Image sensors detect and convey messages used for making images and are applicable in electronic image devices like camera phones, digital cameras, etc. The most common examples are CCD (Charged-couple device) and CMOS (complementary MOS) sensors. In today’s article, we will dwell on the pinout, description, and features of a CMOS sensor, OV2640. We will also differentiate it from an almost similar CMOS sensor, OV7670.
OV2640 is a low-voltage CMOS image sensor with an image processor in a miniature footprint package. It further provides the complete functionality of a single-chip UXGA camera.
(CMOS camera image sensor)
The OV2640 camera module has some alternative image sensors comprising 5MP (OV5640), 3MP (OV3660), 2MP MT9D111, and a 720p sensor.
The table below summarizes the OV2640 pin arrangement.
The features and specifications of the OV2640 image sensor are as follows;
- First, its power supply consists of; 1.7V to 3.3V (I/O), 2.5 to 3.0V DC (Analog), and 1.3V DC ±5% (core).
- Then, it has a pixel size of 2.2 × 2.2 µm and array size of 1600 × 1200 (UXGA).
- Its dynamic range is 50dB, while its S/N ratio is 40dB.
- Some ISP functions in OV2640 are special effects, color saturation, gamma, defect reduction, noise reduction, sharpness, automatic exposure control, and automatic white balance.
- It also has an RGB Bayer array. 1.2Ke well capacity and a rolling shutter type.
- Additionally, its power consumption is as follows, 600µA at standby, 140mW at compressed mode full Res and framerate, and 125mW at YUV mode full res and framerate.
An image displaying the Y, U, and V components (top to bottom)
- The image format is type 1/4” with a sensitivity of 0.6V/Lux-sec and a dark current of 15mV/s at 60°C.
- Besides, its output format is Raw/RGB/YUV RGB data, and its resolution is UXGA SVGA and below.
- The package dimension is 5725 × 6285µm, whereas its image area is 3590 × 2684µm.
- Its maximum image transfer rate is [email protected], [email protected], and 1600 × [email protected]
Why is OV2640 an Excellent Sensor?
Despite not being fancy based on its image quality, resolution, and sensor format, OV2640 still stands out as an excellent image sensor.
- The SOC sensor comprises an on-chip ISP that performs auto-white balance and auto-exposure in small sensor packages. The outcome is a nicely-represented image.
- Furthermore, it has a Digital Video Port (DVP) sensor interface with an associated pixel clock, vertical/synchronization signal, and 8-bit data.
- Then, it is user-friendly for low-end RISC and ARM microcontrollers such as ESP32 and STM32.
- Next, its hardware JPEG encoder feature lessens memory footprint usage and divests the processing power from the MCUs.
A YUV format image/1600×1200 RGB565 often occupies a RAM space of 3.66MB. Contrarily, a JPEG format with a similar image occupies 150KB space (approximately ×25 compression ratio).
So, a higher compression ratio or lower image resolution results in a smaller JPEG image size output. As such, you can easily process and store it in the internal RAM of a microcontroller.
What Make it Even More Popular?
Several factors contribute to the popularity of OV2640. Consider the few below;
OV2640 on Arduino
OV2640 on Arduino dates back to 2012, when a dedicated team presented the sensor into the communication protocol (Arduino platform). Additionally, they made the camera driver an open source and provided an SPI camera solution.
Back then, it was difficult for MCUs, e.g., Arduino, to handle image sensors with equal to or resolutions higher than 2MP. Thus, the team achieved huge success by ensuring OV2640 is supporting the Arduino UNO development board.
Newer OV2640s have an Arduino-based open-source platform attached to an Arduino board and a Rev.C+ shield replacing the old camera shield.
OV2640 on ESP32 CAM board
At first, ESP32 wasn’t able to support a camera. But later in 2018, manufacturers started rolling out updated ESP32 versions that support a parallel camera. Over time, newer ESP32 boards now have camera interfaces having external PSRAM. Therefore, it is now easy to use the camera application on the MCU for applications like AI or IoT.
Note; ESP32 has integrated Bluetooth and Wi-Fi features, making it efficient and cost-effective.
OV2640 CCM Compact Camera Modules
Last but not least, the OV2640 sensor has a variety of CCM camera modules with distinct cable lengths and lenses.
OV2640 VS OV7670：What’s the Difference?
OV7670 and OV2640 image sensors can be confusing since they have similar features. However, to distinguish between the two, let us consider some of their dissimilarities.
|OV2640 sensor||OV7670 sensor|
|Standard SCCB interface||Standard SCCB interface compatible with I2C interface|
|Output support for YCbCr (4:2:2), YUV (422/420), and Raw RGB. RGB (RGB565/555).GRB422 formats.||Output support for YCbCr (4:2:2), YUV (4:2:2), and Raw RGB, RGB (GRB 4:2:2,RGB565/555/444) formats.|
|Supports image sizes: SVGA, SXGA, UXGA, and any size scaling down from SXGA to 40×30.||Supports image sizes: CIF, VGA, and any size scaling down from CIF to 40×30.|
|External/internal frame synchronization||None|
|Windowing, panning, and zooming functions||None|
Generally, OV2640 is a powerful on-chip ISP with JPEG encoding, good image quality, and a friendly camera interface making OV2640 well-known in camera applications like IoT.
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