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HOKUYO LASER RANGE FINDER COMPARISON

LASER RANGE FINDER Comparison TABLE

  UTM-30LX-EW UST-10LX URG-04LX-UG01
LIGHT SOURCE Semiconductor laser diode (FDA approval, Laser safety class 1) Semiconductor laser diode (FDA approval, Laser safety class 1) Semiconductor laser diode (FDA approval, Laser safety class 1)
SCANNING RANGE 0.1 to 30m 270° max range 0.02 to 10m 270° max range 30m 0.02 to 5.6m 240°
MEASURING ACCURACY +/-30mm +/-40mm +/-30mm
ANGULAR RESOLUTION 0.25° (360/1,400) 0.352° (360/1,024) 0.352° (360/1,024)
SCANNING FREQUENCY 40Hz (2,400rpm) 10Hz (600rpm) 10Hz (600rpm)
MULTI ECHO FUNCTION Max. 3-echo N/A N/A
COMMUNICATION PROTOCOL SCIP 2.2 SCIP 2.0 SCIP 2.0
COMMUNICATION Ethernet 100 BASE-TX Ethernet 100 BASE-TX USB 1.1/2.0
DI/O INTERFACE Scanner synchronous and Failure output N/A N/A
POWER SOURCE 12VDC 12V or 24VDC USB bus power
POWER CONSUMPTION 0.7A or less 0.15A or less (on 24VDC) 0.5A or less
AMBIENT ILLUMINANCE 10,000 lx or less 10,000 lx or less 10,000 lx or less
PROTECTIVE STRUCTURE IP67 (1EC standard) IP65 N/A
WEIGHT 210g 130g 160g
SIZE (W X D X H) MM 62 x 62 x 87.5 50 x 50 x 70 50 x 50 x 70
PRICE (MSRP) $5,175.00 $1,775.00 $1,148.00
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This diagram shows a graphical representation of the scanning range of each Hokuyo range finding laser featured. It characterizes the measurement range and the view angle of each product.

Each product is shown with a different color where the range of possible measurements is the shown by the length of the arc. The angle swept by each of the shapes represents the maximum viewing angle of the specific laser.

The basic goal of each test in both locations (indoor and outdoor) was to examine and compare the range finding ability of the Hokuyo lasers. The placement of the sensors and the testing environment were held constant to increase the effectiveness of the comparison. The tests and results will be further explained in the following sections of this article. Each laser was also tested with a simulated protective acrylic sheet in the path of the laser. This acrylic sheet represents a transparent shield that a user might place around the laser to protect it from any potential harm.

Summary Of Indoor Performance

The accuracy of the UTM-30LX-EW and the UST-10LX are almost identical, except for a few spots where the surface was extremely uneven. Both lasers were measuring objects and surfaces well within their range of measurement. The URG-04LX-UG01 finds some of the key objects in the testing space, but has more trouble connecting the whole picture. However, some of the objects are at a distance that is about the maximum for this sensor, which could be the source of this lack of range data. Overall, each laser performed well in the indoor setting with minimal error and accurate range data.

Indoor Testing Environment

The advantage of this testing environment was the presence of both translucent surfaces (glass) and opaque surfaces (cardboard, plastic and other office furniture items).

Each laser was placed 8” above the surface of the floor and was not obstructed in its field of view by any unintentional objects. A screen shot was captured of the current data being read by the laser. The image of each laser in the same setting will be compared in later sections.

The indoor performance of the UTM-30LX-EW, the UST-10LX, and theURG-04LX-UG01 lasers were performed to compare each in a controlled, low range and low ambient light condition.

This evaluation is achieved by comparing the output of each laser placed in the same location within the test environment. The first test performed was a simple range data capture of the environment without any obstructions.

The results of each laser can be seen below

  • The UTM-30LX-EW
    The UTM-30LX-EW

    The UTM-30LX-EW captures the clearest detail of any of the tested lasers. The stack of flattened boxes can be seen at about 45° and the garbage can is the round shape at about -40°. The beams of the glass door are also visible at about -55° and -75°. The objects are all in the same locations as in the plots of the other two lasers.

  • The UST-10LX
    The UTM-30LX-EW

    The UST-10LX produced a similar range plot as the UTM-30LX-EW, with a few more inconsistencies, where the surface was uneven.

  • The URG-04LX-UG01
    The UTM-30LX-EW

    The URG-04LX-UG01 also created a similar plot to the other two, but with many more inconsistencies. It did miss a few significant portions of the test environment, such as the far left corner (30°) and the door beams.

Indoor Acrylic Test Setup

Each laser was also compared to itself when a mock protective acrylic sheet was placed in front of the laser. The sheet was placed perpendicular to the 0° direction and 8” away from the laser.
It can be easily seen that the performance of the laser is altered when the protective screen is introduced. The sheet causes more discrepancies in the complete range measurement making the outline of the test environment look choppier. However, with the UTM-30LX-EW and the UST-10LX, the general outline of the more flat surfaces (the left side) can still be viewed. It was also observed in this test that there exists a small window where the range data disappears. This window is centered where the acrylic is perpendicular to the sensor. The behavior mimics what would happen if a small opaque object were placed close to the laser.
The results of each laser can be seen below

  • The UTM-30LX-EW indoor results with acrylic
    The UTM-30LX-EW
  • The UST-10LX indoor results with acrylic
    ThThe UST-10LX
  • The URG-04LX-UG01 indoor results with acrylic
    The URG-04LX-UG01

Summary Of Outdoor Performance

The results of the outdoor testing produced much more widely varying results than the indoor testing. The largest difference was the inability of the URG-04LX-UG01 to even work outdoors. The UTM-30LX-EW was the only laser that could distinguish objects well at the longer distance and higher ambient light found in the outdoor environment. The UST-10LX was able to characterize a few points on the larger surfaces in the outdoor setting, but not to the extent of the UTM-30LX-EW. The outdoor environment really highlighted the different abilities of each laser.

Outdoor Testing Environment

The outdoor tests were performed in the parking area in front of the Acroname office.

This was an ideal location, as it allowed for the examination of many of the attributes of the lasers such as maximum range and sunlight operation. Across the field of view of the lasers the ambient illuminance was measured to be anywhere from 15,000 lx to 40,000 lx.

As seen in the image, the parking lot is a fairly narrow strip of pavement with two rows of parking spots on both sides. It contains many different sized cars and a wide range of surface materials. Also, it can be seen that there is a vehicle far in the distance at the center of the image. This vehicle was used to demonstrate the laser’s ability to see an object at a long range. Once again, a screen shot of the captured data was taken to record the laser’s ability in each setting. The mock protective sheet was tested again in the outdoor conditions.

The results of each laser can be seen below
There is no data from the URG-04LX-UG01. The URG-04LX-UG01 is rated as an indoor sensor and did not function in the outdoor setting. It should be pointed out that the scale of the two plots are different, the UTM-30LX-EW plot has a max range that is twice the size of the UST-10LX.

  • The UTM-30LX-EW
    The UTM-30LX-EW

    The data from the The UTM-30LX-EW has a few interesting sections to point out. Along the left side, a long flat wall can be seen with a break (in the 90° direction) due to the green car seen in the photograph. The vehicle in the 0° direction can be seen as the long spire in the center of the image. The saw tooth pattern, seen on the top right, is five cars in their parking spots. The side of the car closest to the sensor can be seen as the flat portion from about -30° to -50°. The small spike on the right side is due to a reading through the glass door of the Acroname office. 

  • The UST-10LX
    The UTM-30LX-EW

    The range data from the The UST-10LXlaser does not create as good of a picture as the UTM-30LX-EW, however it does find a few key objects. It finds two small sections of the wall on the right side of the sensor in the 85° direction and the 35° direction. It also sees the wall directly on the left side and the large electrical box at about -115°.

Outdoor Acrylic Test Setup

The UTM-30LX-EW and the UST-10LX were also tested outdoors with an acrylic sheet. The sheet was placed 4” from the front of the laser.

The acrylic sheet acts in a similar way as it did during the indoor tests. The sheet will allow for measurements, but only where the laser and the acrylic are not perpendicular to each other. This occurrence can be seen in the two images above, where there is once again the window without measurements centered in the 0° direction.

The acrylic sheet acts in a similar way as it did during the indoor tests. The sheet will allow for measurements, but only where the laser and the acrylic are not perpendicular to each other. This occurrence can be seen in the two images above, where there is once again the window without measurements centered in the 0° direction.

The results of each laser can be seen below

  • The UTM-30LX-EW outdoor results with acrylic
    The UTM-30LX-EW
  • The UST-10LX outdoor results with acrylic
    ThThe UST-10LX
SUMMARY

The Hokuyo lasers are excellent range finding sensors that are relatively light and small for their ability. The highly accurate lasers could be used alone to create a two-dimensional line as seen in this article. A more useful application would be to use multiple lasers or a laser on a moving platform to create a point cloud to analyze a 3D space. It is incredibly useful for a robot to have the ability to see and comprehend its surrounding, especially if it is an autonomous system.