Basler L301kc Line Array Camera Technology and Troubleshooting

Basler L301kc Three Line Color Line Array Camera Technology and Application

In the field of high-speed industrial visual inspection, color line array cameras have become an ideal choice for applications such as print inspection, textile sorting, flat panel display quality inspection, and postal sorting due to their continuous scanning, high resolution, and excellent color reproduction capabilities. Basler L301kc, as a Camera Link interface linear array camera based on Kodak KLI-2113 three line CCD sensor, occupies an important position in early high-end detection systems with a 2098 pixel x 3 line array, 8kHz line frequency, and flexible spatial correction function. With the increasing demand for maintenance of discontinued models, on-site engineers often face challenges such as designing spatial calibration parameters, selecting output modes, configuring serial ports, and troubleshooting. This article is based on the complete user manual of L301kc, comprehensively analyzing its core technology, configuration methods, and on-site debugging points from the perspective of system integration, providing practical reference for engineers who maintain and replace the camera.

Product positioning and core specifications

Basler L301kc is a three line color line array camera equipped with Kodak KLI-2113 trilinear CCD image sensor, with 2098 effective pixels per line, pixel size of 14 μ m × 14 μ m, and RGB three line center spacing of 112 μ m. This camera is designed specifically for industrial environments and has the following outstanding features:

High sensitivity and high signal-to-noise ratio: 100% fill factor, typical light response non-uniformity<5%

Multiple output modes: Supports 20MHz 8-bit RGB mode, 60MHz single pixel/40MHz dual pixel 8/10 bit mode

Electronic exposure control: supports ExSync edge control, level control, programmable mode, and Free run internal triggering

Spatial Correction: Achieving precise color alignment through programmable delay compensation of RGB trilinear physical spacing

AOI (Area of Interest): The starting pixel and length can be specified to reduce data processing complexity

Digital Shift: signal multiplication achieved through bit operations (2X/4X/8X)

Programmable gain and bias: RGB three-way independent adjustment, supporting fine white balance adjustment

Key performance parameters:

Pixel clock: 20MHz (8-bit RGB), 40MHz (dual pixel mode), 60MHz (single pixel mode)

Maximum line frequency: 8.0kHz (spatial correction enabled)/9.20kHz (spatial correction disabled)

Minimum line frequency: 1kHz

Power consumption:<5.1W @ 12VDC

Working temperature: 0 ° C to+50 ° C (shell temperature)

Dimensions: 38.1mm × 62mm × 62mm (excluding F-port adapter)

Sensor architecture and signal chain

The sensor of L301kc consists of three independent pixel lines, covering red, green, and blue filters respectively. Each line contains 2098 photodiodes, which are transferred to their respective shift registers after charge accumulation. After variable gain control (VGC) amplification, they are digitized by a 10 bit ADC.

Due to the physical distance of 112 μ m between the three RGB lines (equivalent to 8 pixel intervals, 14 μ m/pixel), the same object point is captured by the three lines at different times in the scanning motion direction. If output is not processed directly, it will result in serious color misalignment ("rainbow effect"). L301kc uses internal FIFO memory to delay the first two channels of data, realigning RGB information before output - this is the core principle of the "spatial correction" function.

Space Correction: Principles and System Design

Space correction is the core technology that distinguishes L301kc from ordinary linear array cameras. Users need to configure two key parameters based on the actual system configuration:

3.1 Starting Line for Space Correction

Determine the 'crossing direction' of the image on the sensor:

If the direction of object motion causes the image to pass through the red line first (when using an objective lens), the starting line is set as the red line.

If it passes through the blue line first, it is set as the blue line.

3.2 Delay in Lines for Space Correction

Specify the time offset when combining RGB trilinear data. For example, if the delay is set to 8, the blue line data is combined with the green line data captured 8 rows ago and the red line data captured 16 rows ago to form a complete RGB pixel.

3.3 System design calculation formula

The manual provides precise optical mechanical matching formulas:

Magnification factor: β=112 μ mn × Δ y, where n is the number of encoder steps (1-16) required to move the image from one line to another, and Δ y is the distance of object movement corresponding to each step.

Field of view length: L=29.372mm × β 1 (effective sensor length=2098 pixels × 14 μ m)

Aspect ratio: directly determined by n, achieving a 1:1 ratio when n=8.

Engineering example: Assuming the encoder has a step size of 0.2mm and a target aspect ratio of 1:1, then n=8, the calculated magnification is 1:14.29, and the single line field of view is 419.6mm. If the sensor needs to cover a 350mm wide conveyor belt, the required n value can be calculated in reverse and the optical magnification can be adjusted.