality of time instants to be different and within a predetermined range,

calculate an image quality index of each of the images captured within the each time interval,

compare the image quality index of a first image among the images captured within the each time interval with at least one press threshold to identify the pressing state of the button within the each time interval, wherein the first image corresponds to a minimum image capture parameter or a maximum image capture parameter among the plurality of time instants within the each time interval, and

calculate the rotational displacement of the button using a second image among the images captured within the each time interval, wherein the second image is one of the images, among the plurality of time instants within the each time interval, whose image quality index meet at least one quality threshold.

15. The optical processing apparatus of claim 14, wherein the button is a watch crown.

16. The optical processing apparatus of claim 14, wherein each image quality index is one of a feature value and image intensity of the corresponding image.

17. The optical processing apparatus of claim 14, wherein the first image is associated with a same time instant among the plurality of time instants within every frame capturing period.

18. The optical processing apparatus of claim 14, wherein the second image is associated with different time instants among the plurality of time instants within the each time interval of two adjacent frame capturing periods.

19. The optical processing apparatus of claim 14, wherein the processing unit is further configured to set the image capture parameter within a different predetermined range when the image quality indices of the images captured within one of the successive frame capturing periods do not meet the at least one quality threshold.

20. The optical processing apparatus of claim 14, wherein the processing unit is further configured to stop outputting the rotational displacement when the image quality index of the first image is between a first press threshold and a second press threshold.