보드 레벨 카메라 모듈용 임베디드 비전 렌즈

임베디드 센서에 맞는 렌즈를 선택하는 방법

렌즈와 센서의 불일치는 비네팅, 색상 그라데이션, 또는 해상도 손실로 나타납니다. 다음 네 가지 매개변수가 서로 일치해야 합니다: 이미지 서클과 센서 대각선 길이, CRA와 센서 마이크로렌즈 설계, 렌즈 MTF와 센서 나이퀴스트 주파수, 그리고 후초점 거리와 센서 스택의 두께입니다.

이미지 서클은 센서의 대각선을 모두 덮어야 합니다.

The lens projects a circular image; your rectangular sensor sits inside that circle. An image circle smaller than the sensor diagonal produces vignetting at the corners. Moderate oversizing is usually acceptable for coverage; run the same CRA, clearance, stack, and MTF checks as any pairing. Undersizing vignettes the corners and fails whenever the image must fill the full frame. Circular-image fisheyes that place the whole image circle inside the frame are the deliberate exception.

1/2.5인치 센서용으로 지정된 렌즈는 해당 크기 이하의 모든 센서를 커버하지만, 1/1.7인치 센서에서는 비네팅 현상이 발생합니다. 데이터시트에는 이미지 서클이 밀리미터 단위나 센서 포맷 명칭으로 표기되는데, 두 값이 항상 동일한 정밀도로 공개되는 것은 아니므로, 제조사 간 포맷 명칭이 정확히 일치한다고 가정하기보다는 센서의 실제 대각선 길이를 기준으로 확인하시기 바랍니다. 전체 커버리지 계산에 대한 자세한 내용은 ‘센서 크기 및 렌즈 호환성’을 참조하십시오.

해상도: 렌즈의 MTF는 센서의 나이퀴스트 주파수를 충족해야 한다

A 12MP sensor with 1.55µm pixels has a monochrome Nyquist frequency near 322 lp/mm, and a Bayer sensor samples each color channel more coarsely than that. If the lens cannot resolve the frequency your task needs at your working aperture, the sensor's extra resolution goes to waste. Check the lens MTF chart at the aperture you intend to shoot.

Commonlands uses 20%-30% MTF at Nyquist as a starting point for embedded work, not a standard: what you actually need follows the contrast and SNR of the task, how much aliasing the pipeline tolerates, and which field positions carry the measurement. Validate it against your own images. The MTF curve guide explains how to read these charts.

초점 거리 계산을 직접 풀어보세요

Run your sensor size, target field of view, and working distance through the field of view calculator or the EFL calculator to get the required focal length for your system, consistent with the same formula used above.

주광선의 각도가 내장 카메라의 화질에 미치는 영향

Chief ray angle (CRA) is the angle at which the lens delivers light to a given point on the sensor. Small-pixel sensors, common at 1.4µm-2.5µm in embedded cameras, use microlenses over each pixel tuned to a specific CRA curve. That curve runs from roughly 0 to 15 degrees at the edge on industrial and machine vision sensors, up to 25 to 35 degrees on mobile-class parts, so pull the curve for your sensor rather than assuming a typical value. When the lens CRA does not track the sensor's design CRA, you get color shading (red, green, and blue channels fall off differently toward the edges) and reduced corner brightness that software cannot fully correct, because the mismatch is wavelength- and angle-dependent at the pixel level rather than a uniform gain error.

This matters most on the small-pixel sensors that dominate embedded and board-camera designs. Sensor datasheets specify a CRA curve; lens datasheets specify a matching CRA spec or curve. When selecting a lens for a sensor with sub-2µm pixels, check that the two curves track across the field, not just at the center. Curve overlap is a screen, not an acceptance test: the tolerable difference depends on the full ray cone at each field point, so on working F-number, plus the wavelength band, the pixel and filter stack, and the corner shading and MTF loss your pipeline accepts. Settle it with flat-field and corner MTF measurements. The full mismatch mechanics and matching procedure are in the chief ray angle and mismatch guide.

Jetson 및 Raspberry Pi 카메라 모듈의 보드 수준 통합

MIPI CSI-2 is an electrical interface between the sensor and the host processor, not a lens mount, and no compute platform defines one. Mount style belongs to the camera board. Plenty of Jetson and Raspberry Pi camera boards do carry an M12 holder soldered or clipped to the PCB, which is why M12 dominates this space, but Raspberry Pi's own line covers three cases: fixed integrated optics on Camera Module 2 and Camera Module 3, and the High Quality Camera, sold both in a C/CS-mount version that ships with a C-mount adapter and in a native M12-mount version.

Common sensors on these boards are the IMX477 (High Quality Camera), IMX219 (Camera Module 2), and IMX708 (Camera Module 3). Read the mechanical drawing for the board you are building on before ordering a lens. Because M12 has no standardized flange distance, focus is set entirely by how far the lens threads into the holder, and back focal length (BFL) varies by lens design.

That variability helps at the board level. When the same lens design moves onto a module whose cover glass and IR filter stack is a different thickness, a holder of the correct height brings the sensor back to the lens's focus position, which is cheaper than requalifying a lens. Confirm holder height against the lens's specified back focal length and your full sensor stack (bare sensor, cover glass, IR filter, any spacer) before finalizing the PCB footprint. The M12 lens holder selection guide covers holder height selection and thread engagement in detail.

Holder height only buys back focus. A thicker or thinner plane-parallel stack sitting in a converging beam adds its own spherical aberration and axial color, and any wedge in that stack tilts the image plane. Moving the lens along the axis corrects none of that.

A different filter also moves the passband, shifting where an IR-corrected design lands in focus, and an interference cut filter shifts its cut-off with ray angle, so the corner response moves differently from the center. Measure corner MTF and color shading on the new module rather than assuming the refocus closed the gap.

Multi-camera Jetson and Raspberry Pi designs raise the integration bar further. A stereo pair should be closely matched in focal length and distortion profile, because those set the disparity-to-range scale and the rectification accuracy, and the rig needs synchronized exposure plus extrinsics that hold their calibration. Back focal length is the one difference that does not need matching: each module is focused individually, which absorbs it.

Bulk-buying from a single production lot reduces optical unit-to-unit spread but does not eliminate it, so verify focus at the corners of the field on each unit during bring-up, not only at the center.

성능, 크기, 비용의 삼각관계

임베디드 렌즈 선정은 광학 성능, 물리적 설치 공간, 단가라는 세 가지 요소 간의 절충 관계이며, 전력 소비는 설치 공간과 연계된 부차적인 요소로 작용합니다. 고정형 산업용 검사 스테이션과 달리, 임베디드 시스템은 대개 이 삼각형의 한쪽 요소를 우선시할 경우 다른 두 요소에서 타협을 피할 수 없습니다.

M12 lenses sit at the small-footprint, low-cost corner. A 3g-15g lens with a fixed aperture draws no power itself and costs a fraction of an industrial optic, but gives up the adjustable iris and ring-driven focus that C-mount designs such as Commonlands' provide. C-mount and CS-mount sit at the opposite corner: an iris ring lets you trade depth of field for light throughput on demand and a focus ring refocuses without re-threading the lens, but the lens weighs 3x-10x more and costs more per unit. For a drone or handheld device on battery power, that weight difference is a meaningful chunk of flight time or user fatigue, not just a spec sheet number.

조리개 제어 역시 덜 눈에 띄는 방식으로 광량과 상호작용합니다. C-마운트의 가변 조리개는 머신 비전 분야에서만 실용적입니다. 이는 일반적으로 조명이 프로그래밍 방식으로 제어되기 때문인데(구조화 조명, LED 링 라이트, 백라이트 어레이 등), 이를 통해 시스템은 센서에 빛이 부족해지지 않도록 하면서도 피사계 심도를 확보하기 위해 조리개를 조일 수 있습니다. 반면, 주변광이나 제어되지 않은 조명에 의존하는 임베디드 시스템은 항상 이러한 절충을 할 수 없기 때문에, 대신 빠른 F-값을 가진 고정 조리개 M12 렌즈를 선택하는 쪽으로 결정이 기울게 됩니다.

구매 결정을 내리기 전에 확인해야 할 주요 사양

초점 거리

초점 거리가 짧을수록 동일한 센서에서 더 넓은 시야를 확보할 수 있습니다. 2mm~4mm는 장애물 회피를 위한 초광각 시야를 제공합니다. 4mm~8mm는 범용 비전 용도로 사용됩니다. 8mm~16mm는 검사 및 바코드 판독에 적합한 좁은 시야를 제공합니다. EFL 계산기를 사용하여 대상 촬영 영역과 작동 거리를 바탕으로 초점 거리를 구해 보세요. 전체적인 방법에 따른 초점 거리 선택 방법은 관련 문서를 참조하십시오.

F값 (조리개)

F값이 낮을수록 더 많은 빛을 받아들입니다. F/1.4 렌즈는 F/2.8 렌즈보다 대략 4배 더 많은 빛을 통과시킵니다. 그 대가로 피사계 심도가 얕아집니다. 저조도 임베디드 비전 환경에서는 F/1.4~F/1.8을 우선적으로 고려해야 하며, 빛의 수집량보다 피사계 심도가 더 중요한 경우에는 F/2.0~F/2.8을 선택하는 것이 합리적입니다. 피사계 심도 계산기를 통해 수치를 확인해 보고, 머신 비전 분야의 F값 항목을 참고하여 두 요소 간의 기본 관계를 파악해 보십시오.

왜곡

Barrel distortion bends straight lines into curves. No fixed percentage is required by an application: what a measurement pipeline tolerates depends on the camera model it calibrates to, how well features localize at the field positions being measured, the accuracy the task needs, and whether the compute budget covers an undistort pass. Distortion the calibrated model captures gets corrected; distortion the model does not fit becomes residual error. Standard wide-angle M12 lenses commonly run 10%-20% distortion, and Commonlands low-distortion models bring that under 1%, which keeps an uncalibrated pinhole model usable. See the low-distortion lens guide.

열적 안정성

Thermal range is wider outside a climate-controlled factory. An embedded camera in a vehicle or an outdoor enclosure can see -30 degrees C to +70 degrees C across a day, and a drone camera can move from sun-heated ground to cold altitude in minutes. Thermal expansion and the temperature dependence of refractive index shift the focal plane as the assembly heats and cools, and at fast apertures on small-pixel sensors the depth of focus is tight enough that a poorly athermalized lens can drift out of focus with no mechanical fault involved. Construction is one screening input, not a thermal spec: suitability is settled by a focus or MTF measurement across your operating temperature range on the assembled lens, holder, and sensor, and Commonlands can run that test on request.

무게

이는 드론, 휴대용 기기, 로봇 팔과 같은 장비에서 특히 중요한데, 이러한 장비의 경우 추가되는 질량이 비행 시간, 사용자의 피로도 또는 서보 부하에 영향을 미치기 때문입니다. M12 렌즈의 무게는 일반적으로 3g~15g이며, C-마운트 렌즈는 일반적으로 50g~200g입니다. 광학 사양을 충족하면서도 가장 가벼운 렌즈를 선택하십시오.

IP 등급

IP67, defined in IEC 60529, means dust-tight plus 30 minutes under a meter of water. That is an immersion test, not a rain or spray test. IP6K9K (industry shorthand IP69K) comes from ISO 20653, a road-vehicle standard with its own high-pressure, high-temperature jet procedure. They are separate standards run as separate tests, so cite them separately rather than as one washdown rating.

Ratings apply to the tested lens variant in its mounted configuration under the standard's water and dust exposures; they do not cover steam, detergents, repeated sanitation cycles, or the rest of the camera. Where the lens sits behind a sealed window in a rated housing, the housing carries the requirement and the lens may need no individual code. Match the test to the exposure the camera actually sees.

See the IP rating guide for test methods, and note that ruggedization is a selective feature on specific SKUs, not a property of all C-mount or M12 lenses; see the ruggedized lens guide.