Camera for measuring depth image and method of measuring depth image using the same
Provided are a depth camera and methods of measuring a depth image by using the depth camera. The depth camera is a time-of-flight (TOF) depth camera including: an illumination device that illuminates a patterned light to an object; a filter unit that reduces noise light included in light reflected by the object; and an image sensor that provides a depth image of the object by receiving light that enters through the filter unit. The illumination device includes: a light source; and a patterned light generator that changes the light emitted from the light source into the patterned light. The filter unit includes a band pass filter and an optical modulator. The patterned light generator may be a diffractive optical element or a refractive optical element.
1. A time-of-flight (TOF) depth camera comprising:
an illumination device configured to illuminate a patterned light to an object, the patterned light comprising spots in a lattice arrangement;
a filter device configured to reduce noise light included in light reflected by the object; and
an image sensor configured to:
receive light that enters through the filter device;
measure a phase delay of the received light;
measure first distances from the TOF depth camera respectively to first regions of the object corresponding to the spots included in the patterned light, based on the measured phase delay;
measure second distances from the TOF depth camera respectively to second regions of the object corresponding to gaps between the spots included in the patterned light, using an interpolation method; and
provide a depth image of the object, based on the measured first distances and the measured second distances,
wherein the filter device comprises a band pass filter, and an optical modulator, and
wherein the filter device is disposed between the object and the image sensor.
2. The TOF depth camera of claim 1 , wherein the illumination device comprises:
a light source configured to emit light; and
a patterned light generator configured to change the emitted light into the patterned light.
3. The TOF depth camera of claim 2 , wherein the patterned light generator is a diffractive optical element.
4. The TOF depth camera of claim 2 , wherein the patterned light generator is a refractive optical element.
5. A method of measuring a depth image, using a time-of-flight (TOF) depth camera, the method comprising:
irradiating a patterned light on an object, the patterned light comprising spots in a lattice arrangement;
reducing, by a filter device, noise light included in light reflected by the object;
receiving light that enters through the filter device;
measuring a phase delay of the received light;
measuring first distances from the TOF depth camera respectively to first regions of the object corresponding to the spots included in the patterned light, based on the measured phase delay;
measuring second distances from the TOF depth camera respectively to second regions of the object corresponding to gaps between the spots included in the patterned light, using an interpolation method; and
providing the depth image of the object, based on the measured first distances and the measured second distances.
6. The method of claim 5 , wherein the irradiating of the patterned light on the object comprises:
emitting light from a light source; and
changing the emitted light into the patterned light.
7. The method of claim 6 , wherein the changing of the emitted light into the patterned light comprises diffracting the emitted light, using a diffractive optical element.
8. The method of claim 6 , wherein the changing of the emitted light into the patterned light comprises refracting the emitted light, using a refractive optical element.
9. The method of claim 6 , wherein an intensity of the spots included in the patterned light is high relative to an intensity of surrounding regions of the spots.
10. The method of claim 8 , wherein the refractive optical element is a micro-lens array.