Method and apparatus for detecting objects based upon color signal separation

• US 4,718,089 A
• Filed: 02/17/1987
• Issued: 01/05/1988
• Est. Priority Date: 12/08/1983
• Status: Expired due to Fees

• Current Assignee: Kubota Corporation
• Original Assignee: Kubota Corporation
• Inventors: Okuyama, Shigeaki, Hayashi, Masahiko, Fujii, Yasuo
• Primary Examiner(s): Shepperd, John W.
• Application Number:
  US07/016,498
• Time in Patent Office: 322 Days
• Field of Search: 358/22, 358/21 R, 358/80, 358/101, 382/17
• US Class Current: 382/164
• CPC Class Codes: G01J 3/46 Measurement of colour; Colour measuring devices, e.g. colorimeters measuring colour temperature G01J5/60

Abstract

A chroma keying generator apparatus is disclosed having a monitor camera transmitting color signals to multipliers for separating a luminance signal from an image signal and amplifying same by selected gain levels, comparison circuits for comparing two color signals with pre-selected reference levels therefor having upper and lower limits and producing outputs denoting that the ratio of the color signal to the luminance signal for a given color falls within a pre-selected reference range, and a gate circuit which evaluates the outputs from the comparison circuits to produce pulses representing a logical "1" when the output is within the reference range and a logical "0" when the output is not within the reference range.

Claims

1. An object detecting system for detecting an article of produce ripened to a desired degree comprising,

a monitor camera for detecting the object and providing a composite image signal including color component signals and a luminance signal to a reception means,

said reception means being adapted to discriminate from among said color component signals and to select that color component signal corresponding to a particular color of the article of produce desired to be harvested and further to product a digital image of said article of produce having the particular color,

a first multiplier (2) for receiving the luminance signal (Y), multiplying the luminance signal by a first gain (K1) and a second gain (K1'"'"'), and outputting resulting values as a first and a second multiplication signals (K1*Y, K1'"'"'*Y),

a second multiplier (2'"'"') for receiving the luminance signal (Y), multiplying the luminance signal by a third gain (K2) and a fourth gain (K2'"'"'), and outputting resulting values as a third and fourth multiplication signals (K2*Y, K2'"'"'*Y),

gain setting means including first, second, third, and fourth control means (C1, C1'"'"', C2, C2'"'"') for setting the first, second, third and fourth gains, respectively, the first and second gains being set so that the first and second multiplication signals correspond to upper and lower limits of a first color component (R) of the article of produce to be harvested, the third and fourth gains being set so that the third and fourth multiplication signals correspond to upper and lower limits of a second color component (B) of the article of produce harvested,

a first comparator (3) for receiving the first color component signal from the monitor camera and for receiving the first and second multiplication signals as threshold values from the first multiplier and further for outputting a first digital signal determined by whether the first color component signal is in a range having the first multiplication signal as an upper limit and the second multiplication signal as a lower limit,

a second comparator (3'"'"') for receiving the second color component signal from the monitor camera and the third and fourth multiplication signals as threshold values from the second multiplier, and further for outputting a second digital signal determined by whether the second color component signal is in a range having the third multiplication signal as an upper limit and the fourth multiplication signal as a lower limit,

a gate circuit (4) for carrying out an AND operation on the first and second digital signals and producing an output signal,

a frame memory (5) for receiving the output signal of the gate circuit as a digital image signal (F) and storing a digital image of the article of produce,

the first, second, third, and fourth control means being associated with a color-coded control panel (6a) for movement thereon along X-Y axes thereof, one pair of said control means serving to define X-axes limits of said gains and another pair of said control means serving to define Y-axis limits of said gains, the X-axis and Y-axis limits thus serving to define a section (f) of the control panel having a color substantially corresponding to said particular color of the article of produce stored in the frame memory as the digital image.

2. A object detecting system as claimed in claim 1, wherein the first and second control means (C1, C1'"'"') are arranged on a panel (6a) one above the other and movable in horizontal directions, and the third and fourth control means (C2, C2'"'"') are arranged on the panel (6a) side by side and movable in vertical directions.

3. An object detecting system as claimed in claim 2, further comprising adjusting means for automatically adjusting an opening degree of a stop of the monitor camera in response to variations in the luminance signal (Y).

4. An object detecting system as claimed in claim 3, wherein the adjusting means includes a motor for driving the stop, a stop encoder operatively connected to the stop, a comparator circuit for receiving a signal from the stop encoder and the luminance signal from the monitor camera, and a circuit for outputting a drive signal to the motor in response to a signal received from the comparator circuit.

5. A object detecting system as claimed in claim 1, further comprising at least one DC restoration circuit for converting each of the luminance signal and the color signals into DC component signals from an absolute ground level prior to input to the multipliers and comparators.

6. A method for detecting a position of an object by receiving an image signal comprising color component signals and a luminance signal from a monitor camera which detects the object, discriminating color component signals corresponding to a particular color of the object from other color component signals to output a digital signal, and producing an image of the object, comprising the steps of:

receiving a luminance signal (Y) from a monitor camera, multiplying the luminance signal by a first gain (K1) and a second gain (K1'"'"'), and forming resulting values as first and second multiplication signals (K1*Y, K1'"'"'*Y),

receiving a luminance signal (Y) from a monitor camera, multiplying the luminance signal by a third gain (K2) and a fourth gain (K2'"'"'), and forming resulting values as third and fourth multiplication signals (K2*Y, K2'"'"'*Y),

setting gain means including first, second, third, and fourth control means (C1, C1'"'"', C2, C2'"'"') for setting first, second, third and fourth gains, respectively, setting the first and second gains so that the first and second multiplication signals correspond to upper and lower limits of a first color component (R) of the object, setting the third and fourth gains so that the third and fourth multiplication signals correspond to upper and lower limits of a second color component (B) of the object,

supplying the first color component signal from the monitor camera and supplying the first and second multiplication signals as threshold values from the first multiplier to a first comparator (3), evaluating whether the first color component is in a range having the first multiplication signal as an upper limit and the second multiplication signal as a lower limit and then forming a first digital signal therefrom,

supplying the second color component signal from the monitor camera and supplying the third and fourth multiplication signals as threshold values from the second multiplier to a second comparator (3'"'"'), evaluating whether the second color component signal is in a range having the third multiplication signal as an upper limit and the fourth multiplication signal as a lower limit and forming a second digital signal therefrom,

carrying out an AND operation on the first and second digital signals by use of a gate circuit (4) and producing an output signal,

receiving the output signal of the gate circuit as a digital image signal (F) of a frame memory (5) and storing a digital image of the object, whereby the position of the object can be determined by using the frame memory.

7. A method as claimed in claim 6, which comprises arranging the first and second control means (C1, C1'"'"') on a panel (6a) one above the other and movable in horizontal directions, and arranging the third and fourth control means (C2, C2'"'"') on the panel (6a) side by side and movable in vertical directions.

8. A method as claimed in claim 7, which comprises coloring portions of the panel (6a) such that a section (f) of the panel determined by positions of the first to fourth control means has a color substantially corresponding to the color of the object desired to be detected.

9. A method as claimed in claim 6, which comprises converting each of the luminance signal and the color signals into DC component signals from an absolute ground level prior to their input to the multipliers and comparators by use of at least one DC restoration circuit.

10. A method for detecting and harvesting an article of produce ripened to a desired state and possessing a particular color hue comprising,

detecting the object by use of a monitor camera and directing a composite image signal including color component signals and a luminance signal to a reception means,

operating said reception means to discriminate from among said color component signals and selecting that color component signal corresponding to a particular color of the article of produce desired to be harvested to create a digital image of said article of produce having the particular color,

using a first multiplier (2) for receiving a luminance signal (Y), multiplying the luminance signal by a first gain (K1) and a second gain (K1'"'"'), and forming resulting values as first and second multiplication signals (K1*Y, K1'"'"'*Y),

using a second multiplier (2'"'"') for receiving a luminance signal (Y), multiplying the luminance signal by a third gain (K2) and a fourth gain (K2'"'"'), and forming resulting values as third and fourth multiplication signals (K2*Y, K2'"'"'*Y),

using a gain setting means including first, second, third, and fourth control means (C1, C1'"'"', C2, C2'"'"') for setting the first, second, third and fourth gains, respectively, the first and second gains being set so that the first and second multiplication signals correspond to upper and lower limits of a first color component (R) of the article of produce to be harvested, setting the third and fourth gains so that the third and fourth multiplication signals correspond to upper and lower limits of a second color component (B) of the article of produce to be harvested,

using a first comparator (3) for receiving a first color component signal from the monitor camera and receiving the first and second multiplication signals as threshold values from the first multiplier and forming a first digital signal determining whether the first color component signal is in a range having the first multiplication signal as an upper limit and the second multiplciation signal as a lower limit,

using a second comparator (3'"'"') for receiving a second color component signal from the monitor camera and the third and fourth multiplication signals as threshold values from the second multiplier, and forming a second digital signal determined by whether the second color component signal in in a range having the third multiplication signal as an upper limit and the fourth multiplication signal as a lower limit,

using a gate circuit (4) for carrying out an AND operation on the first and second digital signals and producing an output signal,

using a frame memory (5) for receiving the output signal of the gate circuit as a digital image signal (F) and storing a digital image of the article of produce,

arranging the first, second, third, and fourth control means on a color-coded control panel (6a) for movement thereon along X-Y axes thereof, defining X-axis limits of said gains by use of one pair of said control means, defining Y-axis limits of said gains by use of another pair of said control means, setting the X-axis and Y-axis limits to define a section (f) of the control panel having a color substantially corresponding to said particular color of the article of produce stored in the frame memory as the digital image, whereby the position of an article of produce can be determined and supplied to external harvesting means.

11. A method as claimed in claim 10, which comprises using an adjusting means for automatically adjusting an opening degree of a stop of the monitor camera in response to variations in the luminance signal (Y).

12. A method as claimed in claim 11, which comprises using an adjusting means including a motor for driving a stop, a stop encoder operatively connected to the stop, a comparator circuit for receiving a signal from the stop encoder and the luminance signal from the monitor camera, and using a circuit for forming a drive signal to the motor in response to a signal received from the comparator circuit.