Laundry machine and control method therefor

1. A method of controlling a washing machine, the method comprising:

detecting properties of laundry in a drum of the washing machine,

wherein detecting the properties of the laundry comprises:

detecting a weight of the laundry,

capturing an image of an interior of the drum using a single camera,

detecting a volume of the laundry in the drum using the captured image, and

calculating a density of the laundry based on the detected volume and the detected weight, and

wherein the method further comprises:

comparing the calculated density with a predetermined reference value,

notifying a user of a change of at least one of a water level of wash water to be supplied to the drum, a rotation speed of the drum, a rotation time period of the drum, or a rotation change cycle of the drum based on whether the calculated density is higher or lower than the predetermined reference value,

waiting for a user to perform an input operation in response to a notification of the change,

based on receiving no input or a signal approving of the change while waiting for the user to perform an input operation, performing a washing process according to the change of at least one of the water level of wash water to be supplied to the drum, the rotation speed of the drum, the rotation time period of the drum, or the rotation change cycle of the drum, and

based on receiving a signal disapproving of the change while waiting for the user to perform an input operation, performing a washing process according to at least one of a water level of wash water to be supplied to the drum, a rotation speed of the drum, a rotation time period of the drum, or a rotation change cycle of the drum that corresponds to the predetermined reference value.

2. The method according to claim 1 , further comprising:

changing at least one of the water level of wash water to be supplied to the drum, the rotation speed of the drum, the rotation time period of the drum, or the rotation change cycle of the drum based on whether the calculated density is higher or lower than the predetermined reference value.

3. The method according to claim 2 , further comprising:

wetting the laundry;

washing the laundry;

rinsing the laundry; and

dehydrating the rinsed laundry,

wherein detecting the properties of the laundry is performed before at least one of wetting the laundry, washing the laundry, rinsing the laundry, or dehydrating the laundry, and

wherein at least one of the water level of wash water to be supplied to the drum, the rotation speed of the drum, the rotation time period of the drum, or the rotation change cycle of the drum is changed based on the detected properties of the laundry in the at least one of wetting the laundry, washing the laundry, rinsing the laundry, or dehydrating the laundry.

4. The method according to claim 2 , further comprising:

based on the calculated density being less than the predetermined reference value, setting at least one of the rotation speed of the drum, the rotation time period of the drum, or the rotation change cycle of the drum to be less than the rotation speed of the drum, the rotation time period of the drum, or the rotation change cycle of the drum corresponding to the predetermined reference value; and

based on the calculated density being greater than the predetermined reference value, setting at least one of the rotation speed of the drum, the rotation time period of the drum or the rotation change cycle of the drum to be greater than the rotation speed of the drum, the rotation time period of the drum or the rotation change cycle of the drum corresponding to the predetermined reference value.

5. The method according to claim 4 , further comprising:

based on the calculated density being less than the predetermined reference value, setting the water level of wash water to be supplied to the drum to be higher than the water level of wash water to be supplied to the drum corresponding to the predetermined reference value; and

based on the calculated density being greater than the predetermined reference value, setting the water level of wash water to be supplied to the drum to be lower than the water level of wash water to be supplied to the drum corresponding to the predetermined reference value.

6. The method according to claim 1 , wherein the drum has an inner circumferential surface that defines a plurality of through-holes configured to communicate wash water into or out of the drum, and

wherein detecting the volume of the laundry is performed by measuring a number of exposed through-holes among the plurality of through-holes of the drum from the image.

7. The method according to claim 6 , wherein capturing the image of the interior of the drum further comprises:

radiating light to the interior of the drum using an illuminating device; and

capturing the image while radiating the light to the interior of the drum.

8. The method according to claim 1 , wherein detecting the volume of the laundry is performed by extracting contours of the laundry from the image.

9. The method according to claim 1 , wherein detecting the volume of the laundry is performed by analyzing light and shadow portions of the laundry appearing in the image.

10. The method according to claim 1 , wherein capturing the image of the interior of the drum further comprises capturing images of the interior of the drum using a plurality of cameras spaced apart from each other, and

wherein detecting the volume of the laundry is performed by processing the images captured by the plurality of cameras.

11. The method according to claim 1 , wherein detecting the weight of the laundry comprises calculating the weight by measuring an electric current that is applied to a motor while rotating the drum at a predetermined angle.

12. The method according to claim 1 , wherein capturing the image of the interior of the drum further comprises:

radiating light to the interior of the drum using an illuminating device; and

capturing the image of the interior of the drum while radiating light to the interior of the drum.

13. The method according to claim 12 , wherein detecting the volume of the laundry in the drum comprises:

determining, from the image, a light portion and a shadow portion of the laundry that are defined by radiating the light to the interior of the drum; and

detecting the volume of the laundry in the drum based on a ratio of the light portion with respect to the shadow portion.

14. The method according to claim 1 , wherein capturing the image of the interior of the drum comprises:

capturing a first image using the single camera;

rotating the drum by less than one revolution from a first position at which the first image is taken; and

capturing a second image using the single camera after rotating the drum by less than one revolution, and

wherein detecting the volume of the laundry comprises generating a stereoscopic image based on the first image and the second image.

15. The method according to claim 14 , wherein rotating the drum by less than one revolution comprises rotating the drum by less than 90 degrees from the first position at which the first image is taken.

16. The method according to claim 14 , wherein rotating the drum by less than one revolution is performed based on maintaining an arrangement or shape of the laundry from the first position of the drum to a second position of the drum at which the second image is taken.

17. The method according to claim 1 , wherein the method comprises notifying the user of the change of the water level of wash water to be supplied to the drum based on whether the calculated density is higher or lower than the predetermined reference value.

18. The method according to claim 1 , wherein the method comprises notifying the user of the change of the rotation speed of the drum based on whether the calculated density is higher or lower than the predetermined reference value.