# Image Adjustment ## Introduction 65R image settings are set by default for the best settings in most use cases. There is also the ability to alter some of the color and exposure settings for custom applications. {% hint style="info" %} Changing these values is not necessary for most applications and may prevent standard analytics from being run. {% endhint %}
### Exposure
In most normal usage, the exposure should not need to be adjusted, however if your images are consistently too bright or too dark, the auto-exposure settings can be modified. These settings will change how bright / dark the image is, as well as the shutter speeds and gains used to capture the image. {% tabs %} {% tab title="Exposure Target" %} #### Range 0 - 255 #### Recommended Value 60 #### Description Sets the average pixel value across the entire frame that the auto-exposure attempts to achieve. It is the highest 8 bits of any imager, and is calculated before any ISP corrections are performed. This means that the final image will likely have an average brightness much higher than this target due to vignetting and gamma correction being applied in later steps. Due to this, in general the target value should be kept lower than 100. {% endtab %} {% tab title="Shutter Min" %} #### Range 200 - {Shutter Max} #### Recommended Value 400 #### Description This value is the shortest shutter speed in us (microseconds) that will be used before the camera drops to a lower ISO. If the camera is already running at the lowest ISO, then the shutter speed will go faster until it hits the limit of the sensor. {% endtab %} {% tab title="Shutter Max" %} #### Range {Shutter Min} – 25000 #### Recommended Value 2000 #### Description This value is the longest shutter speed in us (microseconds) the camera will use before increasing the ISO to attempt to stay below this value. For most flights, you should not see a longer shutter speed unless the field has insufficient lighting, forcing the shutter to go longer (see Shutter Unlock). It is recommended to keep this value lower than 3ms (3000us) to avoid motion blur caused by the groundspeed of the UAV. {% endtab %} {% tab title="Shutter Unlock" %} #### Range 100 – 12800 #### Recommended Value 600 #### Description If the ISO gets set to this value or greater by the auto-exposure, then the shutter max value is ignored, allowing the shutter speed to go slower. This is to prevent the camera from using very high gains, which can have worse effects on image quality than the motion blur from a slow shutter speed . It is also useful for taking images indoors, where lighting is insufficient to capture images otherwise. {% endtab %} {% endtabs %} ### Color Adjustments These settings allow adjustment to the overall brightness, contrast, and saturation of the image without modifying the exposure. They should be used for fine color adjustment if the default settings are not giving the quality of image needed for your application.
{% tabs %} {% tab title="Brightness" %} #### Range -255.0 – 255.0 #### Recommended Value -1.0 #### Description Sets how bright/dark the overall image is. This value is added or subtracted from each pixel. Higher values result in the image looking more washed out, and lower values make it darker. {% endtab %} {% tab title="Contrast" %} #### Range 0.0 – 2.0 #### Recommended Value 1.0 #### Description Adjusts the difference between the light and dark values. This effectively multiplies every value by X. So setting this to 1.1 will take 1.1x each pixel value. For example, if you have a value of 20 and 200 (180 apart) normally, setting contrast to 1.1 will change the values to 22 and 220 (198 apart) effectively increasing the contrast between bright and dark. {% endtab %} {% tab title="Saturation" %} #### Range 0.0 – 2.0 #### Recommended Value 1.0 #### Description Adjusts the vibrancy of the color in the image. This will affect the color and changing this by too much can result in imagery with less ‘true’ color. This increases the ‘contrast’ of each color. For example, if something is bright green, increasing saturation adjusts it to be even more green than a darker green in the same image. {% endtab %} {% endtabs %} ### Black Level Camera black level correction is a processing step that removes the sensor’s inherent offset so that pixels with no light correctly map to true black. This correction compensates for dark current, readout offsets, and analog bias which can change continuously during operation (e.g., based on camera temperature).
{% tabs %} {% tab title="Mode" %} #### Range Fixed / Auto #### Recommended Value Auto #### Description Operation in "Auto" mode causes the camera to continuously compensate for changes in black level values. Operation in "Fixed" mode causes the camera to always apply the same bias for black level correction. {% endtab %} {% tab title="Target (Auto)" %} #### Range 10 - 245 #### Recommended Value 16 #### Description This setting is only preset when operating in `Auto` black level mode. This 12-bit value is set to a small positive value so that software tracking of black level can be accomplished. The small black level offset in imagery can be subsequently removed using the `Color Adjustements` setting for `Brightness`. {% endtab %} {% tab title="DOFF (Fixed)" %} #### Range -8192 - 8191 #### Recommended Value -1280 #### Description This setting is only preset when operating in `Fixed` black level mode. This digital offset (DOFF) register value biases black level correction. An increased (i.e., more negative) DOFF value results in additional black level biasing - i.e., on average, pixel values will decrease. {% endtab %} {% endtabs %} ### Pipeline There are several onboard processing steps that the sensor performs to provide the best data product possible. While we recommend leaving these at their default settings, each of the processing stages can be disabled to get completely unmodified imagery from the sensor.
{% tabs %} {% tab title="Bad Pixel Replacement" %} #### Recommend Enabled #### Description Camera bad pixel replacement is an image processing step that replaces defective sensor pixels (stuck, hot, or dead pixels) with neighboring pixel data. This prevents visible bright or dark specks in the image and improves overall image visual quality. {% hint style="info" %} For execution of bad pixel replacement, additional camera calibration is required over that which is performed by default. Contact Sentera for details. {% endhint %} {% endtab %} {% tab title="Color Correction" %} #### Recommend Enabled #### Description This enables use of the internal color correction matrix on the sensor. The purpose is to compensate for the exact response of the sensor and produce an image with correct color and white balance. Disabling this is not recommended, as the resulting images will appear ‘greenish’ due to the sensitivity profile of the imager. {% endtab %} {% tab title="Gamma Correction" %} #### Recommend Enabled #### Description Enables the use of gamma correction on imagery. Most software expects jpg data to have gamma correction applied, so disabling this is not recommended as the images may appear too dark for most processing. {% endtab %} {% tab title="Image Sharpening" %} #### Recommend Enabled #### Description Enables an image sharpening algorithm to be executed on the imagery. This is done to provide “crisper” imagery with better visual separation of subject matter. {% endtab %} {% tab title="Vingetting Correction" %} #### Recommend RGB: Enabled #### Description Enables onboard correction for lens vignetting effects. This is done by applying a higher gain to the corners and edges of the image where fall off effects due to the lens occur. {% endtab %} {% endtabs %} --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://support.senterasensors.com/65r-sensor-user-guide/65r-sensor/configuration-and-settings/image-adjustment.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.